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Piriform sinus

Piriform sinus

Overview
On either side of the laryngeal
Laryngeal
laryngeal may mean*pertaining to the larynx*in Indo-European linguistics, a consonant postulated in the laryngeal theory*in phonetics, an alternate term for glottal sounds....

 orifice is a recess, termed the piriform sinus (also piriform recess, pyriform sinus, or piriform fossa), which is bounded medially by the aryepiglottic fold
Aryepiglottic fold
The entrance of the larynx is a triangular opening, narrow in front, wide behind, and sloping obliquely downward and backward. It is bounded, in front, by the epiglottis; behind, by the apices of the arytenoid cartilages, the corniculate cartilages, and the interarytenoid notch; and on either side,...

, laterally by the thyroid cartilage
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....

 and hyothyroid membrane
Hyothyroid membrane
The hyothyroid membrane is a broad, fibro-elastic layer, attached below to the upper border of the thyroid cartilage and to the front of its superior cornu, and above to the upper margin of the posterior surface of the body and greater cornua of the hyoid bone, thus passing behind the posterior...

. The fossae are involved in speech.

The term "piriform," which means "pear-shaped," is also sometimes spelled "pyriform" (as in the diagram on this page.)

Deep to the mucous membrane of the piriform fossa lie the recurrent laryngeal nerve
Recurrent laryngeal nerve
The recurrent laryngeal nerve is a branch of the vagus nerve that supplies motor function and sensation to the larynx . It travels within the endoneurial sheath...

 as well as the internal laryngeal nerve
Internal laryngeal nerve
The internal laryngeal nerve is the internal branch of the superior laryngeal nerve. It descends to the hyothyroid membrane, pierces it in company with the superior laryngeal artery, and is distributed to the mucous membrane of the larynx....

, a branch of the superior laryngeal nerve
Superior laryngeal nerve
The superior laryngeal nerve is a branch of the vagus nerve. It arises from the middle of the ganglion nodosum and in its course receives a branch from the superior cervical ganglion of the sympathetic....

.
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Encyclopedia
On either side of the laryngeal
Laryngeal
laryngeal may mean*pertaining to the larynx*in Indo-European linguistics, a consonant postulated in the laryngeal theory*in phonetics, an alternate term for glottal sounds....

 orifice is a recess, termed the piriform sinus (also piriform recess, pyriform sinus, or piriform fossa), which is bounded medially by the aryepiglottic fold
Aryepiglottic fold
The entrance of the larynx is a triangular opening, narrow in front, wide behind, and sloping obliquely downward and backward. It is bounded, in front, by the epiglottis; behind, by the apices of the arytenoid cartilages, the corniculate cartilages, and the interarytenoid notch; and on either side,...

, laterally by the thyroid cartilage
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....

 and hyothyroid membrane
Hyothyroid membrane
The hyothyroid membrane is a broad, fibro-elastic layer, attached below to the upper border of the thyroid cartilage and to the front of its superior cornu, and above to the upper margin of the posterior surface of the body and greater cornua of the hyoid bone, thus passing behind the posterior...

. The fossae are involved in speech.

The term "piriform," which means "pear-shaped," is also sometimes spelled "pyriform" (as in the diagram on this page.)

Deep to the mucous membrane of the piriform fossa lie the recurrent laryngeal nerve
Recurrent laryngeal nerve
The recurrent laryngeal nerve is a branch of the vagus nerve that supplies motor function and sensation to the larynx . It travels within the endoneurial sheath...

 as well as the internal laryngeal nerve
Internal laryngeal nerve
The internal laryngeal nerve is the internal branch of the superior laryngeal nerve. It descends to the hyothyroid membrane, pierces it in company with the superior laryngeal artery, and is distributed to the mucous membrane of the larynx....

, a branch of the superior laryngeal nerve
Superior laryngeal nerve
The superior laryngeal nerve is a branch of the vagus nerve. It arises from the middle of the ganglion nodosum and in its course receives a branch from the superior cervical ganglion of the sympathetic....

. The internal laryngeal nerve supplies sensation to the area, and it may become damaged if the mucous membrane is inadvertently punctured.

While accurate, the diagram is misleading in that the piriform sinus is not a subsite of the larynx. Rather, it is a subsite of the hypopharynx
Hypopharynx
In human anatomy, the hypopharynx is the bottom part of the pharynx, and is the part of the throat that connects to the esophagus.The superior boundary of the hypopharynx is at the level of the hyoid bone....

. This distinction is important for head and neck cancer staging
Cancer staging
The stage of a cancer is a descriptor of how much the cancer has spread. The stage often takes into account the size of a tumor, how deeply it has penetrated, whether it has invaded adjacent organs, how many lymph nodes it has metastasized to , and whether it has spread to distant organs...

 and treatment.

Clinical significance


It is a common place for food to become trapped; if foreign material becomes lodged in the piriform fossa of an infant, it may be retrieved nonsurgically. If the area is injured (eg., by a fish bone), it can give the sensation of food stuck in the throat. Moreover, it is a place for concealment of drugs during smuggling.