THE MUSCLES OF THE LEG AND FOOT 



29C 



tibia to the middle of the tarsus. A subcutaneous bursa is sometimes found on 

 the wide part of the tendon at the point of tlie hock. (Either or })oth of these 

 bursas may be involved in so-called "capped hock.") 



Relations. — Posteriorly, the gastrocnemius, fascia, and skin; anteriorly, the 

 femoro-patellar capsule, the popliteus, the deep flexor, and the popliteal vessels; 

 internally, the tibial nerve. 



Blood-supply. — Femoro-popliteal artery. 



Nerve-supply. — Tibial nerve. 



4. Deep digital flexor or flexor pedis perforans (M. flexor digitalis pedis pro- 



f 



Fig. 206. — Injected Synovial Sheaths and BtjrS/E 

 OF Tarsal Region of Horse, External View. 

 a. Synovial sheath of anterior or long digital 

 extensor; h, synovial sheath of lateral digital exten- 

 sor; c, c', bursa under superficial flexor tendon; d, 

 capsule of hock joint; /, anterior or long extensor; 

 2, lateral extensor; S, 3, 3, annular ligaments; 4, 

 deep digital flexor; o, tendon of gastrocnemius; 6, 

 superficial flexor tendon; 7, tibia; S, tar.sus; 9, tuber 

 calcis; 10, metatarsus. (After EUenberger, in Leiser- 

 ing'a Atlas.) 



Fig. 20.5. — Injected Synovi.\l Sheaths and Burs.b 



OF T.4.RSAL ReGIO.N OF HoRSE, InNER ViEW. 



a, Synovial sheath of peroneus tertius and 

 tiliialis anterior; b, bur.sa under inner (cunean) tendon 

 of tibialis anterior; c, synovial sheath of flexor longus 

 s. accessorius; d, tarsal slieath of deep flexor; e, e', 

 bursa under superficial flexor tendon; /, /', tibio-tarsal 

 joint capsule; 1, anterior extensor; 2, tibialis anterior; 

 2', inner (cunean) tendon of 2; 3, flexor longus; 4, 

 deep digital flexor; 5, superficial flexor tendon; 6, 

 gastrocnemius tendon; 7, tibia; S, tarsus; 9, tuber 

 calcis; 10, large metatarsal bone; 11, inner small 

 metatarsal bone; 12, 12', fascial bands, (.\fter EUen- 

 berger, in Leisering's Atlas.) 



fundus; deep and oblique flexors of the phalanges). — The belly of this muscle lies 

 on the posterior surface of the tibia, and is divisible into three parts or heads, 

 which, however, finally unite on a common tendon of insertion. 



Origin. — (1) The posterior edge of the external condyle of the tibia; (2) the 

 external border of the external condyle of the tibia, just behind the facet for the 

 fibula; (3) the middle third of the posterior surface and the upper part of the ex- 

 ternal border of the tibia, the posterior border of the fibula, and the interosseous 

 ligament.^ 



^ The origins of these heads are given in the order in which they may be most conveniently 

 dissected, not in order of size and importance. 



