THE ANTERIOR LIMB 257 



into either the right or the left vessel opens the unpaired median 

 sacral vein. The seventh pair of lumbar veins opens into the 

 dorsal side of the common hypogastric vein. 



4. The external iliac vein (v. iliaca externa), the continuation of 

 the femoral vein of the thigh, approaches the inferior cava 

 from the dorsal side of the inguinal ligament. It receives the 

 inferior epigastric vein from the abdominal wall and the vesical 

 vein from the bladder, the latter accompanying the umbilical 

 artery and receiving in the female also the veins of the uterus. 



0. The sympathetic trunk (truncus sympathicus). Its lumbar and 

 sacral portions, and, with due care, its caudal portions may be 

 traced on either side by working between the abdominal aorta 

 (or its continuation, the median sacral artery) and the body- 

 wall. Except on the ventral surface of the sacrum, the ganglia 

 of opposite sides lie close together. The lumbar portion of each 

 trunk comprises seven ganglia with their connections. The 

 ganglia lie on the lateral surfaces of the lumbar arteries near 

 the points where the latter disappear dorsally in the body-wall. 

 The rami communicantes may be found passing from the 

 ganglia toward the spinal nerve-roots. The sacral portion 

 comprises four ganglia of which the first is much larger than the 

 others. The caudal portion of each trunk comprises two minute 

 ganglia and an unpaired terminal ganglion unites the two 

 trunks. 



VIII. THE ANTERIOR LIMB 

 For this dissection the skin must first be reflected from the 

 lateral surface of the limb and the side of the neck to the dorsal 

 median line. It is advisable at first to divide the skin at the elbow, 

 leaving the forearm and hand covered, so that the tendons of the 

 muscles do not become dried out before they can be examined. 



Covering the side and ventral surface of the neck is a broad thin 

 sheet of muscle, the platysma, replacing the cutaneus maximus of 

 the trunk. It forms a continuous layer over the dorsal surface of 

 the neck, at which place it is also^ continuous with the cutaneus 

 maximus. Passing forward from the manubrium sterni is a narrow 

 band of fibres, closely associated with the platysma but lying be- 

 neath it, the depressor conchae (parotideoauricularis) posterior, 



