Anatomy of pharynx & neck spaces

By

Dr. Muaid I. Aziz

FICMS

Anatomy of the pharynx

It’s a fibromuscular tube

12 cm in length

attached above to the base of the skull & below with the oesophagus

As its deficient anteriorly , its widely communicates with the nose, mouth & larynx

Anatomy of pharynx

Nasopharynx

Oropharynx

hypopharynx

The buccopharyngeal fascia is a thin fibrous coat of areolar tissue covering the pharyngeal constrictor muscles.

It contains the pharyngeal plexus of nerves and veins.

MUSCLE LAYERThe muscles of the

pharyngeal wall are arranged into an inner longitudinal layer and outer circular layer. The inner layer is formed by three paired muscles: stylopharyngeus

palatopharyngeus

salpingopharyngeus .

The outer layer has three paired muscles: the superior, middle and inferior constrictors.

Each of the constrictors is shaped like a fan, arising from the lateral wall of the pharynx and sweeping around to be inserted into the median raphe posteriorly.

The muscles overlap

each other from below upwards. Although they form an almost complete coat for the side and posterior walls of the pharynx, their attachments anteriorly separate the edges and it is through these intervals that structures pass from the exterior of the pharynx towards its lumen.

The inferior constrictor is made up of two muscle groups:

the thyropharyngeus superiorly and the cricopharyngeus inferiorly.

The fibres of the cricopharyngeus are continuous with the circular fibres of the upper oesophagus.

Posteriorly, there is a small triangular interval between the upper end of the cricopharyngeus and the lower fibres of the thyropharyngeus, so-called 'Killian's dehiscence'.

During deglutition the longitudinal muscles elevate the larynx and shorten the pharynx while the constrictors contract in a coordinated way to propel the bolus through the oropharynx into the oesophagus.

Anatomy of pharynx

Nasopharynx

Oropharynx

hypopharynx

Nasopharynx

Extend from base of skull to the upper surface of the soft palate at the level of C1.

Communicate w the nose through the choana

Orophayngeal isthmus ?

Main structures are

1. Openings of the auditory tubes

2. Pharyngeal recesses

3. Pharyngeal tonsil

or tonsils?

ET opening

In the lateral wall

Inverted J shaped tubal elevation

Tubal tonsil

Salpingopharyngeal fold & muscle

Pharyngeal recess ( fossa of rosenmuller)

Pharyngeal tonsil (adenoid tissue)

Oropharynx Extend from lower surface of the soft

palate to the upper border of the epiglottis (1/2 way down C3 vertebrae)

Palatine , lingual tonsils & the valecullae are in the oropharynx

The palatine tonsil:

The palatine tonsil is located between the diverging palatopharyngeal and palatoglossal folds.

A sulcus usually separates the tonsil from the base of the tongue, the tonsillolingual sulcus.

Palatine tonsil It is a large lymphatic collection

It extend up to soft palate & down to base of the tongue

Its medial surface covered by pharyngeal mucosa w downward epithelial growths ( crypts) (intratonsillar cleft)

Palatine tonsil

Its lateral surface covered by fibrous tissue ( false capsule)

Superior constrictor muscle is the bed of the fossa

Passavants ridge

Arterial supply

Tonsillar br of facial art.

Lingual art

Ascending pharyngeal art.

Descending & greater palatine art.

Venous supply

Form a plexus round the capsule & pierce the sup. Constrictor m to drain into pharyngeal plexus

External palatine & paratonsillar veins from soft palate

Lymph Drainage:

Jugulodigastric nodes

(which lies below and behind the angle of the mandible).

Nerve supply

Tonsillar branch of IX.

Otalgia?

valleculae

A shallow fossae lies between epiglottis & base of the tongue

Separated by median glossoepiglottic fold &limited infero- laterally by lateral glossoepiglottic fold.

Lymphoid tissue of the pharynx:

The wall of the upper aero digestive tract contains a large amount of un encapsulated lymphoid tissue in the lamina propria, the so-called gut-associated lymphoid tissue (GALT).

This is particularly prominent in the pharynx at the entrance to the upper aero digestive tract.

The nasopharyngeal, tubal, palatine and lingual tonsils form a ring of GALT at the level of the oropharyngeal and nasopharyngeal isthmus, known as Waldeyer's ring.

Lymphatic efferents leave this tissue and drain to regional lymph nodes.

movei

Hypopharynx( laryngopharynx)

Extend from the upper border of epiglottis to the level of cricoid cartilage at C6

Bordered anteriorly by larynx .posteriorly by RPS

Pyriform recesses

Post wall

Postcricoid area

movei

Potential spaces around the pharynx

The retropharyngeal space lies between the prevertebral fascia and the buccopharyngeal fascia.

The space is closed above by the base of the skull and on each side by the carotid sheath. Inferiorly, it is continuous with the superior mediastinum.

The para pharyngeal space is lateral to the pharynx on each side and can be visualized as an inverted cone with its base under the temporal bone and its apex in the neck at the hyoid bone .

Laterally, it is bounded by the fascia overlying the pterygoid muscles, the medial aspect of the deep lobe of the parotid gland and the ascending ramus of the mandible.

Medially, the space abuts the fascia overlying the pharyngeal constrictors and the tensor and levator palatini. Anteriorly, it is bounded by the pterygomandibular raphe and the posterior wall is formed by the posterior part of the carotid sheath and prevertebral fascia .

Divided by styloid process into pre & post styloid spaces

They communicate with each other and the submandibular spaces, which allows the spread of infection and tumour along fascial planes with little resistance.

swallowing

Deglutition is the act of swallowing, through which a food or liquid bolus is transported from the mouth through the pharynx and esophagus into the stomach.

Normal deglutition is a smooth coordinated process that involves a complex series of voluntary and involuntary neuromuscular contractions and typically is divided into three distinct phases: Oral Pharyngeal Esophageal Total swallow time from oral cavity to stomach is

no more than 20 seconds

Oral phase

The process begins with contractions of the tongue and striated muscles of mastication.

In the oral phase, a formed bolus is positioned in the middle of the tongue. The bolus is then pressed firmly against the tonsillar pillars, triggering the pharyngeal phase.

The oral preparatory phase refers to processing of the bolus to render it swallowable.

The oral propulsive phase refers to the propelling of food from the oral cavity into the oropharynx.

pharyngeal phase The pharyngeal phase of swallowing is the shortest but is

the most complex.

The soft palate elevates closing off the nasopharynx .

The superior constrictor muscle contracts, beginning pharyngeal peristalsis while the tongue base drives the bolus posteriorly.

Respiration ceases during expiration-the larynx elevates and the epiglottis retroflexes, driving the bolus around the opening of the larynx. The arytenoids adduct and are approximated to the base of the epiglottis.

The cricopharyngeal and inferior constrictor muscles then relax, allowing food to pass into the upper esophagus.

The upper esophageal sphincter relaxes during the pharyngeal phase of swallowing and is pulled open by the forward movement of the hyoid bone and larynx. This sphincter closes after passage of the food, and the pharyngeal structures then return to reference position.

The pharyngeal phase of swallowing is involuntary and totally reflexive, so no pharyngeal activity occurs until the swallow reflex is triggered. This swallowing reflex lasts approximately 1 second and involves the motor and sensory tracts from cranial nerves IX (glossopharyngeal) and X (vagus).

Esophageal phase

The bolus is propelled about 25 cm from the cricopharyngeus through the thoracic esophagus via peristaltic contractions.

The lower esophageal sphincter relaxes and the bolus moves into the gastric cardia.

1movei

2 movei