正中神経麻ひを伴った上腕骨か上突起の１例

Abstract

The supracondyloid process of the humerus, one of the normal variants, is a bony process about five centimeters above the medial epicondyle. It is a vestige of the entepicondylar foramen in primitive reptiles, which persists in some mammals.Its incidence in Caucasian's humeri is 0.5-1.2%, while that in Japanese' humeri is 0.1-0.3%.This variant usually remains asymptomatic, but occasionally causes pain and paresthesia in the arm and hand, compressing the median or ulnar nerve, or the brachial artery or its branch.In this paper, we present such a case of “processes supracondyloideus humeri syndrome”.The case was a forty-two-year-old Japanese man, who complained of pain in the left shoulder and elbow. The examination revealed a tender bony protrusion in his left upper arm about five centimeters above the medial epicondyle. Percussion on the protrusion elicited pain and paresthesia in the forearm and radial three fingers. Supination of the forearm with the elbow in extension exacerbated the pain.Hypesthesia and hypalgesia was discovered in the left thumb, index and middle finger.Roentgenography revealed the supracondyloid process, about sixteen milimeters in length.At surgery, we found a fibrous membrane, expanding from the tip of the process toward the intermuscular septum. The median nerve, which had been compressed by the membrane, was released when the latter was thoroughly incised.After the operation, the pain, paresthesia and hypesthesia disappeared completely.