THE MUSCLES ON THE INNER SIDE OF THE THIGH. 345 
in contact with the cecum on the right side and the iliac colon on the left side. 
The psoas muscle lies along its inner border, with the anterior crural nerve in the 
interval between them. 
After passing beneath Poupart’s ligament, and over the capsule of the hip-joint, 
the muscle occupies the outer part of Scarpa’s triangle, internal to the sartorius and 
rectus femoris muscles. 
The pectineus arises from the sharp anterior portion of the ilio-pectineal 
line of the pubis, and (sometimes) from the triangular surface of the pubic 
bone in front of this. Forming a broad muscular band, it is directed obliquely 
downwards, backwards and outwards, to be inserted into the upper half of 
the line leading from the small trochanter of the femur to the linea aspera ; 
its lower attachment being placed in front of the insertion of the adductor brevis 
muscle. 
The pectineus forms a part of the floor of Scarpa’s triangle. Covered by the 
pubic portion of the fascia lata, it is partially concealed by the femoral vessels and 
the insertion of the ilio-psoas. It lies in front of the pubic bone, the obturator 
externus and adductor brevis muscles, and the superficial part of the obturator 
nerve. Its outer border is separated from the psoas by the internal circumflex 
artery. Its inner border is in contact above with the adductor longus: separated 
from it below by the deep femoral vessels. The muscle may be occasionally divided 
into inner and outer parts, the former innervated by the obturator, the latter by 
the anterior crural nerve. 
THE MUSCLES ON THE INNER SIDE OF THE THIGH. 
The muscles on the inner 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 muscle is a long flat band placed on the inner side of the thigh 
and knee. It arises by a linear origin from the lower half of the edge of the 
symphysis pubis, and for a similar distance from the adjoining part of the pubic 
arch. Its flattened fleshy belly passes down on the inner side of the thigh to 
the knee, where it ends in a tendon, inserted into the inner side of the shaft of 
the tibia just below the inner tuberosity, behind the sartorius and above the semi- 
tendinosus. It is separated from the sartorius tendon by a bursa, and beneath its 
tendon is another bursa common to it and the semitendinosus. 
The gracilis is superficial in its whole extent. Its deep surface covers the 
borders of the adductor longus and adductor-magnus muscles, as well as the super- 
ficial part of the obturator nerve. At the inner side of the knee it lies between 
the sartorius and semitendinosus. 
The adductor longus is a triangular muscle arising by a rounded tendon in 
the angle between the crest and symphysis of the pubis. Extending downwards 
and outwards, it is inserted into the middle two-fourths of the linea aspera. 
Lying in the same plane as the pectineus, the adductor longus is in contact with 
that muscle near its origin, but is separated from it below by an interval through 
which the deep femoral vessels pass. Its inner border is in contact with the 
gracilis and sartorius muscles. Its anterior surface forms part of the floor of 
Scarpa’s triangle above, part of the floor of Hunter’s canal below. It is covered 
near its insertion by the sartorius and the femoral vessels, and is connected to 
the origin of the vastus internus by an aponeurotic expansion of fascia beneath 
the sartorius, forming the roof of Hunter’s canal. Its posterior surface is in 
relation with the adductor brevis and the adductor magnus muscles, the deep 
femoral vessels, and the superficial part of the obturator nerve. The adductor 
longus may be double, or more or less fused with the pectineus. 
The adductor brevis is a large muscle which arises from the body of the 
pubis from an oval surface surrounded by the other muscles of this group. 
Directed downwards and outwards, the muscle expands, to be inserted by a 
linear attachment to the lower two-thirds of the line leading from the small 
a 
