What is the definition or description of: arm numbness?

Decreased sensation: Less sensitivity to pin or light touch in the arm. May correspond to anatomical distribution such as ulnar or median nerve, or perhaps cervical anatomical correlates. May be localized using standard testing. Causes are multiple.

Arm numbness : Lack of normal feeling in an arm can be caused by a local nerve trauma (a cut) or compression at the elbow or at the level of the wrist (e.g. Carpal tunnel syndrome) or it can be caused by compression of a nerve root in the neck. Tracing the numbness, physical exam and diagnostic tests (emg, ncv, mri) can identify the cause usually very well and suggested treatments can usually prevent permanency.