4G6 THE MUSCULATURE 



In the proximal part of the thigh the anterior group of muscles is separated 

 from the medial group by the ilio-psoas muscle (fig. 411) and by the femoral 

 blood-vessels and nerve, and from the posterior group by the gluteus maximus 

 (fig. 413). More distally it is separated from the medial group by the medial 

 intermuscular septum and from the posterior by the lateral intermuscular septum 

 (see p. 468). The medial and posterior groups are closely associated. The 

 adductor magnus belongs ontogenetically to both. 



The three groups of muscles, with numerous modifications, are represented in the thighs 

 of amphibia and all higher vertebrates. In the human arm they are Ukewise represented, the 

 adductor group in a much reduced form by the coraco-brachiahs. The quadriceps is represented 

 by the triceps in the arm, the long head of the triceps corresponding with the rectus femoris. 

 The hamstring muscles are represented by the biceps and the brachialis. 



FASCIA 



The fasciae and the relations of the musculature of the thigh may be followed in the cross- 

 sections figs. 407, 410, 414. 



The tela subcutanea of the thigh varies considerably in thickness in different regions, 

 but is well developed throughout and contains a considerable amount of fat. Over the front 

 of the thigh, especially in the upper medial region, one or more deeper membranous layers 

 may usually be separated from the superficial adipose layer. Between the former and the 

 latter are situated the inguinal lymphatic nodes and the saphenous vein. The deepest layei 

 near the inguinal (Poupart's) ligament is fused with the fascia lata (see below). Medially it 

 is attached to the pubic arch. Thus fluids beneath the tela subcutanea of the abdomen and 

 perineum do not readily pass into the region of the thigh. 



Over the lower half of the patella a subcutaneous bursa (b. praepatellaris subcutanea) is 

 found. Another is usually found over the upper end of the patellar ligament (b. infrapatellaris 

 subcutanea). 



The muscles of the thigh are enclosed in a dense fascial sheet, the fascia lata (figs. 387, 410). 

 The gluteal portion of this and the ilio-tibial band have already been described (p. 457). The 

 ventral portion of the fascia, composed chiefly of transverse fibres, is a dense, fibrous membrane. 

 Above it is attached to the inguinal ligament from the anterior superior spine to the pubic 

 tubercle. Below it extends over the knee, where it is united to the capsule of the joint and is 

 strengthened by expansions from the vastus lateralis and medialis. Between the front of the 

 patella and the fascia is a bursa (b. praepatellaris subfascialis). Above the knee the fascia is 

 strengthened by an arciform process which extends obliquely distally across the fascia from the 

 ilio-tibial band to the capsule of the knee. This gives rise to a fold in the skin when the leg is 

 extended and the muscles are not tense. Over the medial and posterior regions of the thigh 

 the fascia is less dense. It extends from the body and inferior ramus of the pubis, the inferior 

 ramus and tuber of the ischium, and the sacro-tuberous ligament into the fascia of the back 

 of the leg. Above the pophteal space it is strengthened by a transverse band of fibres. Near 

 the knee the tendons of the quadriceps, sartorius, gracilis, and semitendinosus become bound 

 to the fascia by membranous laminse. 



The relations of the fascia lata to the inguinal ligament and the iliac fascia are somewhat 

 complex. The fascia of the ilio-psoas muscle extends over the muscle to its femoral insertion. 

 Above the inguinal ligament this fascia is called the fascia iliaca; below the ligament, the fascia 

 ilio-pectinea. This fascia is firmly united to the lateral extremity of the inguinal ligament. 

 The pectineus muscle is likewise invested with a fascial membrane which extends over the 

 muscle from the pubis to the femur and is fused laterally with that of the ilio-psoas. This 

 combined fascia is firmly bound between the two muscles to the ilio-pectineal eminence. The 

 ilio-pectineal fascia divides the space beneath the inguinal ligament into a lateral lacuna 

 musculorum, which contains the ilio-psoas muscle and the femoral (anterior crural) nerve, and 

 a medial lacuna vasorum, which contains the femoral artery and vein. Medial to the vein 

 is the femoral ring, bounded medially by the lacunar (Gimbernat's) ligament. This is closed 

 off from the abdominal cavity by a septum derived from the transversalis fascia, the femoral 

 septum, but offers passage for lymph-vessels. 



a and b in the diagram indicate the regions through which pass sections A and B, fig. 407 (p. 458); 

 1. Arteria circumflcxa femoris lateralis. 2. A. circumflexa femoris medialis. 3. A. fem- 

 oralis. 4. A. femoralis profunda. 5. A. glutea inferior (sciatic). 6. A. poplitea. 7. Bursa 

 prajpatellaris subfascialis. 8. Adductor (Hunter's) canal. 9. Fascia lata. 10. Femur — a, 

 distal extremity. 11. Funiculus spermaticus (spermatic cord). 12. Musculus adductor 

 brevis. 13. M. adductor longus. 14. M. adductor magnus. 15. M. biceps fcmoris^a, 

 long head; b, tendon of origin; c, short head. 10. M. gastrocnemius — a, lateral head; b, medial 

 head. 17. M. gluteus maximus. 18. M. gracilis — a, tendon. 19. M. rectus femoris — a, 

 tendon. 20. M. sartorius. 21. M. semimembranosus — a, tendon. 22. M. semitendinosus 

 — a, tendon. 23. M. sphincter ani. 24. M. vastus intermedins (crureus) — a, tendon. 25. 

 M. va,stus lateralis — a, tendon. 26. M. vastus medialis — a, tendon. 27. Nervus cutaneous 

 femoris anterior. 28. N. cutaneous femoris posterior (small sciatic). 29. N. gluteus inferior. 

 .30. N. obturatoriu.s — a, superfifnal branch; 1), deep Ijranch. 31. N. peroneus communis 

 (external popliteal). 32. N. sapluinus (groat saphenous). 33. N. tibialis (internal popliteal). 

 34. Patella. 35. Septum intx^rniusculare iaicrale. 30. Septum intermusculare mediale. 37. 

 Tractus iliotibialis (ilio-tibial band). 38. Vena femoralis. 39. Vena poplitea. 40. V. 

 eaphena magna (great saphenous vein). 



