Pharynx
The pharynx is the superior dilated part of the alimentary tract that connects the nasal and oral cavities to the esophagus.
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Gross anatomy
It is composed of three parts:
-
nasopharynx: posterior to the nasal choanae, extending from the vault of the pharynx superiorly to the soft palate inferiorly
- communicates with the nasal cavity anteriorly
-
oropharynx: posterior to the base of tongue, inferior to the soft palate, bounded laterally by the palatoglossal and palatopharyngeal arches, and superior to the superior tip of the epiglottis
- communicates with the oral cavity anteriorly
-
laryngopharynx (or hypopharynx): inferior to the superior border of the epiglottis and the pharyngoepiglottic folds, superior to the cricoid cartilage
- communicates with the larynx anteriorly
Musculature
The are two groups of muscles in the wall of the pharynx, the external circular layer and the internal longitudinal layer.
The external circular layer is composed of the three constrictor muscles:
The internal longitudinal layer is composed of the three paired muscles:
Innervation
The muscles of the pharynx are supplied by the pharyngeal plexus, a network of nerves from pharyngeal branches of the vagus and glossopharyngeal nerves.
Sensory innervation is primarily from the glossopharyngeal nerve with a few notable exceptions:
- the superior nasopharynx is supplied by the pharyngeal nerve of the maxillary division of the trigeminal nerve (V2)
- the valleculae are supplied by the internal laryngeal nerve (a branch of the vagus nerve)
- the rest of the laryngopharynx is supplied by the recurrent laryngeal nerve (a branch of the vagus nerve)
Blood supply
Numerous branches anastomose in the pharynx, providing it with a rich arterial supply:
- ascending pharyngeal artery (from the external carotid artery (ECA))
- ascending palatine artery (from the facial artery)
- lingual artery (from the ECA)
- tonsillar artery (from the facial artery)
- greater palatine artery (from the maxillary artery)
- artery of the pterygoid canal (from the maxillary artery)
- superior laryngeal artery (from the superior thyroid artery)
- inferior laryngeal artery (from the inferior thyroid artery, off the thyrocervical trunk)
Veins of the same name drain either into the pterygoid venous plexus or directly into the internal jugular vein.
Lymphatic drainage
Most lymph drains back to the retropharyngeal nodes.
Related Radiopaedia articles
Anatomy: Head and neck
- skeleton of the head and neck
-
cranial vault
- scalp (mnemonic)
- fontanelle
-
sutures
- calvarial
- facial
- frontozygomatic suture
- frontomaxillary suture
- frontolacrimal suture
- frontonasal suture
- temporozygomatic suture
- zygomaticomaxillary suture
- parietotemporal suture (parietomastoid suture)
- occipitotemporal suture (occipitomastoid suture)
- sphenofrontal suture
- sphenozygomatic suture
- spheno-occipital suture (not a true suture)
- lacrimomaxillary suture
- nasomaxillary suture
- internasal suture
- basal/internal
- skull landmarks
- frontal bone
- temporal bone
- parietal bone
- occipital bone
- skull base (foramina)
-
facial bones
- midline single bones
- paired bilateral bones
- cervical spine
- hyoid bone
- laryngeal cartilages
-
cranial vault
- muscles of the head and neck
- muscles of the tongue (mnemonic)
- muscles of mastication
-
muscles of facial expression
- occipitalis muscle
- circumorbital and palpebral muscles
- nasal muscles
- buccolabial muscles
- elevators, retractors and evertors of the upper lip
- levator labii superioris alaeque nasalis muscle
- levator labii superioris muscle
- zygomaticus major muscle
- zygomaticus minor muscle
- malaris muscle
- levator anguli oris muscle
- risorius muscle
- depressors, retractors and evertors of the lower lip
- depressor labii inferioris muscle
- depressor anguli oris muscle
- mentalis muscle
- compound sphincter
- orbicularis oris muscle
- incisivus superior muscle
- incisivus inferior muscle
- muscle of mastication:
- elevators, retractors and evertors of the upper lip
- muscles of the middle ear
- orbital muscles
- muscles of the soft palate
- pharyngeal muscles
- suprahyoid muscles
- infrahyoid muscles
- intrinsic muscles of the larynx
- muscles of the neck
- accessory muscles of the neck
- deep cervical fascia
-
deep spaces of the neck
- anterior cervical space
- buccal space
- carotid space
- danger space
- deep cervical fascia
- infratemporal fossa
- masticator space
- parapharyngeal space
- stylomandibular tunnel
- parotid space
- pharyngeal (superficial) mucosal space
- perivertebral space
- posterior cervical space
- pterygopalatine fossa
- retropharyngeal space
- suprasternal space (of Burns)
- visceral space
- surgical triangles of the neck
- orbit
- ear
- paranasal sinuses
- nose
- oral cavity
- pharynx
- larynx
- viscera of the neck
- blood supply of the head and neck
-
arterial supply
-
common carotid artery
- carotid body
- carotid bifurcation
- subclavian artery
- variants
-
common carotid artery
- venous drainage
-
arterial supply
- innervation of the head and neck
-
cranial nerves
- olfactory nerve (CN I)
- optic nerve (CN II)
- oculomotor nerve (CN III)
- trochlear nerve (CN IV)
-
trigeminal nerve (CN V) (mnemonic)
- trigeminal ganglion
- ophthalmic division
- maxillary division
- mandibular division
- abducens nerve (CN VI)
- facial nerve (CN VII)
-
vestibulocochlear nerve (CN VIII)
- vestibular ganglion (Scarpa's ganglion)
- glossopharyngeal nerve (CN IX)
-
vagus nerve (CN X)
- superior laryngeal nerve
- recurrent laryngeal nerve (inferior laryngeal nerve)
- (spinal) accessory nerve (CN XI)
- hypoglossal nerve (CN XII)
- parasympathetic ganglia of the head and neck
- greater occipital nerve
- third occipital nerve
-
cervical plexus
- muscular branches
- longus capitis
- longus colli
- scalenes
- geniohyoid
- thyrohyoid
-
ansa cervicalis
- omohyoid (superior and inferior bellies separately)
- sternothyroid
- sternohyoid
- phrenic nerve
- contribution to the accessory nerve (CN XI)
- cutaneous branches
- muscular branches
- brachial plexus
- pharyngeal plexus
-
cranial nerves
- lymphatic drainage of the head and neck
- embryological development of the head and neck
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