522 APPLIED ANATOMY. 



the thigh down. The tendons of the semimembranosus and semitendinosus form 

 the inner hamstring tendons and the biceps the outer hamstring tendon (Fig. 530). 



The adductor muscles are the adductor brevis, adductor longus, adductor 

 magnus, and gracilis ; for clinical purposes the pectineus may also be included, 

 although it is morphologically simply a detached portion of the iliacus. The quad- 

 ratusfemoris and obturator externus belong morphologically to the adductor group, 

 but from a clinical standpoint they are associated more with the external rotators of 

 the hip than the adductors of the thigh. The adductor muscles separate the flexor 

 and extensor groups on the inner side of the thigh. The adductor longus arises 

 by a strong tendon from the body of the pubis just below its spine and inserts into 

 approximately the middle third of the femur in the linea aspera (Fig. 531). When 

 the thigh is abducted the tense edge of its tendon is evident, and if followed upwards 

 it leads to the spine of the pubis. It lies on the same plane as the pectineus, which is 

 immediately above; sometimes, especially in the female, an interval exists between the 

 two through which the adductor brevis may be visible. Near its insertion it forms 

 part of the floor of Scarpa' s triangle and the upper part of the floor of Hunter' s canal. 



The adductor brevis arises from the descending ramus of the pubis just below 

 the origin of the adductor longus and inserts into the femur from the lesser trochanter 

 to the linea aspera. It lies directly behind the upper portion of the adductor longus 

 and in front of the adductor magnus. 



The adductor magnus arises from the ramus of the ischium, from the adductor 

 brevis in front to the hamstring tendons on the tuberosity behind. It is inserted into 

 nearly the whole length of the linea aspera, and by a distinct tendinous band into 

 the adductor tubercle at the upper edge of the internal condyle. Its upper portion 

 is sometimes called the adductor minimus. It is pierced near the bone by the per- 

 forating branches of the profunda femoris artery and near its lower portion by the 

 femoral artery and vein. It forms part of the floor of Hunter's canal. Its homologue 

 in the upper extremity is the coracobrachialis muscle. 



The gracilis arises from the pubis just to the inner side of the adductor brevis and 

 passes straight down the thigh to insert into the tibia, beneath the sartorius and above 

 the semitendinosus. It is sometimes represented in the upper extremity by a slip 

 from the lower border of the pectoralis major called the chondro-epitrochlearis. 



The pectineus arises from the iliopectineal line to insert just behind and below the 

 lesser trochanter. It lies on the same level as the adductor longus and just above it. 



SURFACE ANATOMY. 



If the thigh is flexed and rotated outward the sartorius is seen crossing it obliquely, 

 and Scarpa' s triangle is evident as a depression downward from Poupart's ligament. 

 The muscular mass of the upper inner portion of the thigh is composed of the 

 gracilis and adductor muscles. Immediately above the patella is the flat tendon of 

 the rectus, and above and to the inner side of the patella is a rounded mass formed 

 by the vastus internus (Fig. 532). Running upward and inward from the outer 

 edge of the patella to the middle of the thigh is a groove which separates the rectus 

 and vastus externus. On the outer side a flat groove is formed by the iliotibial 

 band of the fascia lata. At its posterior border is the external intermuscular septum 

 between the vastus externus and biceps. 



Scarpa's Triangle. This occupies approximately the upper third of the 

 thigh. Its base is formed by Poupart's ligament, its outer side by the sartorius 

 muscle, and its inner side by the adductor longus. Its floor is formed by the iliacus, 

 psoas, pectineus, sometimes a portion of the adductor brevis, and the adductor longus 

 muscles. It contains the femoral artery and vein, the anterior crural nerve, the long 

 saphenous vein, and numerous lymphatics (Fig. 533). At its upper and inner part is 

 the saphenous opening, at which femoral herniae make their appearance. Psoas 

 abscesses follow the tendon of the psoas muscle down and make their appearance in 

 Scarpa's triangle, sometimes to one side and sometimes to the other of the artery. 

 Pus from hip-joint disease likewise comes to the front at the upper part of the triangle 

 on one side or the other of the femoral artery. The apex of Scarpa's triangle is a 

 favorite site for ligation of the femoral artery. 



