Rectus Capitis Posterior Major
Neck · Head & Neck
The rectus capitis posterior major is the larger of the two posterior rectus muscles and forms the medial border of the suboccipital triangle. It arises from the spinous process of the axis and widens as it ascends to insert on the lateral part of the inferior nuchal line of the occipital bone. Because its fibres run from the axis up and slightly laterally to the occiput, it extends the head and rotates it toward the same side. Like the rest of the suboccipital group, it is supplied by the suboccipital nerve, the dorsal ramus of C1.
Origin, Insertion, Action & Nerve
Origin
Spinous process of the axis (C2)
Insertion
Lateral part of the inferior nuchal line of the occipital bone
Action
Extends the head and rotates it to the same side
Nerve
Suboccipital nerve (dorsal ramus of C1)
Attachments explained
The Rectus Capitis Posterior Major is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.
Origin
Spinous process of the axis (C2)
Insertion
Lateral part of the inferior nuchal line of the occipital bone
Action & function
When the Rectus Capitis Posterior Major contracts, it produces the following movement: Extends the head and rotates it to the same side.
As part of the Neck group of the Head & Neck, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.
Nerve supply & clinical relevance
The Rectus Capitis Posterior Major receives its nerve supply from the Suboccipital nerve (dorsal ramus of C1). This nerve carries fibres from spinal segment(s) C1.
Because a muscle can only contract when its nerve is intact, injury to the Suboccipital nerve or to its spinal roots (C1) can weaken or paralyse the Rectus Capitis Posterior Major, impairing the movements it normally produces (extends the head and rotates it to the same side). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Rectus Capitis Posterior Major (the OIANS method)
Separate the posterior major from the posterior minor by their origins: major starts lower on the spinous process of the axis, minor on the posterior tubercle of the atlas. Because the major has a slightly oblique course from axis to occiput, it both extends and rotates the head to the same side, whereas the more vertical minor only extends. Contrasting the two origins and actions side by side keeps them apart.
Study it as a wall of the suboccipital triangle, sharing the suboccipital nerve (dorsal ramus of C1) with its three companions. Grouping the two posterior recti with the two obliques under one nerve, and noting that the major reinforces the inferior oblique in producing same-side rotation, ties the whole suboccipital region into a single coherent unit for revision.
Frequently asked questions
Where is the Rectus Capitis Posterior Major located?
The Rectus Capitis Posterior Major is a muscle of the Neck group, located in the Head & Neck.
What is the origin of the Rectus Capitis Posterior Major?
Spinous process of the axis (C2)
What is the insertion of the Rectus Capitis Posterior Major?
Lateral part of the inferior nuchal line of the occipital bone
What movements does the Rectus Capitis Posterior Major produce?
Extends the head and rotates it to the same side
What nerve supplies the Rectus Capitis Posterior Major?
Suboccipital nerve (dorsal ramus of C1)
Is the Rectus Capitis Posterior Major free to study in OIANS?
The Rectus Capitis Posterior Major is always free to browse. Its full origin, insertion, action and nerve details are open to everyone in the Muscle Directory. Quiz and Flashcard practice for the Head & Neck is part of the one-time Lifetime upgrade, though; only the Upper Limb decks are free to test yourself on.
Related muscles
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