The largest and most powerful part of the quadriceps femoris, located on the lateral side of the thigh. It acts to extend the knee joint and is often a site of trigger points in athletes.
Rectus Femoris
One of the four quadriceps muscles and the only one that crosses both the hip and knee joints. It acts as both a powerful knee extensor and a hip flexor, often contributing to anterior pelvic tilt.
Hamstrings
A group of three muscles located on the posterior thigh: the biceps femoris, semitendinosus, and semimembranosus. They are responsible for knee flexion and hip extension, and their tightness often influences pelvic tilt and low back strain.
Sciatic Nerve
The largest and longest nerve in the human body, beginning in the lower back and running down the back of each leg. Compression or irritation of this nerve can cause “sciatica,” characterized by radiating pain, numbness, or weakness.
Sacroiliac Joint
Commonly referred to as the SI joint, it is the joint between the sacrum and the ilium of the pelvis. It is a strong, weight-bearing joint that can be a significant source of low back and hip pain when dysfunctional.
Thoracolumbar Fascia
A large area of connective tissue in the lumbar region that serves as an attachment site for various muscles, including the latissimus dorsi and the transverse abdominis. It acts as a structural bridge between the upper and lower body.
Multifidus
A series of small, triangular muscle bundles located deep to the erector spinae. They provide essential stability to each individual segment of the spine and are frequently weakened in patients with chronic low back pain.
Erector Spinae
A group of three muscles—the iliocostalis, longissimus, and spinalis—that run parallel to the spinal column. They are primary extensors of the vertebral column and play a critical role in maintaining upright posture.