634 DISSECTION OF THE LEG. 



from the ligament, the tendon enters a distinct fibrous sheath, which con- 

 ducts it along the tarsus to its insertion into the projection at the base of 

 the metatarsal bone of the little toe. 



In the leg the muscle reaches in front of the peroneus longus. On the 

 outer side of the os calcis it is contained in a sheath above the tendon of 

 the former muscle ; and each sheath is lined by a prolongation from the 

 common synovial membrane behind the outer ankle. 



Action. If the foot is unsupported this peroneus extends the ankle, 

 and moves the foot upwards and outwards in eversion. 



Like the long muscle, it is able if the foot is supported to raise the heel, 

 and to bring back tiie fibula as the body rises from stooping. 



SECTION VII. 



LIGAMENTS OF THE KNEE, ANKLE, AND FOOT. 



Directions. In examining the remaining articulations of the limb, the 

 student may take first the knee-joint, unless this has become dry ; in that 

 case the ligaments of the leg, ankle-joint, and foot may be dissected whilst 

 the knee is being moistened. 



Dissection. For the preparation of the ligaments of each articulation, 

 it is sufficient to detach the muscles and tendons from around it, and to 

 remove the areolar tissue or fibrous structure which may obscure or con- 

 ceal the ligamentous bands. In the knee a kind of aponeurotic capsule is 

 to be defined on the front of the joint. 



Some tendons, namely, those of the biceps, popliteus, adductor magnus, 

 and semimembranosus, are to be followed to their insertion, and a part of 

 each is to be left. 



ARTICULATIONS OF THE KNEE. The knee is the largest hinge joint 

 in the body, and is formed by the contiguous ends of the tibia and femur, 

 with the patella. The articular surfaces of the bones are covered with 

 cartilage, and are maintained in apposition by strong and numerous liga- 

 ments. 



The capsule (fig. 216) is an aponeurotic covering on the front of the 

 joint, which closes the wide intervals between the anterior and the lateral 

 ligaments ; and is derived from the fascia lata united with fibrous offsets 

 of the extensor and flexor muscles. It covers the anterior and the exter- 

 nal lateral ligament, being inserted below into the heads of the tibia and 

 fibula ; and it blends on the inner side with the internal lateral ligament. 

 It is not closely applied to the synovial membrane, but it is united below 

 with the interarticular fibro-cartilages. 



Dissection. Four external ligaments, anterior and posterior, internal 

 and external, are situate at opposite points of the articulation. The poste- 

 rior and the internal lateral ligament will appear on the removal of the 

 areolar tissue from their surfaces ; but the anterior and the external lateral 

 are covered by the aponeurosis on the fore part of the joint, and will not 

 be laid bare till this lias been cut through. If there is a second external 

 lateral band present, it is not concealed by the aponeurosis. 



The external lateral ligament (fig. 216, 2 ) is round and cord-like. It is 

 attached to the outer condyle of the femur below the tendon of the gas- 



