THE MUSCLES OF THE LEG AND FOOT 337 
Insertion.—(1) The ridge on the front of the proximal end of the large meta- 
tarsal bone; (2) the first and second tarsal bones. 
Action.—To flex the hock joint. 
Structure—The origin is fleshy, and forms a groove in which lie the common 
tendon of the long extensor and peroneus tertius and a synovial pouch which de- 
scends from the femoro-tibial joint. Many superficial fibers arise from the deep 
fascia at the proximal part of the leg and thus from the tibial crest. Passing down- 
ward on the tibia, the belly is united by tendinous and fleshy fibers with the per- 
oneus tertius, and terminates close to the tarsus in a point on the tendon of inser- 
Fic. 294—Insectep SyNoviaL SHEATHS AND Burs Fie. 295.—Inyectep SynoyiaL SHEATHS AND BURS® 
or Tarsat Recron or Horse; Meprau VIiEw. or Tarsat ReGIon oF Horse; LATERAL VIEW. 
a, Synovial sheath of peroneus tertius and tibialis a, Synovial sheath of long digital extensor; 6, 
anterior; }, bursa under medial (cunean) tendon of synovial sheath of lateral digital extensor; c, c’, bursa 
tibialis anterior; c, synovial sheath of flexor longus; under superficial flexor tendon; d, capsule of hock joint; 
d, tarsal sheath of deep flexor; e, e’, bursa under 1, long extensor; 2, lateral extensor; 3, 3, 3, annular 
superficial flexor tendon; /, f’, tibio-tarsal joint capsule; ligaments; 4, deep digital flexor; 5, tendon of gastroc- 
1, long extensor; 2, tibialis anterior; 2’, medial (cun- nemius; 6, superficial flexor tendon; 7, tibia; 8, tarsus; 
ean) tendon of 2; 3, flexor longus; 4, deep digital 9, tuber calcis; 10, metatarsus. (After Ellenberger, 
flexor; 5, superficial flexor tendon; 6, gastrocnemius in Leisering’s Atlas.) 
tendon; 7, tibia; 8, tarsus; 9, tuber calcis; 10, large 
metatarsal bone; 17, medial small metatarsal bone; 
12, 12’, fascial bands. (After Ellenberger, in Leisering’s 
Atlas.) 
tion. The latter emerges between the branches of the peroneus tertius and bi- 
fureates, the anterior branch being inserted into the large metatarsal bone, the 
medial one into the first tarsal bone. The tendon is provided with a synovial sheath 
at its emergence, and a bursa is interposed between the medial branch and the 
medial ligament of the hock. 
Relations.—Superficially, the long and lateral extensors, the peroneus tertius, 
and the deep peroneal nerve; deeply, the tibia, the deep flexor, and the anterior 
tibial vessels. 
‘In surgical works the medial branch is termed the cunean tendon; it is sometimes resected 
or the relief of bone spavin. 
22 
