THE MUSCLES ON THE MEDIAL SIDE OF THE THIGH. 411 



The psoas minor receives a nerve from the first or second lumbar nerve. The iliacus is 

 supplied by branches from the femoral nerve (L. 2. 3. 4.) within the abdomen. 



Actions. The psoas minor assists the psoas major in flexing forwards and laterally the 

 vertebral column. 



Besides this action the psoas major acts with the iliacus muscle as a flexor of the hip-joint. 

 With the thighs fixed the two muscles can draw the trunk downwards. 



M. Pectineus. The pectineus muscle arises by fleshy fibres from, (1) the 

 sharp anterior portion of the linea terminalis of the pubis, and the triangular 

 surface of the pubic bone in front of the linea terminalis (Fig. 366, p. 412), 

 (2) the femoral surface of the ligamentum lacunare, and (3) the pectineal portion 

 of the fascia lata which covers it. 



Forming a broad muscular band, which lies in the floor of the femoral triangle, 

 medial to the ilio-psoas, it is inserted by a thin flat tendon, about two inches in 

 length, into the proximal half of the pectineal line, leading from the back of 

 the lesser trochanter of the femur towards the linea aspera ; its distal attachment 

 being placed in front of the insertion of the adductor brevis muscle (Fig. 365, 

 p. 410). The muscle may be occasionally divided into medial and lateral parts, 

 the former innervated by the obturator, the latter by the femoral nerve. 



Nerve-Supply. The pectineus is always supplied by a branch of the femoral nerve (L. 2. 3.) 

 which passes medially behind the femoral vessels to enter its lateral border. It receives in 

 some instances an additional nerve from the obturator, or when that is present, the accessory 

 obturator nerve. 



Actions. The muscle is mainly an adductor of the hip-joint. It is also a flexor of the hip. 



THE MUSCLES ON THE MEDIAL SIDE OF THE THIGH. 



The muscles on the medial side of the thigh include the adductors of the femur 

 the adductor longus, adductor brevis, and adductor magnus ; the gracilis, and the 

 obturator externus. 



The gracilis is superficially placed along the medial side of the thigh. The 

 adductor muscles are placed in the medial part of the thigh between the hip bone 

 and the femur, and in different vertical planes. The adductor longus is in the 

 same plane as the pectineus and lies superficially in the femoral triangle; the 

 adductor brevis, on a more posterior plane, is in contact with the obturator externus, 

 and along with it is largely concealed by the pectineus and adductor longus ; the 

 adductor magnus, the largest and most posterior of these muscles, is in contact 

 with the other adductors and the sartorius anteriorly, while its posterior surface 

 is in relation to the hamstring muscles on the back of the thigh. 



M. Gracilis. The gracilis muscle is a long flat band placed on the medial 

 side of the thigh and knee. It arises by a tendon from the lower half of the edge 

 of the symphysis pubis, and for a similar distance along the border of the pubic 

 arch (Fig. 366, p. 412). 



Its flattened belly passes distally, on the medial side of the thigh to the knee, 

 to end in a tendon, placed between the sartorius and semitendinosus, which expands 

 to be inserted into the medial surface of the body of the tibia just distal to the 

 medial condyle, behind the sartorius, and proximal to and in front of the 

 semitendinosus (Fig. 376, p. 420). It is separated from the sartorius tendon by 

 a bursa, and deep to its tendon is another bursa, common to it and the semi- 

 tendinosus. It is superficial in its whole extent. 



Nerve-Supply. Obturator nerve (L. 2. 3.). 



Actions. The gracilis has a threefold action. It adducts the thigh, and it flexes and rotates 

 medially the tibia. 



M. Adductor Longus. The adductor longus is a triangular muscle which lies 

 in the floor of the femoral triangle and the floor of adductor canal (Hunter's). It 

 arises from the anterior surface of the body of the pubis in the angle between the 

 crest and symphysis (Fig. 366, p. 412). 



It extends distally and laterally, it is inserted into the middle two-fourths 

 of the medial lip of the linea aspera in front of the adductor magnus. 



