Talk:Paper - Some rare muscular anomalies (1915)

SOME RARE MUSCULAR ANOMALIES. By Marearet O. MEEK, Girton College.

In a male subject dissected in Michaelmas Term 1913 a rare form of misplacement of the insertion of the latissimus dorsi and teres major muscles was found. The terminal ends of these muscles, united and not separated by the usually existing bursa, passed upwards and, becoming attached in

Fie. 1,

passing to the long head of the triceps, were finally inserted into the capsule of the shoulder below the coracoid process above the subscapularis insertion. ‘The capsule was closed and did not show the usual perforation under the subscapular tendon (fig. 1). This anomalous insertion differed from any of the usual forms of the arcus muscularis axillaris in that it lay behind the axillary artery. The anomaly was present on both sides. The same arm had a separate accessory extensor longus pollicis whose tendon lay in the same compartment of the dorsal carpal ligament as the Some Rare Muscular Anomalies 877

extensor digitorum communis, beside but separate both in belly and tendon from the extensor indicis. The first lumbrical was dicephalic, having an additional origin from the tendon of the extensor sublimis digitorum. On the ulnar side of the flexor profundus tendons for the middle and ring fingers there were separate lumbrical slips attached to the medial sides of the third phalanges, and the normally arising lumbrical for the little finger was inserted into the medial side of the ring finger.

Tensor Plice Douglasii.—iIn a female subject dissected during the present term there were on each side two small flat oblique muscular fasciculi under the fascia transversalis, attached laterally to the deep surface of the transversalis tendon, and medially inserted, one into the lateral margin of Douglas’s fold, the other into the transversalis tendon 1 cm. above and

lateral to the fold. These are apparently varieties of the slip described by Professor Gruber (Virchow’s Archiv, xxx. p. 87) under the name “tensor lamine posterioris vagine musculi recti abdominis.” The upper one was about 20 mm. long; the lower larger, about 35 mm. long; the interval between the two was about 10 mm., and they lay nearly parallel, ascending at an angle of about 35°; each was about 15 mm. wide. Gruber’s specimen was single on both sides, and was 10 cm. long. He gives references to three other examples of somewhat similar muscles. Other muscular slips in this locality have been described under the name pubio-peritonealis, but the present specimen is peculiar in its shortness, it having no pubic attachment, and in being double on both sides (fig. 2). The curious specimen figured by Gruber (Bulletin de l Académie Imp. de S. Petersbowrg, 1873) was single at origin but divided above into five bands. From his description it must have been a muscle of the same order as that now described.

VOL. XLIX. (THIRD SER. VOL. X.)—JULY 1915. 27