The vastus lateralis muscle is a common site for
intramuscular injection. To inject, first locate the greater trochanter of the
femur. The top border of the vastus lateralis muscle can be found a hand width
below the groin. The bottom border of the vasus lateralis muscle is found a
hand above the knee. The side borders are from the mid anterior thigh to the
mid lateral thigh. Squeezing the muscle before injection increases the
thickness and depth of the muscle and avoids nerve injuries. Make sure you do
not advance the needle deep to touch the bone. Aspirate before you inject.
The profunda femoris artery is the main blood supply of the
thigh. The profunda femoris artery arises from the posterolateral aspect of the
femoral artery about 4 cm below the inguinal ligament. The profunda femoris
artery crosses the pectineus muscle and the adductor brevis muscles, and runs
under the adductor longus muscle. Then it runs between the adductor magnus and
the adductor longus muscles. When it reaches the adductor magnus, it gives
three perforating branches and it ends by perforating the adductor magnus as
the fourth perforating branch. The perforating arteries are called “perforating”
because they perforate the insertion of the adductor margnus in order to reach
the back of the thigh. The first three perforating arteries are branches of the
profunda femoris itself, while the fourth perforating artery is a continuation
of the profunda femoris artery itself. During posterior exposure of the hip,
partial section of more than 2cm of the gluteus maximus tendon attachment on
the femur can be associated with a risk of injury to the first perforating
branch. The profunda femoris artery gives the medial circumflex femoral artery
and the lateral circumflex femoral artery. The MCFA will give the ascending,
the acetabular, and transverse branches. The LCFA will give the ascending, the
descending, and transverse branches.
