23 



to be inserted into a ridge on the side of the fibula. Beneath this a 

 deeper ligament runs from the posterior portion of the outer condyle, 

 downwards and backwards, to the anterior aspect of the head of the 

 fibula ; and the most anterior fibres are attached to the external semi- 

 lunar cartilage. A synovial ligament, composed of synovial membrane, 

 and containing a few blood-vessels, runs from the Haversian mass of fat 

 to the front of the intercondyloid notch of the femur. Alar ligaments 

 are two thin folds of the same structure, which lie on either side of the 

 patella, and are inserted into the upper part of the middle ridge on that 

 bone. Their free borders are directed inwards, towards the mesial line 

 of the joint. The outer is much less distinct than the inner. The an- 

 terior crucial ligament arises from the inner side of the outer condyle, 

 far back. It passes downwards, forwards, and inwards ; and is inserted 

 by two slips into the anterior cornu of the internal semilunar cartilage, 

 and into the inner and anterior border of the internal condyle of the 

 tibia. The posterior crucial runs from the posterior and superior part 

 of the deep pit between the condyles of the femur, downwards and for- 

 wards, to be inserted into the spine of the tibia on the outer side of the 

 posterior cornu of the internal semicircular cartilage, sending a small 

 slip into the inner edge of the outer cartilage. There are two of these 

 latter bodies — one semilunar, internal, with a thick outer rim, attached 

 by its anterior cornu to the head of the tibia and transverse ligament, 

 and by its posterior to the back of the spine of the tibia, and by a strong 

 slip that passes behind the posterior crucial into the inner surface of the 

 outer condyle of the femur. The external is larger, and forms a com- 

 plete deep cup for the outer condyle. Its lower surface is irregular, to 

 suit the upper part of the tibia and fibula, especially in front ; it is con- 

 nected to the internal by a broad and flat transverse ligament in front 

 of the anterior crucial, and behind the Haversian mass of fat. Beneath 

 the transverse ligament lies another broad flat band, from the front of 

 the internal condyle of the tibia to the lower surface of the external 

 semilunar cartilage. This body is connected to the anterior edge of the 

 fibula by two small flat bands, one above the other, the lower being the 

 larger, and both running backwards and outwards ; behind, it is con- 

 nected to the posterior edge of the head of the fibula by a small trans- 

 verse slip. 



The superior tibio-peronseal ligament passes from the outer and an- 

 terior part of the head of the tibia to the inner aspect of the head of the 

 fibula, underneath the outer semilunar cartilage. An inferior ligament 

 unites these bones below. 



The chief agent in the joint to limit rotation consists of the strong 

 tendon of the long extensors, which, arising from the external condyle 

 of the femur, passes along the outer side of the tibial tubercle through 

 the joint, enclosed in a fold of synovial membrane. The origin of the 

 flexors externally likewise is a strong protective to the articulation. If 

 the joint be suspended, it naturally rotates outwards. The anterior 

 crucial is far stronger than the posterior. The strong prismatic ossified 

 ligamentum patellse anteriorly limits flexion forwards. This is con- 



