146 HIP JOINT. 



surface of their bones. These fibrous bands are attached at each side 

 to the lateral margins of the phalanges ; they are thick in the inter- 

 spaces of the joints, thin where the tendons lie upon the joints, and 

 they are lined upon their. inner surface by synovia! membrane. 



LIGAMENTS OF THE LOWER EXTREMITY. 



The ligaments of the lower extremity^ like those of the upper, may 

 be arranged in the order of the joints to which they belong ; these 

 are, the 



1. Hip joint. 



2. Knee joint. 



3. Articulation between the tibia and fibula. 



4. Ankle joint. 



5. Articulation of the tarsal bones. 



6. Tarso-metatarsal articulation. 



7. Metatarso-phalangeal articulation. 



8. Articulation of the phalanges. 



1 . Hip Joint. The articulation of the head of the femur with the 

 acetabulum constitutes an enarthrosis, or ball and socket joint. The 

 articular surfaces are the cup-shaped cavity of the acetabulum and the 

 rounded head of the femur ; the ligaments are five in number, viz. 



Capsular, Cotyloid, 



Ilio-femoral, Transverse. 



Teres, 



The capsular ligament (fig. 61, 8) is a strong ligamentous capsule, 

 embracing the acetabulum superiorly, and inferiorly the neck of the 

 femur, and connecting the two bones firmly together. It is much 

 thicker upon the upper part of the joint, where more resistance is 

 required, than upon the under part, and extends farther upon the 

 neck of the femur on the anterior and superior than on the posterior 

 and inferior side, being attached to the intertrochanteric line in front, 

 to the base of the great trochanter above, and to the middle of the 

 neck of the femur behind. 



The ilio-femoral ligament (fig. 61, 9) is an accessoiy and radiating 

 band, which descends obliquely from the anterior inferior spinous pro- 

 cess of the ilium to the anterior intertrochanteric line, and strengthens 

 the anterior portion of the capsular ligament. 



The ligamentum teres (fig. 62, 7), triangular in shape is attached 

 by a round apex to the depression just below the middle of the 

 head of the femur, and by its base, which divides into two fasciculi, 

 into the borders of the notch of the acetabulum. It is formed by a 

 fasciculus of fibres, of variable size, surrounded by synovial membrane ; 

 sometimes the synovial membrane alone exists, or the ligament is 

 wholly absent. 



