306 TSU MUSCLES. 



a phalangeal reinforcing sheath, and finally terminates on the semilunar 

 crest of the os pedis. This tendon, therefore, on leaving the tarsus, com- 

 ports itself exactly like that of the anterior limb. 



Belations. — Outwards, with the lateral extensor of the phalanges, the 

 soleus, and the tibial aponeurosis. Inwards, with this aponeurosis and the 

 oblique flexor Behind, with the gastrocnemii, the perforatus, and the 

 fibrous band of tlie tendon of the hock. In front, with the tibia. 



Aciion. — This muscle flexes the phalanges on one another and on the 

 metatarsus. It may also extend the foot in pressing, during its contraction, 

 behind the tibio-tarsal articulation. In addition to this, its tendon acts, 

 while the animal is standing, as a mechanical support to the phalanges and 

 the articular angle of the fetlock. 



6. Ohliqm Flexor of the Phalanges. (Fig. 137, 22.) 



Synonyms.— Peroneo-TphalimgeTis—Girard. The tibialis posticus of Man. (Flexor 

 pedis accessorius—Percivall. Small tibio-phalangeus — Leyli.) 



Situation — Direction. — A muscle situated behind the tibia, between 

 the popliteus and the perforans, in a direction slightly oblique downwards 

 and inwards. 



Form — Structure. — It is composed of a fleshy fusiform body, intersected 

 by numerous fibrous bands, and provided with a funicular tendon inferiorly. 



Attachments. — The superior extremity is fixed behind the external 

 tuberosity of the tibia — origin. The tendon is united, by its inferior 

 extremity, to that of the perforans towards the upper third of the meta- 

 tarsal region — termination. 



Relations. — The muscular portion responds : in front, to the perforans, 

 the popliteus, and the posterior tibial artery; behind, to the gastrocnemii 

 and the perforatus. The tendon, at first lodged in a muscular channel 

 in the perforans and covered by the tibial aponeurosis, afterwards enters a 

 tortuous sheath at the inner side of the tarsus, and which is formed by the 

 groove that bends behind the infero-internal tuberosity of the tibia. 



Action. — It is a congener of the deep flexor. 



DIFTEKENTIAIi CHARAOTBKS OF THE MUSCLES OE THE LEG M OTHER THAN SOLffED 



ANIMALS. 



A. Anterior Tibial Region. 



EuMTNANTS.^Among these animals, the Ox presents : 



1. A complex muscle, whioh is represented in the Horse by the anterior extensor of 

 the phalanges, and the tendinous cord of the flexor metatarsi. Single at its superior 

 extremity, which begins by a tendon arising from the digital fossa situated between the 

 trochlea and the external condyle of the femur (Fig. 138, 1), this muscle comprises in 

 its middle part three fleshy divibions which are terminated inferiorly by tendons. 



One of these divisions, situated in front of, and within the other two, has its tendon 

 prolonged to the superior extremity of the principal metatarsal bone, and is also inserted 

 into the cuneiform bones. It is a flexor of the metatarsal region, and replaces the 

 tendinous cord which performs this function in Solipeds (Fig. 138, 2). 



The second, placed without the pi-eceding, constitutes a common extensor of the 

 digits, whose ti ndon comports itself exactly like that of the anterior limb (Fig. 138, 5, 

 5', 6) (see p. 270). 



The third, concealed by the other two, forms the proper extensor of the internal digit, 

 and resembles its fellow in the fore extremity . see p. 270). 



2. An anterior tibial muscle (muscular portion of the flexor of the metatarsal of 

 the Horse). It is a triangular, muscular body, lodged in the antero-external fossa of 

 the tibia, into the upper part of which it is inserted, and is succeeded by a tendon that 



