Topics

Topic

design image
Rotatores thoracis muscles

The rotatores thoracis are small, deep intrinsic muscles of the back that belong to the transversospinalis group, along with multifidus and semispinalis. They are best developed in the thoracic region and contribute to fine postural adjustments and proprioception rather than gross spinal movement. Each rotatores muscle spans from the transverse process of one vertebra to the spinous process of the vertebra above (rotatores brevis) or two levels above (rotatores longus).

They are clinically significant because of their role in spinal stability, their involvement in chronic back pain syndromes, and their visibility on modern imaging.

Synonyms

  • Rotatores muscles of thorax

  • Musculi rotatores thoracis

  • Deep transversospinalis muscles

Origin, Course, and Insertion

  • Origin:

    • Arise from the transverse processes of thoracic vertebrae

  • Course:

    • Short, oblique fibers pass superomedially from transverse process to spinous process

    • Fibers are more prominent in the mid-thoracic region

  • Insertion:

    • Rotatores brevis: Insert into the lamina and spinous process of the vertebra immediately above

    • Rotatores longus: Insert into the spinous process of the vertebra two levels above

Relations

  • Anteriorly: Costovertebral joints and posterior thoracic cavity

  • Posteriorly: Erector spinae and thoracolumbar fascia

  • Laterally: Intertransversarii muscles and ribs

  • Medially: Spinal canal and dura mater (deep relation)

Function

  • Produce small rotary movements of vertebral column

  • Contribute to proprioception (contain high density of muscle spindles)

  • Assist in spinal extension and stabilization when acting bilaterally

  • Important for fine-tuning posture and thoracic spine mechanics

Clinical Significance

  • Weakness or strain may contribute to chronic thoracic back pain

  • Hypertrophy or spasm can compress adjacent facet joints

  • Targeted in physiotherapy and spinal rehabilitation programs

  • Can be visualized on MRI to assess spinal stability, atrophy, or pathology

MRI Appearance

T1-weighted images:

  • Muscles appear as low-to-intermediate signal intensity bands deep to multifidus

  • Fat planes and intramuscular fatty streaks appear bright

T2-weighted images:

  • Muscles show low-to-intermediate signal intensity

  • Pathology such as edema or inflammation appears as bright signal

STIR (Short Tau Inversion Recovery):

  • Normal muscles show low-to-intermediate signal

  • Inflammation, edema, or acute injury shows bright hyperintensity

T1 Fat-Sat Post-Contrast:

  • Normal muscles enhance mildly and homogeneously

  • Pathology shows focal or diffuse enhancement (e.g., myositis, tumor infiltration)

3D T2 SPACE / CISS:

  • Rotatores appear as intermediate signal muscle slips compared to muscle baseline

  • Surrounded by bright CSF in spinal canal and fat in paravertebral region, improving contrast

CT Appearance

Non-Contrast CT:

  • Appear as soft tissue density bands adjacent to vertebral laminae

  • Difficult to distinguish individually without high-resolution scans

  • Fat planes between muscles and bone are visible

Post-Contrast CT:

  • Normal muscle shows mild homogeneous enhancement

  • Pathology (abscess, neoplasm, inflammation) shows irregular or rim enhancement

  • Atrophy may appear as decreased bulk with fatty replacement

MRI image

Rotatores thoracis muscles mri axial anatomy image-img-00000-00000

CT image

Rotatores thoracis muscles ct axial anatomy image-img-00000-00000