The arytenoid cartilages () are a pair of small three-sided

pyramid A pyramid (from el, πυραμίς ') is a structure whose outer surfaces are triangular and converge to a single step at the top, making the shape roughly a pyramid in the geometric sense. The base of a pyramid can be trilateral, quadrilat ...

s which form part of the

larynx The larynx (), commonly called the voice box, is an organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal inlet is about ...

. They are the site of attachment of the

vocal cords 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 speech ...

. Each is pyramidal or ladle-shaped and has three surfaces, a base, and an apex. The arytenoid cartilages allow for movement of the vocal cords by articulating with 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 ...

. It may be affected by

arthritis Arthritis is a term often used to mean any disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, swelling, and decreased range of motion of the affected joints. In som ...

dislocations In materials science, a dislocation or Taylor's dislocation is a linear crystallographic defect or irregularity within a crystal structure that contains an abrupt change in the arrangement of atoms. The movement of dislocations allow atoms to sl ...

, or sclerosis.

Structure

The arytenoid cartilages are part of the posterior part of the

Surfaces

The posterior surface is triangular, smooth, concave, and gives attachment to the

arytenoid muscle The arytenoid muscle is a single muscle of the larynx. It passes from one arytenoid cartilage to the opposite arytenoid cartilage. It has oblique and transverse fibres. It is supplied by the recurrent laryngeal nerve. It approximates the arytenoi ...

and transversus. The antero-lateral surface is somewhat convex and rough. On it, near the apex of the cartilage, is a rounded elevation (colliculus) from which a ridge (crista arcuata) curves at first backward and then downward and forward to the

vocal process In the human larynx, the vocal process is the anterior angle of the base of the arytenoid cartilage, as it projects horizontally forward and gives attachment to the vocal ligament. The arytenoids are paired cartilages with a medial and a lateral ...

. The lower part of this crest intervenes between two depressions or foveæ, an upper, triangular, and a lower oblong in shape; the latter gives attachment to the

thyroarytenoid muscle 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 ...

(vocal muscle). The medial surface is narrow, smooth, and flattened, covered by

mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is ...

. It forms the lateral boundary of the intercartilaginous part of the

rima glottidis The rima glottidis is the opening between the two true vocal cords anteriorly, and the two arytenoid cartilages posteriorly. It is part of the larynx. Anatomy The rima glottidis is the narrowest part of larynx. It is longer (~23 mm) in males t ...

Base and apex

The base of each cartilage is broad, and on it is a concave smooth surface, for articulation with the

. * Its lateral angle is called the

muscular process The muscular process of arytenoid cartilage is the posterolateral projection of the (short, rounded, and prominent) lateral angle of the base of the arytenoid cartilage. The muscular process gives insertion to the posterior cricoarytenoid muscles ...

. * Its anterior angle is called the

. The apex of each cartilage is pointed, curved backward and medialward, and surmounted by a small conical, cartilaginous nodule, the

corniculate cartilage The corniculate cartilages (cartilages of Santorini) are two small conical nodules consisting of elastic cartilage, which articulate with the summits of the arytenoid cartilages and serve to prolong them posteriorly and medially. They are situated ...

. It articulates with the cricoid lamina with a

ball-and-socket joint The ball-and-socket joint (or spheroid joint) is a type of synovial joint in which the ball-shaped surface of one rounded bone fits into the cup-like depression of another bone. The distal bone is capable of motion around an indefinite number of ...

Function

The arytenoid cartilages allow the

vocal folds 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 speech ...

to be tensed, relaxed, or approximated. They articulate with the supero-lateral parts of the

lamina, forming the cricoarytenoid joints at which they can

come together "Come Together" is a song by the English rock band the Beatles, written by John Lennon and credited to Lennon–McCartney. The song is the opening track on their 1969 album ''Abbey Road'' and was also released as a single coupled with "Somethin ...

, move apart, tilt anteriorly or posteriorly, and rotate.

Clinical significance

Arthritis

Rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are involv ...

and

osteoarthritis Osteoarthritis (OA) is a type of degenerative joint disease that results from breakdown of joint cartilage and underlying bone which affects 1 in 7 adults in the United States. It is believed to be the fourth leading cause of disability in the w ...

can affect the

cricoarytenoid joint The cricoarytenoid joint is a joint connecting the cricoid cartilage and the arytenoid cartilage. It is a very shallow ball-and-socket joint. It allows for rotation and gliding motion. This controls the abduction and adduction of the vocal cords. ...

. This can cause

airway obstruction Airway obstruction is a blockage of respiration in the airway that hinders the free flow of air. It can be broadly classified into being either in the upper airway (UPA) or lower airway (LOA). Airway obstruction is a life-threatening condition ...

, which may be life-threatening.

Dislocation

Rarely, the arytenoid cartilage may be

dislocated A joint dislocation, also called luxation, occurs when there is an abnormal separation in the joint, where two or more bones meet.Dislocations. Lucile Packard Children’s Hospital at Stanford. Retrieved 3 March 2013 A partial dislocation is refe ...

. This is most often caused by

tracheal intubation Tracheal intubation, usually simply referred to as intubation, is the placement of a flexible plastic catheter, tube into the vertebrate trachea, trachea (windpipe) to maintain an open airway or to serve as a conduit through which to administer ce ...

major trauma Major trauma is any injury that has the potential to cause prolonged disability or death. There are many causes of major trauma, blunt and penetrating, including falls, motor vehicle collisions, stabbing wounds, and gunshot wounds. Dependin ...

to the larynx, or more rarely a

laryngeal mask airway A laryngeal mask airway (LMA), also known as laryngeal mask, is a medical device that keeps a patient's airway open during anaesthesia or while they are unconscious. It is a type of supraglottic airway device. They are most commonly used by anae ...

. This may cause symptoms with problems breathing, such as "breathiness" when breathing.

Electromyography Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyog ...

and CT scans of the larynx may be used to assess a dislocation in detail. Dislocations may be reduced using an

endoscope An endoscope is an inspection instrument composed of image sensor, optical lens, light source and mechanical device, which is used to look deep into the body by way of openings such as the mouth or anus. A typical endoscope applies several modern t ...

Laryngeal cancer

Some cases of

laryngeal cancer Laryngeal cancers are mostly squamous-cell carcinomas, reflecting their origin from the epithelium of the larynx. Cancer can develop in any part of the larynx. The prognosis is affected by the location of the tumour. For the purposes of staging, ...

cause the arytenoid cartilage to appear sclerotic. This may be observed, and is highly predictive of laryngeal cancer.

History

Etymology

The term "arytenoid" comes from

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

ἀρύταινα ''arytaina'' meaning "ladle" and εἶδος ''eidos'', meaning "form". They are also often described as "pyramid" shaped. The word "arytenoid" is pronounced .

Other animals

The arytenoid cartilages are in the larynxes of many animals, including

horses The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million yea ...

Additional images

File:Gray953.png, Sagittal section of the larynx and upper part of the trachea. File:Gray955.png, The entrance to the larynx, viewed from behind. File:Gray960.png, Muscles of the larynx, seen from above. File:Slide5vvv.JPG, Arytenoid cartilage File:Slide5kkkk.JPG, Arytenoid cartilage

References

{{Authority control Larynx Human head and neck Human voice