KNEE JOINT. 147 



The cotyloid ligament (fig. 62, 6) is a prismoid cord of fibro-car- 

 tilage, attached around the margin of the acetabulum, and serving to 

 deepen that cavity and protect its edges. It is much thicker upon the 

 upper and posterior border of the acetabulum than in front, and consists 

 of fibres which arise from the whole circumference of the brim, and 

 interlace with each other at acute angles. 



The transverse ligament is a strong fasiculus of ligamentous fibres, 

 continuous with the cotyloid ligament, and extended across the notch 

 in the acetabulum. It converts the notch into a foramen, through 

 which the articular branches of the internal circumflex and obturator 

 arteries enter the joint. 



The fossa at the bottom of the acetabulum is filled by a mass of 

 fat, covered by synovial membrane, which serves as an elastic 

 cushion to the head of the bone during its movements. This was 

 considered by Havers as the synovial gland. 



The synovial membrane is extensive ; it invests the head of the 

 femur, and is continued around the ligamentum teres into the ace- 

 tabulum, whence it is reflected upon the inner surface of the capsular 

 ligament back to the head of the bone. 



The muscles immediately surrounding and in contact with the hip- 

 joint are, in front, the psoas and iliacus, which are separated from the 

 capsular ligament by a large synovial bursa ; above, the short head of 

 the rectus, and the gluteus minimus ; behind, the pyriformis, gemellus 

 superior, obturator internus, gemellus inferior, and quadratus femoris ; 

 and to the inner side, the obturator externus and pectineus. 



Actions. The movements of the hip-joint are very extensive ; they 

 are flexion, extension, adduction, abdttction, circumduction and rotation. 



2. Knee Joint. The knee is a ginglymoid articulation of large size, 

 and is provided with numerous ligaments ; they are thirteen in 

 number. 



Anterior or ligamentum patellae. 



Posterior or ligamentum posticum Winslowii, 



Internal lateral, 



Two external lateral, 



Anterior or external crucial, 



Posterior or internal crucial, 



Transverse, 



Two coronary, 



Ligamentum mucosum, ? / / 

 Ligamenta alaria, \ 



Two semiltinar fibro-cartilages, 

 Synovial membrane. 



The first five are external to the articulation ; the next five are 

 internal to the articulation ; the remaining three are mere folds of 

 synovial membrane, and have no title to the name of ligaments. In 

 addition to the ligaments, there are two fibro-cartilages, which are 

 sometimes very erroneously considered among the ligaments ; and a 



