Massage.
LandmarkHipDraft

Ischial tuberosity

The "sit bone": the thick knob of bone at the bottom of the pelvis that takes your weight when sitting.

BoneIschium (hip bone)
RegionHip

Find it

  1. Explain what you are about to do and get consent first, as this area is close to the groin. Work through the drape.
  2. Client side-lying with the top hip and knee bent (this moves gluteus maximus off the bone), or prone.
  3. Place your fingertips at the crease under the buttock (the gluteal fold), roughly in line with the middle of the buttock, and press gently up towards the head to meet a firm knob.
  4. Confirm with the client prone: ask them to bend the knee against light resistance, and feel the hamstring tendons tighten just below the tuberosity.

The hamstrings arise here: semimembranosus from the upper outer part, and the long head of biceps femoris with semitendinosus from the lower inner part. The hamstring part of adductor magnus and the sacrotuberous ligament attach to the lower part.

Gluteus maximus covers the tuberosity when standing but slides off it when sitting, which is why we sit on bone.

Muscles attaching or palpated here

  • Adductor magnus — Large, triangular inner-thigh muscle with an adductor part and a hamstring part, which pulls the thigh inwards and helps extend the hip.
  • Adductors — Group of five muscles on the inner thigh, running from the pubic bone and sitting bone to the femur and tibia, that pull the legs together.
  • Biceps femoris — Two-headed hamstring muscle on the outer back of the thigh that bends the knee, and with its long head also extends the hip.
  • Deep hip rotators — Six small, deep muscles behind the hip joint, running from the pelvis to the top of the femur, that laterally rotate the hip and steady the head of the femur in its socket.
  • Gemelli — Two small, paired deep hip muscles, above and below the obturator internus tendon, that help it laterally rotate the hip.
  • Gluteus maximus — The largest and most superficial buttock muscle, and the main extensor of the hip.
  • Hamstrings — Group of three muscles on the back of the thigh, running from the sitting bone to below the knee, that bend the knee and extend the hip.
  • Obturator externus — Flat, triangular muscle covering the outside of the front of the pelvis whose tendon wraps under the neck of the femur to laterally rotate the hip.
  • Obturator internus — Fan-shaped deep hip muscle that starts inside the pelvis, turns around the back of the ischium and laterally rotates the hip.
  • Quadratus femoris — Flat, four-sided deep muscle between the ischial tuberosity and the back of the femur that strongly laterally rotates and adducts the hip.
  • Semimembranosus — Broad, flat inner hamstring muscle lying under semitendinosus that bends the knee, extends the hip and turns the leg inwards.
  • Semitendinosus — Inner hamstring muscle with a long, cord-like lower tendon that bends the knee, extends the hip and turns the leg inwards.

Sources

  1. Wikipedia: Ischial tuberosity
  2. Gray's Anatomy (1918), The Hip Bone (Bartleby, archived)