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Iliac crest

The iliac crest is the superior curved border of the ilium, forming the uppermost margin of the pelvis. It extends from the anterior superior iliac spine (ASIS) to the posterior superior iliac spine (PSIS), curving superiorly and laterally. It serves as a prominent bony landmark palpable subcutaneously in nearly all individuals.

The iliac crest provides extensive muscular and fascial attachments, including the abdominal muscles (external oblique, internal oblique, and transversus abdominis), erector spinae, quadratus lumborum, and latissimus dorsi. It also contributes to the origin of the tensor fasciae latae and insertion of the thoracolumbar fascia.

The crest has significant clinical and surgical relevance: it is commonly used as a donor site for autologous bone grafting, as a landmark in lumbar punctures, pelvic surgery, and hip replacement, and as a guide in spinal and orthopedic interventions.

Synonyms

  • Crista iliaca

  • Pelvic crest

  • Superior border of ilium

Function

  • Provides muscular and fascial attachment for abdominal, spinal, and pelvic muscles

  • Serves as a palpable surface landmark for clinical procedures (lumbar puncture, pelvic surgery)

  • Source of cortical and cancellous bone for grafting in reconstructive surgery

  • Contributes to pelvic ring stability and load transmission between trunk and lower limbs

Nerve Supply

  • Primarily from lateral cutaneous branches of intercostal nerves (T11–T12)

  • Iliohypogastric nerve (L1) and ilioinguinal nerve (L1) supply skin and fascia overlying the crest

  • Deep innervation contributions from lumbar plexus branches to muscle attachments

Arterial Supply

  • Iliolumbar artery (branch of posterior division of internal iliac artery)

  • Deep circumflex iliac artery (branch of external iliac artery)

  • Small contributions from superior gluteal artery

Venous Drainage

  • Mirrors arterial pattern:

    • Iliolumbar vein → internal iliac vein

    • Deep circumflex iliac vein → external iliac vein

    • Tributaries drain into superior gluteal venous system

MRI Appearance

T1-weighted images:

  • Iliac crest cortex shows low signal intensity (dense cortical bone)

  • Bone marrow within ilium shows intermediate to high signal depending on fat content

  • Clear demarcation of muscle attachments along the crest

T2-weighted images:

  • Cortex remains low signal

  • Marrow appears variable, with fat showing low-intermediate and edema or infiltration showing hyperintensity

  • Useful in detecting bone marrow edema, fractures, or lesions

STIR:

  • Fat suppression highlights bone marrow edema, fractures, infection, or neoplastic infiltration

  • Muscular and fascial attachments also appear more conspicuous

T1 Fat-Saturated (Pre-contrast):

  • Suppresses marrow fat, making edema or infiltration stand out as intermediate signal areas

T1 Fat-Saturated Post-Contrast (Gadolinium):

  • Enhances vascularized marrow, periosteum, or soft tissue lesions

  • Helps differentiate tumor vs inflammatory vs traumatic changes

MRI Non-Contrast 3D Imaging:

  • Provides 3D reconstruction of iliac crest morphology, useful in preoperative planning for graft harvesting and orthopedic surgery

CT Appearance

CT Pre-Contrast:

  • Iliac crest cortex visualized as hyperdense rim

  • Detects fractures, cortical irregularities, and bone stock for grafting

  • Excellent for evaluating pelvic alignment and surgical planning

CT Post-Contrast:

  • Enhances soft tissues, musculature, and adjacent vascular structures

  • Useful for detecting tumor invasion, infection, or hematomas at the iliac crest

CT images

Iliac crest CT coronal image

CT images

Iliac crest CT axial image

MRI image

Iliac crest MRI axial anatomy image -img-00000-00000

CT VRT image

Iliac crest CT VRT