Rectus femoris muscle

The rectus femoris muscle is a muscle of the pelvic limb located longitudinally along the cranial face of the femur. It is part of the quadriceps femoris muscle along with the vastus muscles.

Conformation: It is composed of a thick, fusiform, fleshy body and two tendinous ends on either side. Depending on the species, the proximal tendon may be bifid. The distal tendon is wider and thicker, receiving the endings of the other muscles of the quadriceps femoris muscle.

Origin: The origin of this muscle varies greatly depending on the species. Whether single or double, they are located around the acetabulum on the ilium bone.

Insertion: Depending on the interpretation, it is located on the tibial tuberosity or on the base and cranial surface of the patella.

Relations: This muscle is surrounded by the vastus muscles caudally and on the sides. Cranially, it is covered by the tensor fasciae latae muscle and then by the fascia lata. The proximal end is surrounded by the iliacus muscle and the deep gluteal muscle.

Action: Along with the other muscles that make up the quadriceps femoris, it acts as a leg extensor.

Vascularization: Lateral circumflex femoral artery.

Nerve: Femoral nerve.

Description: The rectus femoris muscle is a muscle of the pelvic limb. It is the most superficial and cranial of the muscles forming the quadriceps femoris muscle. This muscle originates near the acetabulum via a tendon that may be single or bifid. It then forms a thick, fusiform fleshy body that runs the entire length of the cranial surface of the femur. It then forms another thick, broad tendon that attaches first to the cranial surface of the patella, then through the patellar ligament to the tibial tuberosity. Near its origin, this muscle covers the deep gluteal muscle and then the intermediate vastus muscle. The medial vastus muscle and lateral vastus muscle surround it on either side. It is itself covered near its origin by the iliacus muscle, then by the tensor fascia lata muscle and the fascia lata. Its action, in common with the other muscles of the quadriceps femoris muscle, serves to extend the leg. Blood supply is provided by the lateral circumflex artery of the thigh. It is innervated by the femoral nerve.

Variations:

• In equines, this muscle is very thick. Its proximal tendon is short and powerful, divided into two equal origins that attach to two grooves located cranially to the acetabulum. The distal tendon is very strong and merges with the tendons of the vastus muscles.