Gluteal Region Anatomy Quiz

Gluteal Region: Lecture Notes

• The gluteal region includes bones, joints, attachments, foramina, hip joint movements, muscles (gluteals, external rotators), nerves, vascular structures, and clinical significance.

Outline

• A revision of prior learning is included.
• Details about the bones, joints, attachments, and foramina of the gluteal region are provided.
• Hip joint motion is discussed in detail.
• Detailed information on gluteal and external rotator muscles is offered.
• Information is provided on the nerves and vascular structures in the area.
• An exploration into the clinical significance of the region and a summary are outlined.

Questions

• Students are asked to name the thigh's medial fascial compartment muscles.
• Students are asked to determine the main motion associated with these muscles.
• Students are asked to identify the main artery supplying the region.
• Students are asked to identify the main nerve supplying the region.

Aims

• Study the bones, joints, attachments and foramina of the region.
• Explore the motions of the hip joint.
• Understand the arrangement and function of the gluteal and external rotator muscles.
• Investigate nerve and blood supply to gluteal and external rotator muscles and hip joint.
• Introduce the clinical importance of the region.

Bones

• Lumbar spine, sacrum
• Ilium, ischium, pubis, and femur are parts of the pelvis
• Sacroiliac joint and hip joint are visible.
• Coccyx is part of pelvis.

Sacroiliac Joint

• Articulation of the sacrum to the pelvis is described.
• Limited motion in the joint exists.
• It's a synovial and cartilaginous structure.
• Ligaments hold the joint together. - The anterior sacroiliac ligament is relatively weak and thin. - The posterior sacroiliac ligament is stronger and is further divided into long and short ligaments. - The interosseous sacroiliac ligament is the strongest ligament.
• Sacrospinous ligament stabilizes the joint.
• Sacrotuberous ligament stabilizes the joint.

Pubic Symphysis

• Articulation between right and left pubic bones.
• Fibrocartilage joint (synchondrosis).
• Supported by ligaments.
• Obturator, greater sciatic, lesser sciatic are foramina present.

Foramina

• Obturator foramen is covered by the obturator membrane.
• Obturator foramen is the origin of obturator internus and externus muscles.
• Obturator foramen allows nerves and vessels to pass through it.
• Greater sciatic foramen: Formed by greater sciatic notch and sacrotuberous/spinous ligaments.
• Greater sciatic foramen: Allows structures to pass from pelvis to gluteal region.
• Lesser sciatic foramen: Formed by lesser sciatic notch and sacrotuberous/spinous ligaments.
• Lesser sciatic foramen: Allows structures to pass from gluteal region to perineum.

Structures passing through sciatic foramina

• Structures that pass through the greater sciatic foramen:
  • Superior gluteal vessels and nerve
  • Inferior gluteal vessels and nerve
  • Sciatic nerve
  • Perforating and posterior femoral cutaneous nerves
  • Nerve to quadratus femoris
  • Pudendal nerve and internal pudendal vessels
• Structures that pass through the lesser sciatic foramen:
  • Tendon of obturator internus
  • Nerve to obturator internus
  • Internal pudendal vessels
  • Pudendal nerve

Hip Joint Motion

• Sagittal plane: Extension/flexion
• Frontal plane: Abduction/adduction
• Transverse plane: Internal/external rotation
• Circumduction: Movement in all three planes.

Hip Problems

• Fracture/dislocations and consequences
• Osteoarthritis (OA)
• Developmental dysplasia of the hip (DDH)
• Bursitis

Muscles

• Two main groups: gluteals and external rotators.

Gluteus Maximus

• Origin: Posterior surface of ilium and sacrum, sacrotuberous ligament
• Insertion: Gluteal tuberosity of femur, iliotibial tract
• Action: Hip extension and external rotation. Stabilises pelvis and knee.
• Antagonists: Hip flexors
• Innervation: Inferior gluteal; L5, S1, S2

Gluteus Medius

• Origin: Ilium between anterior and posterior gluteal lines.
• Insertion: Lateral surface of greater trochanter
• Function: Abduction and internal rotation of the thigh.
• Antagonists: Adductors and external rotators
• Innervation: Superior gluteal, L4,L5, S1

Gluteus Minimus

• Origin: Ilium, between anterior and inferior gluteal lines
• Insertion: Anterior surface of greater trochanter
• Action: Abduction and internal rotation of thigh at hip
• Antagonists: Adductors, external rotators
• Nerve supply: Superior gluteal, L4, L5, S1

Trendelenburg Sign

• Gluteus medius and minimus are required to maintain stability of the pelvis during single-leg stance.
• Weakness manifests as pelvis sagging to the unsupported side.
• Caused by nerve damage (superior gluteal).

External Rotators

• Piriformis
• Gemellus
• Quadratus femoris
• Obturator internus
• Obturator externus

Piriformis

• Origin: Middle three parts of sacrum
• Insertion: Upper border of greater trochanter
• Action: Abduction and external rotation of thigh
• Antagonists: Adductors, internal rotators
• Innervation: Branches from L5, S1 and S2

Quadratus Femoris

• Origin: Upper and outer ischial tuberosity
• Insertion: Quadratus tubercle of the intertrochanteric crest
• Action: External rotation of hip and stabilization
• Antagonists: Internal rotators
• Innervation: L4-L5-S1

Obturator Internus

• Origin: Obturator membrane and surrounding bones
• Insertion: greater trochanter, above the intertrochanteric fossa
• Action: External rotation and stabilization of hip
• Antagonists: Internal rotators
• Nerve supply: L5, S1, S2.

Gemellus

• Origins: Superior and inferior ischial spine/tuberosities
• Insertion: with obturator internus
• Action: Assists obturator internus
• Antagonists: Internal rotators
• Nerve supply: Obturator internus and Quadratus femoris

Obturator Externus

• Origin: External surface of obturator membrane and ischiopubic ramus
• Insertion: Trochanteric fossa
• Action: External rotation of thigh
• Antagonists: Internal rotators
• Innervation: Obturator (L3, L4)

Nerves

• The nerves of the gluteal region originate from both the lumbar and sacral plexuses.
• Muscles of the region are often innervated by individual nerves rather than branches of larger nerves.
• Sensory (cutaneous) nerves arise from the lumbar and sacral plexuses.

Nerves 2 (Motor)

• Superior gluteal (L4,L5,S1): Gluteus medius, minimus, and tensor fasciae latae
• Inferior gluteal (L5,S1,S2): Gluteus maximus
• Obturator internus (L5,S1,S2): Obturator internus and gemellus superior
• Quadratus femoris (L4,L5,S1): Quadratus femoris, gemellus inferior
• Piriformis (S1,S2): Piriformis
• Obturator externus (L3, L4): Obturator externus

Nerves 3 (Motor)

• Superior gluteal
• Inferior gluteal
• Sciatic
• Piriformis
• Pudendal

Nerves 4 (Motor)

• Pudendal, supplies "naughty bits"
• Sciatic: Important, traverses the gluteal region but doesn't innervate gluteal muscles. (supplies posterior thigh, lower leg and foot).

Nerves 5 (Sensory)

• Subcostal
• Iliohypogastric
• Lumbar 1-3: Posterior rami, perforating cutaneous nerve
• Sacral posterior rami

Nerves 6 (Hip Joint)

• Hip joint supply: Femoral nerve, obturator nerve (and/or accessory obturator), nerve to quadratus femoris, superior gluteal nerve, sciatic.

Nerve 7 - Sciatic Nerve

• Detailed description of the sciatic nerve

Nerve 8 - More Sciatic Nerve

• Detailed description of various branches of the sciatic nerve

Nerve 9 - Sciatic Variations

• Percentage of variations in relation of the sciatic nerve to the piriformis muscle in 1510 extremities.

Nerve 10 - Injection Site

• Safe injection site for nerves in the gluteal region.

Vascular Structures

• Superior gluteal artery
• Inferior gluteal artery: Both branches of internal iliac artery, pass through greater sciatic foramen.
• Trochanteric anastomosis and cruciate anastomosis.

Vascular Structures 2

• superior and inferior gluteal arteries.
• internal pudendal artery

Vascular Structures 3 (Hip Joint)

• Head of femur--supplied by posterior branch of obturator artery (intracapsular) or medial circumflex femoral artery
• Remainder of hip joint--supplied by medial and lateral circumflex femoral arteries (extracapsular).

Vascular Structures 4 (Hip Joint)

• Arterial supply to hip joint from obturator and circumflex femoral arteries

Pelvic Motion During Gait

• Pelvic rotation. occurs across the transverse plane
• Pelvic tilt. occurs in the frontal plane.

Summary

• Students should be able to categorize and name the gluteal and external rotator muscles and understand their functions.
• Identify the major nerves in the gluteal area, and understand what they innervate or the cutaneous areas that they supply.
• Know the major vascular structures and blood supply to the hip joint.
• Have a basic understanding of the clinical relevance of the area and how injuries can impact the region.

Look Forward

• Read and review the general details discussed
• Focus on muscle structures, locations, and functions
• Study vascular structures and nerves
• Prepare for the following week's lecture on the posterior thigh and knee.