ADDUCTOR MAGNUS MUSCLE. 579 



from the linea aspera, and end in a chain of anastomoses in the ham- 

 strings. 



The PROFUNDA VEIN results from the union of the different branches 

 corresponding with the offsets of its companion artery. It accompanies 

 closely the artery of the same name, to which it is superficial, and ends 

 above in the femoral vein. 



Dissection. To bring into view the remaining muscles, viz., adductor 

 magnus, obturator externus, and the psoas and iliacus insertion, the ad- 

 ductor brevis is to be cut through near the pelvis, and to be thrown down. 

 Then the investing layer of fascia and areolar tissue is to be removed 

 from each muscle. 



After the adductor magnus has been learnt, it will be needful to detach 

 a few of the upper fibres to examine the obturator externus. 



The ADDUCTOR MAGNUS (fig. 128, E ) is narrow at the pelvis, and wide 

 at the femur. It is triangular in form, with its base directed upwards, 

 one side being attached to the femur, and the other free at the inner part 

 of the thigh. 



The muscle arises along the pubic arch of the innominate bone outside 

 the other adductors, reaching from the symphysis to the lower part of the 

 ischial tuberosity. The anterior fibres diverge from their origin, being 

 horizontal above but more oblique below, and are inserted (from above 

 down) into the line from the great trochanter to the linea aspera ; into 

 the linea aspera ; and into the line leading from that crest of bone to the 

 inner condyle for about an inch. The posterior fibres from the ischial 

 tuberosity are vertical in direction, and end at the lower third of the 

 thigh in a tendon, which is inserted into the inner condyle of the femur, 

 and is connected by a fibrous expansion to the inner condyloid ridge. 



The muscle consists of two parts, which differ in their characters. The 

 anterior one, thin and fleshy, forms a septum between the other adductors 

 and the muscles on the back of the thigh ; but the posterior piece, partly 

 fleshy and partly tendinous, constitutes the inner thick margin of the 

 muscle. On the anterior surface are the other two adductors and the pec- 

 tineus, with the obturator nerve and the profunda artery. The posterior 

 surface touches the ham-string muscles and the great sciatic nerve. In 

 contact with the upper border are the obturator externus and the quadra- 

 tus femoris, with the internal circumflex vessels ; and along the inner border 

 lie the gracilis and the sartorius. At its attachment to the femur the 

 muscle is closely united with the other adductors, particularly the adduc- 

 tor longus, and is there pierced by apertures for the passage of the femoral 

 and perforating arteries. 



Action. This muscle is used as an adductor, but chiefly as a projector 

 forwards of the femur in walking : in the last office it receives help from 

 the other adductors internally, and from the gluteus medius and minimus 

 externally. 



The femur being fixed it will act powerfully in keeping the pelvis erect 

 on the head of the thigh bone. 



The opening in the adductor for the transmission of the femoral vessels 

 into the popliteal space is tendinous at the anterior, but fleshy at the pos- 

 terior aspect. It is situate at the point of junction of the middle with the 

 lower third of the thigh, and is larger than is necessary for the passage of 

 the vessels. On the outside it is bounded by the vastus internus ; and on 

 the inside by the tendon of the adductor magnus, with some fibres added 

 from the tendon of the long adductor. 



