HAP. v.] TITE CATS MUSCLES. IGl 



tuberosity — its passage becoming facilitated by synovial membrane. 

 It cuds in the plantar fascia, wliicli invests the under surface of 

 the foot and gives origin to the flexor brevis digitorum. 



The solcus arises from the summit of the back part of the 

 fibula and is inserted into the tuberosity of the os calcis beneath 

 (i.e., covered in by) the tendo Achillis. 



These three muscles raise the heel and are great agents in 

 jumping. 



The poplilcus is a short oblique muscle, which takes origin by 

 a thick tendon from and just outside the external condyle of the 

 femur. It is inserted on the posterior surface of the tibia, above 

 the oblique line and conterminous with the origins of the tibialis 

 posticus and flexor longus hallucis (Fig. 85). 



Flexor hrcvis digitoruiii or perforatum. — This muscle takes origin 

 from the plantar surface of the plantar fascia of the plantaris. It 

 is made up of four small muscles, placed side by side, which send 

 tendons to the four digits ; the muscle and tendon going to the fifth 

 digit being the most slender. These tendons go to the second pha- 

 langes, but each splits opposite the proximal phalanx to allow a tendon 

 of the flexor longus to pass through the perforation thus formed. 



^\lq, flexor longus digitoriun pedis or preforans is rather small, and 

 arises from the hinder surface of the tibia, below the poplitcus, 

 from the summit of the fibula and from the intermuscular fascia 

 between it and the tibialis posticus. It ends below in a tendon 

 which passes down a groove behind — or rather on the inner side 

 of — the internal malleolus. This groove is lined by a separate 

 synovial membrane, and is just behind that for the tibialis posticus. 

 The tendon passes into the plantar region and ends by dividing 

 into four tendons, which are inserted into the distal phalanges of 

 the digits after perforating the tendons of the flexor brevis. 



The flexor hiirjiis liallucis is a large muscle which takes origin 

 from the back of the fibula and tibia and interosseous ligament 

 — below and external to the origin of the last described muscle. It 

 ends in a tendon which passes in a synovial sheath behind the 

 internal malleolus, and beneath the sustentaculum tali of the os 

 calcis in a deep groove. It ends by coalescing with the tendon of 

 the flexor longus digitorum. It is much connected with the peronei 

 which border it externally. 



Lumbricalcs. — There are three of these muscles in the hind-paw, 

 and they resemble those of the fore-paw. One passes from between 

 the deep flexor tendons of the index and third digits to the tibial 

 side of the third digit. The second goes from between the deep 

 tendons of the third and fourth digits to the tibial side of the 

 fourth digit, and the third goes from the deep flexor tendon of 

 the fifth digit to the tibial side of the same digit. 



Accessorius. — This is a very small muscle of two bellies, which 

 arise on the plantar surface of the conjoined deep flexor tendon, 

 and end by two delicate tendons, which join the tendons of the flexor 

 brevis, going to the third and fourth digits (Fig. 85). 



M 



