777 K HIP-JOINT 143 



it is made up of transverse fibers limited by the transverse 

 ligament and longitudinal fibers, which arise from the acetabu- 

 lar fossa, and some pass in from the capsule under the transverse 

 ligament. Its function may be (1) to check movement; (2) 

 a remnant from lower animals ; (3) to carry synovia and vessels 

 (this is most probable). The motion it checks is a most un- 

 natural one, viz., is tense, with thigh flexed, adducted, and 

 rotated in. Sometimes it is a mere synovial fold, and some- 

 times is wanting. 



The capsule springs from the outer surface of the base of 

 the cotyloid ligament, from the edge of the acetabulum and 

 margin of the transverse ligament; below it is attached to 

 the anterior intertrochanteric line and to the back of the neck 

 of the femur in a line parallel to the posterior intertrochanteric 

 and about | inch above it. The digital fossa is outside the 

 capsule; it is impossible to have a true extracapsular fracture 

 of the neck of the femur. At the attachment to bone the 

 innermost layer of the capsule is reflected in smooth or longi- 

 tudinal folds (retinacula) up the neck to the articular cartilage 

 of the head, with which it fuses. This layer of the capsule 

 lined with epithelium is a thin but firm membrane, seen by the 

 microscope to be formed of parallel, transverse, or circular 

 bands; outside this are connective-tissue layers separating it 

 from the accessory bands. 



The accessory ligaments are either circular or longitudinal. 

 The circular bands form the zona orbicularis, which is most 

 distinct on the under wall of the capsule, because less covered 

 here by the longitudinal bands. It occupies the middle third 

 of the capsule, and continues upon the upper and lower thirds 

 as transverse or scattering bands of connective tissue. 



The accessory longitudinal bands spring from each of the 

 three bones forming the acetabulum, and are only lacking in 

 that part of the capsule which rises from the transverse liga- 

 ment. They go between the circular fibers, over them, or end 

 in them. 



The iliofemoral ligament extends obliquely across the front 

 of the capsule, attached above to the lower part of the anterior 

 inferior spine, and from a point behind this, just above the 

 acetabulum, and below to the whole length of the anterior 

 intertrochanteric line. It is covered by a fine layer of circular 

 fibers, and pierced by some fibers of origin of the outer head 



