364 



THE ARTICULATIONS. 



lower part of the anterior intertrochanteric line ; the other passes downward 

 and outward to be inserted into the upper part of the same line and adjacent 

 part of the neck of the femur. Between the two bands is a thinner part of the 

 capsule. Sometimes there is no division, but the ligament spreads out into a flat, 

 triangular band, which is attached below into the whole length of the anterior inter- 

 trochanteric line. This ligament is frequently called the Y-shaped ligament of 

 Bigelow. Its upper band is the ilio-trochanteric ligament. 



The Ligamentum Teres is a triangular band implanted by its apex into the 

 depression a little behind and below the centre of the head of the femur, and 

 by its broad base into the margins of the cotyloid notch, becoming blended with 

 the transverse ligament. It is formed of connective tissue, surrounded by a tubular 

 sheath of synovial membrane. Sometimes only the synovial fold exists, or the 

 ligament may be altogether absent. The ligament is made tense when the hip is 



semiflexed, and the limb then adducted and 



^__^ rotated outward ; it is, on the other hand, 



relaxed when the limb is abducted.. It has, 

 however, but little influence as a ligament, 

 though it may to a certain extent limit move- 

 ment, and would appear to be merely a modi- 

 fication of the folds which in other joints 



OBTURATOR 

 '" MEMBRANE. 



FIG. 254. Hip-joint, showing the ilio-femoral 

 ligament. (After Bigelow.) 



FIG. 255. Vertical section through hip-joint. (Henle.) 



fringe the margins of reflection of synovial membranes (see page 314). 



The Cotyloid Ligament is a fibre-cartilaginous rim attached to the margin of 

 the acetabulum, the cavity of which deepens ; at the same time it protects the 

 edges of the bone and fills up the inequalities on its surface. It bridges over the 

 notch as the transverse ligament, and thus forms a complete circle, which closely 

 surrounds the head of the femur, and assists in holding it in its place, acting as a 

 sort of valve. It is prismoid in form, its base being attached to the margin of the 

 acetabulum, and its opposite edge being free and sharp ; whilst its two surfaces 

 are invested by synovial membrane, the external one being in contact with the 

 capsular ligament, the internal one being inclined inward, so as to narrow the 

 acetabulum and embrace the cartilaginous surface of the head of the femur. It 

 is much thicker above and behind than below and in front, and consists of close, 

 compact fibres, which arise from different points of the circumference of the 

 acetabulum and interlace with each other at very acute angles. 



The Transverse Ligament is in reality a portion of the cotyloid ligament, 



