Topics

Topic

design image
C3–C4 intervertebral disc

The C3–C4 intervertebral disc is the fibrocartilaginous structure situated between the third (C3) and fourth (C4) cervical vertebrae in the cervical spine. It consists of a gelatinous nucleus pulposus, which provides cushioning, surrounded by a tough, fibrous annulus fibrosus that contains the nucleus and maintains spinal stability. The disc is approximately 3–5 mm thick in adults and contributes to cervical spine mobility, allowing flexion, extension, lateral bending, and rotation. The C3–C4 disc also functions as a shock absorber, distributing axial loads and reducing stress on the vertebral bodies and facet joints. Age, trauma, or degenerative changes can lead to disc dehydration, bulging, herniation, or osteophyte formation, which may impinge on adjacent spinal nerves or the spinal cord.

Location

  • Situated between the C3 and C4 vertebral bodies, anterior to the spinal cord

  • Posterior boundary is formed by the posterior longitudinal ligament

  • Lateral boundaries are the uncovertebral joints (of Luschka)

  • Anterior boundary is the vertebral body endplates, which anchor the annulus fibrosus

Function

  • Provides cushioning and load distribution between C3 and C4 vertebrae

  • Enables flexibility and mobility of the cervical spine

  • Maintains vertebral alignment and spinal stability

  • Protects the spinal cord and nerve roots from mechanical stress

MRI Appearance

T1-weighted images:

  • Normal C3–C4 disc shows intermediate signal intensity, slightly lower than adjacent vertebral bone marrow

  • Nucleus pulposus may appear slightly more hyperintense than annulus fibrosus in younger adults

  • Degenerative changes may cause loss of signal (desiccation) or disc height reduction

T1 Post-Contrast (Gadolinium-enhanced):

  • Normal discs usually do not enhance significantly

  • Enhancement is seen in degenerative annular tears, inflammation, or post-surgical changes

  • Useful for detecting infection (discitis), neoplasm, or inflammatory pathology

T2-weighted images:

  • Healthy nucleus pulposus is hyperintense, while annulus fibrosus is hypointense

  • Degenerated or dehydrated discs show reduced T2 signal, often referred to as a “dark disc”

  • T2 images are excellent for visualizing herniation, bulging, or annular fissures

STIR (Short Tau Inversion Recovery):

  • Fat suppression highlights edema or inflammation in the disc or adjacent vertebral endplates

  • Disc degeneration may appear as high signal in vertebral endplates (Modic changes type I)

  • Detects early infection or inflammatory changes not visible on conventional sequences

CT Appearance:

  • Disc itself appears as soft tissue density between hyperdense vertebral bodies

  • Disc height and intervertebral space are well assessed

  • Calcified discs, osteophytes, or bony endplate irregularities are clearly visualized

  • CT is particularly useful in trauma, preoperative planning, and bony degenerative assessment

MRI images

C3–C4 intervertebral disc