The Posterior Limb. , 155 



which accompanies the obturator artery, and is distributed to the 

 obturatores, adductores, and gracilis muscles. 



The sciatic nerve, together with the superior and inferior gluteal 

 nerves, arise from the loop connecting the last lumbar and first sacral 

 nerves (ansa lumbalis iii). 



The internal pudendal nerve is formed from the loop connecting the 

 second and third sacral nerves (ansa sacralis ii), but chiefly from the 

 second. 



The Articulations of the Posterior Limb. 



The more perfect development and larger size of the joints of the 

 posterior limb make them much more favorable for examination than 

 the corresponding parts of the anterior limb. 



The muscular attachments should be removed from about the 

 articular capsules and the structures examined as follows: 



A. The hip-joint (articulatio coxae) is an enarthrosis, formed bv the 

 head of the femur with the parts of the ischium, ilium, and the os aceta- 

 buli enclosing the acetabulum, together with the articular capsule 

 (capsula articularis) and accessory ligaments. 



The articular capsule extends from the acetabular margin to the 

 proximal end of the neck of the femur. It is strongest on its dorsal side. 

 The external supports of the joint comprise the iliofemoral, ischiocapsular, 

 and pubocapsular ligaments. 



By dividing the capsule, the contents of the joint and the smooth 

 articular surfaces may be examined ; also the attachment of the head 

 of the femur to the wall of the acetabular fossa through the round liga- 

 ment (lig. teres femoris). The glenoid lip (labrum glenoidale) is the 

 ring of fibrocartilage surrounding the margin of the acetabulum and 

 connecting with the articular capsule. 



B. The knee-joint (articulatio genu) is a hinge-joint, or ginglymus 

 with a slight spiral trend. It is formed by the articular surfaces of the 

 medial and lateral condyles of the femur and tibia, with the associated 

 articular capsule, ligaments, and inarticular fibrocartilages (see section. 

 Fig- 13)- 



The tibial collateral ligament (lig. collaterale tibiale) is a stout band 

 of connective tissue stretching from the medial condyle of the femur to 

 the posteromedial angle of the medial condyle of the tibia. 



The fibular collateral ligament is a similar structure connecting the 

 lateral condyle of the femur with the lateral surface of the tibia imme- 

 diately in front of the head of the fibula. 



The sesamoid bones of the popliteal region have articular surfaces 

 taking part in the formation of the joint. That on the medial condyle 

 of the femur is contained in the medial head of the gastrocnemius, that 

 on the lateral condyle of this bone in the lateral head of the gastroc- 

 nemius and the plantaris, and that on the lateral tibial condyle in the 

 popliteus. 



The common tendon of the quadriceps femoris, the patella, and the 



