KNEE JOINT. 129 



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

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

 the upper and outer 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 fasciculus 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 with 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 ; it is thence reflected upon the inner surface of the cap- 

 sular ligament. 



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 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, abduction, circumduction, and 

 rotation. 



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

 size, and is provided with numerous ligaments ; they are thirteen in 

 number. 



Anterior or ligamentum patella?, 



Posterior or ligamentum posticum Winslowi, 



Internal lateral, 



Two external lateral, 



Anterior or external crucial, 



Posterior or internal crucial, 



Transverse, 



Two coronary, 



Ligamentum mucosum, ) , . 

 Ligamenta alaria, } J alse * 



Two semilunar fibro-cartilages, 

 Synovial membrane. 



The^ue first are external to the articulation; the jive next are 

 internal to the articulation ; the three remaining 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 



17 



