Abstract:
Embodiments of a medical hand-grip element for injection of a substance from an ampoule, comprise a drive device for driving the ampoule and the injection needle, a delivery device for delivering the medicinal substance out of the ampoule and a coupling device for rotationally fixed coupling of the ampoule with the injection needle and for preventing a relative movement between the ampoule and the injection needle is disclosed. Embodiments of injection systems, injection units, injection needles and handling methods for them are also disclosed in which the risk of injury and contamination for the user is reduced by providing approaches for covering the ends of the cannulas of the injection needles during a number of handling steps.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority from pending European Patent Application No. 07014560 filed Jul. 25, 2007, which is incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     The present invention relates to devices and methods for injection of media into human and animal tissue, in particular into hard tissue. 
     2. Description of Prior Art 
     U.S. Pat. No. 4,787,893 discloses a hand-grip element for injection of liquid substances, in particular anesthetics, in which rotation of a receptacle sleeve is induced by a drive motor. The ampoule with the substance to be injected can be inserted into the receptacle sleeve, so that the rotational movement is transferred to the ampoule and the injection needle connected to it. The hand-grip element is thus used not only for injection but also for penetrating into or through tissue, i.e., bones, for example, in particular the jawbone, into which the substance is to be injected. 
     The connection of the ampoule to the injection needle is accomplished by puncturing a rubber stopper, the so-called septum, which is provided at one end of the ampoule, so that the injection needle protrudes into the ampoule reservoir with the injection liquid. However, this connection has proven to be a disadvantage because in drilling through the bone, the needle, which serves as the drill, is decelerated but the holding power of the rubber stopper for the needle is too low to transfer the decelerating effect to the ampoule as well, which thus results in a relative movement between the needle and the ampoule. Abrasion occurs on the rubber stopper due to this relative movement, i.e., due to the rubber stopper rotating more rapidly and the decelerated injection needle rotating more slowly. At least some of the abrasion enters the injection liquid in the form of fine rubber particles, so there is the risk that these particles may be injected into the tissue with the injection liquid. More of the abrasion enters the hand-grip element, where it can lead to negative effects or damage to components. 
     Therefore, the object of the present invention is to design a hand-grip element so that no abrasion occurs. 
     SUMMARY 
     According to one embodiment, the medical hand-grip element comprises a coupling arrangement for rotationally fixed coupling or connection of the ampoule to the injection needle. The coupling arrangement, also referred to as “antitwist protection,” produces a coupling, preferably mechanical, of the ampoule to the injection needle between the ampoule and the injection needle, so that the ampoule and the injection needle rotate at essentially the same rotational speed, so that a relative movement between the ampoule and the injection needle and thus abrasion of the rubber stopper (septum) of the ampoule are prevented. 
     In order for the ampoule and the injection needle to rotate at essentially the same rotational speed, a reliable transfer of torque from the drive device of the medical hand-grip element to the ampoule and the injection needle and also a transfer of the resulting braking force, e.g., occurring during the drilling through bone tissue, to the injection needle and the ampoule are necessary. In one embodiment, the coupling arrangement therefore has a coupling device with at least one coupling element which is designed in particular as a spring strap, spring arm, tension surface, thread, entraining element and/or form-fitting element, or is connected to such a coupling device. The at least one coupling element couples the ampoule and/or the injection needle directly or indirectly to the drive device and preferably also to the coupling arrangement, so that essentially the same torque acts on the ampoule, the injection needle and the coupling arrangement. 
     Another requirement for the drive of the ampoule and the injection needle with essentially the same rotational speed consists of a reliable connection of the ampoule to the injection needle. Therefore, in one embodiment, the coupling arrangement has a connecting member for the ampoule and the injection needle. This joint connecting member can include, for example, a borehole or a hollow shaft into which the injection needle and/or the ampoule can be inserted at least partially or has a protrusion to which the injection needle and/or the ampoule can be connected. The connecting member may of course have a different design. 
     During operation of the medical hand-grip element, the coupling arrangement, which is preferably provided with the coupling element and the connecting device, as well as the ampoule and the injection needle, thus form a unit on which substantially the same torque acts and which thus rotates at substantially the same rotational speed. In other words, the unit is designed to transfer and/or receive a uniform common torque and a uniform common rotational speed. 
     According to a especially preferred embodiment, the connecting device of the coupling arrangement is designed as a hollow shaft with one coupling element each for transfer of torque for the ampoule and for the injection needle. This design ensures an especially reliable transfer of torque, stable bearing support and extremely smooth operation of the injection needle and the ampoule. 
     If the coupling arrangement is designed as a hollow shaft, it then surrounds the ampoule and the injection needle at least partially. The coupling arrangement and/or the connecting device may, however, also be arranged at least partially between the ampoule and the injection needle, e.g., when the connecting device has a thread onto which the injection needle is screwed. 
     To further support the rotationally fixed connection between the ampoule and the injection needle, in one embodiment it is provided that a chucking element is provided on the coupling arrangement, reinforcing the connection of these two elements. The chucking element is preferably provided on a coupling element or is designed as part thereof so that it is advantageously arranged in the immediate area of torque transfer. The chucking element especially preferably has at least one conical surface on the inside of the hollow shaft which serves as the connecting device. The conical surface is designed so that it presses a part of an injection needle inserted into the hollow shaft, in particular a section of the needle apron, against the ampoule. This chucking device which is formed by parts of the injection needle and the chucking element in the hollow shaft represents a very simple and effective reinforcement of the rotationally fixed connection between the ampoule and the injection needle. 
     The drive device of the medical hand-grip element for injection of a medicinal substance comprises at least one rotating component that transmits a torque, e.g., a shaft, one or more gear wheels, a transmission, etc. In one embodiment, the drive device also has a motor, for example an electric motor or a motor operated with a fluid, in particular compressed air. The motor is either arranged in the medical hand-grip element or it is designed as a separate component and can be connected by a connecting device on the medical hand-grip element. The drive motor is especially preferably designed as part of a dental treatment unit, for example, a portable drive and control unit or a dental chair, so that the medical hand-grip element can be driven and can optionally be controlled for injection of a medicinal substance via this treatment unit. The control includes in particular the selection and/or adjustment of operating parameters by the user. The motor is supplied with electric power either via a power supply network or by means of a battery which, in a preferred embodiment, is arranged together with the motor in the hand-grip element, so that the hand-grip element is designed as a wireless appliance without any connection to an external unit. 
     The delivery device of the medical hand-grip element for injection of a medicinal substance is designed as a manually operable delivery device in one embodiment, e.g., as a rotatable or pivotable lever by means of which a rack can be moved in the direction of the ampoule. The ampoule has on one end a displaceable closure cap which is displaced directly or indirectly by the rack, so that the contents of the ampoule are forced out of it. A motor-driven delivery device is provided as an alternative with which a drive motor displaces a rack or a plunger in the direction of the ampoule. 
     The medical hand-grip element for injection of a medicinal substance is designed as a straight elongated hand-grip element or handpiece in one embodiment. However, the hand-grip element may of course also have other forms, e.g., it may have an angled form, in particular in the form of a pistol, or it may be designed as a contra-angle handpiece with a front section or a head section arranged at an angle. 
     Another disadvantage of the hand-grip element from U.S. Pat. No. 4,787,893 is that for loading the hand-grip element with the ampoule and the injection needle, the front part of the hand-grip element which holds the ampoule has to be separated from the handle part, the ampoule has to be inserted into the front part, the front part has again to be attached to the handle part and then from the outside the injection needle has to be connected to the front part of the hand-grip element and must be pushed through the rubber stopper of the ampoule. This loading operation is time-consuming and tedious for the user. 
     Thus another object of the present invention is to create a hand-grip element that can be loaded with the ampoule and the needle more easily. 
     According to one embodiment, this object is achieved by a medical hand-grip element for injection of a medicinal substance which has a preferably circular receptacle opening at one end of the hand-grip element which is designed so that the ampoule can be inserted into the hand-grip element from this end of the hand-grip element through the receptacle opening. This advantageously eliminates the need for having to disassemble the hand-grip element in loading the medical hand-grip element and in general the operation of loading the medical hand-grip element is facilitated. 
     In one embodiment, the receptacle device or connecting device in which the ampoule is arranged after insertion into the medical hand-grip element is completely inside the medical hand-grip element and is surrounded by an outer sleeve of the hand-grip element. Therefore in an advantageous manner a protective function for the user from the rotating ampoule is achieved. 
     In another embodiment, the receptacle opening is designed as part of the connecting device of the coupling arrangement. With the insertion of the ampoule through the receptacle opening, the rotationally fixed coupling of the ampoule to the injection needle is at least initiated. 
     Another disadvantage of the injection system described in U.S. Pat. No. 4,787,893 is that it does not offer a continuous hygiene chain and thus does not provide complete protection of the user from injuries and contamination, e.g., due to inadvertent puncturing by the used needle. 
     Therefore, one goal of the present invention is to create an injection system, an injection unit, an injection needle and handling procedures by which the user&#39;s risk of injury and contamination is greatly reduced. 
     According to one embodiment, this object is achieved by an injection system having an ampoule, an injection needle connectable to the ampoule and a locking mechanism, whereby an inseparable or single use locking mechanism is provided for locking the ampoule to the injection needle. 
     An inseparable locking mechanism, also referred to herein as a single use or non-releasable locking mechanism, is understood to be a locking mechanism which is designed so that a single locking or connection between the ampoule and the injection needle can be established, whereby these components are locked together, but the lock can not be released without destruction. The locking mechanism is therefore not intended and is not designed accordingly to be separated again. It follows that the locking mechanism cannot be re-used, either for previously connected components or for new components. The connection of the ampoule to the injection needle is thus inseparable for the user. 
     This embodiment achieves the result that after connecting the ampoule to the injection needle and thus in particular after injection of the medicinal substance into the target tissue and after contact of the injection system with the patient, the end of the cannula of the injection needle that is connected to the ampoule and protrudes through the septum into the interior space of the ampoule, for example, continues to remain in or on the ampoule. Therefore, the user is protected from injuries due to this end of the cannula. 
     A corresponding method for removing an ampoule and an injection needle from an injection device, e.g., from a medical hand-grip element or from a syringe rack comprises the steps:
         providing an injection device having an ampoule and an injection needle, whereby the ampoule and the injection needle are connected to one another by an inseparable locking mechanism,   joint removal of the ampoule and the injection needle from the injection device.       

     The inseparably connected ampoule and injection needle are preferably removed through a receptacle opening at one end of the hand-grip element. 
     In one embodiment, the locking mechanism is designed as a form-fitting mechanism or catch mechanism, whereby a part of the locking mechanism is provided on the ampoule and another part is provided on the injection needle. The part provided on the ampoule preferably comprises a setback in the outer sleeve of the ampoule, in particular the ampoule neck which is designed as a constriction in the outer sleeve. The injection needle, in particular a specially provided part of the injection needle engages in this setback in a form-fitting or locking manner. 
     In one embodiment, the injection needle has a cannula and a cannula apron, whereby the cannula apron has a holding section for the cannula and an adjacent connecting section for connecting the injection needle to an injection device, e.g., a medical hand-grip element or a syringe frame, and for connection to the ampoule. Preferably at least one part of the inseparable locking mechanism is provided on the connecting section of the cannula apron. Because of the small dimensions of the injection needle and the cannula apron, the design of the cannula apron as a connecting element to the injection device and as a locking mechanism with the ampoule is especially advantageous. 
     In one embodiment, the part of the locking mechanism provided on the injection needle comprises a form-fitting element or a catch element for engaging in the setback on the ampoule. This catch element arranged on the connecting section of the cannula apron is preferably designed as a catch nose having a contact face, which is arranged essentially at a right angle to the connecting section over its entire length. This design and an adequate length of the contact face, so that the contact face and the catch nose protrude far into the setback on the ampoule, ensure the inseparability of the locking mechanism by preventing the catch element from being pulled out of the setback. 
     In a preferred embodiment, the cannula apron and/or various sections, e.g., coupling elements of the cannula apron, additionally also serve as a connecting element with an injection device and/or as an antitwist protection and/or as a coupling device for the transfer of torque and/or as a chucking device for chucking the ampoule with the injection needle. The advantage of this embodiment lies in the extremely user friendly design because by connecting the injection needle to the ampoule and/or by inserting the injection needle into the injection device, several functions can be activated without the user thereby having to take additional measures or perform additional actions. 
     The nonreleasable locking mechanism between the ampoule and the injection needle may of course also have a different design and in particular may have a different nonreleasable locking mechanism than the form-fitting mechanism or catch mechanism described above. Thus in another embodiment, a first thread is provided on a metal cuff of the ampoule and a second thread is provided on the injection needle, whereby at least one of the two threads is plastically deformable and/or or has a plastically deformable component or is provided with a blocking element so that the threads are no longer detachable from one another after being joined. 
     Another approach to the problem of reducing the risk of injury and contamination for the user before and after the injection procedure consists of the fact that the injection needle has a cannula and a cannula apron, whereby the cannula has a first end for penetration into the human or animal tissue and a second end for puncturing the septum of the ampoule, the cannula apron at least partially surrounds the cannula and the cannula apron for protecting the user from unintentional injuries protrudes beyond the second end of the cannula. 
     Through this embodiment, the user is protected in particular from unwanted injuries due to the cannula in particular when the cannula is not connected to an ampoule, i.e., on removal of the injection needle from the package or when connecting the injection needle to the ampoule, for example. 
     The inside diameter of the cannula apron is preferably approximately the same size or slightly larger than the outside diameter of the ampoule at least in a section, in particular in a section in which the cannula apron protrudes above the cannula, so that the ampoule can be inserted into the cannula apron. The cannula apron thus advantageously also serves to receive, support and guide the ampoule. 
     An embodiment of a method for loading an injection device, in particular a medical hand-grip element for injection of a medicinal substance from an ampoule into human or animal tissue also reduces the risk of injury for the user. The method includes the steps:
         providing the medical injection device,   providing an ampoule containing a medicinal substance and providing an injection needle,   connecting the ampoule to the injection needle,   inserting the ampoule into the medical injection device.       

     By connecting the ampoule to the injection needle before insertion into the injection device, the connection process is facilitated. Usually first the ampoule is inserted into the injection device, in particular into a medical hand-grip element, and then the injection needle is connected to the ampoule through a receptacle opening in the injection device. The receptacle openings for the injection needles are often very small so the insertion of the injection needle into this opening is difficult, which increases the risk of missing the opening and puncturing next to the opening. This is prevented by the method proposed here. 
     In an especially preferred embodiment of this method, an injection needle is used, which has a cannula apron which protrudes beyond the second end of the cannula, as described above. This further reduces the risk of injury to the user when connecting the ampoule to the injection needle. 
     In another embodiment, the ampoule is inserted through a receptacle opening on one end of the injection device, in particular on the hand-grip element, and/or the ampoule is secured with the injection needle by a coupling arrangement to prevent a relative movement. 
     In another embodiment, the ampoule and the injection needle connected to it are also separated from the medical injection device jointly again. This achieves the result that the end of the cannula of the injection needle, which is connected to the ampoule, remains in the ampoule even when separated from the injection device. This protects the user from injury due to this end of the cannula. 
     Another measure for preventing unwanted injury to the user due to the injection needles consists of creating an injection unit comprising an injection needle with a cannula and a cannula apron, a protective element that at least partially surrounds the injection needle and a connecting device, in particular a catch connection having two fixed positions, whereby one of the two positions is designed as a nonreleasable fixed position and the injection needle and the protective element are designed to be displaceable relative to one another to assume the two fixed positions. 
     If the injection needle is inserted into the nonreleasable fixed position, the protective element and the injection needle are no longer separable from one another. The protective element preferably surrounds that end of the cannula of the injection needle which penetrates into the tissue of the patient. After conclusion of the injection process, the injection needle, preferably still connected to the injection device, is inserted into the protective element to assume the inseparable fixed position. Then the injection needle and the protective element may be disposed of jointly and/or optionally released from the injection device jointly in advance. Due to the inseparable connection between the injection needle and the protective element, there is no risk of the user inadvertently releasing the injection needle from the protective element or becoming injured with the used injection needle either in disposal or in separating the injection device. 
     In an especially preferred embodiment, at least a part of the packing of the injection needle, e.g., a package container, is used as the protective element. The separable fixation position of the connecting device is the position in which the injection needle is situated before use. The user releases the injection needle before use from the package/the protective element and connects it to the ampoule and/or the injection device. After the end of the injection, the user slides the injection needle back into the package/protective element, this time selecting the inseparable fixed position. This embodiment has the advantage that a single element serves both as the package and as the protective element. 
     In one embodiment, the fixed positions are formed by setbacks or grooves and the connecting device comprises an engagement element, in particular a catch element for engagement in the fixed position, whereby preferably the fixed positions are provided on the protective element and the engagement element is provided on the injection needle, in particular on the cannula apron. These embodiments allow a reliable fixation in the fixed positions with at the same time good displaceability and ease of manufacture of the connecting device. 
     In one embodiment, the inseparability of one of the two fixed positions is achieved by an essentially rectangular edge, which is designed so that the catch element cannot be moved above it, whereas the other detachably designed fixed position has at least one steadily rising side wall, so that a catch element accommodated therein can be extracted, for example. 
     In another embodiment, the protective element has engagement means for a needle changer on its outside, so that removal of the injection needle from the protective element and insertion of the injection needle into the protective element can be performed with the help of a needle changer. The engagement means are designed in particular as a setback, a groove or a ring groove. 
     A corresponding method for disposal of an injection needle comprises the steps:
         providing an injection needle,   providing a protective element,   inserting the injection needle into the protective element, and   inseparable joining of the injection needle to the protective element.       

     In an especially preferred embodiment, the injection needle which is inseparably connected to the protective element is connected to an ampoule at its other cannula end which is not accommodated in the protective element, in particular being connected by an inseparable locking mechanism as already described above, so that the two ends of the cannula are not exposed in disposal of the injection needle. Therefore, the risk of injury for the user in separating the injection needle from the injection device and in its disposal is further reduced. 
     Alternatively, in this method an injection needle which has a cannula apron as also described further above is used, said apron extending beyond the second cannula end, which is not accommodated in the protective element, thereby further reducing the risk of injury. 
     The invention is explained in greater detail below on the basis of preferred embodiments and with reference to the accompanying drawings: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an outside view of an embodiment of a medical hand-grip element for injection of a medicinal substance. 
         FIG. 2  shows a sectional diagram through the medical handle of  FIG. 1 . 
         FIG. 3  shows an enlarged detail of the head section of the medical hand-grip element for injection of a medicinal substance of  FIG. 2 . 
         FIG. 4  shows a sectional diagram of a second embodiment of a head section of a medical handle for injection of a medicinal substance. 
         FIG. 5  shows a sectional diagram of a third embodiment of a head section of a medical handle for injection of a medicinal substance. 
         FIG. 6  shows a sectional diagram of a fourth embodiment of head section of a medical hand-grip element for injection of a medicinal substance. 
         FIG. 7  shows a perspective view of an embodiment of a cannula apron of an injection needle. 
         FIG. 8  shows an embodiment of an injection unit and an ampoule separate from it. 
         FIG. 9  shows the injection unit and the ampoule from  FIG. 8  joined together. 
         FIG. 10  shows an embodiment of a needle changer with an injection unit clamped in it. 
         FIG. 11  shows an enlarged detail view of an embodiment of a connecting device in an injection needle for connecting an injection needle to a protective element. 
         FIG. 12  shows an embodiment of a needle holder and an injection unit connected to it as well as a medical hand-grip element into which the injection unit can be inserted. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiment of a medical hand-grip element  1  illustrated in  FIG. 1  serves as a dental intraosseous handpiece, in particular for creating a borehole in a jawbone and for subsequent injection of a medicinal substance, in particular an anesthetic into the borehole and the bone. The elongated tubular hand-grip element  1  has an outer sleeve  15  with a handle section  15 B and a head section  15 A connected thereto. The handle section  15 B and the head section  15 A are joined together by a thread  27  (see  FIG. 2 ). A receptacle opening  14 , preferably circular, through which an ampoule  2  containing the anesthetic can be inserted into the hand-grip element  1  is provided at the end of the head section  15 A of the hand-grip element  1 . An injection needle  4  which protrudes out of the hand-grip element  1  is connected to the ampoule  2 . 
     The injection needle  4  comprises an elongated cannula  74  which serves in a known way as a drilling instrument for cutting the borehole into the bone as well as for dispensing the anesthetic. To this end it has at least one cutting edge  86  on one end section (see  FIG. 4 ) which, when the injection needle  4  is made to rotate, cuts bone shavings from the bone and thereby creates the borehole into the bone. The cannula  74  is additionally furnished with a cavity  87  which runs through its interior and serves as a channel for conducting the anesthetic, and an opening  88  which is connected to the cavity  87  for dispensing the anesthetic to the bone. The cannula  74  is additionally shaped so that its one end can penetrate through the rubber stopper or the septum  72  of the ampoule  2  into the interior space of the ampoule  2  containing the anesthetic. 
     To dispense the anesthetic or the medicinal substance from the ampoule  2  a delivery device  5  is provided, which, according to the embodiment in  FIGS. 1 and 2 , is designed as a manually operable delivery device. The delivery device  5  comprises a rotatable or pivotable lever  16 , which is connected by an entraining device to a plunger or a rack  17 , which is accommodated in the hand-grip element  1 , so that it is displaceable in the direction of the ampoule  2 , so that by displacing the rack  7  the anesthetic is delivered out of the ampoule  2  and through the cannula  74 . 
     On the end of the hand-grip element  1  which is opposite the opening  14 , a connecting device  18  is provided, serving to connect the hand-grip element  1  to a drive motor. The drive motor sets the injection needle  4  and the ampoule  2  in rotation via the drive device  3  which is arranged in the interior of the hand-grip element  1 . The connecting device  18  is designed as a plug connection, a form-fitting connection or a screw connection, for example. 
       FIG. 2  shows an enlarged sectional diagram of the medical hand-grip element  1  of  FIG. 1  with an ampoule  2  accommodated completely in the interior of the hand-grip element  1  and with an injection needle  4  that is connected to the ampoule  2  and is accommodated at least partially in the hand-grip element  1 . 
     The ampoule  2  is inserted into a connecting member  6 , which can be, e.g., a hollow shaft  7 . The connecting member  6  is situated in an internal borehole  38  of the hand-grip element  1 . The internal borehole  38  has two openings on its opposite ends for the delivery device  5  and for the insertion of the ampoule  2  and the injection needle  4 . The opening of the internal borehole  38  for insertion of the ampoule  2  and the injection needle  4  is connected to the receptacle opening  14  of the hand-grip element  1  or is part of the receptacle opening  14 . 
     The inside diameter of the hollow shaft  7  corresponds approximately to the outside diameter of the outer shaft  71  of the ampoule  2  so that the ampoule  2  is accommodated tightly in the hollow shaft  7 . The length of the hollow shaft  7  is somewhat shorter than the length of the ampoule  2  so that the ampoule  2  protrudes out of the hollow shaft on both of its ends. 
     On the outside of the hollow shaft  7  a gear wheel  19  is provided which is part of the drive device  3  for rotatingly driving the ampoule  2  and the injection needle  4 . The gear wheel  19  meshes with another gear wheel  20 , which is pressed onto a shaft arrangement  21 . The shaft arrangement  21  includes a planetary gear  22  and is connected to an entraining device  23 . At least a part of the shaft arrangement  21  and the entraining device  23  are accommodated in a bearing sleeve  24  whose flange-like end  25  is part of the connecting device  18 . A drive motor, e.g., a brushless electric motor can be connected to the connecting device  18 , its rotational movement which is stepped down by the planetary gear  22  being transmitted to the hollow shaft  7 . The rotatable hollow shaft  7  is accommodated in a bearing sleeve  26  and is slidingly supported therein. The bearing sleeve  26  is secured on a rotationally fixed component of the hand-grip element  1  via protrusions  28 , e.g., on the outer sleeve  15 . 
     Except for the gear wheel  19 , the entire drive device  3  is arranged in an enlarged area of the outer sleeve  15 , on the underside of the hand-grip element  1 . The broadening in the outer sleeve  15  decreases in the direction of the head section  15 A so that the drive device  3  is arranged obliquely, at an acute angle to the longitudinal axis of the hand-grip element  1 . 
     The delivery device  5  comprises a manually operable pivotable lever  16  and a rack  17  which is accommodated in a protective sleeve  29 . A latch  30  is provided on the lever  16  and connected to it, the front end of the latch  30  being designed with a wedge shape. The latch  30  is prestressed by a spring  31  in the direction of the rack  17 . By pivoting the lever  16  alternately in the direction of the opening  14  and in the opposite direction, the rack  17  is displaced in the direction of the ampoule  2 . This is accomplished by the fact that the wedge-shaped front end of the latch  30  engages between two teeth of the rack  17  through an opening  32  in the protective sleeve  29  and thereby displaces the rack  17 . If the lever  16  is pivoted in the opposite direction, then the wedge-shaped front end of the latch  30  becomes detached from the rack  17  to engage back in the rack  17  with the next movement of the lever  16  in the direction of the opening  14 . 
     A fixation device  33  which comprises a ball and a spring prestressing the ball, for example, prevents the rack  17  from slipping back in the direction of the connecting device  18  during the operation of the lever  16  and thus during the process of delivery of the anesthetic in that the ball of the fixation device  33  engages between two teeth on the rack  17 . 
     The end of the rack  17  facing the opening  14  is designed as a rotatable shift part  34  with a wedge  35 . The wedge  35  is mounted on a shaft  36  which is rotatably connected to a bearing  37 . The bearing  37  is secured in a receptacle of the rack  17 . If the rack  17  is moved in the direction of the opening  14 , the wedge  35  engages with the displaceable sealing cap  73  of the ampoule  2  and shifts it in the direction of the septum  72  so that the substance contained in the ampoule  2  is pressed out of the ampoule  2  into the cannula  74 . Since the ampoule  2  rotates during operation of the hand-grip element  1 , it is necessary to support the wedge  35  rotatably so as to prevent the ampoule  2  from being braked by the rack  17  and thereby resulting in an unwanted relative movement between the ampoule  2  and the injection needle  4 . 
     The receptacle opening  14  is of such dimensions that the injection needle  4  can be inserted together with the cannula apron  75  which at least partially surrounds the cannula  74  through the receptacle opening  14  into the into the hand-grip element  1 . The injection needle  4  is connected to the hand-grip element  1  via a coupling device  8 , whereby parts of the coupling device  8  are provided on the injection needle and additional coupling elements are provided on the hand-grip element  1 . The coupling device  8 , however, serves not only for connecting the injection needle  4  to the hand-grip element  1  but also for transferring the torque from the connecting device  6  to the injection needle  4 . 
     Another coupling device  8 ″ is provided on the connecting member  6  or the hollow shaft  7 . The coupling device  8 ″ comprises multiple spring straps  11  which are under tension radially toward the inside in the direction of the ampoule  2  and which secure the ampoule  2  in and on the connecting device  6 . This coupling device  8 ″ also additionally serves to transfer the torque from the connecting device  6  to the ampoule  2 . 
     It can be seen from  FIG. 2  that for the rotationally fixed connection of the ampoule  2  to the injection needle  4 , the coupling arrangement  9  suppresses a relative movement between these two elements by ensuring that the torque generated by the drive device  3  is reliably transferred to the ampoule  2  and to the injection needle  4  by the coupling devices  8  and  8 ″ and that the ampoule  2  and the injection needle  4  are connected fixedly to one another via the connecting device  6  with the hollow shaft  7 . Through and jointly with the coupling device  9 , the injection needle  4  and the ampoule  2  thus form a unit for transferring and/or receiving a uniform joint torque and a uniform joint rotational speed. 
       FIGS. 3-6  show various embodiments of the head section of medical hand-grip elements for injection of a medicinal substance from an ampoule  2 , whereby  FIG. 3  is an enlarged diagram of the head section  15 A of the hand-grip element  1  of  FIG. 2 . 
     The coupling device  8  for fastening the injection needle  4  on the hand-grip element  1  and for transferring the torque to the injection needle  4  comprises a chucking sleeve  40  having multiple spring arms  41  on whose end catch elements  41 A are provided, e.g., in the form of catch noses. As the mating coupling element, a ring groove  83  runs around the cannula apron  75  of the injection needle  4  (see also  FIG. 7 ) with the catch elements  41 A engaging into the ring groove  83 , so that the injection needle  4  is secured axially on the hand-grip element  1 . The spring arms  41  are surrounded by an actuator element, e.g., a shift sleeve  42 , which is displaceable along the longitudinal axis of the hand-grip element  1  and is prestressed by a spring element  43  in the direction of the receptacle opening  14 . Contact faces  44 A,  44 B provided on the shift sleeve  42  as well as on the spring arms  41  are shaped so that the catch elements  41 A are pressed by the shift sleeve  42  into the ring groove  83 . 
     If the shift sleeve  42  is pressed against the spring force of the spring  43  and moved in the direction of the delivery device  5 , then the contact faces  44 A,  44 B are separated from one another and the catch elements  41 A can yield radially outward into a setback  45  of the shift sleeve  42  so that they come out of the ring groove  83  and the injection needle  4  can be separated from the hand-grip element  1 . 
     The components  41 ,  42 ,  43 ,  83 , etc., of the coupling device  8  described here thus form a coupling part which serves exclusively to secure the injection needle  4  on the hand-grip element  1 . According to this embodiment, the torque is transferred to the injection needle  4  via a second separate coupling part with other elements. Therefore several, preferably four, entraining elements  46 , e.g., in the form of receptacles or setbacks are provided on the hollow shaft  7  and are separated from one another by separation elements  47 , e.g., four webs. If the injection needle  4  is connected to the hand-grip element  1 , then one or more coupling elements  84  of the injection needle  4  (see also  FIG. 7 ), e.g., coupling noses which are part of the cannula apron  75 , engage in the entraining elements  46  of the hollow shaft  7 . If the hollow shaft  7  is set in rotation, then the entraining elements  46  of the hollow shaft  7  transfer the rotational movement and the torque to the coupling elements  84  and the injection needle  4 . 
     In contrast with that, the embodiment of the coupling device  8  illustrated in  FIG. 4  is designed so that the fixation of the injection needle  4  on the hand-grip element  1  and the torque transfer to the injection needle  4  take place at the same site and through the same components. To this end, the hollow shaft  7  has a section  7 A with a widened diameter on one end. An inside thread  10 A which can be screwed onto the outside thread  10 B of the injection needle  4 , preferably of the cannula apron  75  is provided on this section  7 A. If the hollow shaft  7  is set in rotation, then the rotational movement and the torque are transferred to the injection needle via the thread  10 A,  10 B. Instead of the threaded connection, other known connections may of course also be provided, e.g., bayonet connections, form-fitting connections with chucking straps, etc. 
     The coupling device  9  of  FIG. 4  also has a chucking device  12  for chucking the ampoule  2  with the injection needle  4 . This chucking device  12  may serve as an additional securing device for the rotationally fixed connection between the injection needle  4  and the ampoule  2 ; alternatively, however, it may also be provided instead of the coupling device  8 ″ (see  FIG. 2 ). In this case, the torque is likewise transferred from the drive device  3  and the connecting device  6  to the ampoule  2  via the chucking device  12 , so the chucking device  12  simultaneously also serves as the coupling device  8 ′. 
     The chucking device  12  includes a chucking element  13 , e.g., a conical surface on the coupling arrangement  9 , in particular on the widened section  7 A of the hollow shaft  7 . A mating chucking element  85 , e.g., in the form of one or more wings is provided on the injection needle  4 , in particular on the cannula apron  75 . If the injection needle  4  is inserted into the hand-grip element  1  as shown in  FIG. 4 , then the conical surface  13  comes in contact with and presses the wing  85  radially inward in the direction of the ampoule  2 . The wing  85  and the cannula apron  75  are thus pressed against the ampoule  2 , thereby establishing a frictional connection between the ampoule  2  and the injection needle  4 . This frictional connection serves to provide a antitwist protection and also to transfer the torque and the rotational movement to the ampoule  2 . 
       FIGS. 2-4  also show an inseparable locking mechanism  76  for inseparable locking of the ampoule  2  to the injection needle  4 , which is described further below, in particular in conjunction with  FIGS. 7-9 . 
       FIGS. 5 and 6  show the head section  15 A of a hand-grip element  15  for another type of injection needle which is provided with reference numeral  4 ′. This injection needle  4 ′ is a very popular design and therefore is also referred to as a standard needle. It comprises a cannula  74 ′ whose design is the same as that of cannula  74 , and a cannula apron  75 ′. The cannula apron  75 ′ is provided with an inside thread  48 A which is provided for connection to a mating thread  48 B on an injection device, e.g., a medical hand-grip element  1 . 
     On the basis of the design of the injection needle  4 ′ and the cannula apron  75 ′, it is necessary to design the coupling arrangement  9  for rotationally fixed connection of the ampoule  2  to the injection needle  4 ′ differently than that described for  FIGS. 2-4 . The coupling arrangement  9  according to  FIG. 5  again comprises a connection device  6 ′ with a hollow shaft  7 ′. The hollow shaft  7 ′ is connected like the hollow shaft  7  from  FIG. 2  to a gear wheel  19  to be set in rotation by the drive device  3  and it is provided with a first coupling element  8 ″ which secures the ampoule  2  in the hollow shaft  7 ′ and secures the torque transfer to the ampoule  2 . In contrast with the hollow shaft  7 , however, the hollow shaft  7 ′ is divided into two parts and has two separable sections  7 ′A,  7 ′B. A coupling device  8 ′ having multiple chucking straps  53  is provided on the section  7 ′A, these chucking straps  53  being prestressed toward the inside, i.e., in the direction of the longitudinal axis of the hand-grip element  1  and which secure the ampoule  2  in the hollow shaft section  7 ′A. 
     The end of the hollow shaft  7 ′ facing the injection needle  4 ′ has a protrusion  49 , which is connected to a connecting element  50 , e.g., by a thread, wherein the connecting element  50  is also part of the coupling arrangement  9  and the connecting device  6 ′. A part of the coupling device  8  with the outside thread  48 B for connecting to the injection needle  4 ′ is provided on this connecting element  50 . The connecting element  50 , the protrusion  49  and the wall section of the hollow shaft  7 ′ connected to the protrusion  49  all have a narrow borehole  51  through which the cannula  74 ′ of the injection needle  4 ′ is guided, so that the cannula  74 ′ can pass through the septum  72  of the ampoule  2  into the interior of the ampoule  2 , which is filled with the substance to be injected. The connecting element  50  and the protrusion  49  are rotatably mounted in the hand-grip element  1  by means of a bearing  52 . The bearing  52  is accommodated in a bearing seat  56  of the head section  15 A. 
     The transfer of the torque and the rotational movement to the injection needle  4 ′ and the ampoule  2  is accomplished in this embodiment via the hollow shaft  7 ′ with the coupling device  8 ″ (see  FIG. 2 ) and the coupling device  8 ′, the protrusion  49 , the connecting element  50  and the coupling device  8  with the thread  48 A,  48 B. The rotationally fixed connection between the ampoule  2  and the injection needle  4 ′ accomplished by the coupling device  9  is guaranteed by the rotationally fixed accommodation of the ampoule  2  in the hollow shaft  7 ′ by the coupling device  8 ″ and the coupling device  8 ′, the rotationally fixed connection of the injection needle  4 ′ to the connecting element  50  (which is given with the threads  48 A,  48 B at least in the direction of rotation of the threads  48 A,  48 B when the threads  48 A,  48 B are screwed together as far as the stop) and the rotationally fixed connection of the connecting element  50  to the protrusion  49  of the hollow shaft  7 ′. 
     On the basis of the closed shaping of the hollow shaft  7 ′ on the end facing the injection needle  4 ′ with the protrusion  49  arranged in front of it, it is impossible with the embodiment according to  FIG. 5  to shift the ampoule  2  from the front end of the hand-grip element  1  into the hollow shaft  7 ′. Instead of this, the hand-grip element  1  is designed in two parts so that the head section  15 A can be separated from the handle section  15 B of the hand-grip element  1 , whereby in the separated state the hollow shaft section  7 ′A remains in the head section  15 A and the hollow shaft section  7 ′B remains in the handle section  15 B. After separating the two parts  15 A,  15 B of the hand-grip element  1 , the ampoule  2  may be inserted into the hollow shaft section  7 ′A and then the two sections, namely the head section  15 A and the handle section  15 B can be joined together again, whereby the part of the ampoule  2  protruding beyond the head section  15 A and the hollow shaft section  7 ′A is inserted into the hollow shaft section  7 ′B. Next the injection needle  4 ′ can be screwed on to the connecting element  50 . 
     The connection of the two hollow shaft sections  7 ′A,  7 ′B is accomplished by pushing them into and/or over one another. The connection of the head section  15 A and the handle section  15 B is accomplished by a coupling device  54 . The coupling device  54  may have chucking straps prestressed toward the outside on the head section  15 A, engaging in the recesses of the handle section  15 B, for example. The chucking straps are brought out of engagement with the recesses by means of an elastic release mechanism  55  so that the head section  15 A and the handle section  15 B can be separated from one another. Other coupling mechanisms may of course also be used. 
     In another embodiment (not shown here), the hollow shaft is not designed to be separable but instead has a receptacle opening for the ampoule on the end facing away from the injection needle. Due to a separation of the hand-grip element as described above into a head section  15 A and handle section  15 B and due to the fact that the entire hollow shaft remains in the head section  15 A, this receptacle opening is made accessible and the ampoule can be inserted into the hollow shaft from the rear end of the hollow shaft. 
     The hand-grip element  1  and the coupling device  9  according to  FIG. 6  are also designed for connection of a standard needle  4 ′. Again a connecting element  50  is provided with a coupling device  8  having a thread  48 A,  48 B for connection of the injection needle  4 ′. The connecting element  50  is connected to a protrusion  49  on the hollow shaft  7 ′ whereby the protrusion  49  passes completely through the connecting element  50 . A bearing  52 , e.g., a friction bearing, supports the connecting element  50  and the protrusion  49 . A borehole  51  for the cannula  74 ′ of the injection needle  4 ′ passes through the protrusion  49  and the adjacent connecting wall of the hollow shaft  7 ′. 
     The hollow shaft  7 ′ as part of the connecting device  6 ′ is designed as a short receptacle into which only a part of the ampoule  2  can be inserted. Multiple chucking straps  53  of the coupling device  8 ′ secure the ampoule  2  on the hollow shaft  7 ′. 
     The transfer of the rotational movement and the torque from the drive device  3  to the injection needle  4 ′ and the ampoule  2  is accomplished according to this embodiment via the protrusion  49  which is provided with a gear wheel  57  on the hollow shaft  7 ′, the coupling device  8 ′ and the ampoule  2  on the one hand and on the connecting element  50 , the coupling device  8 ″ and the injection needle  4 ′ on the other hand. An intermediate gear wheel  58  connects the gear wheel  20  that is pressed onto the shaft  21  to the gear wheel  57 . The intermediate gear wheel  58  may be designed to step down the rotational speed. 
     The rotationally fixed connection between the ampoule  2  and the injection needle  4 ′ accomplished by the coupling arrangement  9  is ensured by the rotationally fixed accommodation of the ampoule  2  in the hollow shaft  7 ′ by the coupling device  8 ′, the rotationally fixed connection of the injection needle  4 ′ to the connecting element  50  (which in the case of the threads  48 A,  48 B is given at least in the direction of rotation of the threads  48 A,  48 B, when the threads  48 A,  48 B are screwed together as far as the stop) and by the rotationally fixed connection of the connecting element  50  to the protrusion  49 . 
     Again the separation of the hand-grip element  1  into its two sections  15 A,  15 B is necessary for insertion of the ampoule  2  into the hollow shaft  7 ′. After separation, the hollow shaft  7 ′ remains in the head section  15 A so that the ampoule  2  can be inserted into the hollow shaft  7 ′ in the direction of the protrusion  49 . The locking of the head section  15 A to the handle section  15 B is accomplished via a coupling device  54 , which has a form-fitting element  60  which is prestressed by a spring  59  on the head section  15 A and has a sleeve-shaped mating element  61  which at least partially surrounds the handle section  15 B and has a receptacle for engagement of a part of the form-fitting element  60 . If a user presses on the form-fitting element  60  and displaces it against the spring force of the spring  59 , then the form-fitting element  60  is released from the receptacle of the mating element  61  and the two sections  15 A,  15 B can be separated from one another. 
       FIG. 7  shows an enlarged diagram of the cannula apron  75  of the injection needle  4  from  FIGS. 2-4 . The cannula apron  75  has a holding section  77  and a connecting section  78  connected thereto. As can be seen from  FIG. 4  in particular, a borehole  89  in which the cannula  74  is accommodated, runs through the entire cannula apron  75 , whereby the borehole  89  has at least two sections  89 A,  89 B with different diameters. The section  89 A is at least mostly arranged in the holding section  77  and the section  89 B is at least mostly arranged in the connecting section  78  of the cannula apron  75 . More than two sections with different diameters may of course also be provided. 
     The inside diameter of the borehole section  89 A is approximately equal to the outside diameter of the cannula  74  at least in a sectional area, so that the cannula  74  comes in contact with the cannula apron  75  and is fixedly connected to it, e.g., is glued or cast and held in it. The diameter of the section  89 B is of such a dimension at least in a sectional area that an ampoule  2  or a part of an ampoule can be inserted into this sectional area. 
     The holding section  77  runs generally conically toward its free forward end, and in a preferred embodiment, it has a geometric recess  90 , e.g., a groove or a polygon on its other end, which faces the connecting section  78  for joining to a needle changer. A ring-shaped flange or bulge  91 , which surrounds the cannula apron  75 , is connected to this recess  90 ; in a preferred application, as explained in greater detail below, this flange or bulge  91  has a catch element or engagement element  104 . 
     The connecting section  78 , which is essentially cylindrical in shape on its outside, serves to connect the cannula apron  75  to an injection device, in particular to a hand-grip element  1 , and to an ampoule  2 . Connected to the bulge  91  there is a coupling element, e.g., a ring groove  83  which is provided as part of a coupling device with which the catch elements of an injection device can engage for connecting and securing the cannula apron  75  and thus an injection needle on the injection device (see also  FIG. 3  and the respective description). 
     A ring collar  92  which preferably has a chamfer on the side facing away from the ring groove  83  is connected to the ring groove  83  so that a catch element which is to engage in the ring groove  83  can better overcome the ring collar. Several function parts extend out from the ring collar  92 , at least one of these function parts being designed as an elastic component. To promote the spring effect, in a preferred embodiment, the wall thickness of at least the elastic function part is smaller than the wall thickness of the ring collar  92 . 
     A first function part is designed as chucking element  85 , e.g., as a wing, as part of a chucking device. The wing  85  is movable radially inward in the direction of the longitudinal axis of the cannula apron  75  and serves to chuck the cannula apron  75  and the injection needle  4  with the ampoule  2  (see also  FIG. 4  and the respective description). Another function element is formed by the at least one coupling element  84 , e.g., in the form of a coupling nose, which is part of a coupling device or entraining device for transfer of a rotational movement and a torque to the cannula apron  75  and the injection needle  4  (see also  FIG. 3  and the respective description). 
     Another function element is part of an inseparable locking mechanism  76  for locking the ampoule  2  to the injection needle  4 . The function element is preferably designed as an elongated elastic catch element  80  on which the coupling element  84  is especially preferably also arranged. A catch nose  81  with a contact face  82  for engagement in a setback on an ampoule  2  protrudes radially inward in the direction of the borehole  89  from the at least one catch element  80  (see also detailed description further below). 
       FIGS. 8 and 9  show an injection system  70  for injection of a medicinal substance into human or animal tissue, comprising an ampoule  2  and an injection needle  4 , whereby in  FIG. 8  the ampoule  2  is separated from the injection needle  4  and  FIG. 9  shows the ampoule  2  connected to the injection needle  4 . The injection needle depicted in the two  FIGS. 8 and 9  corresponds to the injection needle  4  already described with the cannula apron  75  of  FIGS. 2-4  and  7 . However, it is of course also possible for the injection system  70  to be equipped with an injection needle of a different design as long as this injection needle has the technical features essential for the injection system  70 . 
     The ampoule  2  corresponds to a traditional ampoule and comprises a hollow outer sheath  71  with a first end and a second end, the septum  72  arranged on one end and a sealing cap  73  arranged on the other end, which is displaceable into the hollow outer sleeve  71 . The outer sheath  71  has a constricted area or a setback  79  in the area of the end where the septum  72  is arranged. The septum  72  consists of a disk-shaped rubber sheet which is applied to one end of the outer sheath  71  and is attached thereto by a metal cuff  93 . The metal cuff  93  has an opening in the center so that the cannula  74  of the injection needle  4  can penetrate through the septum  72  into the interior of the ampoule  2 . 
     The injection system  70  has an inseparable locking mechanism  76  for locking the ampoule  2  to the injection needle  4  so that after connecting the ampoule  2  to the injection needle  4  an inseparable or single use connection is formed. As defined above, an inseparable or single use locking mechanism is understood to refer to any locking mechanism which is designed so that a single locking or connection between the ampoule  2  and the injection needle  4  can be established, whereby these components are locked together, but the lock cannot be released without being destroyed. The locking mechanism is thus not intended and not designed for being separated again. The connection of the ampoule  2  to the injection needle  4  is thus inseparable for the user. 
     The locking mechanism  76  is preferably designed as an inseparable catch device with at least one catch element  80  and at least one receptacle in which the catch element  80  engages, whereby especially preferably the constriction or setback  79  provided on the ampoule  2  is used as the receptacle so that no separate receptacle need be created for this. According to this, the at least one catch element  80  is arranged on the injection needle  4 , preferably on the connecting section  78  of the cannula apron  75  as already mentioned in conjunction with  FIG. 7 . Each catch element  80  comprises an elastically designed elongated strap  80 A with a free end and an end connected to the ring collar  92  and opposite the former. The at least one strap  80 A is separated from the adjacent structure by two slots  94 . 
     On its inside facing the borehole  89 , the strap  80 A has a catch nose  81  which is provided for engagement in the setback  79  of the ampoule  2 . On its side facing the holding section  77 , the catch nose  81  is provided with a contact face  82  which is arranged essentially at a right angle to the connecting section  78  over its entire length. On the opposite side, the catch nose  81  has an inclined face or a chamfer. 
     In connecting the ampoule  2  to the injection needle  4 , the ampoule  2  is inserted into the borehole  89  of the injection needle  4  until the catch noses  81  come in contact with the metal cuff  93  of the ampoule  2  on their chamfered sides. Because of the elastic design of the straps  80 A, the catch elements  80  bend radially outward so that the catch noses  81  slide with their chamfered sides over the metal cuff  93  until they engage in the setback  79  of the ampoule  2  (see  FIG. 9 ). The design of the catch noses  81 , in particular the contact faces  82 , which run at a right angle to the connecting section  78  in particular and come in contact with a mating face of the setback  79 , and the length of the catch noses  81  produce such a tight connection that it is impossible to separate the injection needle  4  from the ampoule  3 , e.g., by pulling the ampoule  2  and the injection needle  4  apart axially. The ampoule  2  and the injection needle  4  thus remain permanently locked together after they have been joined so that the risk of injury for the user is reduced because the end  74 B of the cannula  74  is permanently accommodated in the ampoule  2 . 
       FIG. 8  also shows that injection needle  4  has another safety feature for protecting the user from unwanted injuries. The cannula  74  of the injection needle  4  has a first end  74 A for penetrating into human or animal tissue and a second end  74 B for puncturing the septum  72  of the ampoule  2 , whereby the cannula apron  75  at least partially surrounds the cannula  74  and whereby the cannula apron  75  protrudes beyond the second end  74 B of the cannula  74  to protect the user from unwanted injuries. The cannula apron  75  preferably protrudes beyond the cannula  74  by a few millimeters, especially preferably approximately 2-5 millimeters. Through this measure the risk of unwanted puncturing in connecting the injection needle  4  to the ampoule  2  or an injection device is reduced in particular. 
       FIGS. 8 ,  9  and  11  also show an injection unit  100  which comprises an injection needle  4  with a cannula  74  and a cannula apron  75  and a protective element  101  which at least partially surrounds the injection needle  4 . In addition, a connecting device  102 , in particular a catch connection having two fixed positions  103 A,  103 B is provided, whereby one of the two fixed positions is designed as an inseparable fixed position  103 B and whereby the injection needle  4  and the protective element  101  are designed displaceably in relation to one another to assume the two fixed positions  103 A,  103 B. 
     The injection needle shown here corresponds to the injection needle  4  already described having the cannula apron  75  of  FIGS. 2-4  and  7 , but it should be pointed out that it is possible to equip the injection unit  100  with an injection needle of a different design as long as this injection needle has the technical features essential for the injection unit  100 . 
     The protective element  101  is an elongated element preferably made of plastic and having an internal borehole  109 , into which the at least one part of the injection needle  4  can be inserted. The internal borehole  109  has multiple sections with different inside diameters so that different sections of the injection needle  4 , e.g., the holding section  77  and the connecting section  78  can be accommodated in these sections. The sections having the different inside diameters are separated from one another by ring shoulders or steps. The protective element  101  additionally has a closed end  111  with a continuous transverse wall and an open end with an opening  110  for inserting the injection needle  4 . On the outside circumference of the protective element  101 , engagement means  107  for a needle changer  108  are provided, e.g., one or more setbacks or a groove. In a preferred embodiment at least a portion of the packaging of the injection needle is used as the protective element  101 , in particular that part of the packaging which surrounds the end of the cannula  74  which is provided with the cutting edge  96 . 
     The connecting device  102  comprises parts on the protective element  101  and parts on the injection needle  4 . The fixed positions  103 A,  103 B which are formed in particular by setbacks or grooves  106 A,  106 B are preferably provided on the inside of the protective element  101 , whereas the engagement element  104  for engaging in the fixed positions  103 A,  103 B, in particular a catch element, is provided on the injection needle  4 , in particular on the cannula apron  75  (see  FIG. 11 ). The engagement element  104  is formed by the flange or bulge  91  or by a section thereof, in particular by an edge on the flange  91 . 
     The two fixed positions  103 A,  103 B are arranged side-by-side and/or in series one after the other, so that the engagement element  104  can engage in only one of the two fixed positions  103 A,  103 B. The inseparability of the fixed position  103 B is achieved in one embodiment by an edge  105  arranged essentially at a right angle with respect to the inside wall of the borehole  109 . In contrast with that, the other detachably designed fixed position  103 A has at least one steadily ascending side wall. An inseparable fixed position is understood to refer to any fixed position designed so that a unique locking or connection can be established between the injection needle  4  and the inseparable fixed position, whereby the connection can no longer be released without destroying it. Therefore, this connection is not intended or designed to be separated again. The connection of the injection needle  4  to the protective element  101  is thus inseparable for the user. 
     The connecting device  102  allows the protective element  101  to be used in a double function, namely first as a storage and/or delivery and/or packaging container in which the sterile unused injection needle  4  is stored, for example, while on the other hand it serves as a protective container after conclusion of use of the injection needle  4 , whereby after completion of use, it is to be guaranteed that the used injection needle  4  is not inadvertently used again or that the protective container becomes detached from the used injection needle and there is a risk that a user might be injured on the uncovered cannula tip. 
     This is achieved by the connecting device  102  with the two fixation positions  103 A,  103 B. If the protective element  101  serves to store the injection needle  4 , then the engagement element  104  is in the releasable position  103 A (see  FIG. 9 ) to which the injection needle  4  can also be brought repeatedly and released again. For use of the injection needle  4 , it is pulled out of the protective element  101  and the connecting device  102  through the opening  110 . If the use of the injection needle  4  is terminated and if the injection needle  4  is to be disposed of, then the engagement element  104  is brought into engagement with the inseparable fixed position  103 B. This is accomplished by inserting the injection needle  4  through the opening  110  into the protective element  101 , whereby the engagement element  104  first engages in the releasable fixed position  103 A which is closer to the opening  110 . If the user inserts the injection needle  4  further into the borehole  109  of the protective element  101  in the direction of the closed end  111 , then the engagement element  104  slides over the steadily rising side wall of the releasable fixed position  103 A, overcomes the edge  105  arranged at a right angle and engages in the nonreleasable fixed position  103 B (see  FIG. 11 ). Then the injection needle  4  can be disposed of together with the protective element  101  without there being a risk that the protective element  101  will become detached from injection needle and cause injuries. 
     In a preferred embodiment, the injection needle  4  remains connected with the ampoule  2  even after engagement in the nonreleasable fixed position  103 B, so that the two ends  74 A,  74 B of the cannula  74  are covered so this further reduces the risk of injury. This situation is depicted in  FIG. 12  where a needle changer  108  is used, as described in greater detail below, for the handling of the protective element  101 , so that the protective element  101  is now largely accommodated in the needle changer  108 . The injection needle  4 , the ampoule  2  and the protective element  101  form a unit which is attached to the needle changer  108  and which is separated from the injection device, e.g., a medical hand-grip element  1 . By activation of the pushbutton  112 , the injection needle  4 , the ampoule  2  and the protective element  101  can be released from the needle changer  108  and discarded. 
       FIG. 10  shows a needle changer  108  which facilitates the removal of the injection needle  4  from the protective element  101  and its insertion into the protective element  101 . The needle changer  108  comprises a body  113  which is preferably ergonomically shaped. In particular the needle changer  108  has one or more recesses  114  on its outside circumference, e.g., setbacks, notches, grooves, strips or guides for engagement and for improved positioning of the user&#39;s hand. 
     Two angled boreholes  115 ,  116 , preferably arranged approximately at a right angle to one another, are arranged in the body  113  of the needle changer  108 . The borehole  115  is provided to receive the protective element  101  through the opening  117  and is adapted in its shape to the external shape of the protective element  110 . For example, it has several sections with different inside diameters. A spring element  118 , in particular a spiral spring, a shift element  119  with a borehole  120 , e.g., a displaceable shaft and a pushbutton  112  connected to the shift element  119  or some other actuating element are provided in the borehole  116 . The pushbutton  112  is arranged in a recess in the borehole  116  with an enlarged inside diameter and protrudes beyond the borehole  116  with its free end so that it is readily accessible for the user and is easy to operate. The shift element  119  is secured in the needle changer  108  by a pin  122  which is guided in an elongated hole in the shift element  119 . 
     If no protective element  101  is inserted into the needle changer  108 , then the spring element  118  pushes the shift element  119  in the direction of the pushbutton  112  so that a portion  119 A of the shift element  119  which is arranged between the borehole  120  and the spring element  118  is situated in the borehole  115 . If a protective element  101  is inserted into the borehole  115 , the protective element  101  displaces the part  119 A against the force of the spring element  118  in the direction of the spring element  118  so that at least a portion of the borehole  120  of the shift element  119  is aligned with the borehole  115  and the protective element  101  can be shifted through the borehole  120  in the direction of the closed end of the borehole  115 . A catch element  121 , e.g., a catch nose, which engages in the engaging means  107  of the protective element  101  is provided on the part  119 A of the shift element  119 . The protective element  101  is secured in the needle changer  108  due to the catch element  121  and the spring force of the spring element  118 , which presses the protective element  101  against the inside wall of the borehole  115 , so that the injection needle  4  can be removed from the protective element  101  or can be inserted into it. 
     The release of the protective element  101  is accomplished by pressing on the pushbutton  112  so that the shift element  119  is shifted against the force of the spring element  118  in the direction of the spring element  118  and releases the protective element  101 . If the protective element  101  is used as packaging and for disposal of the injection needle  4 , then the protective element  101  can remain in the needle holder  101  during the use of the injection needle  4 . 
     A method for handling an injection needle and for loading and unloading an injection device, in particular a medical hand-grip element  1 , is described below. This method is designed so that the risk of injury of the user with the injection needle  4  and unintentional puncturing is greatly reduced. This method consists of a plurality of individual steps, some of which can be combined into separate sub-methods. The use of a single step or one or more of these sub-variants, some of which were already described in the description of  FIGS. 1-12 , also reduces the risk of injury for the user at least in a partial step of handling of an injection needle or an injection device. The greatest protection in the form of a continuous closed hygiene chain, however, is achieved by using the overall method described below. 
     The starting point for this method is an unused injection needle, usually sterile, which is accommodated in a package, e.g., a packaging container. The injection needle is preferably designed as injection needle  4  according to  FIGS. 2-4  and  7 - 9 . The package container is designed in two or more parts and comprises the protective element  101 . The injection needle  4  is a accommodated in the protective element  101  and is in the releasable fixed position  103 A. 
     In a first step, the packaging container is opened and all the parts of the packaging container except for the protective element  101  are removed from the injection needle  104 . These packaging parts may be disposed of because they will not be needed further. Thus the user has an injection unit  100  comprising the injection needle  4  and the protective element  101  as illustrated in  FIG. 8 . The two ends  74 A,  74 B of the cannula  74  are covered by the protective element  101  and by the cannula apron  75  protruding beyond the end of the cannula  74 B, respectively, so that the user is protected from unintentional puncturing by the cannula. 
     In the next step, the user attaches the injection unit  100  to the ampoule  2  by inserting the ampoule  2  into the cannula apron  75 , whereby at the same time the cannula  74  punctures through the septum  72  and penetrates into the interior of the ampoule  2 , which is filled with the substance to be injected. The cannula apron  75  here is designed so that the ampoule is centered with respect to the cannula even on insertion. In addition, a nonreleasable locking mechanism  76  is preferably also provided, so that the ampoule  2  and the injection needle  4  are inseparably joined together. The situation after joining the ampoule  2  to the injection unit  100  is illustrated in  FIG. 9 . As also explained below, the ampoule  2  remains connected to the injection needle  4  during the entire remaining procedures including disposal so that the cannula end  74 B is covered by the ampoule  2  and there is no risk for the user of being injured with this cannula end  74 B. 
     In the next step, the injection unit  100 , which is now connected together with the ampoule  2 , is connected to the injection device, in particular to a medical hand-grip element  1 . If a medical hand-grip element  1  is used, the connection is accomplished preferably by insertion of the ampoule  2  and the injection needle  4  through a receptacle opening  14  on one end of the hand-grip element  1 , as described already above. Through the connection to a medical hand-grip element  1 , a coupling between the ampoule  2  and/or the injection needle  4  and a coupling element  10 ,  11  for transfer of a driving movement and a torque and/or a chucking between the ampoule  2  and the injection needle  4  by a chucking device and/or a coupling of the ampoule  2  to the injection needle  4  for a rotationally fixed connection of the two elements by a coupling device  9 , as also explained in detail above preferably also take place at the same time. 
     Next, the protective element  101  is removed from the injection needle  4 , whereby a needle changer  108  as described above is preferably used for this purpose. The protective element  101  especially preferably remains in the needle changer  108 . The injection device is then ready to be used for injection of the medicinal substance. This is shown in  FIG. 1  on the example of a medical hand-grip element  1 . 
     After conclusion of use of the injection needle  4 , it is inserted into the protective element  101 , whereby as described above, the injection needle  4  is pushed into the nonreleasable fixed position  103 B so that a nonreleasable connection is formed between the injection needle  4  and the protective element  101  (see  FIG. 11 ). As already mentioned, the protective element  101  is preferably part of the packaging of the injection needle and especially preferably is secured in the needle changer  108 , but it is also possible to use a separate protective element  101  that is not used as the packaging for the unused injection needle  4  and/or to perform the insertion of the injection needle  4  into the protective element  101  without a needle changer  108 . 
     In the next step, the ampoule  2 , the injection needle  4  and the protective element  101  are separated from the injection device, in particular from the medical handpiece  1 , as illustrated in  FIG. 12 . 
     Then the ampoule  2 , the injection needle  4  and the protective element  101  are discarded jointly as a unit, preferably being inseparably joined together by the locking mechanism  76  and by the connecting device  102 . 
     As indicated by the description of the method and the construction of the injection needle  4 , the injection system  70  and the injection unit  100 , both ends  74 A,  74 B of the cannula  74  are covered during the entire procedure—except the use of the needle immediately before, during and after the injection—so the user is provided with maximum protection from injuries. 
     The embodiments described herein are not limiting in any way, but instead are illustrative of all embodiments that use or include the basic logical or functional principles. In particular the injection systems, injection units, injection needles and handling methods described herein can be used not only in combination with the medical hand-grip element described here but may also be used with all other injection devices, e.g., as part of syringes or with syringe racks. 
     Additionally all the different embodiments described here may also be combined with one another, and several or all of the methods described here may be executed simultaneously or in succession as part of an overall process, the devices described here may be used in these methods or in individual method steps and/or the methods may be performed with the devices described.