Dr. T. Balasubramanian M.S.
Is a potential space that lie on either side of the
larynx. They are two in number. It is shaped like a pyramid with the
base poinint above and the apex below. They belong to the
hypopharyngeal area of the pharynx. It has two parts; the shallow
upper part and a deeper lower part.
Boundaries: The pyriform fossa is bounded laterally by
the mucosa covering the lamina of the thyroid cartilage. Medially it
is bounded by the aryepiglottic fold and arytenoid cartilages above
and the cricoid cartilage below. Superiorly it is bounded by the
lateral glosso epilglottic fold (Pharyngoepiglottic fold),
inferiorly it continues with the oesophagus.
showing the larynx as viewed from
Deep to the mucous membrane of the lateral wall of the
pyriform fossa lies the internal laryngeal branch of the superior
laryngeal nerve. It supplies sensori fibres to this area.
Clinical importance of pyriform fossa:
1. Anatomically it is a hidden area. Any malignancy in
this area will initially cause fewer symptoms and has a tendency to
present very late.
2. This area is richly endowed with lymphatics. They
drain into the upper deep cervical group of lymph nodes. Any
malignancy in this area has a tendency for nodal
3. Foreign bodies in the throat commonly gets lodged
4. Since superior laryngeal nerve lies superfically in
this area, it can be topically blocked by placing cotton plegets
soaked in 4% xylocaine in this area. This is known as the pyriform
Examination of the pyriform fossa:
The superficial shallow portion of the pyriform fossa is
easily visible in a laryngeal mirror. This portion will be visible
in the indirect laryngoscopy examination. The deeper portion of the
pyriform fossa is hidden and is not visible to the IDL mirror. Only
a direct examination using a upper oesophageal speculum will reveal
Tumors involving the pyriform fossa commonly arise from
its deep portion. This may escape detection during a IDL scopy
examination. But if one looks for pooling of saliva in the involved
pyriform fossa the underlying growth can be suspected. Hence pooling
of saliva is an important clinical sign indicating a under lying
tumor in the deep portion of the pyriform fossa, or the presence of
a foreign body can also be suspected by this sign.
Causes for pooling of saliva in the pyriform
Pooling of saliva in the pyriform fossa is not only
caused by growth affecting this area causing obstruction to saliva
being swallowed, but also due to intense cricopharyngeal muscle
1. Malignant growth involving the deep portion of the
2. Foreign body being lodged in the pyriform
3. Growth involving the crico pharynx or upper oesophagus
can also cause pooling of saliva.
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