THE LIMBS OF THE HORSE 125 



from an oblique groove on the ventral surface of the puhis, and enters 

 the joint cavity through the acetabular notch dorsal to the transverse 

 ligament, to blend with the femoral attachment of the round ligament. 



The articulation between the acetabulum and the head of the femur 

 being of the nature of a ball-and-socket joint, the range of movement 

 in it is considerable. Flexion and extension, abduction and adduction, 

 circumduction, and rotation are all possible, but not in like degree. 

 The movements of liexion and extension are most free, while abduction 

 is limited by the round and accessory ligaments, and adduction is 

 similarly restricted by the close association of the gluteal muscles with 

 the joint. 



Dissection. — The anterior, lateral, and posterior aspects of the leg are 

 occupied by a thick layer of muscles closely invested by stout fascia. 

 In consequence, it is impossible to distinguish the boundaries of the 

 various muscles by palpation in the proximal half of the leg. The 

 medial surface, on the contrary, carries no muscles, with the result that 

 the flat surface of the tibia can readily be felt through the skin. 



As the tarsus is approached, the tendons of some of the muscles 

 become sufficiently obvious to permit of ready recognition. For 

 example, the tendon of Achilles (gastrocnemius and plantaris tendons) 

 is visible in its relation to the tuber of the calcaneus, a hollow on each 

 side of the limb giving it greater prominence. A sharp fold of skin on 

 the flexor aspect of the tarsus is also a prominent feature of the super- 

 ficial anatomy of the limb, and marks the position of the tendons of 

 the peroneus tertius, long digital extensor, and anterior tibial muscles. 



A horny callosity ("chestnut"), similar to that present in the distal 

 part of the forearm, projects from the skin over the distal part of the 

 medial surface of the tarsus. 



The skin should be removed from the whole of the leg and tarsus, 

 and as far in a distal direction as the junction of the proximal and 

 middle thirds of the metatarsus. 



Care must be taken not to injure the superficial veins and the 

 cutaneous nerves. 



V. saphena. — The origin of the saphenous vein as the medial dorsal 

 vein of the metatarsus is now exposed. The vein crosses the flexor 

 aspect of the tarsus, and then runs up the medial aspect of the leg 

 and thigh in order to reach the apex of the femoral triangle. Near 

 the tarsus the saphenous vein is connected with the anterior tibial, 

 and in the proximal third of the leg it is joined by the recurrent 

 tibial vein. 



V. kecurkens tibialis. — The recurrent tibial begins at the tarsus 

 as the continuation of the lateral plantar metatarsal vein. Near its 

 origin it is connected with the posterior tibial and recurrent tarsal 

 veins. It follows the medial border of the tendon of Achilles and the 

 medial head of the gastrocnemius muscle to join the saphenous vein 

 in the proximal part of the leg. Union with either the posterior 



