114 SPECIAL ANATOMY. 



eminentia media. Posteriorly a thick fibrous band passes from it around the 

 lig. crucial, postic., and is attached behind this to the condyl. extern, femoris. 

 The internal cartilage is larger, does not so much cover the fossa; attaches 

 itself by the cornua before and behind the projections of the eminent, media; 

 the posterior cornu is covered by the lig. cruciat. postic. 



Ligaments: 1. Lig. capsulare genu, large and loose, weakest in front and at 

 the sides, behind united with lig. poplitaum ; passes off from the superior bor- 

 ders of the Condyli femor. to the circumference of the articular surfaces of the 

 Tibia and the posterior of the Patella, behind lig. Patella. 



2. Lig. poplitaum [the posterior ligament of Winslow], oblique from Condyl. 

 extern, femoris to the internal border of the Condyl. internus tibia; strong, flat. 



3. Lig. Patella, a portion of tendo comm. extensorius, thick, almost triangular, 

 broad at the apex of the Patella, narrower at the inferior part, the tuberosit. 

 tibiae. 



4. Ligg. lateralia genu. a. externum, round, tendon like, lies before and be- 

 tween the two heads of the m. biceps fern. ; from condyl. extern, fern, to the 

 outer portion of the capitul. fibula ; extern, breve lies behind a, and is attached 

 higher up to capit.fib. b. internum, broad and thin, from the posterior portion 

 Of condyl. intern, femor. to the condyl. intern, tibia, is below covered by the ten- 

 dons of thePes anserinus (see Myology),ancl connected with the Cartil. semilunar. 

 intern. Both lie rather posteriorly behind the centre of motion of the joint, are 

 slackened in flexion and limit extension. 



5. Ligg. cruciata s. interossea, crossed like the capital letter X between the 

 articular surfaces of oss. femor. et tibia, in the Incisura intercondyloidea. 



a. Lig. cruciat. anticum. passes from the posterior internal surface of the 

 Condyl. extern, to the most anterior portion of the eminentia media tibia; be- 

 hind it the longer and thicker (b), lig. (ruciat. posticum ; from the anterior inner 

 surface of Condyl. intern, to the posterior extremity of the eminentia media. It 

 is connected with the Cartil. semilun. externa; it slackens under extension, 

 and stretches in flexion of the joint, whilst the Lig. antic, is slackened in 

 fisxion. 



A synovial capsule is very distinct; a shut sac lies above between tendo 

 extensor et femur; at the sides of the patella, on the inner side especially, 

 beneath the m. vastus internus, the ligg. alaria which blend behind with a 

 fibrous fold, Lig. mucosum s. adiposum. It invests the whole internal surface 

 of the capsular ligament, the two surfaces of the Cartilagg. semilunares, and 

 envelopes the lig. cruciata. Between it and the lig. patella much fat is found, 

 as well as about the ligg. cruciata, and chiefly in the incis. intercondyl. 



Movements: 1. Flexion. The heel may touch the thigh. 

 The posterior, lateral, and posterior crucial ligaments are relaxed, 

 the ligament of the patella is stretched, and the bone is fixed, in 

 front of the space between the femur and tibia. 



2. Extension. The articular surfaces of the tibia with the 

 cartil. semilunar. roll from behind forwards, until the thigh and 

 leg lie in the same line. Lig. patellae and cruciat. anticum are 

 relaxed, the rest become stretched. The Patella may be dis- 

 placed. 



3. Rotation, inwards and outwards, is very limited, and is only 

 performed by the condylus internus. It is effected, outwards, 

 by the action of the m. biceps fern. ; inwards, by the m. pop- 

 litseus. 



