2 66 THE INFERIOR EXTREMITY 



The articularis genu merely lifts the upper part of the synovial 

 stratum of the capsule of the knee to prevent its being caught 

 between the bones as the knee joint is extended. 



MEDIAL SIDE OF THE THIGH. 



The group of adductor muscles on the medial aspect of the 

 thigh, together with the blood-vessels and nerves associated 

 with them, must next be dissected. As the dissection 

 proceeds the following structures will be displayed : 



fPectineus. 

 Adductor longus. 



,, , I Adductor brevis. 

 Muscles, 4 Adductor magnus- 



Gracilis. 

 l.Obturator externus. 



. , . f Profunda femoris (and its branches). 

 Arteries, ( Obturator> 



^ / The two divisions of the obturator nerve. 



' \The accessory obturator nerve, when present. 



The adductor muscles are disposed in three strata. The 

 anterior strattim is formed by the pectineus and the adductor 

 longus, which lie in the same plane. Their adjacent borders 

 touch one another proximally, but distally they are separated 

 by a small interval. The second stratum is formed by the 

 adductor brevis ; and the third, or posterior layer^ by the 

 adductor magnus. The gracilis muscle, also an adductor, 

 extends along the medial aspect of the thigh. It is a long, 

 strap-like muscle, applied against the adductor brevis and 

 adductor magnus. Interposed between the three muscular 

 layers are the two divisions of the obturator nerve. The 

 anterior division is placed between the anterior and middle 

 layers ; the posterior division lies between the middle and 

 posterior layers. In other words, the adductor brevis inter- 

 venes between them. At the distal border of the adductor 

 longus, a fine branch from the anterior division of the 

 nerve makes its appearance ; it takes part in the formation 

 of the sub -sartorial nerve plexus already dissected. The 

 profunda artery and its branches also are to be followed. 

 For a part of its course this vessel is placed between the 

 anterior and middle muscular strata. 



M. Adductor Longus. The adductor longus muscle is 



