Ceratocricoideus
Larynx · Head & Neck
The ceratocricoideus is a small, inconstant muscle of the larynx that is not present in every person. When it is found, it runs from the posterolateral part of the cricoid cartilage upward to the inferior horn of the thyroid cartilage, bridging the cricothyroid joint on its posterior aspect. Because it spans this joint, its role is to assist the cricothyroid in steadying and controlling movement at the cricothyroid articulation, contributing indirectly to the tensing of the vocal folds. Like the other intrinsic laryngeal muscles that cross the midline of vocal control, it is supplied by the recurrent laryngeal nerve, a branch of the vagus nerve (CN X). Its variable presence makes it primarily a point of anatomical interest rather than a muscle with an indispensable independent function.
Origin, Insertion, Action & Nerve
Origin
Posterolateral cricoid cartilage
Insertion
Inferior horn of the thyroid cartilage
Action
Inconstant muscle; assists cricothyroid in stabilizing the cricothyroid joint
Nerve
Recurrent laryngeal nerve (vagus, CN X)
Attachments explained
The Ceratocricoideus 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
Posterolateral cricoid cartilage
Insertion
Inferior horn of the thyroid cartilage
Action & function
When the Ceratocricoideus contracts, it produces the following movements: Inconstant muscle; assists cricothyroid in stabilizing the cricothyroid joint.
As part of the Larynx 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 Ceratocricoideus receives its nerve supply from the Recurrent laryngeal nerve (vagus, CN X).
Because a muscle can only contract when its nerve is intact, injury to the Recurrent laryngeal nerve can weaken or paralyse the Ceratocricoideus, impairing the movements it normally produces (inconstant muscle). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Ceratocricoideus (the OIANS method)
Approach the ceratocricoideus as a variant, and study it in the shadow of the cricothyroid joint it reinforces. Fix in mind that it attaches from the posterolateral cricoid cartilage to the inferior horn of the thyroid cartilage, precisely the two cartilages that meet at that joint. If you can picture the cricothyroid joint, you can reconstruct where this muscle sits and why its job is to stabilise that articulation rather than to move the folds on its own.
Anchor the nerve by grouping this muscle with the rest of the intrinsic larynx. Every intrinsic laryngeal muscle except the cricothyroid is supplied by the recurrent laryngeal nerve from the vagus (CN X), and the ceratocricoideus follows that rule. Because it works with the cricothyroid, students sometimes expect the external laryngeal nerve, so make a deliberate note that its supply is the recurrent laryngeal nerve to avoid that trap.
Frequently asked questions
Where is the Ceratocricoideus located?
The Ceratocricoideus is a muscle of the Larynx group, located in the Head & Neck.
What is the origin of the Ceratocricoideus?
Posterolateral cricoid cartilage
What is the insertion of the Ceratocricoideus?
Inferior horn of the thyroid cartilage
What movements does the Ceratocricoideus produce?
Inconstant muscle; assists cricothyroid in stabilizing the cricothyroid joint
What nerve supplies the Ceratocricoideus?
Recurrent laryngeal nerve (vagus, CN X)
Is the Ceratocricoideus free to study in OIANS?
The Ceratocricoideus 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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