Posterior iliac spine

The posterior iliac spine is a bony projection located on the ilium, which is part of the pelvis. It is divided into two distinct parts: the posterior superior iliac spine (PSIS) and the posterior inferior iliac spine (PIIS).

Anatomy

The posterior iliac spine is situated at the back of the ilium, one of the three bones that make up the pelvis. The ilium is the uppermost and largest part of the pelvis, and the posterior iliac spine is located at its posterior end.

Posterior Superior Iliac Spine (PSIS)

The posterior superior iliac spine is the uppermost part of the posterior iliac spine. It serves as an important landmark for various medical and anatomical procedures. The PSIS is easily palpable through the skin and is often used as a reference point in clinical settings.

Posterior Inferior Iliac Spine (PIIS)

The posterior inferior iliac spine is located just below the PSIS. It is less prominent than the PSIS but still serves as an important anatomical landmark. The PIIS provides attachment points for ligaments and muscles, contributing to the stability and movement of the pelvis.

Function

The posterior iliac spine serves several functions:

• It provides attachment points for various ligaments and muscles.
• It acts as a landmark for anatomical orientation and medical procedures.
• It contributes to the stability and movement of the pelvis.

Clinical Significance

The posterior iliac spine is often used as a reference point in medical imaging and surgical procedures. It is also a common site for the attachment of ligaments and muscles, making it significant in the study of biomechanics and orthopedics.

Related Structures

• Anterior superior iliac spine
• Anterior inferior iliac spine
• Ilium (bone)
• Pelvis
• Sacrum

See Also

• Pelvic girdle
• Hip bone
• Sacroiliac joint
• Lumbar vertebrae