300 ARTICULATIONS. 



lines external to the cotyloid ligament; but opposite the notch where the 

 margin of this cavity is deficient, it is connected with the transverse ligament, 

 and by a few fibres to the edge of the obturator foramen. Its lower circumference 

 surrounds the neck of the femur, being attached, in front, to the spiral or an- 

 terior intertrochanteric line ; above, to the base of the neck ; behind, to the 

 middle of the neck of the bone, about half an inch above the posterior inter- 

 trochanteric line. It is much thicker 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 part. Its external surface (Fig. 194) 

 is rough, covered by numerous muscles, and separated in front from the Psoas 

 and Iliacus by a synovial bursa, which not unfrequently communicates 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 Ilio-femoral Ligament (Fig. 194) 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 

 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. Sometimes, only the synovial fold exists, or the ligament may be 

 altogether absent. The use of the round ligament is to check rotation out- 

 wards, as well as adduction in the flexed position : it thus assists in preventing 

 dislocation of the head of the femur forwards and outwards, an accident likely 

 to occur from the necessary mec.hanism of the joint, if not provided against 

 by this ligament and the thick anterior part of the capsule. 1 



The Cotyloid Ligament is a fibre-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 pris- 

 moid 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 liga- 

 ment, the internal one being inclined inwards 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 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 the head 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 

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

 ligarnentum teres, as far as the head of the femur. 



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



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

 Struthers. Edinburgh Medical Journal, 1858. 



