THE CAT. 



[CHAP, iv 





the pit between the condyles of the tibia to the inner and posterior 

 part of the external condyle. The posterior (or internal) one ( pc) 

 goes from a more posteriorly situated part of the same pit to the 

 front part of the concavity between the condyles or the outer side of 

 the inner condyle. Two nbro-cartilaginous crescentic structures (s), 



the semi-lunar cartilages, are inter- 

 posed between the femur and the 

 tibia, reposing on the outer and inner 

 margins of the upper surface of the 

 latter. 



A capsiilar ligament surrounds the 

 knee-joint incompletely, being deficient 

 beneath the tendons of the muscles, 

 and in the regions occupied by the 

 other ligaments. 



A very large membrane of the kind 

 called synovial (the largest such mem- 

 brane in the cat's body) lines the knee- 

 joint, extending up above (and within) 

 the patella, and investing the crucial 

 ligaments in front, and both surfaces of 

 the semi-lunar cartilages. 



The upper ends of the tibia and 

 fibula are connected by two small flat 

 and oval surfaces, bound together by a 

 tibio-fibular ligament (ff) passing from 

 the head of the fibula to the external 

 tuberosity of the tibia. 



An inter-osseous membrane, or liga- 

 ment (/), passes from the external 

 ridge of the tibia to the adjacent 

 surface of the fibula. It does not 

 ascend quite to the summit of the 

 interval between the leg-bones. 



The ARTICULATIONS AND LIGAMENTS OF THE FOOT are SO closely 



connected with those of the inferior ends of the leg-bones that these 

 latter may best be described with the former. 



The ANKLE-JOINT is strengthened by anterior and posterior liga- 

 mentous bands. 



The internal lateral ligament of the ankle-joint passes down 

 (broadening as it descends) from the end of the internal malleolus 

 somewhat to the astragalus and oscalcis, but especially to the tube- 

 rosity of the naviculare. 



The external lateral ligament also radiates as it descends from the 

 lower end of the fibula to the os calcis. The internal malleolus 

 descends somewhat below the external one, and the tibia descends a 

 little more behind the astragalus than it does in front of it. 



A certain amount of motion is possible between the distal tarsals, 

 and the astragalus and os calcis a movement facilitated by the 

 presence of synovial membrane. 



Fig. 75. VERTICAL SECTION THROUGH 

 KNEE-JOINT. 



a. Anterior crucial ligament (cut 



short). 

 6. Bursa. 



c, c, c. Capsular ligament. 

 /. (Above) femur. 

 /. (In the joint) adipose tissue. 

 Ip. Ligament of the patella. 

 p. Posterior crucial ligament. 

 pa. Patella. 

 s. Inter-articular cartilage. 



