Appendicular skeleton 3 of 4

Overview

This lecture explains the structure and function of the pelvic girdle, focusing on its bones, features, and differences between male and female pelvises relevant to movement and support.

Structure and Function of the Pelvic Girdle

• The pelvic girdle must connect to the femur for both movement and weight support (e.g., standing, walking, running, jumping).
• It includes the sacrum and coccyx (fused vertebrae) and two coxal (hip) bones.
• Each coxal bone is formed by the fusion of three bones: ilium, ischium, and pubis.

Key Features of the Coxal (Hip) Bone

• The acetabulum is the socket where the femur head articulates (acetabulum = vinegar cup).
• The ilium is the large, superior portion of the coxal bone.
• The ischium is located inferiorly and posteriorly in the coxal bone.
• The pubis is the anterior, inferior part and can be palpated near the groin area.

Notable Bone Landmarks and Structures

• Iliac crest: the top edge of the ilium.
• Anterior/posterior superior and inferior iliac spines: protrusions for muscle attachment.
• Greater and lesser sciatic notches: passageways for nerves, separated by the ischial spine.
• Ischial tuberosity: rough area on the ischium for muscle attachment.
• Ischial and pubic rami: bone projections connecting ischium and pubis.
• Pubic tubercle: pointy area you can feel near groin.
• Obturator foramen: large opening in the coxal bone.
• Pubic symphysis: cartilage joint where pubic bones meet.

Differences Between Male and Female Pelvises

• Female pelvis has a wider pubic angle (over 100°), broader ilia, and wider pelvic openings.
• Male pelvis has a narrower pubic angle (90° or less) and more curved sacrum and coccyx.

Key Terms & Definitions

• Coxal bone — hip bone, formed by ilium, ischium, and pubis.
• Acetabulum — socket for the femur head.
• Iliac crest — upper edge of the ilium.
• Obturator foramen — large hole in the pelvis.
• Pubic symphysis — joint where the two pubic bones meet.
• Pubic angle (arch) — angle between pubic bones, wider in females.

Action Items / Next Steps

• Practice identifying pelvic bone landmarks on diagrams or models.
• Review key terms and definitions for memorization.