22 THE SURGICAL ANATOMY OF THE HORSE 



The Ligaments 



The Internal Straight Ligament (6) of the patella is seen to be 

 much more tense than was the outer ligament. This is due to the 

 position of the patella. The ligament runs from the anterior surface of 

 the patella to the inner division of the anterior tuberosity of the tibia. 

 The internal lateral ligament of the stifle is, as already stated, covered by 

 the insertion of the gracilis. 



The Great Suspensory Ligament is plainly visible, and makes its first 

 appearance a short distance below the hock. Behind the ligament is 

 the perforans tendon. The ligament is crossed upwards and forwards by 

 the internal metatarsal vein. Above the fetlock, as already described, it 

 divides into two portions, and the inner branch is seen to cross this aspect 

 of the fetlock joint and to join the extensor pedis tendon in a manner 

 resembling that of the outer branch. 



The inner portions of the three annular bands already referred to are 

 now seen. Underneath the most superior of the bands the tendons of 

 the flexor metatarsi and extensor pedis muscles run, whilst the remaining 

 two bands arch over the tendon of the last-named muscle only. 



Muscles and Tendons 



The Quadriceps Extensor Cruris. — Of these muscles only the inferior 

 third of the vastus internus and of the inner portion of the rectus femoris 

 is represented (i). Their insertion, action, and nerve-supply have already 

 been given. 



The Gracilis (2). — The inferior third of this muscle is shown as a 

 broad, flat sheet, which conceals to a great extent the corresponding 

 portion of the sartorius. The gracilis arises from the ischio-pubic 

 symphysis, and is inserted into the internal tuberosity of the tibia. It 

 is a powerful adductor of the limb, and derives its nerve-supply from the 

 obturator nerve. 



