The development of the human body; a manual of human embryology . If, now, this loop idea be tested by the distribution ofthe nerves to the lower limb, it will be found that the firstmyotome to pass out upon the dorsum of the ilium is thesecond lumbar, and following that there are met succes-sively, from before backward, the remaining lumbar andthe first and second sacral myotomes. The arrangementof these myotomes upon the dorsal surface of the pelvisand the muscles to which they contribute may be seenfrom Fig. 117. In this portion of their course they repre-sent portions of the dorsal half of
The development of the human body; a manual of human embryology . If, now, this loop idea be tested by the distribution ofthe nerves to the lower limb, it will be found that the firstmyotome to pass out upon the dorsum of the ilium is thesecond lumbar, and following that there are met succes-sively, from before backward, the remaining lumbar andthe first and second sacral myotomes. The arrangementof these myotomes upon the dorsal surface of the pelvisand the muscles to which they contribute may be seenfrom Fig. 117. In this portion of their course they repre-sent portions of the dorsal half of the loops, the remainingportions extending downward on the anterior surface of the =34 THE DEVELOPMENT OF THE HUMAN BODY. leg. Only the sacral myotomes, however, extend through-out the entire length of the limb into the foot, the secondlumbar myotome extending down only to about the middleof the thigh, the third to about the knee, the fourth toabout the middle of the tibial region, and the fifth as faras the base of the fifth metatarsal bone. Each of these dm. Fig. 116.—Diagram of a Segment of the Body and Limb. bl, Axial blastema; dm, dorsal musculature of body; rl, nerve to limb; s, septum between dorsal and ventral musculature; , dorsal layer of limb musculature; and , dorsal and ventral divisions of a spinal nerve; vm, ventral musculature of the body.—{Kollmann.) myotomes at the point indicated bends toward the innerside of the leg and passes upward again on its posterior sur-face toward the trunk, representing in this portion of itscourse the ventral portion of the loop. The two sacralmyotomes can be traced into the foot, the first giving rise THE LIMB MUSCLES. 235 to the musculature of the inner portion and the second to//
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectembryol, bookyear1902
