1334 



HUMAN ANATOMY. 



d. The nerve to the short head of the biceps (Fig. 1115) apparently arises from the lateral 

 margin of the upper part of the great sciatic nerve. The fibres comprising it can be traced back 

 to the fifth lumbar and first and second sacral nerves, sometimes in combination with the roots 

 of the inferior gluteal nerve. Leaving the great sciatic in the middle of the thigh, often as a 

 common trunk with the articular branch, it enters the substance of the short head of the biceps. 



Gluteus 

 maximus 



Br. from V. 



lumbar nerve 



I. sacral nerve. 



posterior division 



Cutaneous hr. 



from loop of 



posterior sacrals 



II. sacral nerve, 



posterior division 



III. sacral ne 

 posterior division 



IV. sacral nerve 

 posterior division 



Cutaneous br. 

 from loop ol pos- 

 terior sacral 

 nerves 



r.reat sacro- 

 sciatic ligament 



Nerve to obtu- 

 rator interims 

 Cutaneous and 

 muscular branch 

 of IV. ant. sacral 



Small sciatic 

 nerve 



Tuberosity 

 of ischium 



Inferior pti- 

 deudal nerve 



Gluteus 

 medius 



Tensor fasciae latae 

 'Uperior gluteal 



nerve 

 Gluteus minimus 



Pyriformis 



Trochanter major 

 Nerve to quadralus 



femoris 



Tendon of obturator internus 

 with Kemellussuperiorabo 

 Gemellus interior 



Branch to hipjoint 



Inferior gluteal 



nerve 

 Quadratus femoris 



Great sciatic 

 nerve 



Deep dissection of right buttock, showing emergence of great sciatic nerve below pyriformis muscle; also 

 muscular branches and posterior divisions of sacral nerves. 



4. The articular branches supply the knee and are usually two in number. 

 The upper arises either in common with the nerve to the short head of the biceps or 

 independently from the lateral portion of the great sciatic. Descending- on the pos- 

 terior surface of the femoral head of the biceps it passes between the external condyle 

 of the femur and the tendon of the biceps and supplies the lateral portion of the 

 capsular ligament of the knee. The lower arises from the external popliteal nerve 

 in the upper portion of the popliteal space and divides into two portions which 

 supply the lateral and posterior portions of the capsular ligament of the knee. From 

 the branch to the posterior part of the capsule is given off a tiny thread to the 

 superior tibio-fibular articulation. 



TERMINAL BRANCHES. 



The terminal branches of the sacral plexus arc the external and the internal 

 popliteal, and these are usually fused in the upper part of their course into the great 

 sciatic nerve. 



