Muscular and other abnormalities in a case of Edwards' syndrome (18-trisomy).

This paper describes the anatomical variations observed in a specimen exhibiting Edwards' Syndrome (18-trisomy). The clinical and autopsy data are compared with those reported in earlier literature. Aside from having a tracheoesophageal fistula, the viscera were characterized by abnormalities of the heart, lungs, liver and kidneys. The facial musculature was relatively undifferentiated. Only a few abnormalities were recorded in the otomandibular and suprahyoid structures. The infrahyoid region had three pairs of supernumerary muscles, including the "sternohyoideus azygos." The bluk of abnormalities were found in the muscles and nerves of the upper limb. These included the absence of the palmaris longus and brevis, the subclavius and the extensor digiti quinti proprius; the presence of supernumerary muscles, e.g., the "rhomboideus occipitalis," the "latissimocondyloideus," and the "subclavius posticus." The deltoid and the pectoralis major were fused to form the "deltopectoral" complex. A definitive musculocutaneous nerve was found in the right arm only. In the lower extremity supernumerary muscles included the "tenuissimus," "peroneus quinti digiti," and the "extensor primi internodii hallucis."