Anterior inferior iliac spine

Anterior inferior iliac spine
The obturator externus muscle (anterior inferior iliac spine visible in upper right)
Right hip-joint from the front (anterior inferior iliac spine visible at upper left)
Details
Identifiers
Latin	spina iliaca anterior inferior
TA98	A02.5.01.112
TA2	1328
FMA	63614
Anatomical terms of bone [edit on Wikidata]

The anterior inferior iliac spine (AIIS) is a bony eminence on the anterior border of the hip bone, or, more precisely, the wing of the ilium.

Structure

The AIIS is a bony eminence on the anterior border of the ilium. It is below the anterior superior iliac spine.

Development

The AIIS is formed from a separate ossification centre to the rest of the ilium.^[1]

Function

The upper portion of the spine gives origin to the straight head of the rectus femoris muscle.^[1] A teardrop-shaped lower portion gives origin to the iliofemoral ligament of the hip joint and borders the rim of the acetabulum.^[1]

Anteromedially and inferiorly to the AIIS is the iliopsoas groove, the passage for the iliopsoas muscle as it passes down to the lesser trochanter of the femur. A vague line, the inferior gluteal line, might run from the AIIS to the greater sciatic notch which delineates the inferior extent of the origin of gluteus minimus muscle.^[1]

Clinical significance

Rectus femoris muscle may avulse from the AIIS with significant mechanical stress.^[2] This may be surgically reattached.^[2]

Additional images

• 
  Left hip-joint, opened by removing the floor of the acetabulum from within the pelvis
• 
  Hip joint. Lateral view. Anterior inferior iliac spine visible to the left.

Notes

1. Morris CE (2005). Low back syndromes: integrated clinical management. McGraw-Hill Professional. pp. 49–50. ISBN 0-07-137472-8.
2. Maalouly J, Aouad D, Ayoubi R, Dib N, Darwish M, Saidy E, Nehme A (October 2020). "Anterior inferior iliac spine avulsion fracture post hip arthroscopy for Femoroacetabular impingement". Trauma Case Reports. 29: 100342. doi:10.1016/j.tcr.2020.100342. PMC 7453136. PMID 32885017.