Gluteal Region and Hip

Bones & Joints - Bony Blueprint

• Pelvic Girdle: Composed of Ilium, Ischium, Pubis; fuse at Acetabulum.
  • Ilium: ASIS, Iliac crest, Gluteal lines (posterior, anterior, inferior).
  • Ischium: Ischial tuberosity, Ischial spine, Greater & Lesser sciatic notches.
• Proximal Femur: Head, Neck, Greater & Lesser trochanters, Intertrochanteric line & crest.
• Hip Joint (Coxal): Synovial ball-and-socket type.
  • Articulation: Femoral head with lunate surface of Acetabulum.
  • Acetabular labrum: Fibrocartilaginous rim, deepens socket, ↑ stability.
  • Key Ligaments: Iliofemoral (Y-ligament of Bigelow), Pubofemoral, Ischiofemoral. Ligamentum teres (artery to femoral head in children).

⭐ The Iliofemoral ligament (Y-ligament of Bigelow) is the strongest ligament in the body, preventing hip hyperextension during standing and maintaining upright posture with minimal muscle effort.

Gluteal Muscles - Power Packers

• Gluteus Maximus:
  • Largest, most superficial.
  • Action: Powerful hip extension (climbing, rising), lateral rotation.
  • Innervation: Inferior Gluteal Nerve (L5, S1, S2).
• Gluteus Medius & Minimus:
  • Deep to Maximus; fan-shaped.
  • Action: Main hip abductors, medial rotation (anterior fibers); crucial for pelvic stability during gait.
  • Innervation: Superior Gluteal Nerve (L4, L5, S1).
• Tensor Fasciae Latae (TFL):
  • Anterolateral; functionally synergistic.
  • Action: Hip flexion, abduction, medial rotation; tenses iliotibial tract.
  • Innervation: Superior Gluteal Nerve.

⭐ Trendelenburg Sign: Pelvis sags towards the unsupported (lifted leg) side, indicating weakness of the contralateral (stance leg) gluteus medius and minimus, innervated by the Superior Gluteal Nerve.

Gluteal Nerves - Wire Wonders

• Sup. Gluteal (L4,L5,S1): G. medius, minimus, TFL. Lesion: Trendelenburg gait. 📌 Superior Supports Stance.
• Inf. Gluteal (L5,S1,S2): G. maximus. Lesion: Difficulty climbing stairs.
• Sciatic (L4-S3): Exits < piriformis. Branches: Tibial, Common Peroneal.
• N. to Obturator Int. (L5,S1,S2): Obturator internus, Sup. gemellus.
• N. to Quadratus Fem. (L4,L5,S1): Quadratus femoris, Inf. gemellus.
• Post. Fem. Cutaneous (S1-S3): Sensory post. thigh, gluteal fold.
• Pudendal (S2-S4): Perineal sensation & motor.

⭐ Superior Gluteal N. injury causes Trendelenburg gait: contralateral pelvic drop.

oka

Gluteal Vasculature - Crimson Canals

• Arteries (from Internal Iliac A.):
  • Superior Gluteal A. (SGA):
    • Exits pelvis via greater sciatic foramen, SUPERIOR to piriformis.
    • Supplies: Gluteus medius, minimus, TFL.
  • Inferior Gluteal A. (IGA):
    • Exits pelvis via greater sciatic foramen, INFERIOR to piriformis.
    • Supplies: Gluteus maximus, obturator internus, quadratus femoris.
• Veins: Accompany arteries, drain to Internal Iliac V.
• Anastomoses: Cruciate & trochanteric (collateral supply).

⭐ SGA vulnerable to injury in posterior hip dislocation or IM injections (superomedial gluteal quadrant).

Clinical Correlations - Gluteal Gotchas

• Trendelenburg Gait/Sign:

  • Cause: Superior gluteal n. (L4-S1) injury → gluteus medius/minimus weak.
  • Manifestation: Pelvis drops on contralateral (swing) side during single-leg stance.

• Piriformis Syndrome: Sciatic nerve compression by piriformis. Buttock pain radiating down leg, mimics sciatica.

• Intragluteal Injections: Safest: Superolateral quadrant. Avoids sciatic nerve. 📌 "High and Outer".

• Weaver's Bottom (Ischial Bursitis): Ischial tuberosity bursa inflammation. Localized pain on direct pressure/sitting.

• Gluteus Maximus Lurch: Inferior gluteal n. (L5-S2) injury. Backward trunk lurch at heel-strike.

⭐ Positive Trendelenburg sign indicates weakness of hip abductors (gluteus medius & minimus) on the stance phase side causing contralateral pelvic drop during gait or single leg stance.

High‑Yield Points - ⚡ Biggest Takeaways

• Gluteus maximus: chief hip extensor; supplied by inferior gluteal nerve.
• Trendelenburg sign: indicates gluteus medius/minimus weakness (hip abductors); due to superior gluteal nerve injury.
• Sciatic nerve: exits pelvis via greater sciatic foramen, typically inferior to piriformis muscle.
• Piriformis syndrome: results from sciatic nerve compression by the piriformis muscle.
• Safe intramuscular injection site: superolateral quadrant of gluteal region to avoid sciatic nerve.
• Femoral head blood supply: primarily medial circumflex femoral artery in adults; artery of ligamentum teres (from obturator artery) in children.