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

pyramid A pyramid () is a structure whose visible surfaces are triangular in broad outline and converge toward the top, making the appearance roughly a pyramid in the geometric sense. The base of a pyramid can be of any polygon shape, such as trian ...

s which form part of the

larynx The larynx (), commonly called the voice box, is an organ (anatomy), 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 ...

. They are the site of attachment of the

vocal cords In humans, the vocal cords, also known as vocal folds, are folds of throat tissues that are key in creating sounds through Speech, vocalization. The length of the vocal cords affects the pitch of voice, similar to a violin string. Open when brea ...

. 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. They may be affected by arthritis,

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 sli ...

, 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 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. 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 (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 ...

. 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 ...

Base and apex

The base of each cartilage is broad, and on it is a concave smooth surface, for articulation with the cricoid cartilage. * Its lateral angle is called the muscular process. * Its anterior angle is called the vocal process. The apex of each cartilage is pointed, curved backward and medialward, and surmounted by a small conical, cartilaginous nodule, the corniculate cartilage. 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, the vocal cords, also known as vocal folds, are folds of throat tissues that are key in creating sounds through Speech, vocalization. The length of the vocal cords affects the pitch of voice, similar to a violin string. Open when brea ...

to be tensed, relaxed, or approximated. They articulate with the supero-lateral parts of the cricoid cartilage 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 the band's 1969 studio album ''Abbey Road''. It was also a double A-side single in the U ...

, 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 synovial joint, joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and h ...

and

osteoarthritis Osteoarthritis is a type of degenerative joint disease that results from breakdown of articular cartilage, joint cartilage and underlying bone. A form of arthritis, it is believed to be the fourth leading cause of disability in the world, affect ...

can affect the cricoarytenoid joint. This can cause

airway obstruction Airway obstruction is a blockage of respiration in the airway that hinders the free flow of air. Airway obstructions can occur either in the upper airway or lower airway. The upper airway consists of the nose, throat, and larynx. The lower ai ...

, which may be life-threatening.

Dislocation

Rarely, the arytenoid cartilage may be dislocated. 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 c ...

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. Dependi ...

to the larynx, or more rarely a laryngeal mask airway. 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 electromyo ...

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 ...

Laryngeal cancer

Some cases of

laryngeal cancer Laryngeal cancer is a kind of cancer that can develop in any part of the larynx (voice box). It is typically a squamous-cell carcinoma, reflecting its origin from the epithelium of the larynx. The prognosis is affected by the location of the tumo ...

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 classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

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 milli ...

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