Gluteal and Posterior thigh muscles

• Gluteal region


  • Buttocks and hip region
  • Gluteal muscles constitute the bulk of this region
• Muscles of gluteal region


  • Abductors of thigh
  • Rotators of thigh
• Posterior thigh region


  • Extensors of hip
  • Flexors of knee
• Muscles of the gluteal region


  • Superficial layer: gluteus maximus, gluteus medius, gluteus minimus, tensor fasciae latae
  • Deep layer: piriformis, obturator internus, superior and inferior gemelli, quadratus femoris
• Gluteus maximus


  • The largest, heaviest, and most coarsely fibered muscle of the body
  • Covers all other gluteal muscles except the anterosuperior third of the gluteus medius
  • The ischial tuberosity can be felt on deep palpation through the inferior part of the muscle
  • The inferior gluteal nerve and vessels enter the deep surface of the gluteus maximus at its center
  • The superior part of its course, the sciatic nerve passes deep to the gluteus maximus
• When the thigh is flexed

  The inferior border of the gluteus maximus moves superiorly, leaving the ischial tuberosity subcutaneous
• You do not sit on your gluteus maximus; you sit on the fatty fibrous tissue and the ischial bursa that lie between the ischial tuberosity and skin
• The gluteus maximus slopes inferolaterally at a 45° angle from the pelvis to the buttocks
• Gluteus maximus


  • Largest and most superficial gluteal muscle
  • Attaches to the iliotibial tract and gluteal tuberosity of the femur
• Gluteus maximus


  • Superficial 3/4 attaches to iliotibial tract
  • Deep distal 1/4 attaches to gluteal tuberosity of femur

  
• The gluteus medius and minimus lie deep to the gluteus maximus on the external surface of the ilium
• The gluteus medius and minimus abduct or stabilize the thigh and rotate it medially
• The gluteus maximus extends and laterally rotates the thigh
• The gluteus maximus functions primarily between the flexed and standing positions of the thigh
• Paralysis of the gluteus maximus does not seriously affect walking on level ground
• Gluteal bursae


  • Separate the gluteus maximus from adjacent structures
  • Reduce friction and permit free movement
• Gluteus medius and gluteus minimus

  • Fan-shaped muscles that converge toward the same target
  • Share the same actions and nerve supply
  • Supplied by the superior gluteal artery
• The gluteus medius and minimus lie deep to the gluteus maximus and abduct or stabilize the thigh and rotate it medially
• Testing the gluteus medius and minimus

  1. Person side-lying with test limb uppermost and lowermost limb flexed for stability

  2. Abduct the thigh without flexion or rotation against straight downward resistance

  3. Gluteus medius can be palpated inferior to the iliac crest, posterior to the tensor fasciae latae
• Obturator internus


  • Located partly in the pelvis, covers most of the lateral wall of the lesser pelvis
  • Leaves the pelvis through the lesser sciatic foramen, makes a right-angle turn, and attaches to the medial surface of the greater trochanter
• Gemelli

  • Narrow, triangular extrapelvic reinforcements of the obturator internus
• Quadratus femoris


  • Short, flat quadrangular muscle located inferior to the obturator internus and gemelli
  • A strong lateral rotator of the thigh
• Quadratus femoris


  • Short, flat quadrangular muscle
  • Located inferior to the obturator internus and gemelli
  • Strong lateral rotator of the thigh
• Tensor fasciae latae


  • Served by the superior gluteal neurovascular bundle
  • Primarily a flexor of the thigh because of its anterior location
  • Does not act independently
  • Acts in concert with the iliopsoas and rectus femoris to produce flexion
  • Undergoes hypertrophy when the iliopsoas is paralyzed
  • Works in conjunction with other abductor/medial rotator muscles (gluteus medius and minimus)
  • Lies too far anteriorly to be a strong abductor, probably contributes primarily as a synergist or fixator
• Piriformis


  • Pear-shaped muscle
  • Located partly on the posterior wall of the lesser pelvis, and partly posterior to the hip joint
  • Leaves the pelvis through the greater sciatic foramen, almost filling it, to reach its attachment to the superior border of the greater trochanter
  • Landmark of the gluteal region
  • Determines the names of the blood vessels and nerves in the gluteal region
• Obturator internus and gemelli

  • Form a tricipital (three-headed) muscle
  • Obturator internus originates on the inner surface of the obturator membrane and passes through the lesser sciatic foramen to attach to the medial surface of the greater trochanter
  • Superior and inferior gemelli are small accessory muscles that attach the obturator internus to the greater trochanter
• The hamstring muscles (semitendinosus, semimembranosus, and biceps femoris long head) share common features: proximal attachment to the ischial tuberosity deep to the gluteus maximus, distal attachment to the bones of the leg, and innervation by the tibial division of the sciatic nerve
• Nerve to obturator internus

  Arises from the anterior divisions of the anterior rami of the L5-S2 nerves, paralleling the course of the pudendal nerve, supplying the superior gemellus as it passes around the base of the ischial spine, and then supplying the obturator internus muscle after entering the perineum via the lesser sciatic foramen
• Gluteus maximus


  Covers most structures in the gluteal region, can be felt to contract when straightening up from bending over
• Gluteus medius


  Superior part can be palpated between the superior part of the gluteus maximus and the iliac crest
• Piriformis


  Superior border indicated by a line joining the skin dimple formed by the PSIS to the superior border of the greater trochanter