ANKLE JOINT. 



59 



Fig. 46. 



(Fig. 46), arises from a roughness in front of 

 the spine of the tibia, and is inserted into the 

 postciior part of the internal face of the ex- 

 ternal condyle. The posterior^ commences 

 at a roughness behind the spine of the tibia, 

 and is inserted at the anterior part of the 

 external face of the internal condyle of the 

 femur. 



The synovial membrane is the most exten- 

 sive in the skeleton ; it forms folds in the in- 

 terior of the joint, one of which is called the 

 ligamentuni Tnucosum^ which is triangular 

 in shape, passing from the condyloid notch to 

 a mass of fat in front of the tibia. The alar 

 ligaments are fringed folds of the synovial 

 membrane, containing masses of fat on each 

 side of the patella. 



The tibia and fibula are connected above by the 



Anterior Superior Ligament'^ (Fig. 44). — A short, strong liga- 

 ment, extending obliquely between the heads of the two bones in 

 front. 



Posterior Superior Ligament^ (Fig. 45). — Passes obliquely be- 

 tween the heads of the two bones behind. The synovial membrane 

 of this articulation is generally distinct from that of the knee-joint. 



Interosseous Ligament^^ (Fig. 46). — Is stretched between the 

 tibia and fibula throughout their entire length, and opening at its up- 

 per part, transmits the anterior tibial artery. 



Anterior Inferior Ligament (Fig. 48). — Is a broad band pass- 

 ing obliquely between the two bones in front, and at their lower 

 extremity. 



Posterior Inferior Ligament. — Is somewhat similar, passing ob- 

 liquely between the lower extremities of the two bones. Besides 

 these, the tibia and fibula are united by short strong fibres, passing 

 from the contiguous surface of the two bones. 



ANKLEJOINT. 



It is the most perfect hinge in the body. 



Internal Lateral or Deltoid Ligament^ (Fig. 47). — Is triano-ular; 

 its apex is attached to the internal malleolus, and its base to the 

 OS calcis, astragalus and calcaneo-scaphoid ligament. The tibialis 

 posticis runs in a trochlea upon it. 



External Lateral Ligament^'' ^ (Fig. 48). — Consists of three 

 parts, which arise from the external malleolus ; the anterim- passes 

 forwards, and is inserted into the astragalus ; the middle descends, 

 and is inserted into the os calcis ; the joos^e^-eor passes backwards, 

 and is fastened to the astragalus. The synovial membrane is large 



