Kinesiology

Lesson 13 of 16

Hip and pelvis

The hip is a stable, mobile ball-and-socket joint, and the pelvis transfers forces between trunk and legs. Hip muscles act in groups to flex, extend, abduct, adduct, and rotate the thigh. Their contribution changes with whether the leg is free or bearing weight. Ensure draping, consent, and positioning are especially clear around the pelvis and gluteal region.

Key points

• Iliopsoas is a principal hip flexor and connects lumbar region with the femur.
• Gluteus maximus extends and laterally rotates the hip; its contribution rises in powerful tasks.
• Gluteus medius and minimus abduct the hip and help control pelvic position during single-leg support.
• Deep lateral rotators contribute to hip rotation and joint control.
• Adductors move the thigh toward midline and may assist other actions by position.
• Do not assume asymmetry or tissue tenderness indicates pathology.

Key terms

Iliacus

O: iliac fossa; I: lesser trochanter via iliopsoas tendon; A: flexes hip.

Psoas major

O: T12-L5 vertebral bodies, discs, and transverse processes; I: lesser trochanter; A: flexes hip and assists trunk flexion.

Gluteus maximus

O: posterior ilium, sacrum, coccyx, and sacrotuberous ligament; I: iliotibial tract and gluteal tuberosity; A: extends and laterally rotates hip.

Gluteus medius

O: external ilium between anterior and posterior gluteal lines; I: lateral greater trochanter; A: abducts and stabilizes pelvis, anterior fibers medially rotate.

Piriformis

O: anterior sacrum; I: superior greater trochanter; A: laterally rotates extended hip and abducts flexed hip.