Anatomy of the Gluteal Region and Back of Thigh: Muscles, Nerves, and Vessels, Study notes of Physiology

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GLUTEAL REGION

BACK OF THIGH

By :

Prof.Saeed Abulmakarem

Dr. Sanaa Al-Shaarawi

OBJECTIVES

 At the end of this lecture, the student should be able

to identify :

 Contents of gluteal region:  Groups of Glutei muscles and small muscles (Lateral Rotators).  Nerves & vessels.  Foramina and structures passing through them as: 1 - Greater Sciatic Foramen. 2 - Lesser Sciatic Foramen.

• Back of thigh : Hamstring muscles.

CONTENTS II – NERVES: (all from sacral plexus):

1. Sciatic nerve.
2. Superior gluteal n.
3. Inferior gluteal n.
4. Post. cutaneous n. of thigh.
5. Nerve to obturator internus.
6. Nerve to quadratus femoris.
7. Pudendal nerve. 2 3 1 4 5 6 7

CONTENTS III - VESSELS: (all from internal iliac vessels):

1. Superior gluteal
2. Inferior gluteal
3. Internal pudendal vessels. Internal pudendal

Lesser sciatic foramen  Lesser sciatic notch of hip bone is transformed into foramen by Sacrotuberous & sacrospinous ligaments.

• Structures passing through

Lesser sciatic foramen :

• Tendon of obturator internus.
• Nerve to obturator internus.
• Pudendal nerve.
• Internal pudendal vessels.

• ORIGINS
• Gluteus minimus:
• Anterior part of the gluteal surface of ilium
• Gluteus medius:
• Middle part of the gluteal surface of ilium,
• Gluteus maximus:
• Posterior part of the gluteal surface of ilium,
• Main origin: Back of sacrum & coccyx & back of Sacrotuberous ligament Glutei Muscles

NERVE SUPPLY & ACTION of Gluti muscles

• Gluteus medius & minimus:
• Nerve supply:
• Superior gluteal nerve.
• Action:
• abduction & medial rotation of hip joint.
• Normally they prevent lateral tilt of the pelvis by contraction of ABDUCTORS on opposite side, on raising the other limb from ground.
• If the pelvis tilts,this is means +ve Trendlenburge’s sign.
• Right pelvic tilt (the left side of the pelvis is elevated higher than the right side) as in picture.
• This requires a muscular effort by the hip abductors (glutei medii and minimi of opposite side) to pull the pelvis up.
• Gluteus maximus:
• Nerve supply:
• Inferior gluteal nerve.
• Action:
• Extension & lateral rotation of the hip joint.
• Through its attachment to iliotibial tract, it stabilizes the femur on tibia during standing.

Small muscles (Lateral Rotators)

• Obturator Internus:
• Origin:
• Inner surface of the side wall of the pelvis.
• Insertion:
• Into the medial surface of the greater trochanter.
• Nerve supply:
• Nerve to obturator internus.
• Superior & Inferior Gemelli:
• Origin:
• Superior gemellus;
• upper part of lesser sciatic notch.
• Inferior gemellus:
• lower part of lesser sciatic notch.
• Insertion:
• Upper & lower parts into tendon of obturator internus.
• Nerve supply:
• Superior gemellus: nerve to obturator internus
• Inferior gemellus: nerve to quadratus femoris.

NERVES SUPERIOR GLUTEAL:

• Course:
• Passes through GSF, above piriformis, then between gluteus medius & minimus
• Branches:

1. Muscular to gluteus medius, minimus & tensor fasciae lata
2. Articular to hip joint INFERIOR GLUTERAL:

• Course:
• passes through GSF, below piriformis, then deep to gluteus maximus
• Branches: muscular to gluteus maximus NERVE TO QUADRATUS FEMORIS:
• Course:
• passes through GSF, below piriformis
• Branches:

1. Muscular to quadratus femoris & inferior gemellus
2. Articular to hip joint

POSTERIOR CUTANEOUS NERVE OT THIGH : Course: Passes through GSF, below piriformis, then descends deep to deep fascia. Branches: Cutaneous branches to: gluteal region, back of scrotum (labium majus) back of thigh & upper part of back of leg. SCIATIC : Course: passes through GSF, below piriformis, then superficial to: ischial spine, superior gemellus, tendon of obturator internus, inferior gemellus, quadratus femoris & adductor magnus. Branches: No branches in gluteal region, Divides into tibial & common peroneal nerves, in the middle of back of thigh NERVES

Biceps Femoris : (^) • Origin:

• The long head from the ischial tuberosity.
• The short head from the linea aspera.
• Insertion:
• Mainly into the head of the fibula. Nerve supply:
• The long head is supplied by the tibial part of sciatic;
• the short head is supplied by the common peroneal part of the sciatic. Action :
• Flexion of knee.
• Lateral rotation of flexed leg.
• Long head: extends hip.

SEMITENDINOSUS

• Origin:
• Ischial tuberosity.
• Insertion:
• Upper part of the medial surface of the shaft of the tibia (SGS).. Nerve supply:
• Tibial portion of the sciatic. Action:
• Flexes and medially rotates the leg at the knee joint;
• Extends the thigh at the hip joint.

ADDUCTOR MAGNUS (HAMSTRING PART)

• Origin:
• Ischial ramus and ischial tuberosity
• Insertion:
• Adductor tubercle of the medial condyle of the femur.
• Nerve supply:
• The tibial portion of the sciatic.
• Action:
• Extends the thigh at the hip joint.

BLOOD SUPPLY

• The four perforating branches of the profunda femoris artery (deep artery of thigh) provide a rich blood supply to this compartment.
• The profunda femoris vein drains the greater part of the blood from the compartment.