. Cunningham's Text-book of anatomy. Anatomy. MOKPHOLOGY OF THE LIMB-PLEXUSES. 741 the medial side of the lower liinb. Apart from this break in their distribution, a definite numerical order may be followed in the arrangement of the perineal nerves. The higher parts of the perineum are innervated by the higher spinal nerves; the lower parts, by the lower nerves. This is best exemplified in the distribution of the cutaneous nerves. The base of the penis and scrotum (or mons Veneris) is supplied by the first lumbar nerve (ilio-inguinal). The dorsal nerve of the penis (or clitoris), when traced b
. Cunningham's Text-book of anatomy. Anatomy. MOKPHOLOGY OF THE LIMB-PLEXUSES. 741 the medial side of the lower liinb. Apart from this break in their distribution, a definite numerical order may be followed in the arrangement of the perineal nerves. The higher parts of the perineum are innervated by the higher spinal nerves; the lower parts, by the lower nerves. This is best exemplified in the distribution of the cutaneous nerves. The base of the penis and scrotum (or mons Veneris) is supplied by the first lumbar nerve (ilio-inguinal). The dorsal nerve of the penis (or clitoris), when traced back to the pudendal plexus, is found to come from the second, and to a less extent from the third sacral nerves; the scrotal nerves (perineal branches of the pudendal and posterior cutaneous nerve of the thigh) similarly arise from the third, and to a less extent from the second sacral nerves ; the skin of tbe ischio -rectal fossa and anus is innervated by the inferior haemorrhoidal (third and fourth sacral nerves), and the perineal branch of the fourth sacral nerve. The ano-coccygeal nerve (coccygeal plexus), lastly, supplies the skin round the coccyx (fourth and fifth sacral and coccygeal nerves). Judged from its nerve supply the perineum is to be regarded as occupying, for the most part, a position behind or more caudal than that of the lower limb in re- lation to the trunk. There is here a remarkable gap in the numerical sequence of the nerves supplying the ventral axis of the body. All the nerves between the first lumbar and the second sacral fail to reach the mid ventral line of the trunk and are wholly concerned in the innervation of the lower limb. At the preaxial border of the limb (groin) the first lumbar nerve, the highest nerve supplying the perineum, is concerned also in innervating the skin of the limb. At the postaxial border of the limb (fold of the nates and back of the thigh), the nerves which are the highest of those con- stituting the pudendal plexus (the se
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
