Gluteal Region Dr Sama ul Haque Objectives Identify

Gluteal Region Dr. Sama ul Haque

Objectives • Identify the bony landmarks of the pelvis and hip on the articulated skeleton and bones. • Enlist the prominent bony features of the femur. • Identify the muscles of the gluteal region in terms of their origin, insertion, nerve supply and actions. • Identify the superior gluteal and inferior gluteal nerves in relation to Piriformis muscle. • Explain how the anatomical position affects the muscle function.

The Gluteal Region Ø It extends from the iliac crest (waist) above to the gluteal fold below. Ø Buttock: The lower part of the gluteal region which presents a rounded bulge due to fat is called buttock. Ø Hip: It is the anterosuperior part of the gluteal region.

Hip Bone

Bony Pelvis

Femur

Movements at Hip Joint

Muscles of gluteal region

Gluteus maximus (Chief extensor) Ø Most powerful & the bulkiest muscle of the body. (Anti-gravity muscle) Ø N. S: Inferior gluteal nerve (L 5, S 1, S 2) Ø Actions: § Chief extensor of thigh at hip. Helps in rising from sitting, bending or squatting positions and in climbing upstairs & cycling. § Supports the extended knee through iliotibial tract § Lateral rotator of thigh.

Gluteus maximus

Gluteus medius & Gluteus minimus (Abductors) Ø Both fan shaped & lie under G. Maximus Ø N. S: Superior gluteal nerve (L 5, S 1, ) Ø Actions: § Powerful abductor of thigh at hip joint. § Most important action is to prevent the opposite side of the pelvis tilting downwards as in walking & running.

Gluteus medius and minimus

Muscles of gluteal region

Gluteus maximus Tensor Fascia Latae iliotibial tract Tensor Fasciae Latae

Piriformis & Obturator Internus (Origin)

Piriformis & Obturator Internus (Insertion) Femur

Muscles of gluteal region

Gemellus Superior Gemellus Inferior Quadratus Femoris

Greater and Lesser Sciatic Foramen

Structures passing through greater sciatic foramen 1. Piriformis Muscle 2. Above Piriformis: Ø Superior gluteal nerve Ø Superior gluteal vessels 3. Below Piriformis: Ø Inferior gluteal nerve Ø Inferior gluteal vessels Ø Sciatic nerve Ø Post. Cutaneous nerve of thigh Ø Nerve to quadratus femoris Ø Nerve to obturator internus Ø Pudendal nerve Ø Internal Pudendal vessels

Structures passing through greater sciatic foramen

Structures passing through lesser sciatic foramen Ø Nerve to obturator internus Ø Pudendal nerve Ø Internal Pudendal vessels Ø Tendon of obturator internus The first three structures after coming out of the pelvis through greater sciatic foramen, reenter the pelvis by passing through the lesser sciatic foramen.

Structures passing through greater sciatic foramen

Site for Intramuscular Injection

(A)Standing Position (B)During walk (C)Positive Trendelenburg Sign

Normal Positive sign Trendelenburg Sign * Loss of abductor function (gluteus medius & minimus) causes the pelvis to tilt down when supporting the body on the affected side (*). (damage to superior gluteal nerve). This function of these muscles is called “stabilization of the pelvis”.

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