222 ARTICULATIONS. 



at the upper and fore part of the joint where the greatest amount of resistance is 

 required, than below where it is thin, loose, and longer than in any other situation. 

 Its external surface is rough, covered by numerous muscles, and separated in front 

 from the Psoas and Iliacus by a synovial bursa, which not unfrequently commu- 

 nicates by a circular aperture with the cavity of the joint. It differs from the 

 capsular ligament of the shoulder, in being much less loose and lax, and in not 

 being perforated for the passage of a tendon. 



The llio-femoral Ligament (fig. 127) is an accessory band of fibres, extending 

 obliquely across the front of the joint : it is intimately connected with the capsular 

 ligament, and serves to strengthen it in this situation. It is attached, above, to the 

 anterior inferior spine of the ilium ; below, to the anterior inter-trochanteric line. 

 The Ligamentum Teres is a triangular band of fibres, 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, which consists of two bundles of fibres, into the margins of 

 the notch at the bottom of the acetabulum, becoming blended with the transverse 

 ligament. It is formed of a bundle of fibres, the thickness and strength of which 

 are very variable, surrounded by a tubular sheath of synovial membrane. Some- 

 times, the synovial fold only exists, or the ligament may be altogether absent. 

 The use of the round ligament is to check rotation outwards, when combined with 

 flexion : it thus assists in preventing dislocation of the head of the femur forwards 

 and outwards, an accident likely to occur from the necessary mechanism of the joint, 

 if not provided against by this ligament and the thick anterior part of the capsule. 1 



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

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

 edges of the bone, and fills up the inequalities on its surface. It is prismoid in 

 form, its base being attached to the margin of the acetabulum, 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 inwards so as to narrow the acetabulum and embrace the cartila- 

 ginous 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 a strong flattened band of fibres, which crosses the 

 notch at the lower part of the acetabulum, and converts it into a foramen. It is 

 continuous at each side with the cotyloid ligament. An interval is left beneath 

 the ligament for the passage of nutrient vessels to the joint. 



The Synovial Membrane is very extensive. Commencing at the margin of the 

 cartilaginous surface of the head of the femur, it covers all that portion of the 

 neck which is contained within the joint ; from this point it is reflected on the 

 internal surface of the capsular ligament, covers both surfaces of the cotyloid 

 ligament, and the mass of fat contained in the fossa at the bottom of this cavity, 

 and is prolonged in the form of a tubular sheath around the ligamentum teres, 

 as far as the head of the femur. 



The Muscles in relation with the joint are, in front, the Psoas and Iliacus, sepa- 

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

 the Kectus and Gluteus minimus, the latter being closely adherent to it ; internally, 

 the Obturator externus and Pectineus ; behind, the Pyriformis, Gemellus superior, 

 Obturator internus, Gemellus inferior, Obturator externus, and Quadratus femoris. 



The Arteries supplying it are derived from the obturator, sciatic, internal cir- 

 cumflex, and gluteal. 



The Nerves are articular branches from the sacral plexus, great sciatic, obtu- 

 rator, and accessory obturator nerves. 



Actions. The movements of the hip, like all enarthrodial joints, are very exten- 

 sive; they are, flexion, extension, adduction, abduction, circumduction, and rotation. 



1 See. an interesting paper, " On the Use of the Bound Ligament of the Hip-joint," by Dr. J. 

 STEUTHERS. Edinburgh Medical Journal, 1858. 



