Muscles of the Gluteal Region

DR. NIVIN SHARAF MDLMCC

Objectives• Identify the bony landmarks of the pelvis and hip on the articulated

skeleton and bones. Include: pelvis (ilium, ischium, pubis, iliac crest, iliac fossa, anterior superior iliac spines, pubic tubercle, pubic crest, acetabulum, obturator foramen, greater and lesser sciatic notches, ischial spine, sacroiliac joint, greater and lesser sciatic foramina, ischial tuberosity), femur (head, neck, shaft, greater and lesser trochanters, intertrochanteric line and crest, linea aspera).

• Explain how the anatomical position affects the muscle function. . • Locate the piriformis muscle and the suprapiriform and the infrapiriform

spaces. • Identify the superior gluteal nerve in the suprapiriform space and the sciatic

and inferior gluteal nerves emerging via infrapiriform space. • . Summarize the muscles of gluteal region and thigh in terms of their

location, origin, insertion, nerve supply and actions.

Bony Skeleton

FYI

Anterior. Posterior.Proximal:-head,-fovea-neck,-greater + lesser trochanters, -intertrochanteric line + crest-gluteal tuberosity -linea aspera.

Distal:-supracondylar lines-epicondyles,-condyles-adductor tubercle

FEMURgreater trochanter head

necklesser trochanter

intertrochanteric line

lateral epicondyle

medial epicondyle

lateral condyle

medial condyle

intertrochantericcrest

linea asperagluteal tuberosty

adductor tubercle

supracondylarlines

Sciatic foramen

Movements of Hip Joint

Internal rotation

External rotation

Gluteal region

• Gluteal muscles: a-Gluteus maximus b-Gluteus medius c-Gluteus minimus• Tensor fasciae latae -iliotibial tract.• Small lateral rotators of thigh.• Sciatic and posterior cutaneous nerve of thigh.• Superior and inferior gluteal ARTERIES.

Gluteal region:

-Gluteus maximus(most powerful extensor,also lateral rotator)

Insertion:Gluteal tuberosity +Iliotibial tract (band)

gluteus maximus

iliotibial tractTensor FasciaeLatae

Gluteusmaximus

Gluteus Maximus

Lateral View Posterior View

Gluteus Maximus

Gluteus Maximus and Tensor Fascia Lata insert into Iliotibial Tract- Iliotibial tract is a thickening of the deep fascia (fascia lata) that extends from the ilium to the tibia. - Tension from contraction of gluteus maximus and tensor fasciae latae stabilizes the lower limb as a weight-bearing column.

FYI

Tensor Fascia Lata

PosteriorLateral

Illio Tibial Tract (Band)

Is the thickened lateral part of fascia latae.Receive insertions of:

1- tensor fasciae l. 2- superf ¾ of gluteus

maximus.Attached to oblique ridge on the front of lat condyle of tibia.Stabilize femur on tibia during standing.

Gluteus Medius

helps to keep the pelvis level when the opposite leg is raised during activities such as running,Walking, or standing on one leg

Extends, Abducts and Medial and Lateral rotations (Ant and posterior fibers)

Gluteus MinimusPosterior View

Small Lateral Rotators of Thigh1. Piriformis .2. Obturator internus.3. Superior gemillus4. inferior gemillus5. Quadratus femoris.

Action• Gluteus maximus:1- main extensor of hip. 2- lateral rotation of hip 3- Maintain knee joint in

Extension through the iliotibial tract.• gluteus medius, gluteus minimus, tensor fascia latae

:1- extension of hip 2- abduction of hip 3-medial rotation (anterior fibers)4-contract during walking to prevent tilting of pelvis.

Nerve supply

• Inferior gluteal nerve → gluteus maximus.• Superior gluteal nerve →gluteus medius. gluteus minimus. tensor fascia latae

Intrinsic muscles

• Infra and supra Piriformis space

Superior gluteal nerve

Deep to gluteus maximus:-abductors:

gluteus mediusgluteus minimus

(anterior fibres medially rotate)

-lateral (external) rotators:piriformisobturator internus(associated gemelli)quadratus femoris

[obturator externus is also alateral rotator]

inferior gamellus

superior gamellus

gluteus medius

gluteus minimus

piriformis

obturator internus

quadratus femoris

gluteus maximus

Lateral and Medial Rotation of the hip

Gluteus medius and minimus: abduction of femur and stabilization of pelvis

Trendelenburg Sign.

Loss of abductor function(gluteus medius & minimus)causes the pelvis to tilt downwhen supporting the bodyon the affected side (*).

(I.e. damage to superior gluteal nerve).

This function of these muscles is called “stabilization of the pelvis”.

Normal Positive sign

*

Superior and Inferior Gluteal Nerves

Superior:Gluteu MediusGluteus Minimus

InferiorGluteus Maximus

QUIZ

Intragluteal Injections

• What?

• Why?

Avoid Sciatic Nerve Injury

Sciatic Nerve (L4-S3)

• Thickest nerve in the body

• About 2cm in diameter

• L4, L5, S1, S2, and S3 Inside the pelvis

• Leave through greater sciatic Foramen, below piriformis.

FYI!

Sciatic Nerve Variations!

Action N supply Insertion Origin MuscleLateral

rotationS1,2 Upp border

of g trochanter

3 middle Sacral peices

Piriformis

Lateral rotation

N to obturator int

T of obt. int Spine of ischium

Sup gemillus

Lateral rotation

N to quadratus f

T of obt. int Upp margin of ischial tuberosity.

Inf gemillus

Lateral rotation

N to obturator int

Med surf of g trochanter

ObturatorMembrane

Obturator internus

Lateral rotation

N to quadratus f

Quadrate t Ischial tuber Quad fem

QUIZ

References

• www.netteranatomy.com• www.studentconsult.com• www.google.com• Gray’s Anatomy for students