Lecture Notes: The Pelvic Girdle

Overview

• Main Function: Attaches the lower limbs to the axial skeleton via strong ligaments.
• Components: Primarily made up of two hip bones (coxal bones).
• Development: Coxal bones represent three fused bones from fetal development: the ilium, ischium, and pubis.

Hip Joint

• Type: Ball and socket joint called the acetabulum.
• Connection: Connects the femur to the pelvic girdle.
• Characteristics:
  • More stable than the shoulder joint.
  • Stability sacrifices mobility.

Ilium

• Position: Most superior bone of the three.
• Structure:
  • Body Area: Main area of the ilium.
  • Ala (Wing): Upper wing area.
  • Iliac Crest: Thickened region, felt as the "hips".
  • Anterior Superior Iliac Spine: Attachment for thigh muscles.
  • Anterior Inferior Iliac Spine: Additional attachment point.
  • Posterior Iliac Spines: Not easily visible but located in the posterior.
  • Articulation: Auricular surface connects with the sacrum forming the sacroiliac joint.

Ischium

• Position: Most inferior component of the hip bone.
• Structure:
  • Joins with the pubis at the pubic arch region.
  • Greater Sciatic Notch: Upper notch area.
  • Lesser Sciatic Notch: Lower notch in the ischium.

Pubis

• Position: Anterior part of the hip bone.
• Structure:
  • Pubic Symphysis: Joins the two pubis bones, characterized by thick cartilage.
  • Obturator Foramen: Passageway for blood vessels and nerves, created by pubis and ischium.

Male vs. Female Pelvis

• Adaptation: Female pelvis is adapted for childbearing.
• True vs. False Pelvis:
  • False Pelvis: Superior region, including the iliac crest.
  • True Pelvis: Actual opening, broader in females.
• Differences:
  • Female Pelvis: Broader, more circular, rounded pubic arch.
  • Male Pelvis: Heavier, stockier, acute angle at the pubic arch.
• Q Angle:
  • Female: Broader, tilted forward pelvis creates a Q angle, affecting femur orientation.
  • Male: Straighter femur alignment for weight transfer.
• Sacrum & Sciatic Notch:
  • Female Sacrum: Wider and sciatic notch broader.
  • Male Sacrum: Narrower sacrum and sciatic notch.

Implications

• Weight Bearing: Male pelvis supports heavier weight, whereas adaptations in females accommodate childbirth.
• Knee Pressure: Females' broader pelvis places extra pressure on knees.

These notes summarize the key points on the structure and function of the hip girdle as presented in the lecture, including differences between male and female pelvises and implications for movement and childbearing.