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Rectus capitis posterior minor muscle

The Rectus capitis posterior minor muscle is a small, deep muscle located at the posterior aspect of the upper cervical spine, forming part of the suboccipital muscle group. It plays an essential role in fine head movements and proprioception. Clinically, it is significant due to its proximity to the dura mater and its potential role in cervicogenic headaches.

Synonyms

  • RCPm

  • Musculus rectus capitis posterior minor

  • Posterior minor rectus muscle of the head

Function

  • Assists in extension of the head at the atlanto-occipital joint

  • Provides proprioceptive feedback

  • Helps stabilize the head and neck

Origin and Insertion

  • Origin: Posterior tubercle of the atlas (C1 vertebra)

  • Insertion: Medial part of the inferior nuchal line of the occipital bone

Nerve Supply

  • Suboccipital nerve (dorsal ramus of the first cervical spinal nerve, C1)

Artery Supply

  • Branches of the vertebral artery

  • Occasionally supplied by the deep cervical artery

Vein Supply

  • Drained by veins accompanying the arteries (vertebral venous plexus and deep cervical veins)

MRI Appearance

  • T1-weighted: Appears as an intermediate to low signal intensity structure, distinguishing muscle from surrounding fat and connective tissue.

  • T2-weighted: Normal muscle demonstrates relatively low signal intensity, but increased signal may indicate edema or pathology.

  • STIR: Suppressed (low signal) under normal conditions; high signal if there is edema, injury, or inflammation

CT Appearance

  • Appears as a small, symmetric muscle band posterior to the atlas, best visualized on high-resolution axial images

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MRI images

Rectus capitis posterior minor muscle MRI axial image