1.  Technical Field
The present disclosure generally relates to safety shields for medical needles, and more particularly, to safety shields that protect a needle point of a medical needle for tissue biopsy. 
2.  Description of the Related Art
Problems associated with inadvertent needle sticks are well known in the art of blood sampling, percutaneous medication injection and other medical procedures involving use of medical needles.  Significant attention has been focused on needle stick problems due to the contemporary sensitivity of exposure to AIDS, Hepatitis and other serious blood-borne pathogen exposures. 
Procedures for removing a needle from a patient commonly require a technician to use one hand to place pressure at the wound site where the needle is being withdrawn, while removing the needle device with the other hand.  It is also common practice for an attending clinician to give higher priority to care for the patient than is given to disposal of a needle.  In the case of typical needle devices without safety shields, such priority either requires the convenience of an available sharps container within reach or another means for safe disposal without leaving the patient's side.  Providing adequate care while following safety procedures is often compounded by the patient's physical condition and mental state, such as in burn units and psychiatric wards.  Under such conditions, it is difficult to properly dispose of a used needle while caring for a patient. 
The widespread knowledge and history associated with needle care and disposal problems have resulted in numerous devices for preventing accidental needle sticks.  Problems of current safety devices include difficulty of use and high cost due to their complexity and number of parts. 
Other known devices employ sheaths that are telescoping, pivoting, etc.  These devices, however, may be disadvantageously cumbersome to activate.  Further drawbacks of current devices include high manufacturing cost due to complexity and the number of parts.  Thus, these type prior art devices may not adequately and reliably shield medical needle apparatus to prevent hazardous exposure. 
Consequently, there remains a need to provide a more satisfactory solution for needle safety devices by overcoming the disadvantages and drawbacks of the prior art.  Therefore, it would be desirable to provide a more adequate and reliable medical needle shield apparatus that employs a safety shield slidably movable along a medical needle to prevent hazardous exposure to a needle tip.  Such a needle shield apparatus should be easily and reliably movable to shield a needle tip of a needle cannula.