At the conclusion of this chapter, the student should be able
- 1. Name, locate, and describe the structure and ligamentous
reinforcements of the articulations of the pelvic girdle and hip
- 2. Name and demonstrate the movements possible in the pelvic
girdle and hip joint, regardless of starting position.
- 3. Name and locate the muscles and muscle groups of the pelvis
and hip, and name their primary actions as agonists, stabilizers,
neutralizers, or antagonists.
- 4. Analyze the fundamental movements of the pelvis and thigh
with respect to joint and muscle actions.
- 5. Describe the common athletic injuries of the pelvis, hip,
- 6. Perform an anatomical analysis of the hip region in a motor
The relationship between the pelvic girdle and hip is somewhat
similar to that between the shoulder girdle and shoulder joint.
Just as the scapula tilts or rotates to put the glenoid fossa in
a favorable position for the movements of the humerus, so does the
pelvic girdle tilt and rotate to put the acetabulum in a favorable
position for the movements of the femur. There are these differences, however.
Whereas the left and right sides of the shoulder girdle can move
independently, the pelvic girdle can move only as a unit. The difference
in depth of socket also limits the movement at the hip joint but
is vital to accommodate the weight-bearing function of this joint.
Furthermore, whereas the movements of the shoulder girdle take place
in its own joints (sternoclavicular and acromioclavicular), the
pelvic girdle is dependent on the lumbosacral and other lumbar joints,
and the hip joints, for its movements. Hence, an analysis of the
movements of the pelvic girdle must always be stated in terms of
both spinal and hip action.
The pelvis (Figure 7.1) is a rigid bony basin that serves as
a massive connecting link between the trunk and the lower extremities.
Each pelvic bone (os innominatum) is made up of three bones: the
ilium, ischium, and pubis. These bones become fused into a single
bone by about the time of puberty. The two pelvic bones together
form the pelvic girdle. This bony girdle or basin is firmly attached
to the sacrum at the sacroiliac articulation, an articulation that
is difficult to classify. It presents some of the characteristics
of a diarthrodial joint, an articular cavity being present for part
of the articulation. It is unlike other diarthrodial joints in one
important respect, however. No movement can be voluntarily effected
at the sacroiliac joint. Any movement that does occur is involuntary.
Just how much motion can occur at the sacroiliac joint is debatable.
Some anatomists say that a slight “giving” may
occur there as a shock absorption device; others claim that no motion
occurs at the joint normally, except in women during pregnancy and
parturition, when the ligaments relax to permit a slight spreading
of the bones.