70 



THE ANATOMY OF THE HORSE. 



The Flexou Metatarsi (fig. 3). Tliis muscle consists of two parallel 

 portions — a superficial and a deep. The superficial division exists in 

 the fonn of a tendinous cord with little or no 

 muscular tissue, and arises, in common with the 

 extensor pedis, from the pit between the trochlea 

 and external condyle of the fenmr. This tendon 

 of origin passes through the notch between the 

 anterior and external tuberosities at the upper 

 end of the tibia, and is there enveloped by the 

 -B synovial membrane of the femoro-tibial joint. In 

 the leg the tendinous cord rests on the deep 

 division of the muscle, and passes under the 

 annular band at the lower extremity of the tibia, in 

 company with the tendon of the extensor pedis. 

 At the front of the hock it is perforated by the 

 tendon of the deep division, and then bifurcates, 

 one branching continuing do^\'nwards to be inserted 

 into the upper extremity of the large metatarsal 

 bone, the other deviating outwards to be inserted 

 into the cuboid. 



The deejy division of the flexor metatarsi rests on 

 the tibia, and its muscular fibres arise from the 

 upper part of the outer surface of that bone. At 

 the lower end of the tibia it is succeeded by a 

 tendon which perforates that of the superficial 

 division of the muscle, and divides, one branch 



Flexor Mktat.rsi Muscle P'^^^"^8^ ^^ ^^ tWr<^(^ iutO the head of the large 



(Chauieau). metatarsal bone, along wuth the large division of 



1. Superficial division of ^j^^ superficial cord, while the other branch is 

 carried inwards to bo inserted into the cuneiform 

 parvum. 



Action. — To flex the hock. In this action the 

 superficial tendinous cord plays merely a mechanical 

 part, flexing the liock when the stifle is flexed. 



The External Popliteal Nerve (Plate 18). 



This nerve has already been seen in the hip and 



thigh. It is a branch given off by the great sciatic; 



and, descending in front of the parent nerve, it 



passes between the biceps and the outer head of the gastrocnemius, 



where, a little behind the external lateral ligament of the stifle, it 



divides into the musculo-cutaneous and anterior tibial nerves. 



The MuscuLO-CuTANEOus Nerve descends along the line of contact 

 of the extensor pedis and peroneus, supplying filaments to the latter 

 muscle. At the lower tliird of the leg, as has already been seen, the 



Fig. 3. 



the muscle; 2. Its origin 

 from the femur ; 3. Its 

 cuboid branch ; 4. Its 

 metatarsal branch ; 5. 

 Deep division of the 

 muscle ; ti. Its tendon 

 passing through that of 

 the sui)ei-ficial division ; 

 7. Cuneiform branch of 

 this tendon ; 8. Metatarsal 

 branch of the same ; \K 

 Extensor pedis ; A. Pero- 

 neus ; B. Insertion of 

 middle straight patellar 

 ligament ; C. Femoral 

 trochlea. 



