Joints of the Pelvis: Pelvis & Hips Anatomy Introduction

Hip Joints

  • The head of the femur (thigh bone) is round and comprises half of the hip joint.
  • The acetabulum is a cavity located on the lateral (outer) surface of the hip bones and comprises the other half of the joint. This is the socket in which the head of the femur fits, creating the “ball and socket” hip joint.
  • “The femur sits in the acetabulum at an angle… pointing anteriorly about 10 to 25 degrees… The femoral heads are anterior to the hip sockets, not parallel to them.” (Judith Lasater)
  • Ligaments connect the ball to the socket and provide great stability to the joint.
  • The hip joint is “multi-axial,” meaning that it can move around more than one axis.

Sacroiliac Joints

  • The sacroiliac (SI) joints connect the hip bones to the sacrum.
  • The SI joints are capable of supporting the body’s weight. (Inner Body)

Sacrococcygeal Joint

  • The sacrococcygeal joint connects the sacrum with coccyx, allowing some slight movement of the tailbone.

Pubic Symphysis

  • Also called the symphysis pubis.
  • On the anterior (front) side of the pelvis, the pubic symphysis connects the left and right pubic bones.
  • It is comprised of strong ligaments which soften during pregnancy to allow for the baby’s passage from the pelvis.