Anatomy of Gluteal Region

Anatomy of Gluteal Region.

1. Gluteal Region For the students of Gulf Medical University, Ajman, BPT Dr. Seyed Morteza Mahmoudi , MBBS Gulf Medical University, Ajman

2. Contents Gluteal region and boundaries Cutaneous innervation Muscles of gluteal region Arteries of gluteal region Nerves of gluteal region

3. Gluteal region The transitional area between the trunk and the lower extremity. Anatomically it is part of the trunk. Functionally it is part of the lower extremity. The gluteal region includes the rounded, posterior buttocks and the laterally placed hip region.

4. Boundaries Superiorly: iliac crest (at L4), Medially: intergluteal cleft, Laterally: Greater trochanter, Inferiorly: gluteal fold The gluteal muscles form the prominent majority of the gluteal region.

5. SUPERFICIAL FASCIA Cutaneous Nerves Upper-outer quadrant: Lateral branch of subcostal nerve. Lateral branches of iliohypogastric nerve Upper-inner quadrant: Posterior primary rami of L1,2,3 Posterior primary rami of S1,2,3 Lower-outer quadrant: Posterior divisions of lateral cutaneous nerve of thigh Lower-medial quadrant: Perforating cutaneous branches of S 2,3 Gluteal branches of posterior cutaneous nerve of thigh.

6. Muscles of the Gluteal Region

7. Muscles of the Gluteal Region Gluteus maximus : Largest muscle responsible for the prominence of the buttocks Origin- Outer surface of ilium behind posterior gluteal line Posterior surface of sacrum, coccyx and sacrotuberous ligament . Insertion – 75% of fibres into ilio-tibial tract – 25%(deep) into gluteal tuberosity.

8. Nerve - inferior gluteal nerve. Action - Extensor & lateral rotator of thigh at hip joint. Helps to maintain extension at knee through the ilio-tibial tract Paralysis of muscle – inability to raise the trunk from sitting or stooping positions 3 bursae are related to this muscle - trochanteric , ischial & gluteofemoral ( v.lateralis )

9.                   Iliotibial tract & Tensor fascia lata

10. Tensor fascia lata Arises from anterior part of iliac crest, ASIS and notch below and inserts into the iliotibial tract . Nerve: Superior gluteal nerve Action: Assists gluteus maximus in keeping knee in extended position Muscles of the Gluteal Region

11. Muscles of the Gluteal Region

12. Gluteus medius Posterior part covered by gluteus maximus Origin Outer surface of ilium b/w iliac crest above & posterior gluteal line behind and middle gluteal line below. Insertion Lateral surface of greater trochanter Nerve – superior gluteal nerve Action With G minimus and tensor fascia lata -powerful abductor at hip. Anterior fibres medially rotate the thigh Walking and running Holds opposite side of pelvis horizontally when foot is off the ground.

13. Muscles of the Gluteal Region

14. Gluteus minimus Origin Outer surface of ilium b/w middle & inferior gluteal lines Insertion - Anterior surface of greater trochanter Nerve -superior gluteal nerve Action With G minimus and tensor fascia lata -powerful abductor at hip. Anterior fibres medially rotate the thigh

15. Trendelenburg test ---- used to assess hip stability. The patient is asked to stand unassisted on each leg in turn, whilst the examiner's fingers are placed on the anterior superior iliac spines. The foot on the contralateral side is elevated from the floor by bending at the knee. In normal function, the hip is held stable by gluteus medius acting as an abductor in the supporting leg. If the pelvis drops on the unsupported side - positive Trendelenburg sign The hip on which the patient is standing is painful or has a weak or mechanically-disadvantaged gluteus medius.

16. A positive Trendelenburg test is found in: Any condition that brings the origin and insertion of gluteus medius together: subluxation or dislocation of the hip coxa vara ( defect of head of femur ) greater trochanter fractures slipped upper femoral epiphysis abductor paralysis or weakness e.g.: polio root lesion post-operative nerve damage muscle-wasting disease Any painful hip disorder which results in gluteal inhibition

17. Short Lateral Rotators of Thigh

18. Piriformis Key muscle of gluteal region Origin Pelvic surface of sacrum 2 nd ,3 rd & 4 th pieces Sacrotuberous ligament Insertion Upper border of greater trochanter Leaves the pelvis through greater sciatic foramen and separates gleuteal vessels and nerves to superior and inferior Nerve S1 2 anterior rami Short Lateral Rotators of Thigh

19. Origin : from pelvic surfaces of Body of ischium Ischial tuberosity Ischio -pubic ramus Obturator membrane & fascia. Insertion : tendon passes out of the pelvis through the lesser sciatic foramen and enters gluteal region >> upper border of greater trochanter. Obturator Internus Nerve : Nerve to obturator internus L5 S1 2 One ½ of muscle in pelvis other ½ in perineum Tendon in gluteal region Short Lateral Rotators of Thigh

20. Gamellus superior Origin-spine of ischium Insertion-tendon of OBT int Nerve- to OBT internus Gamellus inferior Origin- ischial tuberosity Insertion-tendon of OBT internus Nerve-to Quadratus femoris Quadratus femoris Origin- ischial tuberosity Insertion-quadrate tubercle Nerve-sacral plexus Short Lateral Rotators of Thigh

21. Arteries of Gluteal Region Superior gluteal -from internal iliac posterior division above piriformis Inferior gluteal -from internal iliac anterior division-below piriformis Trochanteric anastomosis - main supply to head of femur. Retinacular nutrient arteries pass along neck of femur to head. Formation Superior gluteal A Inferior gluteal A Medial Circumflex A Lateral circumflex A Cruciate anastomosis Inferior gluteal MCF and LCF 1 st perforating branch of PFA

22. Superior gluteal artery Branch from posterior division of the internal iliac artery Leaves the pelvis by passing through the greater sciatic foramen above the piriformis muscle

23. INFERIOR GLUTEAL ARTERY Arises from anterior division of Internal iliac artery. • Leaves the pelvis by passing through the greater sciatic foramen below the piriformis muscle

24. The sacral plexus supplies innervation to the pelvic muscles, gluteal muscles, and perineal muscles. It also forms the sciatic nerve. Sacral plexus Formed by the 4 th & 5 th lumbar ventral rami (lumbosacral trunk) and S 1234 • Forms on the ventral surface of the piriformis muscle

25. Sciatic nerve (L4, L5, SI, S2, S3) • Is the largest branch of the sacral plexus and the largest nerve in body • Consists of two separate nerves, the common peroneal nerve and the tibial nerve • Leaves the pelvis through the greater sciatic foramen below the piriformis muscle

26. Superior gluteal nerve (L4, L5, S1) • Leaves the pelvis through the greater sciatic foramen above the piriformis muscle with the superior gluteal artery and vein • In the gluteal region supplies the gluteus medius , the gluteus minimus , the tensor fasciae latae , and the hip joint

27. Inferior gluteal nerve (L5, S1, S2 ) • Leaves the pelvis through the greater sciatic foramen below the piriformis muscle with the inferior gluteal artery and vein • In the gluteal region supplies the gluteus maximus muscle

28. Posterior femorai cutaneous nerve (SI, S2, S3) • Leaves the pelvis through the greater sciatic foramen inferior to the piriformis • In the gluteal region descends on the posterior surface of the sciatic nerve • Supplies the skin of the buttocks, posterior thigh, popliteal fossa, and external genitalia

29. Nerve to the obturator internus (L5, S1, S2) • Leaves the pelvis through the greater sciatic foramen below the piriformis muscle • In the gluteal region descends on the superior gemellus muscle to pass below the ischial spine and enter the lesser sciatic foramen • Supplies the superior gemellus and obturator internus muscles

30. Nerve to the quadratus femoris (L4, L5, SI) • Leaves the pelvis through the greater sciatic foramen below the piriformis muscle and deep to the sciatic nerve • In the gluteal region runs anterior to the superior and inferior gemellus and obturator internus muscles • Supplies the inferior gemellus and quadratus femoris muscles

31. Pudendal nerve (S2, S3, S4) • Leaves the pelvis through the greater sciatic foramen inferior to the piriformis muscle along with the internal pudendal artery and vein • In the gluteal region descends posterior to the ischial spine and enters the lesser sciatic foramen • Is distributed to the perineum and has no branches in the gluteal region

32. Structures under cover Gluteus Maximus Gluteus medius and minimis Piriformis Superior gamellus and inferior Gamellus Tendon of obturator internus Quadratus femoris Adductor magnus -pubic fibres Origin of hamstrings Structures through greater sciatic foramen a. Above piriformis - superior gluteal vessels and nerves b. Below piriformis - Sciatic n; posterior femoral cutaneous nerves Inferior gluteal vessels & nerves PIN structures Nerve to OBT internus Nerve to quadratus femoris Cruciate anastamosis Bursae- ischial , tronchanteric,ilial & gluteo -femoral