THE HIP-JOINT. 181 



IV. THE AKTICULATIONS OF THE LOWER LIMB. 



THE HIP-JOINT. 



This is a ball and socket joint, in which the globular head of the femur is re- 

 ceived into the acetabulum or cotyloid cavity of the hip-bone. The articular 

 portion of the acetabulum is a horseshoe-shaped, cartilage-covered surface, broader 

 above and behind than in front, and folded round the fossa acetabuli which, extend- 

 ing from the cotyloid notch to the bottom of the cavity, is occupied by adipose 

 tissue covered with synovial membrane, the so-called synovial or Haversian gland. 

 The articular surface of the femur presents a little behind and below its centre a pit 

 in which the interarticular ligament is attached. 



The cotyloid ligament forms a thick fibro-cartilaginous ring round the 

 margin of the acetabulum, increasing the depth of its cavity, and bridging over 



Fig. 207. TRANSVERSE OBLIQUE SECTION OP THE PELVIS AND HIP-JOINT, CUTTING THE FIRST SACRAL 



VERTEBRA AND THE SYMPHYSIS PUBIS IN THEIR MIDDLE, FROM A MALE SUBJECT OF ABOUT NINE- 

 TEEN YEARS OF AGE. (Allen Thomson.) 



1, first sacral vertebra ; 2, ilium ; 3, posterior sacro-iliac ligament ; 4, cavity of the sacro-iliac 

 articulation ; 5, anterior sacro-iliac ligament ; 6, small sacro-sciatic ligament ; 7 ; great sacro-sciatic 

 ligament ; 8, placed in front of the symphysis pubis, in the cut surface of which the small median 

 cavity, the adjacent cartilaginous plates, and the anterior and posterior ligamentous fibres are shown ; 

 9, lower part of the obturator membrane ; 10, cartilaginous surface of the cotyloid cavity, through the 

 middle of which the incision passes transversely, dividing the interarticular ligament and the fat in the 

 fossa acetabuli ; 11, cotyloid ligament ; 12, interarticular ligament connected with the transverse part 

 of the cotyloid ligament ; 13, placed on the cut surface of the head of the left femur near the depression 

 where the interarticular ligament is attached ; 14, 14', upper and lower parts of the capsular ligament. 



the deficiency in its border. Its external surface is in contact with the capsular 

 ligament ; the internal closely embraces the head of the femur, and both are 

 covered by the synovial membrane. Its fibres do not run parallel to the circum- 



N 2 



