Pelvic Girdle (chap 9)

structure

4 bones → Sacrum, Coccyx, two hip bones (Ilium, Ischium, pubis)

2 joints → R/L sacroiliac joint , symphasis pubis, lumbosacral joint

False pelvis

• Bony area between the iliac crest and superior to the pelvis inlet

• Pelvis inlet: line between the lumbrosacral joint and the superior border of symphasis pubis

• No pelvic organs within this region

True Pelvis

• Lies between pelvic inlet and pelvic outlet

• Pelvic outlet: a line between the tip of the coccyx to the inferior border of the symphysis pubis

• makes up pelvis cavity

How do you determine if movement is coming from the hips, pelvic girdle or spine?

• Look art the relationship between the acromion process and the ASIS (anterior superior iliac spine)

  • if the relationship changes → its either spine or pelvic girdle

    • Shoulder stays in place and hip move → pelvic girdle motion

    • hip stays in place and the shoulder moves → spine motion

  • If the relationship does not change → hip motion

Motion of Pelvis on femur

3 DOF

• same motions as femur inside pelvis

• Renamed to indicate motion of pelvis

  • Anterior/Posterior pelvic girdle rotation (flex/ext)

  • L/R Lateral Pelvic Girdle Rotation (AB/AD)

  • L/R Transverse Pelvic Girdle Rotation (int/ext rot)

Motion of the Pelvis

• Open Chain Kinetic Action:

Most distal segment is free to move → throwing, kicking

• Closed Kinetic Chain action

The most distal segments is fixed and cannot move → push-up, squat