THE HIND EXTREMITY. 259 



ischio-femoralis), divides into three portions. The siqw- 

 rior runs to the outer surface of the patella, the middle to 

 the outer surface of the tibia and the outer straight liga- 

 ment of the patella, blending with the faschia lata, the 

 ■inferior is said to blend with gastrocnemius externus, biit 

 careful examination shows that it joins the white fibrous 

 tissue layer, which arises from a ridge in common with 

 that muscle, and with this runs to form that firm tendinous 

 band into which plantaris passes, and which extends to the 

 point of the hock. 



Biceps rotator tibialis arises from the superspinous liga- 

 ment and the transverse process at the posterior part of the 

 sacrum, like the other muscles of the region, somewhat in- 

 definitely. It forms a considerable portion of the fleshy mass 

 of the quarter, and in its course down the limb receives a 

 branch of equal size from the tuberosity of the ischium. 

 Through thus reinforced, it forms a somewhat small tendon, 

 wliich winds round the smooth internal surface of the tibia, 

 where it is lubricated by synovia to reach the sharp ridge 

 on the antero-superior part of that bone. From this tendon 

 also a white fibrous band runs to the hock. This muscle is 

 also termed semi-tendinosus. Posteriorly it is in contact 

 with semi-memhranosus or 



IscMo -tibialis, the muscle which forms the prominence 

 at the posterior part of the quarter. This muscle arises 

 mainly from the tuberosity of the ischium, but superiorly 

 sends a thin band in an upward direction to be attached to 

 the sacro-ischiatic ligament and to the posterior sacral and 

 the anterior coccygeal bones. Inferiorly it passes to the 

 internal surface of the inferior extremity of the femur 

 and of the head of the tibia, and the lateral ligament which 

 connects them. It also sends a band of white fibrou-^ 

 tissue to unite with that of biceps rotator tibialis and 

 run to the point of the hock. By removal of the three 

 last-mentioned muscles we expose superiorly, up at the 

 lateral part of the spine, the coccygeal muscles enveloped 

 in a white fibrous tissue sheath. Below this the sacro- 

 sciatic and the sacro-ischiatic ligaments, on the external 

 surface of which are to be seen the gluteal and sacro- 

 sciatic nerves, and the gluteal arterial branches which 

 emerge from the jDelvis through foramina in the liga- 

 ment. At the infero-posterior part we see certain muscles 

 winding round the neck of the ischium to become inserted 



