Anatomy of the Gluteal Region

The Gluteal Region

• The pelvic girdle bones are connected by strong ligaments.
• Two crucial ligaments are the sacrospinous and sacrotuberous ligaments.
• These ligaments modify the greater and lesser sciatic notches, turning them into foramen.
• The greater sciatic foramen is a vital exit point for lower limb nerves and arteries leading to the gluteal region.
• The lesser sciatic foramen is also a significant aperture.

Apertures of the Pelvic Girdle

• Major nerves and blood vessels emanate from the spine and aorta, passing through the greater sciatic foramen to the gluteal region; crucial for the area's function.
• The greater sciatic foramen serves as a key passageway for nerves and arteries.

Muscles of the Gluteal Region

• Gluteal muscles (maximus, medius, and minimus) and tensor fascia latae are organized into superficial and deep layers.
• Six short lateral rotators are also present within the deep layer.

Deep Layer - Key Principles

• Muscles originating from the intertrochanteric crest, inserting at the greater trochanter, trochanteric fossa, and intertrochanteric crest.
• Muscles are responsible for lateral rotation of the thigh.
• Crucial to stabilizing the hip posteriorly.

Muscle Names

• Individual muscle names, such as piriformis, superior gemellus, inferior gemellus, obturator internus, quadratus femoris, and obturator externus, are precisely identified.

4 Muscles we can observe (2 hidden)

• Visible muscles include piriformis, gluteus medius, gluteus maximus (cut and reflected), and quadratus femoris.
• Obturator internus and externus are concealed.

Piriformis – Landmark of the Gluteal region!

• The piriformis originates from the anterior surface of the sacrum and exits through the greater sciatic foramen.
• The muscle is positioned superior to the border of the greater trochanter.
• Key to determining the gluteal vessels and nerve names.

Gemelli & Obturator internus

• The gemelli originate from the ischial bone (superior from spine, inferior from the tuberosity).
• Obturator internus blends with the tendon of the muscle and attaches to the trochanteric fossa.

Gemelli & Obturator internus

• Obturator internus originates from the pelvic surface of the obturator membrane and surrounding bone.
• It exits via the lesser sciatic notch and blends with the gemelli muscles.

Quadratus Femoris

• The quadratus femoris originates from the lateral border of the ischial tuberosity and attaches to the intertrochanteric crest.

Obturator externus

• The obturator externus originates at the margins of the obturator foramen and the membrane, passing under the femur’s neck to the trochanteric fossa.
• It's often hidden by other lateral rotators.

Nerve Supply

• Various muscles are supplied by different branches of specific nerves (S1, S2, L4, L5).
• Includes Piriformis (S1 & S2), Superior and Inferior Gemellus (L5 & S1, L4 & L5 &S1 respectively), and Obturator Externus (L2, L3, and L4).

Gluteus Medius & Gluteus Minimus

• Originating from the external surface of the ilium as fan-shaped muscles, they attach to the greater trochanter.
• Responsible for abduction and medial rotation of the thigh.
• Ilium spine is crucial in maintaining posture.

Superior Gluteal Nerve & Artery

• The Gluteus Medius and Minimus are supplied by the superior gluteal nerve and artery (L4, L5, and S1).
• Explains the function of abducted thigh movement..

Crucial role in walking

• Gluteus medius and minimus maintain pelvic stability during the unsupported phase of walking; essential for maintaining balance.
• Paralysis of the superior gluteal nerve leads to Trendelenburg gait.

Medial & Lateral rotation in Walking

• Medial and lateral rotations take place during simultaneous hip rotations on opposite limbs as the legs advance.
• This activity ensures the feet remain parallel with the advancing line.

Iliotibial tract (IT band)

• A fibrous reinforcement of the fascia lata, origin originating from the iliac spine's anterolateral tubercle.
• Extends to the tibia's anterolateral tubercle (Gerdy's tubercle).
• Acts as a lateral intermuscular septum, attached to the femur.

Gluteus maximus

• Originating from the posterior third of the iliac crest, sacrum, and coccyx, along with the sacrotuberous ligament.
• The muscle inserts into the IT tract and directly onto the femur (gluteal tuberosity).
• It aids in extension and lateral rotation.

Why do we have Gluteus maximus?

• The strongest hip extensor, its role is mostly for standing and not involved extensively in moving on flat ground.

Why do we have Gluteus maximus? (alternate)

• Primary function is maintaining stance and rising from seating.
• Actively involved in climbing stairs and incline walking.
• Critical for extending the leg in a flexed position, such as running.
• Plays an essential role in stabilizing the knee joint.

Inferior Gluteal Nerve & Artery

• Supplies the gluteus maximus with arterial and nervous supply (L5, S1, S2).

Tensor of the Fascia Lata

• An accessory muscle working synergistically with other muscles involved in hip flexion, medial rotation, abduction, and stabilizing the knee.
• Supplied by the superior gluteal neurovascular bundle.

Gluteal Bursae

• Membranous sacs filled with synovial fluid are located in areas prone to friction among muscles.
• Reduction of friction is crucial to facilitating smooth muscle movements.

Trochanteric Bursa

• The largest gluteal bursa, located between the superior gluteus maximus fibers and the greater trochanter.

Ischial Bursa

• A lesser-known bursa situated between muscles and the ischial tuberosity, prone to friction-related inflammation.

Sciatic nerve

• The sciatic nerve's location is midway between the trochanter & ischial tuberosity, descending from a position above the iliac spine's highest point.

Gluteal Intramuscular Injections

• Safe injection sites are located in the upper lateral quadrant to avoid vessels and nerves.