49

CASE 49


A 55-year-old man presented to his physician with complaints of numbness in his right dominant hand and clumsiness of finger movements. As a child, he had suffered a supracondylar fracture of his right humerus. Healing of the fracture resulted in cubitus valgus. The physical examination detected a modest degree of wasting of the intrinsic hand muscles and a sensory deficit of the skin supplied by the ulnar nerve. The diagnosis was ulnar nerve compression at the elbow. Surgery was performed to move the ulnar nerve to a safer location anterior to the medial epicondyle.



WHAT IS CUBITUS VALGUS AND HOW DOES IT CONTRIBUTE TO ULNAR NERVE COMPRESSION?


Valgus means bent outwards or away from the body. When the normal elbow is fully extended, the forearm is not in a straight line with the humerus, but is slightly abducted away from the midline. Therefore, the forearm normally exhibits a minimal amount of valgus. In men, this deviation is approximately 10 degrees and, in women, it is about 15 degrees. When this angulation becomes excessive, the condition is known as cubitus valgus.


Healing of supracondylar fractures of the humerus can lead to cubitus valgus. Because of the exaggerated angulation of the forearm, the ulnar nerve is pulled more sharply as it travels in the osseofibrous tunnel between the olecranon and the medial epicondyle (Fig. 6-18). This subjects the ulnar nerve to greater frictional forces, which can lead to friction neuritis of the nerve. In turn, the inflammation causes fibrosis and nerve thickening within the confined osseofibrous tunnel.

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Jun 16, 2016 | Posted by in ANATOMY | Comments Off on 49

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