370 



TEE MUSCLES. 



the contour of the external semilunar cartilage and the posterior portion of the 

 external facet on the tibia. 



Action. — It flexes the tibia, and gives 

 F'g- 204. ii a slight rotatory movement outwards. 



5. Deep Flexor of the Phalanges 

 (Flexor Perforans, Flexor Pe- 

 dis) (Figs. 201, 23 ; 203, 23). 



Synonyms. — Tibio-phalangeus — Girard, 

 The flexor perforans and flexor longus pollicis 

 pedis of Man. (Great tibio-phalangeus — Leyh.} 



Extent — Situation — Direction — Com- 

 position. — Extending from the superior 

 extremity of the leg to the third phalanx,, 

 and situated behind the tibia and foot,, 

 the direction of which it follows, this 

 muscle is composed of a muscular body 

 and a tendon. 



Form, Structure, and Attachments of 

 the muscular portion. — This is thick and 

 prismatic, and incompletely divided into 

 two portions — an internal,^ and an ex- 

 ternal,^ which is the most voluminous. 

 It is attached : 1. To the posterior face 

 of the tibia, on the linear imprints which 

 occupy the inferior triangular surface. 

 2. To the supero-external tuberosity of 

 the same bone. 3. To the peroneus. 

 4. To the interosseous ligament uniting 

 that bone to the tibia. 



Direction and Attachments of the 

 tendon. — The tendon commences above 

 the inferior extremity of the tibia, 

 where it is usually double, each muscular 

 portion being succeeded by a tendon, 

 the volume of which is in harmony with 

 the size of the muscle from which it 

 proceeds. The single tendon resulting 

 from the union of these two primary 

 ones, enters the groove formed by the 

 inner face of the os calcis, where it is 

 retained by a fibrous arch which 

 transforms this channel into a perfect 



ARTICULAR CAPSULES AND BTTRS^ IN THE 

 POSTKRIOR LIMB OF THE HORSE. 



I, Tibio-tarsal capsule (bulging anteriorly) ; 2, 

 ibid, (bulging posteriorly); 3. superior cwZ-de- 

 sac of the tarsal bursa ; 4, inferior cuUde-sac 

 of the same; 5, capsu'e of the metatarso 



phalangeal articulation ; 6, 7, 8, superior, middle, and inferior culs-de-sac of the sesamoid bursa ; 

 9, posterior cul-de-sac of capsule of the first interphalangeal articulation; 10, inferior part of the 

 sesamoid bursa completely exposed by excision of the reinforcing membrane of the perforans 

 tendon; 11, lateral cul-de-sac of the second interphalangeal or pedal articulation. T, Tibia; 

 M, matatarsus; C, lateral cartilage turned outwards and forwards; Fs, perforatus tendon; Fp, 

 perforans tendon ; Ls, suspensory or superior sesamoid ligament. 



The tibialis posticus of Man. 



^ The flexor longus pollicis of Man. 



