ABNOKMALITIES OF AETEEIES. . 1057 



takes place. If exceptionally long, it is usually tortuous. In rare cases in man the artery is 

 absent. It occasionally gives off .the middle or a lateral sacral artery, and ilio-lumbar, spermatic, 

 or accessory renal branches may arise from it. 



The hypogastric artery varies as regards length. It is usually longer, and arises at a 

 higher level when the common iliac is short. In rare cases it has been found to arise from the 

 aorta without the intervention of a common iliac. Frequently it does not, even in appearance, 

 end in anterior and posterior divisions, but obviously forms a single trunk, as in the foetus, from 

 which the several branches are given off. 



The visceral branches vary much in number and size, and the middle haemorrhoidal may not 

 be present, its place being taken by branches from the vesical arteries. A renal branch some- 

 times arises from the hypogastric artery. 



The ilio-lumbar branch may arise from the common iliac instead of from the hypogastric artery ; 

 the superior glutaeal and inferior glutseal arteries may arise by a common stem, or the superior 

 glutseal may be absent, and its place taken by a branch from the femoral artery ; the inferior 

 glutseal artery may, as in the fcetus, constitute the main artery of the lower limb, and run distally 

 to become continuous with the popliteal artery. Probably the arteria comitans nervi ischiadici 

 represents the original continuity of the two vessels. Occasionally the lateral sacral arteries do 

 not arise from the hypogastric trunks. 



In some instances the obturator artery arises from the' inferior epigastric artery instead of 

 from the hypogastric. The condition is apparently due to obliteration of the usual origin of the 

 obturator artery and to the subsequent enlargement of the anastomosing pubic branches of the 

 obturator and inferior epigastric arteries. The course of the abnormal obturator artery is of 

 importance. From its origin it descends, into the pelvis minor, on the medial side of the external 

 iliac vein, and in the majority of cases on the lateral side of the crural ring, but in three-tenths 

 of the cases, and more frequently in males than in females, it descends on the medial side of the 



The obturator artery sometimes gives off an accessory pudendal branch which passes along 

 the side of the prostate, pierces the urogenital diaphragm, and terminates by dividing into the 

 profunda artery of the penis and the dorsal artery of the penis. When this occurs the internal 

 pudendal artery is small, and it terminates in the artery to the bulb. Occasionally the accessory 

 pudendal arises from the internal pudendal artery in the pelvis, or from one of the vesical arteries. 



The external iliac artery may be much smaller than usual, especially if the inferior glutseal 



artery persists as the main vessel of the lower limb. It may give off two deep circumflex iliac 



branches, a dorsal artery of the penis, a medial circumflex artery of the thigh, or a vas aberrans, 



and its deep circumflex iliac and inferior epigastric branches may arise at higher or lower levels 



, than usual. 



THE ARTERIES OF THE LOWER LIMB. 



The femoral artery is small, and ends in the profunda and circumflex branches, when the 

 inferior glutseal artery forms the principal vessel of the lower limb. The profunda branch, which 

 arises usually from the lateral side of the femoral trunk, about 37 mm. (1^ in.) distal to the 

 inguinal ligament, may commence at a more proximal or a more distal level, and from the back 

 or the medial side of the femoral trunk. In rare cases when the profunda arises at a more 

 proximal level than usual it may cross anterior to the femoral vein, above the entrance of the 

 . great saphenous vein, after which it passes distally and laterally posterior to the femoral vessels 

 (Johnston, Anat. Anz., Bd., 42, 1912). Absence of the profunda has been noted, and in those 

 cases the branches usually given off by it spring directly from the femoral artery. 



The femoral artery may be double for a portion of its extent, or it may be joined by a vas 

 aberrans given off from the external iliac artery. In addition to its ordinary branches, it may 

 furnish one or both of the circumflex arteries of the thigh, and sometimes it gives off, near the 

 origin of the profunda, a great saphenous artery, such as exists normally in many mammals. 

 This vessel runs distally through femoral trigone and the adductor canal, and accompanies the 

 saphenous nerve to the medial side of the foot. 



The deep circumflex iliac, the obturator, and the inferior epigastric arteries are occasionally 

 given off from the femoral. 



The popliteal artery may exceptionally form the direct continuation of the inferior glutseal 



artery. It sometimes divides at a more proximal or more distal level than usual, and the 



i vision may be into either two or three branches ; if three terminal branches are present, they 



are the anterior and posterior tibial and the peroneal arteries, and if only two, either the 



anterior and posterior tibial, or the anterior tibial and the peroneal arteries. 



Occasionally the artery is double for a short portion of its course, and it has been found to 

 cross first posterior to the medial head of the gastrocnemius to the medial side of the knee, and 

 then anterior to the medial head of the gastrocnemius to regain the popliteal fossa. The 

 number of its branches may be reduced, or they may be increased by the addition of a vas 

 aberrans which connects it with the posterior tibial artery. Its superficial sural branch may 

 enlarge to form a well-marked small saphenous artery. 



The posterior tibial artery may be small or altogether absent, its place being taken by 



tranches of the peroneal artery ; again, it may be longer or shorter than usual, in conformity with 



te more proximal or more distal division of the popliteal trunk. The peroneal artery is large, 



ither the anterior or the posterior tibial artery is small. The perforating branch of the 

 peroneal is almost invariably large when the anterior tibial artery is small; in some cases, 



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