The chondroepitrochlearis muscle: case report.

An extremely rare muscle disorder in the pectoral region is described. It involves a musculotendinous unit which originates from the pectoralis major and inserts onto the medial epicondyle of the humerus. The authors report a case of an 11-year-old boy, affected bilaterally, who underwent surgical treatment to lengthen the chondroepitrochlearis muscle. There was significant cosmetic and functional improvement.