The Quadratus femoris muscle originates from the ischial tuberosity. This robust, quadrilateral muscle plays a crucial role in hip movement and stability.
Understanding the Origin of Quadratus Femoris
The ischial tuberosity, often referred to as the "sit bone," is a prominent bony projection located on the inferior part of the ischium, which is one of the three bones forming the hip (pelvic) bone. The Quadratus femoris muscle arises from the lateral border of this tuberosity. Its fibers then extend horizontally across the posterior aspect of the hip joint.
Anatomical Overview of Quadratus Femoris
The Quadratus femoris is a flat, square-shaped muscle that belongs to the deep lateral rotator group of muscles in the gluteal region, located inferior to the obturator externus and gemelli muscles. Its precise anatomical position and connections are vital for its functions.
Here is a summary of the key anatomical characteristics of the Quadratus femoris muscle:
| Feature | Description |
|---|---|
| Origin | Ischial tuberosity |
| Insertion | Intertrochanteric crest of femur |
| Action | Hip joint: thigh external rotation; stabilizes head of femur in acetabulum |
| Innervation | Nerve to quadratus femoris (L4-S1) |
| Blood Supply | Inferior gluteal artery |
Functional Significance
The primary actions of the Quadratus femoris are:
- External rotation of the thigh: This action helps to turn the leg outward.
- Stabilization of the hip joint: By pulling the head of the femur into the acetabulum (the socket of the hip bone), it contributes significantly to the overall stability of the hip, especially during weight-bearing activities.
Understanding its origin from the ischial tuberosity helps in comprehending its biomechanical leverage for these important movements and its role in maintaining hip integrity.
