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Show 396 MR. G. E. DOBSON ON T H E [Mar. 1, few muscular fibres from the interosseous ligament and adjoining surfaces of the ulna and radius. The palmaris longus arises in common with the flexor carpi ulnaris and flexor digitorum suBlimis, and forms a thin flat tendon which, passing down alongside and internal to that of the former muscle, is inserted into the palmar fascia. The flexor digitorum suBlimis arises as above described, and is also connected with the origin of the pronator radii teres and the flexor digitorum profundus, and divides in the manus into three tendons for the three middle toes. Flexor digitorum profundus arises by five heads, which unite into a common tendon, which in the manus divides into tendons for each of the five toes. There are four lumbricales, inserted respectively into the inner sides of the bases of the first phalanges of the four outer toes. Of the muscles attached to the hind limbs the psoas magnus and psoas parvus are both well developed and nearly equal in size. Their tendons, passing backwards, unite with the outer and inner sides respectively of the fleshy tendon of the iliacus, and are, with it, inserted into the lesser trochanter. The quadratus lumborum is remarkable for its rudimentary form and interrupted connections. It arises as a small bundle of muscular fibres from the side of the fifteenth dorsal vertebra, and from the surface of pait of the last intercostal muscle, forms four slender tendons, which are attached respectively to the tips of the long transverse processes of the second to the fifth lumbar vertebra; the tip of the sixth vertebra receives its tendon from a separate bundle of muscular fibres, which are attached to the inferior surface of the fourth transverse process; and other fibres, arising from the posterior margin and inferior surface of the fifth transverse process, pass backwards to the crest of the ilium, a large part uniting with the iliacus muscle. Thus the four muscles, the jJsoas magnus and p. parvus, the quadratus lumborum and the iliacus, may all be said to be the same muscle, having various origins but the same insertion. This muscle may be considered a differentiated intercostal1, to which the name m. costo-ileo-femoralis might be applied. The sartorius is represented by a muscular aponeurosis, which covers the muscles on the inner side of the thigh connected with the fascia covering the iliacus muscle, and more internally with the pectineal eminence by a slender muscle which arises therefrom, inserted along the prominent ridge on the anterior surface of the tibia. The semitendinosus is also peculiar in its connections. It arises partly from the tuber ischii, and partly from a dense tendinous aponeurosis attached across the upper surface and sides of the tail, by which it is connected with the corresponding muscle of the opposite side. It consists of two laminae, which unite and again divide ; the outer division, smaller, passes outside the leg, and, becoming united with the lower margin of the biceps flexor cruris, is inserted with it into the tibial ridge; the inner, the m. semitendinosus proper, is inserted into the inner side of the same ridge. The leg, there- 1 See Dr. Gadow's paper in Morpholog. Jahrbuch, 1881, pp; 57-100. |