Longissimus Capitis
Back · Trunk
Longissimus capitis is the head-reaching column of the longissimus, the intermediate and longest subdivision of the erector spinae. It arises from the transverse processes of the upper thoracic vertebrae (T1-T5) and the articular processes of the lower cervical vertebrae (C4-C7), and its slender fibres ascend to attach to the posterior margin of the mastoid process of the temporal bone. Because its pull is directed upward and slightly backward onto the skull, contraction of both sides extends the head at the atlanto-occipital and cervical joints, while one side acting alone rotates the face toward the same side. It is supplied, like the rest of the deep back musculature, by the posterior (dorsal) rami of the cervical spinal nerves. Its mastoid attachment places it alongside splenius capitis and sternocleidomastoid as a same-side rotator of the head.
Origin, Insertion, Action & Nerve
Origin
Transverse processes of T1–T5 and articular processes of C4–C7
Insertion
Posterior margin of the mastoid process of the temporal bone
Action
Bilaterally extends the head; unilaterally rotates it to the same side
Nerve
Posterior (dorsal) rami of cervical spinal nerves
Attachments explained
The Longissimus Capitis 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
Transverse processes of T1–T5 and articular processes of C4–C7
Insertion
Posterior margin of the mastoid process of the temporal bone
Action & function
When the Longissimus Capitis contracts, it produces the following movements: Bilaterally extends the head; unilaterally rotates it to the same side.
As part of the Back group of the Trunk, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.
Nerve supply & clinical relevance
The Longissimus Capitis receives its nerve supply from the Posterior (dorsal) rami of cervical spinal nerves.
Because a muscle can only contract when its nerve is intact, injury to the Posterior can weaken or paralyse the Longissimus Capitis, impairing the movements it normally produces (bilaterally extends the head). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Longissimus Capitis (the OIANS method)
Fix longissimus capitis by its two anatomical bookends: it starts low on the upper thoracic and lower cervical vertebrae and ends high on the mastoid process. That long, near-vertical run up the side of the neck is exactly why the muscle is named longissimus, the longest of the erector spinae columns, and why it can both extend and rotate the head. Trace the line of pull in your mind from mastoid down to the transverse processes and the actions follow automatically.
Group it with the other mastoid rotators to avoid confusion. Longissimus capitis, splenius capitis, and sternocleidomastoid all reach the mastoid process and all turn the face to the same side when acting unilaterally, but longissimus capitis is a deep dorsal-ramus muscle rather than a superficial one. Remembering that it is the capitis member of a three-part longissimus family (capitis, cervicis, thoracis) keeps its cephalic destination distinct from its lower siblings.
Frequently asked questions
Where is the Longissimus Capitis located?
The Longissimus Capitis is a muscle of the Back group, located in the Trunk.
What is the origin of the Longissimus Capitis?
Transverse processes of T1–T5 and articular processes of C4–C7
What is the insertion of the Longissimus Capitis?
Posterior margin of the mastoid process of the temporal bone
What movements does the Longissimus Capitis produce?
Bilaterally extends the head; unilaterally rotates it to the same side
What nerve supplies the Longissimus Capitis?
Posterior (dorsal) rami of cervical spinal nerves
Is the Longissimus Capitis free to study in OIANS?
The Longissimus Capitis 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 Trunk 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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