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Head of rib

The head of the rib is the medial, rounded end of a typical rib that articulates with the thoracic vertebral column. It forms an essential component of the costovertebral joint, allowing controlled movement of the rib during respiration while maintaining stability of the thoracic cage.

The head of the rib is an important anatomical landmark in thoracic anatomy, spinal imaging, and musculoskeletal radiology.

Synonyms

  • Costal head

  • Capitulum of rib

Location

  • Situated at the posteromedial end of each rib

  • Adjacent to the thoracic vertebral bodies

  • Positioned posterior to the thoracic cavity

  • Forms part of the costovertebral articulation

  • Typically articulates at the level of its corresponding vertebra

Anatomical components

  • Articular facets:

    • Usually two facets separated by a crest (in typical ribs 2–9)

    • Superior facet articulates with the inferior costal facet of the vertebra above

    • Inferior facet articulates with the superior costal facet of the corresponding vertebra

  • Crest of the head:

    • Separates the two articular facets

    • Provides attachment for the intra-articular ligament

  • Articular cartilage:

    • Covers the facets forming synovial joints

Relations

Anteriorly:

  • Intervertebral disc

Posteriorly:

  • Costotransverse ligaments

  • Paraspinal muscles

Medially:

  • Thoracic vertebral body

Laterally:

  • Neck of the rib

Superiorly and inferiorly:

  • Adjacent thoracic vertebral bodies

Articulations

  • Costovertebral joint:

    • Synovial plane joint between rib head and vertebral bodies

  • Ligamentous support:

    • Radiate ligament of the head of the rib

    • Intra-articular ligament

X-ray appearance

Chest radiograph / thoracic spine views:

  • Head of rib: Seen as a rounded bony density adjacent to the vertebral body

  • Joint space: Thin radiolucent line at the costovertebral articulation

  • Symmetry: Normally symmetric on both sides

  • Overlap: May be partially obscured by vertebral bodies or mediastinal structures

CT appearance

Bone window:

  • Head of rib: Well-defined cortical bone with cancellous center

  • Articular facets: Smooth, well-corticated surfaces

  • Costovertebral joint: Clearly visualized joint space

Lung window:

  • Head of rib: Appears as a dense structure projecting into the posterior lung field

  • Surrounding lung parenchyma: Aerated lung provides high contrast

  • Useful for: Assessing rib contour and its relationship to adjacent lung apex

MRI appearance

T1-weighted images:

  • Cortical bone: Low signal intensity

  • Marrow within rib head: High signal due to fatty marrow

  • Articular cartilage: Intermediate signal

T2-weighted images:

  • Cortical bone: Low signal

  • Marrow: Intermediate signal

  • Joint space: Intermediate-to-high signal reflecting synovial fluid

STIR:

  • Marrow: Suppressed fat signal with uniform appearance

  • Joint space: Hyperintense fluid signal

  • Soft tissues: Ligaments and adjacent muscles well delineated

CT image

Head of rib CT Anatomy, Location and Imaging Appearance -img-00000-00000

X-Ray image

Head of rib x ray Anatomy, Location and Imaging Appearance -img-00000-00000