What makes the muscle bulge in middle?

The muscle bulge in the middle is called the rectus femoris muscle. It is one of the four muscles that make up the quadriceps group, which is located on the front of the thigh. The rectus femoris muscle is responsible for extending the knee joint and flexing the hip joint.

The rectus femoris muscle is located in the middle of the thigh, and it is the largest of the four quadriceps muscles. It originates from the anterior superior iliac spine, which is the bony prominence at the front of the hip bone. The muscle then runs down the front of the thigh and inserts into the tibial tuberosity, which is the bony prominence at the front of the shin bone.

The rectus femoris muscle is innervated by the femoral nerve, which is one of the largest nerves in the body. The femoral nerve originates from the lumbar spine, and it travels down the thigh to innervate the quadriceps muscles.

The rectus femoris muscle is involved in a number of movements, including:

* Knee extension: The rectus femoris muscle is the primary muscle responsible for extending the knee joint. When the rectus femoris muscle contracts, it pulls the shin bone forward, causing the knee to straighten.

* Hip flexion: The rectus femoris muscle also assists in flexing the hip joint. When the rectus femoris muscle contracts, it pulls the thigh bone forward, causing the hip to bend.

The rectus femoris muscle is a powerful muscle that is involved in a number of important movements. It is important to keep the rectus femoris muscle strong and flexible to avoid injury and to maintain good mobility.