CN IX- XII Cheat Sheet

A Home & Health › Medical cheat sheet in English by Siffi

Clinical relevance of CN IX-XII

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PRs

CN IX

Efferent	Afferent
Stylopharyngeus - Pharyngeal plexus	Sensory to posterior 1/3 of tongue (taste, touch, nociception + temp)
Preganglionic Parasympathetic - Otic Ganglion - Parotid Gland	Eustachian tube
	Oropharynx
	Carotid sinus to CNS

Dysfunction =
Swallowing, loss of taste posterior 1/3 of tongue, decreased secretion of parotid gland
Almost never lesioned in isolation
Symptoms may be unnoticeable by the patient - overlap in innervations

CN X

Efferent	Afferent
Thoracic + abdomen Viscera	External Auditory Meatus sensation (Nervus intermedius - VII)
Motor fibres to pharynx + soft palate	Pharynx, larynx, trachea + viscera of tx + abdomen
Superior laryngeal - tensors of vocal folds
Reccurent laryngeal - adduction + abduction fold

Dysfunction=
Hoarseness of voice
Reduced vocal strength
Weak cough
Nasal quality of speech
Nasal regurgitation + dysphagia - in severe cases
Pain/altered sensation in EAM
Reduction in control of circulatory system (BP + HR)
Poor digestion

CN XI

Efferent	Afferent
Traps + SCM (ipsilaterally)	Possible sensory from muscles supplied from C3 & C4

Dysfunction =
Weakness + Difficulty turning head and with shoulder movement
May have some difficulty with swallowing
Rarely affects both Traps & SCM

CN XII

Purely motor nerve that innervates:

Intrinsic muscles of the tongue

Genioglossus, hyoglossus, styloglossus (extrinsic muscles of the tongue)

Geniohyoid

Dysfunction =
Due to the nerve running under the external portion of carotid, this nerve is affected by carotid artery disorders such as: aneurysms + dissection.
Deviation + atrophy (LMNL) of the tongue - deviates towards weak side

Conditions

Vernet's syndrome

IX, X, XI affected

Caused by a thrombus/lesion in lateral sinus - presses on nerves passing through jugular foramen

Collet Sicard Syndrome

IX, X, XI, XII affected (can affect sympathetic)

Caused by a lesion at jugular foramen - schwannoma/other tumours

Villaret's

IX,X,XI,XII + cx sympathetics affected ipsilaterally

Lesion at retropharygeal/retroparotid space

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