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Learning objectives:Be able to discuss the gross anatomy of the pharynxBe able to describe the radiological anatomy of the pharynxBe able to discuss the various clinical significances of the pharynxBe able to discuss the gross anatomy of the esophagus in the neck and its clinical importancePharynx & EsophagusExtends: from the cranial base to the inferior border of the cricoid cartilage ( inferior border of the C6 vertebra posteriorly).

Widest (approximately 5 cm) opposite the hyoid

Narrowest (approximately 1.5 cm) at its inferior end, where it is continuous with the esophagus.

Posterior wall of the pharynx lies against the prevertebral layer of deep cervical fascia.

PharynxThe pharynx divided into three parts :Nasopharynx: posterior to the nose and superior to the soft palate.Oropharynx: posterior to the mouth.Laryngopharynx: posterior to the larynx.

Nasopharynx:Has a respiratory function.

Lies superior to the soft palate

Nose opens into the nasopharynx through the choanae.

Roof and posterior wall: lies inferior to the body of the sphenoid bone and the basilar part of the occipital bone.Lateral wall:Opening of the auditory tube, the elevated ridge of which is called the tubal elevationPharyngeal recess: a depression in the pharyngeal wall behind the tubal elevation.Salpingopharyngeal fold: vertical fold of mucous membrane covering the salpingopharyngeus muscle.

Lymphoid tissue in the pharynx

Lymphoid tissue in the pharynx forms an incomplete tonsillar ring (Waldeyer's ring) around the superior part of the pharynx.

Located at the gateway of the respiratory and alimentary tract and belongs to the mucosa-associated lymphoid tissue (MALT).

Waldeyer's lymphatic ring consists of:Single pharyngeal tonsilPair of tubal tonsilsPair of palatine tonsilsSingle lingual tonsil

Pharyngeal Tonsil (adenoids)Present in the mucous membrane of the roof and posterior wall of the nasopharynx.

Tubal tonsil:Collection of lymphoid tissue in the submucosa near the pharyngeal orifice of the pharyngotympanic tube.

Palatine TonsilsTwo masses of lymphoid tissue

Maximum size during early childhood, but after puberty it diminishes considerably in size.

Located: on the lateral wall of the oral part of the pharynx between the palatoglossal and palatopharyngeal arches.

Covered by mucous membrane

Medial surface: projects into the pharynx and pitted by numerous small openings that lead into the tonsillar crypts.

Lateral surface: covered by a fibrous capsule.

Fibrous Capsule: separated from the superior constrictor muscle by loose areolar tissue and the external palatine vein

Lateral to the superior constrictor muscle: lie the styloglossus muscle, the loop of the facial artery, and the internal carotid artery.

Tonsillar BedFormed by the Superior constrictor of the pharynxFibrous sheet of pharyngobasilar fascia.

Palatine tonsilsReach maximum normal size in early childhood.

After puberty, together with other lymphoid tissues in the body, they gradually atrophy. Blood SupplyArtery: Tonsillar branch of the facial artery.

Veins: pierce the superior constrictor muscle and join the external palatine, the pharyngeal, or the facial veins.

Lymph Drainage of the Tonsil:Upper deep cervical lymph nodes, just below and behind the angle of the mandible

OropharynxDigestive function

Extends: from the soft palate to the superior border of the epiglottis.

Bounded:Superiorly: Soft palateInferiorly: Base of the tongueLaterally: Palatoglossal and Palatopharyngeal arches.

OropharynxFloor: formed by the posterior one third of the tongue and the space between the tongue and epiglottis.

Lateral wall: on each side formed by palatoglossal and the palatopharyngeal arches or folds and the palatine tonsils

Palatoglossal arch: fold of mucous membrane covering the palatoglossus muscle.

Palatopharyngeal arch: fold of mucous membrane covering the palatopharyngeus muscle.

Oropharyngeal isthmus: interval between the two palatoglossal arches, the boundary between the mouth and pharynx.

Laryngopharynx (hypopharynx)Lies posterior to the larynx

Extends: from the superior border of the epiglottis and the pharyngoepiglottic folds to the inferior border of the cricoid cartilage

Posteriorly: related to the bodies of the C4-C6 vertebrae.

Posterior and lateral walls: formed by the middle and inferior constrictor muscles and internally by the palatopharyngeus and stylopharyngeus muscles.

Laryngopharynx communicates with the larynx through the laryngeal inlet

Piriform fossa (recess):

Small depression of the laryngopharyngeal cavity on either side of the laryngeal inlet.

Separated from the laryngeal inlet by the aryepiglottic fold.

Laterally bounded by the medial surfaces of the thyroid cartilage and the thyrohyoid membrane.

Branches of the internal laryngeal and recurrent laryngeal nerves lie deep to the mucous membrane.

Nerves are vulnerable to injury when a foreign body lodges in the recess.

Pharyngeal MusclesArranged mainly into:External circularInternal longitudinal layer

External circular layer:Superior constrictorMiddle constrictorInferior constrictor

Internal longitudinal layer:PalatopharyngeusStylopharyngeusSalpingopharyngeus.

Muscles of the PharynxMuscleOriginInsertionInnervationMain Action(s)External layerSuperior constrictorPterygoid hamulus, pterygomandibular raphePosterior end of mylohyoid line of mandible and side of tonguePharyngeal tubercle on basilar part of occipital bonePharyngeal branch of vagus (CN X) and pharyngeal plexusConstrict walls of pharynx during swallowing

Muscles of the PharynxMuscleOriginInsertionInnervationMain Action(s)External layerMiddle constrictorStylohyoid ligament and greater and lesser horns of hyoidPharyngeal raphePharyngeal branch of vagus (CN X) and pharyngeal plexus, plus branches of external and recurrent laryngeal nerves of vagusConstrict walls of pharynx during swallowing

Inferior constrictorOrigin: Oblique line of thyroid cartilage and side of cricoid cartilage

Insertion: Cricopharyngeal part encircles pharyngo-esophageal junction without forming a raphe

Innervation:Pharyngeal branch of vagus (CN X) and pharyngeal plexusBranches of external and recurrent laryngeal nerves of vagus

Action: Constrict walls of pharynx during swallowing

Muscles of the PharynxMuscleOriginInsertionInnervationMain Action(s)Internal layerPalatopharyngeusHard palate and palatine aponeurosisPosterior border of lamina of thyroid cartilage Side of pharynxEsophagusPharyngeal branch of vagus (CN X) and pharyngeal plexusElevate (shorten and widen) pharynx and larynx during swallowing and speakingSalpingopharyngeusCartilaginous part of pharyngotympanic tubeBlends with palatopharyngeusStylopharyngeusStyloid process of temporal bonePosterior and superior borders of thyroid cartilage with palatopharyngeusGlossopharyngeal nerve (CN IX)

Constrictor muscles leaves four gaps for structures to enter or leave the pharynx:1. Superior to the superior constrictor: Levator veli palatiniPharyngotympanic (auditory) tubeAscending palatine artery 2. A gap between the superior and middle constrictors:StylopharyngeusGlossopharyngeal nerveStylohyoid ligament3. A gap between the middle and inferior constrictors:Internal laryngeal nerveSuperior laryngeal artery and vein4. A gap inferior to the inferior constrictor:Recurrent laryngeal nerveInferior laryngeal artery

Blood Supply of the PharynxAscending pharyngeal, and Tonsillar branches of Facial arteryBranches of maxillary and Lingual arteriesExternal palatine vein (paratonsillar vein) and enters the pharyngeal venous plexus.

Lymph Drainage of the PharynxDirectly into the deep cervical lymph nodes or indirectly via the retropharyngeal or paratracheal nodes into the deep cervical nodesPharyngeal NervesSensory Nerve Nasal pharynx: Maxillary nerve (V2)Oral pharynx: Glossopharyngeal nerveLaryngeal pharynx (around the entrance into the larynx): Internal laryngeal branch of the vagus nerve

Motor Nerve:Derived from the vagus nerve (CN X) via its pharyngeal branch or branches, supply all muscles of the pharynx and soft palate, except the stylopharyngeus which is supplied by CN IX and the tensor veli palatini (supplied by CN V3). Foreign Bodies in the LaryngopharynxForeign bodies (e.g., a chicken bone or fishbone) entering the pharynx may lodge in this recess.

The object may pierce the mucous membrane and injure the internal laryngeal nerve.

Superior laryngeal nerve and internal laryngeal branch are vulnerable to injury during removal of the object if the instrument used to remove the foreign body accidentally pierces the mucous membrane.

Injury to these nerves may result in anesthesia of the laryngeal mucous membrane as far inferiorly as the vocal folds.

A high-density tubiform foreign body in the laryngohypopharynx of a girl aged 14 months.Annular Metal ObjectTonsillitisPalatine tonsils are a common site of infection

Deep cervical lymph node usually enlarged and tender.

Recurrent attacks of tonsillitis are best treated by tonsillectomy.

After tonsillectomy, the external palatine vein, lateral to the tonsil, may be the source of postoperative bleeding.

Peritonsillar abscess (Quinsy)Caused by spread of infection from the palatine tonsil to the loose connective tissue outside the capsule .

Pus forms between the tonsil and tonsillar capsule/superior pharyngeal constrictor

TonsillectomyPerformed by dissecting the palatine tonsil from the tonsillar bed.

Removal of the tonsil and the fascial sheet covering the tonsillar bed because of the rich blood supply of the tonsil.

Bleeding commonly arises from the large external palatine vein or, less commonly, from the tonsillar artery or other arterial twigs.

Glossopharyngeal nerve (CN IX), vulnerable to injury as it accompanies the tonsillar artery

Internal carotid artery is especially vulnerable as it lies directly lateral to the tonsil.

Sinus Tract from the Piriform Recess

Pass from the piriform fossa to the thyroid gland

Potential site for recurring thyroiditis.

Develops from a remnant of the thyroglossal duct that adheres to the developing laryngopharynx. AdenoiditisInflammation of the pharyngeal tonsils (adenoids) is called adenoiditis.

Obstruct the passage of air from the nasal cavities, making mouth breathing necessary and snore loudly at night

Impairment of hearing may result from nasal obstruction and blockage of the pharyngotympanic tubes.

Infection spreading from the nasopharynx to the middle ear causes otitis media may produce temporary or permanent hearing loss.

Nesal conchaBranchial FistulaAbnormal canal, opens internally into the tonsillar cleft and externally on the side of the neck.

Ascends along the anterior border of the SCM in the inferior third of the neck, through the subcutaneous tissue, platysma, and fascia of the neck to enter the carotid sheath.

Passes between the internal and the external carotid arteries

Course can be demonstrated by radiography .

Results from persistence of remnants of the 2nd pharyngeal pouch and 2nd pharyngeal groove.

Branchial Sinus:Embryonic cervical sinus fails to disappear

Retain its connection with the lateral surface of the neck by a branchial sinus, a narrow canal.

Opening of the sinus may be anywhere along the anterior border of the SCM.

Fistula being assessed by threading with proline

Fistulous tract , completely excised

Branchial Cyst:Remnant of the cervical sinus is not connected with the surface, form a branchial cyst (Lateral cervical cyst)

Located just inferior to the angle of the mandible. Imaging FindingsClassically, cyst located at anteromedial border of sternocleidomastoid muscle, lateral to carotid space, and at posterior margin of submandibular gland

Second Branchial Cleft Cyst. MRI images: There is a cystic mass filled with a simple fluid surrounded by a homogeneously enhancing thin-wall in the right neck anteriorly.The cyst is located anterior to the right sternocleidomastoid muscle and inferoposterior to the right parotid gland and is most consistent with a second branchial cleft cyst.REF:http://www.learningradiology.com

EsophagusMuscular tube

Continuous with the laryngopharynx at the pharyngoesophageal junction.

Consists of Striated (voluntary) muscle in its upper third,Smooth (involuntary) muscle in its lower third, Mixture of striated and smooth muscle in between.

EsophagusEsophagusBegins at the level of, the inferior border of the cricoid cartilage at the level of the C6 vertebra.

Pharyngoesophageal junction, narrowest part of the esophagus.

Cervical esophagus inclines slightly to the left as it descends.

LTRTEsophagusCervical esophagus lies between the trachea and the cervical vertebral column.

Recurrent laryngeal nerve lies in the tracheoesophageal groove on each side of the esophagus.

On the left : left lobe of the thyroid gland and the left carotid sheath.

On the right of the esophagus: right lobe of the thyroid gland and the right carotid sheath and its contents.

Cervical EsophagusArteries: branches of the inferior thyroid arteries.

Veins: tributaries of the inferior thyroid veins.

Lymphatic vessels: drain into the paratracheal lymph nodes and inferior deep cervical lymph nodesNerves of the Cervical Esophagus

Somatic motor and sensory to the upper half and parasympathetic by the vagal trunk

Somatic fibers via branches from the recurrent laryngeal nerves

Vasomotor fibers from the cervical sympathetic trunks

Tracheoesophageal Fistula (TEF)Usually combined with some form of esophageal atresia

Superior part of the esophagus ends in a blind pouch

Inferior part communicates with the trachea.

In these cases, the pouch fills with mucus, which the infant aspirates.

Result from abnormalities in partitioning of the esophagus and trachea by the tracheoesophageal septum.

Esophageal CancerDysphagia: most common complain, which is not usually recognized until the lumen is reduced by 30-50%.

Painful swallowing suggests extension of the tumor to periesophageal tissues.

Enlargement of the inferior deep cervical lymph nodes.

Compression of the recurrent laryngeal nerves produces hoarseness.

Esophagoscopy: common diagnostic tool.

MRI

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