Pharynx Dr. Basil M.N. Saeed Assistant Professor Department of Surgery College of Medicine Mosul University

Pharynx Oropharynx Laryngopharynx (( Hypopharynx)) Is a funnel-shaped fibromuscular tube, 10-12 cm in length in adults. Extends from the base of the skull to the level of C6. The pharynx is divided anatomically into 3 parts; Nasopharynx Oropharynx Laryngopharynx (( Hypopharynx))

Behind : The Nose The Mouth The larynx

Nasopharynx Oropharynx Laryngopharynx (Hypopharynx) Seen from behind Nasopharynx Oropharynx Laryngopharynx (Hypopharynx)

Nasopharynx(( Postnasal Space)) This extends from the base of the skull to the hard palate. At the junction of the roof and posterior wall lies a small mass of lymphoid tissue called adenoids (nasopharyngeal tonsil). On the lateral wall, there are the openings of the Eustachian tubes. Behind which are hollows called the fossa of Rosenmuller, which is the site of nasopharyngeal malignancy

-Communicates inferiorly with the oropharynx through the velo-pharyngeal sphincter

Oropharynx Extends from the level of hard palate to the level of hyoid bone and opens anteriorly into the oral cavity. Behind the oral cavity (in front of 2nd&3rd Cervical vertebra) The palatine tonsils are situated in it's lateral wall Between the ant. and post tonsillar pillars. From the soft palate superiorly to tip of epiglottis inferiorly Communicates: Anteriorly with the oral cavity Superiorly with the nasopharynx Inferiorly with the hypopharynx

Hypopharynx Behind the Larynx (in front of 3rd to 6th Cervical vertebra) From the tip of epiglottis superiorly to the lower border of cricoid cartilage inferiorly Communicates: Anteriorly with the Larynx Superiorly with the oropharynx Inferiorly with the esophagus

The hypopharynx does not only lie behind the larynx BUT also Projects laterally on each side of the larynx and is formed of : Postcricoid region ( behind the larynx) Two pyriform fossae (on each side of the larynx

Pharyngeal Wall Histology

Wall Histology The pharyngeal wall consists of 4 layers: 1. Mucous membrane. 2. Pharyngobasilar fascia. 3. Muscle layer. 4. Buccopharyngeal fascia. 1- Mucus Membrane The lining epithelium is stratified squamous except in the nasopharynx, where columnar epithelium is found.

3- Muscular Layer 2- Pharyngobasilar fascia This fascia is strengthened posteriorly by a strong band called the median raphae. 3- Muscular Layer I- Circular (outer): which consist of 3 constrictor muscles overlapping one another from below upwards. 1. Superior constrictor. 2. Middle constrictor. 3. Inferior constrictor.

The inferior constrictor muscle is composed of 2 parts: a. Thyropharyngeus (oblique): arises from the thyroid cartilage. b. Cricopharyngeus (transverse): arises from the cricoid cartilage and passes transversely backwards forming the upper oesophageal sphincter. All the constrictor muscles are inserted posteriorly into the median pharyngeal raphae.

Functions The constrictor muscles propel the bolus of food down into the esophagus The Cricopharygeus (lower fibers of the inferior constrictor) act as a sphincter, preventing the entry of air into the esophagus between the acts of swallowing

Killian dehiscence: this is a potential gap between the fibers of the thyropharyngeus and cricopharyngeus. The mucous membrane may bulge between these two muscles when there is incoordination of the pharyngeal peristaltic waves. Pharyngael Pouch

II- Longitudinal (internal): these muscles elevate the larynx and shorten the pharynx during deglutition: 1. Stylopharyngeus. 2. Salpingopharyngeus. 3. Palatopharyngeus

Buccopharyngeal Fascia This fascia is loosely attached posteriorly to the prevertebral fascia and laterally connected to the styloid process and to the carotid sheath

Subepithelial lymphoid tissue of the pharynx (Waldeyer's ring) Is a collection of sub-epithelial lymphoid tissue around the entrance of the respiratory and alimentary tracts.

Waldeyer's ring is formed by 1. Nasopharyngeal tonsil (adenoid). 2. Tubal tonsils: lie behind the openings of the Eustachian tubes. 3. Palatine tonsils. 4. Lingual tonsils: which is embedded in the posterior 1/3 of the tongue. 5. Lateral pharyngeal bands behind the posterior tonsillar pillar. 6. Lymphoid nodules scattered on the posterior pharyngeal wall

Hypertrophy of the lymphoid tissue of Waldeyer's ring occurs in the earlier years of childhood. Maximum bulk is obtained at the age of 3- 6 years, and in old age it atrophies

Waldeyer's ring is characterized by: 1. Sub-epithelial lymphoid tissue. 2. Lack a definite capsule. 3. They have efferent lymph vessels, but no afferent vessels. 4. Function as one unit: when a member of it is removed, the others parts undergo compensatory hypertrophy.

Palatine Tonsils Two masses of lymphoid tissue situated on each side of the oropharynx. The medial surface is exposed in the pharynx and is pitted by a number of crypts. The tonsil is related anteriorly and posteriorly to the palatoglossus and palatopharyngeus muscles. Laterally the tonsil is enclosed by a dense fibrous capsule separating the tonsil from the superior constrictor muscle (tonsillar bed). This capsule provide a convenient plane of separation of the tonsil during tonsillectomy

Palatine tonsil

Blood Supply of the Tonsil The main supply is the tonsillar branch of the facial artery, and decsending palatine artery. The venous drainage is to the paratonsillar vein which drains to the pharyngeal plexus, and the internal jugular vein. Lymphatic Drainage Deep cervical chain of lymph nodes.

Nerve Supply of the Pharynx Sensory Nerve Supply Nasopharynx: Maxillary nerve, trigeminal Oropharynx: Glossopharyngeal nerve, trigeminal Laryngopharynx: vagus nerve, and glossopharyngeal. Motor supply All the muscles of pharynx, except the stylopharyngeus, supplied by the pharyngeal plexus. Pharyngeal branches of the IX and X nerves, and sympathetic fibers from the superior cervical ganglion. The stylopharyngeus is supplied by the glossopharyngeal nerve

Retropharyngeal Space (Space of Gillette This space lies behind the pharynx and extends from the base of the skull to the superior mediastinum. The anterior wall is formed by the posterior pharyngeal wall and it's covering buccopharyngeal fascia. The posterior wall is formed by the cervical vertebrae and their covering muscles and fascia.

Contents: Retropharyngeal lymph nodes of Rouviere. Usually disappear spontaneously during the 3rd or 4th year of life.

Parapharyngeal Space This potential space lies lateral to the pharynx and connects posteriorly with the retropharyngeal space. It extends from the base of the skull to the hyoid bone. It's bounded medially by the superior constrictor muscle. Laterally lies the medial pterygoid muscle, the mandible and the parotid gland. It's posterior wall is the prevertebral muscles and fascia.

Contents 1. Deep cervical lymphnodes. 2. The last 4 cranial nerves and the cervical sympathetic trunk. 3. Great vessels of the neck: carotid and internal jugular vein.

Parapharyngeal space

Physiology of the Pharynx 1. Food and air inlet. 2. Play an important role in speech through vocal resonance and articulation. 3.The protective function of Waldeyer's ring. 4. Deglutition: it's divided into 3 stages: a. Oral stage (voluntary). b. Pharyngeal stage (involuntary). c. Oesophageal stage (involuntary).

Symptoms of Pharyngeal Diseases 1- Sore throat (pain) a. Inflammatory. b. Neoplastic. c. Neurological: IX neuralgia. d. Blood dyscrasia: agranulocytosis and leukaemia. 2- Dysphagia: is difficulty in swallowing whereas odynophagia is painful swallowing. Dysphagia: Intraluminal, Luminal Extraluminal 3- Difficulty in breathing like stridor in Ludwig's angina. 4- Difficulty in speech: Paralysis of the soft palate(hypernasalily). 5- Neck mass Cervical lymphadenopathy

Examination Nasopharynx: This can be done with postnasal mirror and tongue depressor (posterior rhinoscopy), and it can be thoroughly examined by rigid and flexible endoscopes.

Oropharynx: It is simple with tongue depressor; palpation may be needed for the tongue.

Hypopharynx: It can be done with the use of laryngeal mirror to examine the larynx too. It can be done thoroughly with the use of endoscope. Neck examination: for cervical lymphadenopathy. Other areas : ears are examined for secretory otitis media in cases of nasopharyngeal tumours

Investigations of pharyngeal diseases Radiography: Plain films like lateral X-Ray of the skull, is needed in nasopharyngeal mass like adenoids, and can demonstrate bone erosion in cases of nasopharyngeal cancer. Contrast films: barium swallow is needed in the diagnosis of pharyngeal pouch, esophageal web and hypopharyngeal mass. CT scan MRI scan. Laboratory investigations: CBC, ESR, serum iron and iron binding capacity, monospot test, serology for toxoplasma, brucella, CMV and HIV. Biopsy for suspected lesions in the pharynx may be needed.