Ulnar nerve strains at the elbow.

Twenty unembalmed intact cadavers had strain measurements taken of the ulnar nerve at 5 positions around the elbow and at varying degrees of elbow flexion. A microstrain gauge was implanted directly into the nerve through a superficial incision. Maximum strains in the ulnar nerve occurred at maximum elbow flexion and directly behind the medial epicondyle; meaningfully less strain was seen at lesser degrees of flexion and positions distal and proximal to the epicondyle. A wide range of maximal strains (0% to 14%) was found. Twenty-five percent of the ulnar nerves showed strains of greater than 10% with maximum elbow flexion behind the medial epicondyle. Cubital tunnel syndrome may be at least in part a traction neuropathy.