126 HUMAN ANATOMY. 



ARTICULATIONS OF THE LOWER EXTREMITY. 



THE HIP-JOINT is a true enarthrodial articulation,, formed 

 above by deep cup-like cavity of acetabulum, below by promi- 

 nent spherical head of femur. Its ligaments are the capsular, 

 ilia-femoral, teres, cotyloid, and transverse. 



The capsular ligament, dense and strong, is attached above 

 to margin of acetabulum and cotyloid ligament, and below to 

 the spiral line in front and to the neck behind. It is strength- 

 ened by several accessory bands, the pubo-femoral, ilio-trochan- 

 teric, iscliio-capsular, and ilio-femoral. Of these the latter is the 

 most important, arising above from anterior inferior spine, and 

 attached below to spiral line, and has received the name of 

 Y-ligament of Bigelow. 



The ligamentum tares, or round ligament, is a strong tri- 

 angular band, its base arising from the bottom of acetabulum and 

 margins of cotyloid notch externally, its apex inserted below and 

 behind centre of head of femur. 



The cotyloid ligament encircles and deepens. the acetabulum, 

 and at the inner side, under the name of the transverse ligament, 

 it bridges over the cotyloid notch, converting it into a foramen 

 for the passage of nutrient vessels to the joint. 



There are numerous bursa about the joint, with one of 

 which, beneath the ilio-psoas muscle, the synovial membrane 

 often communicates. 



Its arteries are derived from the sciatic, internal and ex- 

 ternal circumflex, obturator, and gluteal. 



Its nerves are derived from the great sciatic, obturator, 

 accessory obturator, and the sacral plexus. 



THE KNEE-JOINT is a ginglymoid articulation, formed above 

 by condyles of femur, below by head of tibia, and in front by 

 patella. 



Its ligaments are divided into two sets, the external, con- 

 sisting of anterior, posterior, internal lateral, two external lat- 

 erals, and capsular; and internal, consisting of anterior, pos- 

 terior, two semi-lunar nbro-cartllages, transverse, coronary, 

 ligamentum mucosum, and ligamenta alaria. Its joint surface 

 is the most extensive in the body. 



External Set. Anterior, or ligamentum patella, is the 

 tendinous portion of extensors of thigh between patella and 

 tubercle of tibia. The posterior, or ligamentum posticum Wins- 

 lowii, derived principally from the tendon of semi-membranosus, 

 arises from inner tuberosity of tibia, passes upward and outward 

 to be inserted into external condyle of femur. 



