The cricothyroid joint (or articulation) is a joint connecting the

cricoid cartilage The cricoid cartilage , or simply cricoid (from the Greek ''krikoeides'' meaning "ring-shaped") or cricoid ring, is the only complete ring of cartilage around the trachea. It forms the back part of the voice box and functions as an attachment si ...

and the

thyroid cartilage The thyroid cartilage is the largest of the nine cartilages that make up the ''laryngeal skeleton'', the cartilage structure in and around the trachea that contains the larynx. It does not completely encircle the larynx (only the cricoid cartilage ...

. It plays a key role in adjusting human voice pitch by changing the tension of the

vocal cord In humans, vocal cords, also known as vocal folds or voice reeds, are folds of throat tissues that are key in creating sounds through vocalization. The size of vocal cords affects the pitch of voice. Open when breathing and vibrating for speec ...

s. This tension is controlled mostly by the endolaryngeal

vocalis The thyroarytenoid muscle is a broad, thin muscle that forms the body of the vocal fold and that supports the wall of the ventricle and its appendix. It functions to shorten the vocal folds. Structure It arises in front from the lower half of the ...

and the extralaryngeal

cricothyroid muscle The cricothyroid muscle is the only tensor muscle of the larynx aiding with phonation. It is innervated by the superior laryngeal nerve. Its action tilts the thyroid forward to help tense the vocal cords. Structure The cricothyroid muscle o ...

s which change vocal fold tension by narrowing the cricothyroid space created by rotation and gliding movements in horizontal and vertical direction allowed for by the cricothyroid articulation.Hammer GP, Windisch G, Prodinger PM, Anderhuber F, Friedrich G. (2010). The Cricothyroid Joint-Functional Aspects With Regard to Different Types of Its Structure. J Voice. Mar;24:140-145.

Types

Three types A, B, and C have been identified. Type A is found in 56% of females and 66% of males. There is a well-defined "facet". It has a tight capsule and ligaments with either a concavity or a small groin directed from posterior superior to anterior inferior. Horizontal translational movement is about 3.0 mm, vertical gliding about 2.5 mm with great movement horizontally than vertically. The gliding movements are smaller in males than in females. Type B is in 24% of females and 20% of males. In contrary to type A it lacks a definite "facet" and the two cartilaginous parts of the articulation are joined only by soft connective tissue. Horizontal movement is 5.0 mm and vertical, 5.1 mm with no differences between them. Type C concerns all others and has a flat surface with or without a tiny protuberance. Horizontal movement is about 5.1 mm, and vertical 3.8 mm. Type A is less mobile than the other two.

References

External links

* () Human head and neck Joints {{musculoskeletal-stub