282 FASCIA AND MUSCLES OF THE HORSE 



branosus and semitendinosus, and, at the middle of the femur, the femoral vessels; 

 anteriorly, the sartorius. In the upper third of the thigh the sartorius and gracilis 

 are separated by a triangular interval (femoral triangle), in which lie the deep 

 inguinal lymph glands and the femoral vessels. 



Blood-supply. — Femoral and deep femoral arteries. 



Nerve-supply. — Obturator and saphenous nerves. 



Second Layer 



1. Pectineus (Figs. 186, 451, 456). — This muscle is fusiform and extends from 

 the anterior border of the pubis to the middle of the inner l^order of the femur. 



Origin.— The prepubic tendon, the pubo-femoral ligament, and the anterior 

 border of the pubis. 



Insertion. — -The middle of the internal border of the femur, near the nutrient 

 foramen. 



Action. — To adduct the limb and flex the hip joint. 



Structure. — The belly is cylindrical and contains little filwous tissue. Its 

 origin is perforated by the pubo-femoral ligament, and is thus divided into two 

 unequal parts. The large upper part arises mainly from the prepubic tendon 

 — only a very small part gaining direct attachment to the pubis. The small lower 

 part does not reach the bone. The insertion is pointed and tendinous. 



Relations. — Superficially, the gracilis; deeply, the femur, the vastus internus, 

 the terminal tendon of the psoas major and iliacus, and the deep femoral artery; 

 anteriorly, the sartorius, the femoral vessels, the saphenous nerve, and the deep 

 inguinal lymph glands; posteriorly, the adductor, obturator externus, and quadra- 

 tus femoris, and the obturator nerve (anterior division). 



Blood-supply. — Femoral and deep femoral arteries. 



Nerve-supply. — Femoral and obturator nerves. 



The femoral canal is exposed in the dissection of the preceding muscles (Figs. 200, 451). 

 It is bounded anteriorly by the sartorius, posteriorly by the pectineus, and externally by the 

 iliacus and vastus internus. Its internal wall is formed by the femoral fascia and the gracilis. 

 Its upper or abdominal opening (Lacuna vasorum) lies behind and a little internal to the inter- 

 nal inguinal ring and is bounded anteriorly by the inguinal ligament, posteriorly by the ante- 

 rior border of the pubis, and externally by the tendon of the psoas minor. The canal termi- 

 nates below at the insertion of the pectineus. It contains the deep inguinal lymph glands, the 

 femoral artery and vein, and the saphenous nerve. 



2. Adductor^ (Figs. 179, 186,451) (Great and small adductors of the thigh). — 

 This fleshy, prismatic muscle lies behind the pectineus and vastus internus. It 

 extends downward and forward from the ventral surface of the pelvis to the internal 

 condyle of the femur. 



Origin. — The ventral surface of the pubis and ischium and the tendon of the 

 gracilis. 



Insertion. — (1) The posterior surface of the femur from the level of the external 

 trochanter to the groove for the femoral vessels; (2) the internal epicondyle of the 

 femur and the internal lateral ligament of the stifle joint. 



Action. — To adduct the limb and assist in extending the hip joint. It may 

 also rotate the femur outward. 



Structure. — It is almost entirely fleshy, and is composed of parallel bundles 

 united rather loosely. It is usually possible to separate from the principal mass a 

 small anterior short portion,- which is inserted into the femur behind the pectineus. 

 The principal mass^ is perforated below its middle by the femoral vessels, and is 



1 It has been customary to describe two adductors — a parvus or brevis, and a longus or 

 magnus. This division is largely artificial, and has been abandoned in the new nomenclature — • 

 a return to the views of Bourgelat and Girard. 



2 This has been termed by various authors the adductor parvus or brevis. 

 ' Termed by various authors the adductor magnus or longus. 



