60 THE ANATOMY OF THE HORSE. 



this course it corresponds to the interstice between the gracilis and 

 Bar tori us muscles, and is covered by the deep inguinal lymphatic glands. 

 It is closely related to the femoral vein, which lies beneath and slightly 

 posterior to it, except at the brim of the pelvis, where the vein is 

 immediately posterior to the artery. In the present stage of tn"e 

 dissection the vessel disappears between the upper and lower insertions 

 of the adductor magnus, where it will subsequently be followed. The 

 following collateral branches of the femoral are here seen : — 



1. The Profunda or Deep Femoral Artery. This branch is given 

 off under Poupart's ligament at the pelvic brim. At its origin it 

 usually forms a short common trunk with the prepubic artery. It 

 passes downwards and backwards under the pectineus, and will be 

 followed in the next stage of the dissection. 



2. Muscular Branches. The largest of these is a vessel of consider- 

 able size for the supply of the quadriceps extensor cruris muscle. It 

 comes off at about the same level as the profunda, which it generally 

 exceeds in volume ; and, passing over the psoas magnus and iliacus, and 

 under the sartorius, it penetrates between the rectus femoris and vastus 

 internus, in company with the anterior crural nerve. Other innominate 

 arteries of smaller size enter the vastus internus, pectineus, gracilis, 

 sartorius, and adductors. 



3. The Saphena Artery already described (page 58). 



4. The Nutrient Artery of the Femur is given off at the tendon 

 of insertion of the pectineus. 



5. An Articular brauch, of slender volume, descends between the 

 vastus internus and adductor magnus to the stifle-joint. 



The Femoral Vein ascends in close company with the artery, and, 

 receives branches which correspond more or less closely to those just 

 described. At the brim of the pelvis it lies posterior to the artery, and 

 is continued upwards as the external iliac vein. 



The Anterior Crural Nerve (Plate 13) is derived from the lumbo- 

 sacral plexus. It descends between the psoas magnus and parvus; and, 

 passing over the common termination of the iliacus and psoas magnus, 

 where it is covered by the sartorius, it splits into a bundle of branches 

 that together penetrate between the vastus internus and rectus femoris to 

 supply the mass of the quadriceps extensor cruris. While under cover of 

 the sartorius it gives off the internal saphena nerve already described. 



Directions. — The pectineus, adductor parvus, adductor magnus, and 

 semimembranosus muscles are now to be cleaned and isolated. These 

 muscles succeed each other from before to behind in the order named. 

 Some little difficulty may be experienced in finding the line of separa- 

 tion between the two adductors, but a reference to Plate 13 will prove 

 of some assistance. Moreover, the fibres of the small adductor are of a 

 paler colour than those of the adductor magnus. 



