256 INFERIOR EXTREMITY 



The ligamentum teres is not round, as its name might lead one 

 to expect, but somewhat flattened and triangular in shape. Its 

 narrow femoral extremity is implanted into the proximal margin 

 of the fovea capitis femoris, whilst its flattened acetabular end is 

 bifid, and is fixed to the margins of the incisura acetabuli, and 

 also to the transverse ligament. This attachment can be 

 defined by removing the synovial membrane and some 

 areolar tissue. The ligamentum teres is surrounded by a 

 prolongation of the synovial membrane, and a small artery runs 

 along it to the head of the femur. It is difficult to under- 

 stand the part which the ligamentum teres plays in the 

 mechanism of the hip-joint. It presents very - different 

 degrees of strength in different individuals. It becomes 

 very tense when the thigh is slightly flexed and then ad- 

 ducted. 



The Interior of the Joint and the Synovial Membrane. A 

 mass of soft fat occupies the non-articular bottom of the 

 acetabulum. Upon this the ligamentum teres is placed, and 

 blood-vessels and nerves enter it by passing through the 

 notch under cover of the transverse ligament. The vessels 

 come from the medial circumflex and the obturator arteries, 

 and the nerves come from the anterior branch of the ob- 

 turator nerve and from the accessory obturator, when it is 

 present. A nerve-twig is also supplied to the posterior part 

 of the joint by the nerve to the quadratus femoris. 



The synovial membrane lines the interior of the capsule. 

 From this it is reflected on to the neck of the femur, and it 

 clothes the bone as far as the margin of the articular cartilage 

 which covers the head. Along the line of reflection some 

 fibres of the capsular ligament proceed upwards on the neck 

 of the femur and raise the synovial membrane in the form 

 of ridges. These fibres are termed the retinacula or cervical 

 ligaments. 



The cervical ligaments are of some surgical importance. In intra- 

 capsular fracture of the neck of the femur they may escape rupture, and 

 they may then to some extent help to retain the fragments in apposition. 

 Hence examinations of this class of fracture must be conducted gently, 

 lest by rupturing this ligamentous connection the fragments be perma- 

 nently displaced. 



At the acetabular attachment of the capsular ligament the 

 synovial membrane is reflected on to the labrum glenoidale 

 and invests both its surfaces. It also covers the articular 



