Anatomy ofADENOIDS

Gitanjali kumari110201312

Nasopharyngeal tonsil is commonly called as “adenoids”

The adenoid is a median mass of mucosa associated lymphoid tissue situated in the posterior wall of nasopharynx

It is composed of vertical ridges of lymphoid tissue separated by deep clefts

The adenoids – It is a single mass of pyramidal tissue with its base on the posterior nasopharyngeal wall and it’s apex pointed toward the nasal septum.

The surface is invaginated in a series of folds. The epithelium is pseudostratified ciliated epithelium and is infiltrated by the lymphoid follicles.

The formation of the adenoids begins in the 3rd month of fetal development. This starts with glandular primordia in the posterior nasopharynx becoming associated with infiltrating lymphocytes.

In the 5th month sagittal folds are formed which are the beginnings of pharyngeal crypts. The surface is covered with pseudostratified ciliated epithelium.

By the 7th month of development the adenoids are fully formed

EMBRYOLOGY

Arterial supply

Ascending palatine branch of facial artery

Ascending pharyngeal branch of external carotid artery

Pharyngeal branch of third part of maxillary artery

Ascending cervical branch of inferior thyroid artery

Venous drainage is through the pharyngeal plexus and the pterygoid plexus flowing ultimately into the facial and internal jugular veins.

Nerve supply is through glossopharyngeal and vagus nerves

They carry sensations. Lymphatics from adenoids drain

into upper juglar directly and or indirectly via retropharyngeal and pharyngeal nodes

The adenoid is covered by a pseudostratified ciliated columnar epithelium that is plicated to form numerous surface folds.

The nasopharyngeal epithelium lines a series of mucosal folds, around which the lymphoid parenchyma is organized into follicles and is subdivided into 4 lobes by connective tissue septa .

HISTOLOGY

Seromucous glands lie within the connective tissue, and their ducts extend through the parenchyma and reach the nasopharyngeal surface. of adenoid showing lymphoid follicle

CLINICAL CORRELATION

The nasopharyngeal tonsils are prominent in children upto 6 years of age,then gradually undergo atrophy at puberty and almost completely disappear by the age of 20

Adenoiditis:Infections involving adenoids are known as adenoiditis. Enlargement of adenoid tissue shows the following symptoms:

1. Snoring

2. Mouth breathing

3. Vomiting immediatly after feeds - adenoid hypertrophy causes nasal block, this causes the child to swallow air when they are fed. This causes stomach of the child to bloat up which gets releived only when the child vomits.

IT can be enlarged due to allergy infections

Symptoms

Nasal obstruction Nasal discharge Sinusitis Epistaxis Voice change Tubal obstruction Otitis media Adenoid facies

Differences between adenoid and tonsils

TONSILS :-

1) Tonsils are paired.

2) Tonsils are situated in oropharynx.

3) The covering epithelium of Tonsils is stratified squamous.

4) In Tonsils the crypts are present on the medial surface.

5) In Tonsils the capsule is present on the lateral surface.

6) Tonsils are present right up to old age.

TONSILS ADENOID

ENCAPSULATED UNENCAPSULATED

TWO ONE

HAS CRYPTS HAS FURROWS

PRESENT IN OROPHARYNX PRESENT IN NASOPHARYNX

LINED BY SQUAMOUS EPITHELIUM LINED BY CILIATED COLUMNAR EPITHELIUM

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