Lower Limb

APPENDICULAR SKELETON

  • Presented by Dr. Kalim Raza, Assistant Professor, Department of Human Anatomy, Samarkand State Medical University.

Pelvic Girdle

  • Composition: Made up of two hip bones (coxal bones).

  • Function: Strong structure designed to bear body weight and withstand movement stress.

  • Coxal Bones: Comprised of three fused bones:

    • Ilium: Articulates with the sacrum.

    • Ischium

    • Pubis

Acetabulum

  • Also known as the hip socket.

  • Meeting point of the ilium, ischium, and pubis.

  • Located on the lateral surface of the hip bone (coxal bone).

  • Articulates with the head of the femur (features the lunate surface).

    • Acetabular Notch: A gap in the ridge of the acetabulum’s margins.

Anatomy of the Right Hip Bone

  • Key features:

    • Ischium

    • Iliac Crest

    • Anterior Superior Iliac Spine

    • Inferior Gluteal Line

    • Anterior Inferior Iliac Spine

    • Acetabulum and Acetabular Notch

    • Superior Ramus of Pubis, Pubic Tubercle, Inferior Ramus of Pubis.

    • Obturator Foramen, Ischial Ramus, Ischial Tuberosity

    • Lesser Sciatic Notch, Ischial Spine

    • Posterior Inferior Iliac Spine, Greater Sciatic Notch

    • Lunate Surface of Acetabulum, Posterior Superior Iliac Spine

    • Posterior Gluteal Line, Anterior Gluteal Line.

  • Overview: Lateral view of right hip bone marked as posterior and anterior.

Ilium Markings

  • Greater Sciatic Notch: Passage for the sciatic nerve.

  • Iliac Crest: Upper edge of the pelvis.

  • Iliac Fossa: Depression between the iliac crest and arcuate line.

Ischium Markings

  • Ischial Spine: Located above the lesser sciatic notch.

  • Ischial Tuberosity: The bone projection you sit on.

  • Ischial Ramus: Meets the inferior ramus of the pubis.

  • Superior Ramus: Connects with the pubic tubercle.

Pubis Markings

  • Pubic Symphysis: Gap between pubic tubercles, padded with fibrocartilage.

  • Obturator Foramen: Formed by ischial and pubic rami, provides attachment for hip muscles.

  • Pectineal Line: Ridge on the superior ramus of the pubis, continues to iliac crest as arcuate line.

Coxal Bones Articulations

  • Sacroiliac Joint: Articulates the posterior surface of the ilium with the sacrum, stabilized by ligaments.

  • Pelvic Composition: Made up of two coxal bones, the sacrum, and the coccyx, with stability provided by ligaments of the pelvic girdle, sacrum, and lumbar vertebrae.

Pelvic Divisions

  • True Pelvis: Encloses the pelvic cavity, defined by the pelvic brim (upper edge) and the perineum region (support for pelvic cavity organs).

  • False Pelvis: Comprised of the blades of the ilium above the arcuate line.

Male vs. Female Pelvis

  • Female Pelvis: Smoother, lighter, with adaptations for childbearing, including an enlarged pelvic outlet, broader pubic angle (>100°), less sacrum and coccyx curvature, wide circular pelvic inlet.

  • Male Pelvis: Narrower and heavier with prominent muscle and ligament attachments, pelvis modifications for greater stability and less expansion for childbirth.

Anatomical Differences in Skeletons

  • Generalizations: Males typically have rougher, more robust skeletal features compared to females who present a broader, smoother skeleton.

  • Sexual Dimorphism: Notable differences exist in skull shape, pelvic inlet shape, and overall bone weight and markings.

  • Age-Related Changes: Skeletal changes including bony matrix reduction and decreased bone mass begin around age 30-45, progressing into later years.