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Costovertebral joint of first rib (rib head joint)

The costovertebral joint of the first rib is a synovial plane joint formed by the articulation between the head of the first rib and the body of the first thoracic vertebra (T1). Unlike most other ribs, the first rib articulates with a single vertebral body (T1) instead of two adjacent vertebrae.

The articular surfaces are covered by hyaline cartilage and enclosed within a fibrous capsule that is reinforced by the radiate ligament of the head of the rib. The joint allows slight gliding movements, contributing to the mechanics of respiration.

Anatomically, the costovertebral joint of the first rib is located deep to the manubrium and adjacent to the vertebral column, lying in close relation to the subclavian vessels, brachial plexus roots, and sympathetic chain. Its position and stability make it clinically relevant in thoracic outlet syndrome, trauma, and degenerative conditions.

Synonyms

  • First rib head joint

  • Costovertebral articulation of first rib

  • Articulatio capitis costae primae

Function

  • Provides a stable but slightly mobile articulation between the first rib and T1 vertebra

  • Allows limited gliding and rotational movement during inspiration and expiration

  • Maintains the structural integrity of the thoracic cage

  • Acts as a load-bearing joint, transmitting forces between rib and vertebral column

MRI Appearance

T1-weighted images:

  • Articular surfaces appear as low-signal cortical margins with intermediate subchondral marrow signal

  • Joint space is hypointense; surrounding fat aids identification

T2-weighted images:

  • Cartilage appears hyperintense, joint fluid if present also hyperintense

  • Early degenerative changes or synovitis may show increased signal in periarticular tissue

STIR:

  • Fat suppression highlights marrow edema, inflammation, or occult fracture near the rib head or T1 vertebra

  • Sensitive for trauma, infection, or arthropathy

T1 Post-Gadolinium (Gd-enhanced MRI):

  • Demonstrates synovial enhancement in cases of arthritis or infection

  • Enhances visualization of capsular inflammation, tumors, or vascularized lesions around the joint

MRI Non-Contrast Cardiac/Respiratory-Gated 3D Imaging:

  • Provides high-resolution multiplanar visualization of the joint capsule and relation to nearby neurovascular structures

  • Useful in pre-surgical mapping of thoracic outlet compression syndromes

CT Appearance

Non-contrast CT:

  • Excellent delineation of cortical bone, joint surfaces, and osseous alignment

  • Detects fractures, degenerative changes, or congenital anomalies of the rib head

CT Post-Contrast:

  • Enhances visualization of adjacent soft tissue and vascular structures

  • Helps differentiate osseous lesions, tumors, or inflammatory masses from vascular pathology

  • 3D reconstructions allow assessment of joint orientation and thoracic outlet relationships

CT image

Costovertebral joint of first rib (rib head joint) CT axial image -img-00000-00000

MRI image

Costovertebral joint of first rib (rib head joint) MRI coronal image -img-00000-00000