Patent Publication Number: US-2021192977-A1

Title: System for simulating cervical spine motions

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims the priority of U.S. Patent Application No. 62/575,016, filed on Oct. 20, 2017 and incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure pertains to a method and system for evaluating cervical spine stabilization in patient transfer training, and for evaluating tracheal intubation and/or direct laryngoscopy maneuvering techniques. 
     BACKGROUND OF THE ART 
     Patients with suspected spinal cord injuries undergo numerous transfers throughout treatment and care. Effective cervical spine (c-spine) stabilization is crucial to minimize the impacts of the suspected injury. Healthcare professionals are trained to perform transfers using simulation. However, the feedback on the maneuvers is often subjective, i.e., it is performed by an on-site evaluator that visually assesses whether the maneuvers are adequate. 
     Also, c-spine motion may result by the difficulty of rescuers to maintain head and trunk alignment during a rotation step of a transfer motion, in addition to the difficulty in initiating specific phases of the motion synchronously when multiple rescuers perform transfers. It may be difficult for an evaluator to do a proper visual assessment considering rapidity of a rotation step and number of participants. 
     SUMMARY 
     It is an aim of the present disclosure to provide a novel system for simulating cervical spine motions. 
     It is a further aim of the present disclosure to use the system for simulating cervical spine motions for evaluating tracheal intubation maneuvers and/or direct laryngoscopy maneuvers. 
     Therefore, in accordance with a first embodiment of the present disclosure, there is provided a neck mechanism for a mannequin comprising: at least three joint units serially connected to provide joints for at least three rotational degrees of freedom (DOF), with a rotational axis of a first DOF configured to be aligned with a lateral axis of the mannequin, a rotational axis of a second DOF configured to be aligned with an anterior-posterior axis of the mannequin, and a rotational axis of a third DOF configured to be aligned with a cranial-caudal axis of the mannequin, wherein a bottom one of the at least three joint units is adapted to be connected to a torso of the mannequin, and a top one of the at least three joint units is adapted to be connected to a skull. 
     Further in accordance with the first embodiment, for example, the bottom one of the at least three joint units is adapted to be connected to the torso of the mannequin with the second DOF. 
     Still further in accordance with the first embodiment, for example, the top one of the at least three joint units is adapted to be connected to a skull by the third DOF. 
     Still further in accordance with the first embodiment, for example, four joint units, provide concurrently four rotational DOFs, wherein a rotational axis of a fourth DOF is configured to be aligned with the lateral axis of the mannequin. 
     Still further in accordance with the first embodiment, for example, the rotational axes of the first DOF and of the fourth DOF are parallel and spaced apart to another. 
     Still further in accordance with the first embodiment, for example, the rotational axes of the first DOF and of the fourth DOF are parallel and spaced apart relative to the rotational axis of the second DOF. 
     Still further in accordance with the first embodiment, for example, a rotary motion sensor is at each said joint unit. 
     In accordance with a second embodiment of the present disclosure, there is provided a mannequin comprising: the neck mechanism as described above; a skull connected to the top one of the at least three joint units; and a trunk connected to the bottom one of the at least three joint units. 
     Further in accordance with the second embodiment, for example, the trunk has a plurality of metal plates emulating a volume and/or a weight of an anatomical skull. 
     Still further in accordance with the second embodiment, for example, the skull has a disk ring connected to a shaft of the top one of the at least three joint units. 
     Still further in accordance with the second embodiment, for example, elastics connect the skull to the trunk. 
     Still further in accordance with the second embodiment, for example, an airway simulator apparatus has at least one tube defining at least one opening at a level of a face of the mannequin, and being in fluid communication with at least one expandable balloon in the trunk. 
     Still further in accordance with the second embodiment, for example, the airway simulator apparatus includes a mouthpiece connected to the at least one tube at the at least one opening. 
     Still further in accordance with the second embodiment, for example, the at least one tube includes at least one nose tube having an opening defining a nostril. 
     Still further in accordance with the second embodiment, for example, the at least one tube diverges into at least two tracheal tubes, with one said expandable balloon at an end of each said tracheal tube. 
     Still further in accordance with the second embodiment, for example, the at least one tube diverges into an oesophageal tube, with one said expandable balloon at an end of the oesophageal tube. 
     Still further in accordance with the second embodiment, for example, the at least one tube is flexible tubing. 
     Still further in accordance with the second embodiment, for example, the at least one tube is connected to the skull. 
     Still further in accordance with the second embodiment, for example, the trunk comprises an articulated skeleton. 
     Still further in accordance with the second embodiment, for example, at least the neck mechanism, the skull and the trunk are covered by a skin membrane. 
     In accordance with a third embodiment of the present disclosure, there is provided a system for simulating cervical spine motions, the system comprising: a mannequin having a neck mechanism between a torso and a skull, the neck mechanism having at least three degrees of freedom (DOF); sensors to detect cervical spine orientation changes; a processing unit having an orientation calculator module to quantify the cervical spine orientation changes from readings of the sensors, and a performance assessor module to assess the cervical spine motions using the quantified cervical spine orientation changes; and an output for outputting an assessment and/or the cervical spine orientation changes. 
     Further in accordance with the third embodiment, for example, the neck mechanism has at least three joint units serially connected to provide joints for at least three rotational degrees of freedom (DOF), with a rotational axis of a first DOF configured to be aligned with a lateral axis of the mannequin, a rotational axis of a second DOF configured to be aligned with an anterior-posterior axis of the mannequin, and a rotational axis of a third DOF configured to be aligned with a cranial-caudal axis of the mannequin, wherein a bottom one of the at least three joint units is adapted to be connected to a torso of the mannequin, and a top one of the at least three joint units is adapted to be connected to a skull. 
     Still further in accordance with the third embodiment, for example, the bottom one of the at least three joint units is adapted to be connected to the torso of the mannequin with the second DOF. 
     Still further in accordance with the third embodiment, for example, the top one of the at least three joint units is adapted to be connected to a skull by the third DOF. 
     Still further in accordance with the third embodiment, for example, four joint units, provide concurrently four rotational DOFs, wherein a rotational axis of a fourth DOF is configured to be aligned with the lateral axis of the mannequin. 
     Still further in accordance with the third embodiment, for example, the rotational axes of the first DOF and of the fourth DOF are parallel and spaced apart to another. 
     Still further in accordance with the third embodiment, for example, the rotational axes of the first DOF and of the fourth DOF are parallel and spaced apart relative to the rotational axis of the second DOF. 
     Still further in accordance with the third embodiment, for example, the sensors include a rotary motion sensor at each said joint unit. 
     Still further in accordance with the third embodiment, for example, the skull is connected to the top one of the at least three joint units; and the trunk is connected to the bottom one of the at least three joint units. 
     Still further in accordance with the third embodiment, for example, the trunk has a plurality of metal plates emulating a volume and/or a weight of an anatomical skull. 
     Still further in accordance with the third embodiment, for example, the skull has a disk ring connected to a shaft of the top one of the at least three joint units. 
     Still further in accordance with the third embodiment, for example, elastics connect the skull to the trunk. 
     Still further in accordance with the third embodiment, for example, an airway simulator apparatus has at least one tube defining at least one opening at a level of a face of the mannequin, and being in fluid communication with at least one expandable balloon in the trunk, the performance assessor module assessing an airway alignment for direct laryngoscopy and/or tracheal intubation using the quantified cervical spine orientation changes. 
     Still further in accordance with the third embodiment, for example, the airway simulator apparatus includes a mouthpiece connected to the at least one tube at the at least one opening. 
     Still further in accordance with the third embodiment, for example, the at least one tube includes at least one nose tube having an opening defining a nostril. 
     Still further in accordance with the third embodiment, for example, the at least one tube diverges into at least two tracheal tubes, with one said expandable balloon at an end of each said tracheal tube. 
     Still further in accordance with the third embodiment, for example, the at least one tube diverges into an oesophageal tube, with one said expandable balloon at an end of the oesophageal tube. 
     Still further in accordance with the third embodiment, for example, the at least one tube is flexible tubing. 
     Still further in accordance with the third embodiment, for example, the at least one tube is connected to the skull. 
     Still further in accordance with the third embodiment, for example, the trunk comprises an articulated skeleton. 
     Still further in accordance with the third embodiment, for example, at least the neck mechanism, the skull and/or the trunk are covered by a skin membrane 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of a system for simulating cervical spine motions; 
         FIG. 2  is a perspective view of a neck mechanism and skull of a mannequin of the system of the present disclosure; 
         FIG. 3  is an exploded view of a joint unit of the neck mechanism of  FIG. 2 ; 
         FIG. 4  is an exploded view of another of the joint units of the neck mechanism of  FIG. 2 ; 
         FIG. 5  is an exploded view of a skull of the neck mechanism of  FIG. 2 ; 
         FIG. 6  is a graph showing an output of the system of  FIG. 1 ; and 
         FIG. 7  is a schematic view of a mannequin skeleton that may be part of the system of  FIG. 1 ; 
         FIG. 8  is an enlarged schematic view of a torso of the mannequin skeleton of  FIG. 7 ; 
         FIG. 9  is an enlarged schematic view of a lower body of the mannequin skeleton of  FIG. 7 ; 
         FIG. 10  is a perspective view of the neck mechanism and skull of the mannequin of  FIG. 2 , with an airway simulator apparatus; and 
         FIG. 11  is a side view of the assembly of the airway simulator apparatus, the neck mechanism and skull of the mannequin. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings and more particularly to  FIG. 1 , there is illustrated a system for simulating cervical spine motions at  10 , as resulting from cervical spine manipulations for example. The system  10  is of the type having a processing unit  20  used to quantify the manipulations of a mannequin  30 , also known as a dummy, etc. The processing unit  20  is of the type having a non-transitory computer-readable memory communicatively coupled to it and comprising computer-readable program instructions executable by the processing unit  20  to perform numerous functions related to the simulation of cervical spine motions. As shown in  FIG. 1 , the processing unit  20  may have various modules to perform these functions. The system  10  receives data from sensors generically shown as A in  FIG. 1  but described in further detail hereinafter. The sensors A may be any appropriate type of sensor to measure various movements of the mannequin  30  and other parameters such as forces applied to mannequin  30 . An interface  21  may be operatively connected to the processing unit  20  to output quantitative data representative of the transfer manipulations, or airway management during tracheal intubation and/or direct laryngoscopy maneuvers, and may communicate with the operators of the system  10  to warn or alarm them of excessive or improper manipulations. The interface  21  may be a monitor, screen, tablet, etc. 
     The processing unit  20  may have an orientation calculator module  20 A receiving the data from the sensors A. The orientation calculator module  20 A may determine orientation variations sustained by the neck of the mannequin  30  during manipulations. For example, the orientation calculator module  20 A may quantify variations in flexion angle values about one or more flexion axes, about lateral axes of the mannequin  30 . The orientation calculator module  20 A may also quantify lateral flexions as well, i.e., about an anterior-posterior axis of the mannequin  30 . As yet another orientation value that may be calculated by the orientation calculator module  20 A, the rotation may be obtained as well, namely an orientation of a skull relative to a torso along a vertical or cranial-caudal axis of the mannequin  30 . All of these variations of angle values may be in the form of angular rates of change about various axes. 
     The orientation calculator module  20 A may provide an output  21 A as a visual display on the interface  21 , or in the form of a data file for any given training session. In accordance with an embodiment, the output  21 A is in the form of the graph of  FIG. 6  to indicate the angle or angular rates of change for a user to get a quantitative assessment of manipulations being performed. The graph of  FIG. 6  shows a timescale which can be matched with data pertaining to the various manipulations such that a user may see the angles and angular rates of change resulting from various manipulations. 
     The processing unit  20  may be programmed with an orientation threshold database  20 B so as to determine what constitutes permitted versus excessive manipulations. Hence, the orientation calculator module  20 A may provide measured angular rates of change and receive threshold values from the orientation threshold database  20 B. A performance assessor  20 C may then determine whether the movements performed exceed the values programmed into the orientation threshold database  20 B, in which case it may be determined that an excessive or improper transfer manipulation of the mannequin  30  has been performed. It may also or alternatively be determined that an excessive or improper intubation or laryngoscopy manipulation of the mannequin  30  has been performed, for instance by the mannequin  30  being too far aligned related to a sniffing position. The performance assessor module  20 C may therefore indicate in real time that manipulations have been improper. 
     The performance assessor module  20 C, when identifying an excessive or improper manipulation by measured values exceeding beyond those of the orientation threshold database  20 B, may alert the operator of the system  10  via the alert  21 B of the interface  21 , or may provide quantitative data relative to accepted values, such as a sniffing position. This is an advantage over methods in which the quantitative data is provided at a later point, in that corrective measures may be taken right away to practice by re-manipulating the mannequin  30  for a proper manipulation. Moreover, the orientation threshold database  20 B may have various thresholds to provide more than a binary “proper” vs “excessive” assessment. For example, preliminary signals may be emitted to warn the operators of an impending excessive manipulation, for the operators to correct their movements, for instance by slowing down manipulations, and/or by reorienting the mannequin  30 . Such system interventions may provide real time feedback to the operators during training, for the operators to be capable of understanding the manipulations that are not done correctly. 
     The processor unit  20  may also have a force evaluating module  20 D receiving signals from the sensors A to calculate the forces to which the mannequin  30  is exposed. For example, the sensors A may include inertial sensors (e.g., accelerometers) producing data indicative of the forces sustained by the mannequin  30  during the manipulations. The sensors A may include pressure sensors (e.g., manometers) for an airway simulator apparatus, as detailed hereinafter. 
     The mannequin  30  is generally shown in  FIG. 1  as having a torso  31 , or trunk, limbs  32 , a neck  34  and a head  35 . In order for the system  10  to provide a realistic simulation of cervical spine motions, the mannequin  30  may be similar to the human body in terms of weight, dimensions, flexibility, center of mass, and/or range of motion. While the system  10  focusses on simulating the cervical spine motions and providing data relative to neck movement, it is observed that torso  31  manipulations may affect the cervical spine stability. Therefore, by having the mannequin  30  emulating a human body in terms of weight, dimensions, flexibility, center of mass, and/or range of motion, transfer motions of the mannequin  30  may be realistic and therefore simulate adequately cervical spine motions. As part of sensors A, it is contemplated to provide various inertial sensors on or in the mannequin  30 , for instance to evaluate the forces of movement of the mannequin  30  when some specific transfer motions are done such as rotating the mannequin  30 , using the force evaluating module  20 D. 
     Referring to  FIGS. 2 to 5 , a neck mechanism of the mannequin  30  is shown at  40 , while a skull is shown at  50 . The neck mechanism  40  interfaces the skull  50  to the torso  31 . According to an embodiment, the neck mechanism  40  and skull  50  are covered by a material, layers, or like cover emulating soft tissue, but the covering material is removed from  FIGS. 2-5  to better illustrate the neck mechanism  40  and skull  50 . 
     The neck mechanism  40  is designed to simulate movements of the cervical spine, again in terms of weight, dimensions, flexibility/resistance, center of mass, and/or range of motion. According to an embodiment, the neck mechanism  40  allows movements of the skull  50  relative to the torso  31  about three or more axes, with four distinct axes shown in  FIGS. 2-5 , although there may be fewer or more of these axes. The axes of the described embodiment are shown in  FIG. 2 . According to one possible embodiment, there are two flexion axes shown as X 1  and X 2 . The flexion axes X 1  and X 2  may generally be aligned with the lateral axis of the mannequin  30 . The flexion axes X 1  and X 2  may be generally parallel to one another. A rotation of the skull  50  relative to the torso  31  may be permissible about axis Z (aligned with the cranial-caudal axis of the mannequin  30 ), whereas a lateral flexion of the skull  50  relative to the torso  31  may be permissible by way of axis Y, generally aligned with the anterior-posterior axis of the mannequin  30 . 
     To allow such rotational movements, the neck mechanism  40  may therefore have three or more joint units, such as four distinct joint units  41  as in  FIGS. 2-5 , also known as joint assemblies. The joint units  41  are serially interconnected. In an embodiment, an interconnection between one or more of sets of two adjacent joint units  41  forms a rotational joint of the type providing one rotational degree of freedom (DOF). In  FIGS. 2 to 5 , the three lower joint units  41  are generally similar in configuration, but are oriented differently. For example, a bottommost one of the joint units  41  has its rotational axis aligned with axis Y. The second and third of the joint units  41  from the bottom are aligned respectively with axes X 1  and X 2 . A top of the joint units, shown as  41 ′, is aligned with the Z axis. Other alignment arrangements are possible as well. The top joint unit  41 ′ forms a rotational joint with the skull  50 , and provides a fourth DOF to the assembly of the neck mechanism  40  and skull  50 . 
     Reference is now made to  FIG. 3 , in which the third one of the joints  41  from the bottom is shown in greater details. The components of the third joint  41  are also present in the two bottom joints  41 , and as such the two bottom joints  41  are not broken down to avoid redundancy in the text, and an excess of reference numerals in the figures. Each of the joint units  41  has a casing  42  and a base  43 . The casing  42  may have a pair of side walls  42 A, which serve a structural function in holding other parts of the casing  42  together. The side walls  42 A face each other and are spaced apart from one another. The side walls  42 A may each slidingly support an abutment  42 B. For this purpose, the side walls  42 A are shown as having vertical slots, by which the abutments  42 B may be slidingly attached for vertical movement, until a desired position is reached. Fasteners (not shown) may then be used to fix the abutments  42 B in position along the side walls  42 A. As detailed hereinafter, the abutments  42 B may serve to block movement of an adjacent joint unit  41 / 41 ′ and hence be a limit stop. 
     Journal walls  42 C are transversely oriented relative to the side walls  42 A and are connected to them, to concurrently define a cavity. In an embodiment, the side walls  42 A and the journal walls  42 C could be made of a single monolithic piece, such as a tube (e.g., square section tube). The journal walls  42 C each may have a bearing, to rotatingly support a shaft  42 D. Any appropriate type of bearing may be used, including ball bearings, roller bearings, journal bearing, low-friction sleeves, etc. A shaft interface  42 E is also mounted to the shaft  42 D. The shaft interface  42 E is used to connected the joint unit  41  with the adjacent joint unit  41 / 41 ′ as detailed hereinafter. A clamping collar  42 F may also be present to ensure that the shaft  42 D remains in its casing  42 . The walls  42 A and  42 C may be interconnected by any appropriate way (fasteners, welding, etc), but may also be monoblock or integrally formed. A sensor  42 G (part of the sensors A of  FIG. 1 ), is mounted to one of the walls of the casing  42 , and senses the rotation of the shaft  42 D. For example, the sensor  42 G is a rotary encoder, or any other type of sensor used to measure an angular displacement of the shaft  42 D. While the casing  42  is shown as a plurality of components, some of the components may be regrouped in monolithic pieces, etc. 
     The base  43  of the joint unit  41  supports the casing  42 . Hence, the base  43  has a plate  43 A upon which are connected the side walls  42 A and the journal walls  42 C. A plunger  43 B projects from the plate  43 A. In the illustrated embodiment, the plunger  43 B projects downwardly relative to the Z axis, but the reverse arrangement is also contemplated, with the joint units  41  oriented such that the plungers  43 B project upwardly relative to the Z axis. 
     In  FIG. 3 , the plunger  43 B of the exploded joint unit  41  is only partially visible as it projects into the cavity of the lower joint unit  41 . However, the plunger  43 B of the upper joint unit  41 ′ is visible, and has the same configuration as the one that is hidden. The plunger  43 B has a head featuring a bore  43 C, through which the shaft  42 D may pass. The shaft interface  42 E is fixed to the head of the plunger  43 B, and as the shaft  42 D passes through the shaft interface  42 D, a rotational joint is formed between the plunger  43 B of the upper joint unit  41 / 41 ′ and the casing  42  of the lower joint unit  41 . Accordingly, the exploded joint unit  41  of  FIG. 3  allows rotational movement of the upper plunger  43 B relative to the casing  42 , along the second flexion axis X 2 . As for the bottom most one of the joint units  41 , its plunger  43 B visible in  FIG. 2  may be anchored to the torso  31 , although it may also provide a rotation DOF. Similar arrangements are reproduced between the first and second joint units  41  to allow lateral flexion about axis Y, and between the second and third joint units  41  to allow flexion about axis X 1 . 
     Referring to  FIG. 4 , the top joint unit  41 ′ is shown in an exploded view. The joint unit  41 ′ has numerous components in common with the joint units  41  described above with reference to  FIG. 3 , whereby like reference numerals are indicative of like components. It is however observed that the shaft  42 D is vertical in the top joint unit  41 ′, whereby the side walls  42 A and the journal walls  42 C are oriented differently than in the other joint units  41 . The shaft  42 D and shaft interface  42 E of the joint unit  41 ′ are not connected to the plunger of another one of the joint units  41 , but are instead connected to a plunger  45 A centrally located in a disk  45  or disk ring. The plunger  45 A has a similar configuration as the plungers  43 B, but it is part of the disk  45 . In an embodiment, the plunger  45 A is an integral monoblock part of the disk  45 . Accordingly, the disk  45  may rotate about the vertical axis Z by way of its connection to the shaft  42 D of the joint unit  41 ′. A pair of tabs  45 B may be on the underside of the disk  45 . The tabs  45 B may be used as attachments for a head shell that would be positioned onto the skull  50 . The disk  45  is the interface between the neck mechanism  40  and the skull  50 . The skull  50  is therefore anchored to the disk  45  and rotates with it. As an alternative to a disk  45 , a frame could be used. 
     Referring to  FIG. 5 , the skull  50  may be composed of various plates  51  and brackets  52 , with a central plate  51 A mimicking the arcuate shape of a human skull. As the skull  50  may be the support for layers of material imitating soft tissue, the central plate  51 A may define the rounded skull shape, whereas the other plates  51  and brackets  52  give the skull  50  its appropriate diameters and emulate the volume of a skull, as well as the weight and/or center of mass. Moreover, the plates  51  and brackets  52  provide some mass to the skull  50  and therefore allow it to be representative of a real skull. According to one embodiment, the arrangement of plates  51  and brackets  52  aims to have the center of mass of the skull  50  coincide with the center of mass of a human skull. It is therefore contemplated to use a material such as metal for many of the components of the neck mechanism  40  and skull  50 . Also, tendons  53  may be used to emulate the elasticity of soft tissue. For example, the tendons  53  may be elastic bands or cables. Four of the tendons  53  are shown, to give some balance to the assembly. Although not shown, the tendons  53  are attached to anchor points on the torso  31 . The elasticity and/or tension of the tendons  53  are also variables that may affect the realism of the mannequin  30 . 
     Although a given configuration of joint unit  41 / 41 ′ is detailed above, numerous other configurations are considered. For example, instead of using numerous joint units  41 , it is contemplated to provide a joint with multiple rotational DOFs (such as a universal joint or a spherical joint). Moreover, the joint units  41  may have a different configuration, for instance by being simpler hinges made of a bracket and shaft. Sensors of different nature may be used, such as gyroscope, accelerometers, instead of magnetic rotary encoders or optical rotary encoders. Numerous other configurations apply. In contrast to a universal joint, the rotational axes Y, X 1  and X 2  do not share a common point of intersection. The spacing apart of the lateral (X 1 , X 2 ) and anterior-posterior (Y) rotational axes in the neck mechanism  40  may be a realistic emulation of a human spine. 
     Referring to  FIG. 7 , a mannequin skeleton is generally shown at  70 . The mannequin skeleton  70  may or may not be part of the system  10 . The neck mechanism  40  and skull  50  may be used with the mannequin skeleton  70 , to emulate the inertia and elasticity of an unanimated human body, with the inertial of unanimated limbs. The skeleton  70  generally has a torso portion  80 , and a lower body portion  90 . In the illustrated embodiment, the demarcation between the torso portion  80  and a lower body portion  90  is around a waist line of the skeleton  70 . According to an embodiment, the skeleton  70  may be overmolded with a resilient material, such as a rubber or silicone, that will provide a soft tissue appearance and flexibility to the skeleton  70 . When the skeleton  70  is overmolded, it may have the appearance of the mannequin  30  of  FIG. 1 . 
     Referring to  FIG. 8 , the torso portion  80  has various components, generally described as a central member  81 , shoulder blades  82 , resilient joints  83  and arms  84 . The central member  81  is the spinal component of the torso portion  80 . In the illustrated embodiment, the central member  81  has a connector  81 A for interface with the neck mechanism  40  ( FIG. 2 ), for instance by way of fixed connection (no relative movement once locked to one another). As a possibility, the connection of the neck mechanism  40  with the torso portion  80  may be by way of a rotational joint, providing one, two or three rotational degrees of freedom (e.g., the connector  81 A forming with the neck mechanism  40  a spherical joint or universal joint). The connector  81 A is at an end of spinal member  81 B, that extends along the cranial-caudal axis of the torso portion  80 . The spinal member  81 B may flare downwardly (though other contours are also considered), and join an abdominal member  81 C. The spinal member  81 B and abdominal member  81 C have a width proportional to a rib cage. The abdominal member  81 C may form a cavity to receive the electronic components of the system  10 . A lower spinal member  81 D projects downwardly from the abdominal member  81 C, for connection to a lower body of the mannequin. The above configuration for the central member  81  is one of numerous possible configurations. The configuration described above is rigid to be representative of the rigidity of the rib cage portion of a human torso. Shoulder blades  82  are connected to the central member  81  by way of resilient joints  83 , to emulate the soft tissue flexibility in the shoulder region of a human body. This soft tissue flexibility in the human shoulder region poses a challenge in roll-over of the body, as cervical spine stability can be affected by this looseness in the torso. The arrangement of central member  81 , shoulder blades  82  and resilient joints  83  replicates the human torso in the roll-over manipulations. 
     Each of the shoulder blade  82  may have a polygonal body, though other shapes are contemplated as well, for instance made out of a plate. Connection strips  82 A are provided along edges of the shoulder blades  82 , for connection with the resilient joints  83 . Three resilient joints  83  are present, with an elongated resilient joint  83  being between the spinal member  81 B and each of the two shoulder blades  82 . The resilient joints  83  may be made of a rubbery material, such as a rubber or polymer. For example, a silicone may be used as material for the resilient joints  83 , with a suitable density to simulate the shoulder soft tissue (tendons, muscles). According to an embodiment, instead of the three discrete resilient joints  83 , the overmolding of rubbery material joins the shoulder blades  82  with the central member  81 , while emulating soft tissue flexibility present in a human shoulder area by the absence of a rigid connection between the shoulder blades  82  and the central member  81 . Although not shown, elastic bands may also be provided to limit the free movement of the shoulder blades  82  relative to the central member  81 . Hooking members  82 B are on each shoulder blade  82 , for attachment of the tendons  53  ( FIG. 2 ). The hooking members  82 B may have any appropriate shape or configuration, including holes, slots, projecting connectors, etc. A glenoid member  82 C may be provided in each of the shoulder blades  82 , for connection of the arms  84  to the shoulder blades  82 . The glenoid member  82 C may be any appropriate bracket for interfacing the arms  84  to the plates or bodies of the shoulder blades  82 . As a possibility, the glenoid member  82 C may be a rotational joint, providing one, two or three rotational degrees of freedom, to emulate a human shoulder joint. It is also observed that numerous holes are distributed over the torso portion, such as in the spinal member  81 B and the shoulder blades  82 . These numerous holes may be used for the connection of weights to adjust a position of a center of mass of the torso portion  80 . 
     The arms  84  are illustrated as having a sequence of joints and links to reproduce the shoulder joint, upper arm, elbow and lower arm of a human body. According to an embodiment, each arm  84  has a sequence of a first rotational joint  84 A, a second rotational joint  84 B, an upper arm member  84 C with movable weights  84 D, an elbow rotational joint  84 E, a lower arm member  84 F and a wrist rotational joint  84 G. This is one of numerous configurations. For example, instead of rotational joints, the arms  84  may have the members  84 C and  84 F, as well as a hand member (not shown, part of the rotational joint  84 G), be interconnected by the resilient rubbery material overmolded onto the skeleton  70 . 
     The combination of first rotational joint  84 A and second rotational joint  84 B connected to the glenoid members  82 C of the shoulder blades  82  concurrently form two rotational DOFs between the shoulder blades  82  and the upper arm member  84 C, similar to the motion range of a human shoulder joint. As an another example, a spherical joint is provided instead of the arrangement of the two joints  84 A and  84 B. The first rotational joints  84 A have their rotational axis generally parallel to the X axis of the coordinate system, while the second rotational joints  84 B have their rotational axis transverse relative to the rotational axis of first rotational joints  84 A. The upper arm members  84 C and/or the lower arm members  84 F may be threaded rods upon which the weights  84 D may be moved to adjust the position of the center of mass of the members  84 C and  84 F. The elbow rotational joints  84 E and wrist rotational joints  84 G have their axes of rotation generally transverse to a longitudinal axis of the members they are connected to, so as to reproduce elbow and wrist movements. More or less rotational joints may be present as well, such that the arms  84  have some flexibility at the shoulder, elbow and wrist joints. 
     Referring to  FIG. 9 , the lower body portion  90  has a pelvis member  91 , and a pair of legs  94  projecting from the pelvis member  91 . It is observed that the pelvis member  91  is not rigidly connected to the central member  81 , with a gap being defined between the lower spinal member  81 D and the pelvis member  91 . According to an embodiment, a resilient joint (e.g., silicone) or the resilient rubbery material overmolded over the skeleton  70  flexibly join the torso portion  80  to the lower body portion  90 . The pelvis member  91  may be an inverted U-shaped bracket to which the legs  94  are connected. The legs  94  may have a configuration similar to the arms  84 . The legs  94  are illustrated as having a sequence of joints and links to reproduce the high joint, thigh, knee and lower leg of a human body. According to an embodiment, each leg  94  has a sequence of a first rotational joint  94 A, a second rotational joint  94 B, a thigh member  94 C, movable weights  94 D, a knee rotational joint  94 E, a lower leg member  94 F and an ankle rotational joint  84 G, among possible configurations. Again, instead of rotational joints, the legs  94  may have the members  94 C and  94 F, as well as a foot member (not shown, part of the rotational joint  94 G), be interconnected by the resilient rubbery material overmolded onto the skeleton  70 . 
     The combination of first rotational joint  94 A and second rotational joint  94 B connected to the pelvis member  91  concurrently form two rotational DOFs between the pelvis member  91  and the thigh members  94 C, similar to the motion range of a hip joint. As an another example, a spherical joint is provided instead of the arrangement of the two joints  94 A and  94 B. The first rotational joints  94 A have their rotational axis generally parallel to the X axis of the coordinate system, while the second rotational joints  94 B have their rotational axis transverse relative to the rotational axis of first rotational joints  94 A. The thigh members  94 C and/or the lower leg members  94 F may be threaded rods upon which the weights  94 D may be moved to adjust the position of the center of mass of the members  94 C and  94 F. The knee rotational joints  94 E and ankle rotational joints  94 G have their axes of rotation generally transverse to a longitudinal axis of the members they are connected to, so as to reproduce knee and ankle movements. More or less rotational joints may be present as well, such that the legs  94  have some flexibility at the hip, knee and ankle joints. 
     Referring to  FIGS. 10 and 11 , an airway simulator apparatus  100  is shown as part of the mannequin  30 , used in collaboration with the torso  31 , the neck mechanism  40  and the skull  50 . Although not shown, the mannequin  30  featuring the airway simulator apparatus  100  may also have a mannequin skeleton  70 . Moreover, as observed from  FIGS. 10 and 11 , the mannequin  30  may have a soft tissue membrane emulating skin, with the airway simulator apparatus  100  being accessible through a mouth of the mannequin  30 , or through nostrils of the mannequin  30 , the mouth and the nostrils being defined in the skin of the mannequin  30 . The airway simulator apparatus  100  emulates anatomical airways, with at least the following components: a mouthpiece  101 , a throat tube  102 , a pharyngeal tube  103 , nose tube(s)  104 , oesophageal tube  105 , stomach  106 , tracheal tube(s)  107  and lungs  108 . 
     The mouthpiece  101  opens to the month in the skin of the mannequin  30 . The mouthpiece  101  may taper toward the throat tube  102 . The throat tube  102  may then connect with the pharyngeal tube  103 . In an embodiment, the pharyngeal tube  103  has a larger diameter than the throat tube  102 . Nose tube(s)  104  also merge with the pharyngeal tube  103 . As shown in  FIG. 10 , there may be a part of nose tubes  104 , extending all the way to the pharyngeal tube  103 . Alternatively, the nose tubes  104  may merge before connected to the pharyngeal tube  103 . In the shown arrangement, the throat tube  102  and the pharyngeal tube  103  all merge with a common top end of the pharyngeal tube  103 , for instance via an interface. 
     The pharyngeal tube  103  extends toward the torso  31 . Though it bears the moniker “pharyngeal”, the pharyngeal tube  103  may be longer than an anatomical pharynx. The pharyngeal tube  103  may then diverge into the oesophageal tube  105  connected to the stomach  106 , and into the tracheal tubes  107  connected to the lungs  108 . The stomach  106  and the lungs  108  may be expansible balloons or like vessel of elastic material, which can expand when pressurized. In an embodiment, the airway simulator apparatus  100  is generally airtight, such that air blown into the airway simulator apparatus  100  via the mouthpiece  101  or the nose tubes  104  may result in the inflation of the lungs  108 , if not also of the stomach  106 . Accordingly, maneuvers such as mouth-to-mouth resuscitation may be practiced with the mannequin  30  featuring the airway simulator apparatus  100 . The airway simulator apparatus  100  is shown as having both a stomach  106  and lungs  108 , but the airway simulator apparatus  100  may be limited to either one of the stomach  106  and lungs  108 . The various tubes of the airway simulator apparatus  100  may be of a polymer that has a level of elasticity similar to that of human airways. The tubes of the airway simulator apparatus  100  may consequently be flexible tubing. The material used for the stomach  106  and/or the lungs  108  may be different, due to capacity of these human cavities to inflate. As the airway simulator apparatus  100  is under the skin of the mannequin  30 , the arrangement emulates the elasticity of human tissue on the human airways. In an embodiment, the airway simulator apparatus  100  is connected to the skull  50 , extends longitudinally along the neck mechanism  40 . More specifically, the nose tubes  104  may be connected to the central plate  51 A of the skull  50 , among one possibility. 
     As direct laryngoscopy and tracheal intubation are necessary skills in airway management, and thus the airway simulator apparatus  100  may contribute to the training for airway management. Glottis visualization may be effect with the airway simulator apparatus  100 , as it is necessary to perform successfully direct laryngoscopy and intubation. This requires proper positioning of head and neck to visualize the glottis and easily access the tracheal tube through the glottic opening, whereby tracking of the orientation of the neck mechanism  40  and skull  50  may be used in conjunction with the airway simulator apparatus  100 . It is known that an optimal position of the patient&#39;s head and neck at the time of laryngoscopy and intubation may have an impact on the outcome, and one known position is referred to as “sniffing position” (SP). The system  10  may therefore be programmed to measure and/or give feedback about what constitutes the range of angles of the “sniffing position” for the neck mechanism  40  and skull  50 , and monitor the rotations about X 1 , X 2 , Y and Z during simulated direct laryngoscopy and/or tracheal intubation. 
     Accordingly, the airway simulator apparatus  100  defines a realistic airway anatomy and landmarks including pharynx, larynx, epiglottis, arytenoids, false cords, true vocal cords, trachea, lungs, esophagus structures, with some or all of these imbedded in a flexible tubes of the airway simulator apparatus  100 . As the airway simulator apparatus  100  is attached to the mechanical structure of the mannequin  30  (e.g., skull  50  as above, or otherwise neck mechanism  40 ), the airway simulator apparatus  100  changes position with the position of the skull  50  (neck flexion and head extension). The inertia of the skull  50  in combination with the degree of motions motion offered by the neck mechanism  40  allows a more realistic and sensitive positioning of the skull  50  to achieve the sniffing position for the airway simulator apparatus  100 . The sensors in the neck mechanism  40  allow the measurements and feedback of the alignment of sniffing position during the intubation and subsequent superfluous head motions in all of the anatomical planes during the intubation maneuvers. The system  10  therefore proposes a quantitative approach to measure the efficacy of the c-spine stabilization and provide objective feedback during training. The proposed quantitative approach has the potential to be used for personalized feedback during training sessions. 
     Using the readings from the sensors A, the performance assessor module  20 C may perform a characterization of the quality of transfer maneuvers based on the analysis of the temporal and spatial gap between the actual manoeuvre and the ideal representation of the motion, for example during a log-roll. In a perfect log-roll, both head and trunk segments move at the same time (i.e. temporal synchronicity), following concordant paths or “en-bloc” (i.e. spatial synchronicity). The global change in orientation for each segment should therefore be the same throughout the maneuver, and the sensors A can therefore be used to detect variations. Unwanted motion (e.g. head dropped in extension during the roll) will be captured in the global change in orientation experienced by the skull  50 . 
     Temporal synchronization refers to the ability of the rescuers to move the trunk and the head at the same time. Poor communication between the rescuers or difficulty initiating and maintaining smooth motion of the trunk during the roll and push phases (e.g. due to a lack of strength with a large SP) may cause a delay between the motion of the head and the motion of the trunk, specifically at the initiation of a specific phase of a motion. Such delay will therefore be investigated during the initiation of the two phases requiring most of the motion (i.e. roll and push). 
     Spatial synchronicity refers to the idea that both segments move along a proportional arc of circle during both the roll and the push phases, represented by that desired line of identity on a 2D motion graph as in  FIG. 6 . Potential spatial quality indicators may therefore be monitored by the performance assessor module  20 C based on the assumptions regarding ideal log-roll and its representation using a 2D motion graph approach). As such, the deviation from the desired line of identity during the roll and the push phases is investigated as a potential indicator, using the roll and the push best-fit line determined by a least-square approach. An efficient log-roll also assumes that the lead rescuer and assistant(s) have sufficient control over the motion. Perfect control will allow the rescuers to follow the same path throughout the roll and the push phases. Hence, it is hypothesized that the larger the spread between the two curves on the motion phase-plane, the worse the control and hence the result. One way of capturing that “spread” is by calculating the area between the curves. Hence, that area between the curves will be investigated as a possible indicator of acceptable and unacceptable log-rolls. Table 1 below provides performance and quality indicators for log-roll, using data measurements as in  FIG. 6 . 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Performance and Quality Indicators for Log-Roll 
               
            
           
           
               
               
               
               
            
               
                 CATEGORY 
                 VARIABLE 
                 EQUATION 
                 DESCRIPTION 
               
               
                   
               
               
                 Performance 
                 ROMrel peak   
                 Max(ROMrel) 
                 Peak change in global 
               
               
                 measure 
                   
                   
                 orientation of the head relative 
               
               
                   
                   
                   
                 to the trunk. 
               
               
                 Temporal 
                 Delay roll _ini 
                 
                   
                 
                 Delay at roll Initiation 
               
               
                 Quality 
                 Delay roll _end  
                 
                   
                 
                 Delay at Roll termination 
               
               
                 Indicators 
                   
                   
                   
               
               
                 Spatial  
                 Slope Roll   
                 
                   
                 
                 Difference between the slope 
               
               
                 Quality 
                   
                   
                 of the best-fit line of the Roll 
               
               
                 Indicators 
                   
                   
                 curve and the ideal line of 
               
               
                   
                   
                   
                 identify. 
               
               
                   
                 Slope Push   
                 
                   
                 
                 Difference between the slope 
               
               
                   
                   
                   
                 of the best-fit line of the Push 
               
               
                   
                   
                   
                 curve and the ideal line of 
               
               
                   
                   
                   
                 identity. 
               
               
                   
                 ABC Roll-Push   
                 
                   
                 
                 Area contained between the 
               
               
                   
                   
                   
                 curves from the Roll and the 
               
               
                   
                   
                   
                 Push phases. 
               
               
                   
               
               
                     indicates data missing or illegible when filed