Chapter 18Chapter 18

The lowest four cranial nervesThe lowest four cranial nerves

神外 李榮順 30/04/2012

Hypoglossal nerveHypoglossal nerve

Accessory nerveAccessory nerve

Glossopharyngeal nerveGlossopharyngeal nerve

Vagus nerve Vagus nerve

General ConceptGeneral Concept

Supranuclear supply(motor cortex )

Nuclear location(brain stem)

Infranuclear innervation

Primary sensory neuron(ex: DRG, inferior vagusl ganglion)

Secondary sensory neuronSensory cortex thalamus

Hypoglossal nerveHypoglossal nerve•Motor (GSE)

•Location of Hypoglossal nucleus

•Leave the brain stem between

pyramid and olive

•Leave the skull via Hypoglossal

cannel

Innervated muscle: Innervated muscle:

Intrinsic muscle of tongueIntrinsic muscle of tongue

Extrinsic muscle: Extrinsic muscle: styloglossue, hypoglossue, styloglossue, hypoglossue, genioglossusgenioglossus

(Except the palatoglossus)

Nuclear lesionInfranuclear lesion

Supranuclear lesion (upper motor neuron disease)

Nuclear lesion (low motor neuron disease)

Infranuclear lesion

Clinical noteClinical note

Function: tongue Function: tongue protrusionprotrusion

Low motor neuron Low motor neuron lesion:lesion:

((Nuclear lesion, Infranuclear lesion))

1. tongue deviation to lesioned 1. tongue deviation to lesioned sideside

2. muscle fasciculation2. muscle fasciculation atrophy atrophy (weakness)(weakness)

• Upper motor neuron lesionUpper motor neuron lesion (supranuclear lesion)) less deviation less deviation no muscle atrophy no muscle atrophy

Accessory nerveAccessory nerve

Spinal part

(C1-5 anterior gray horn)

foramen

magnum

Cranial part

(nucleus ambiguus)

Accessory nerve

Jugular foramen

Motor (GSE)

dorsal view

Behind the dentate ligament

Muscle innervations

Cranial part:

Join the vagus nerve and distribute to muscles of the soft palate, pharynx and larynx

Spinal part:

Trapezius,

Sternocleidomastoid (SCM)

Clinical noteClinical note

Function (Function (spinal partspinal part):):

1.1. SCM: turning the head SCM: turning the head toward the opposite sidetoward the opposite side

2.2. Trapezius: Trapezius:

elevating the shoulderelevating the shoulder

抓住青春抓住青春的尾巴的尾巴

Glossopharyngeal nerveGlossopharyngeal nerve

Motor nucleusMotor nucleus: ambiguus nucleus: ambiguus nucleus

(stylopharyngeus muscle)(stylopharyngeus muscle)

Parasympathetic nucleus:Parasympathetic nucleus:

inferior salivatory nucleus inferior salivatory nucleus

Sensory nucleus:Sensory nucleus:

solitary nucleussolitary nucleus

spinal nucleus of the trigeminal nervespinal nucleus of the trigeminal nerve

Red: motor

Brown: parasympathetic nerve

Blue: sensory

ambiguus nucleus

Parasympathetic component of CN 9

Tympanic branch lesser petrosal nerve foramen ovale otic ganglion parotid gland

Tympanic branch: sensation of the tympanic membrane

To: spinal nucleus of the trigeminal nervespinal nucleus of the trigeminal nerve

Glossopharyngeal nerveGlossopharyngeal nerve

Motor nucleusMotor nucleus: ambiguus nucleus: ambiguus nucleus

(stylopharyngeus muscle)(stylopharyngeus muscle)

Parasympathetic nucleus:Parasympathetic nucleus:

inferior salivatory nucleus inferior salivatory nucleus

Sensory nucleus:Sensory nucleus: (GVA, SVA, GSA)

solitary nucleussolitary nucleus

spinal nucleus of the trigeminal nervespinal nucleus of the trigeminal nerve

Solitary nucleus

Visceral afferent nucleus:

primary afferents supplying the alimentary tract and respiratory tract

Sensory component of CN 9Sensory component of CN 9

GVA: GVA:

SVA:SVA:

Carotid branch

Carotid sinus, stretch receptor (blood pressure)

Baroreceptor baroreceptor nucleus

Glomus cell of carotid body

Chemoreceptor (CO2, O2) dorsal respiratory nucleus

Taste of the posterior third of tongue: gustatory nucleus

Both of GVA and SVA convey in the inferior glossopharyngeal ganglion

GSA: superior glossopharyngeal ganglion spine nucleus of trigeminal nerve

(common sensation from orpharynx and posterior third of the tongue)

Referred pain Referred pain

GSA:

1. superior glossopharyngeal ganglion spine nucleus of trigeminal nerve (common sensation from orpharynx and posterior third of the tongue)

2. Tympanic branch: sensation of the tympanic membrane

general

Vagus nerveVagus nerve

Motor nucleusMotor nucleus: ambiguus nucleus: ambiguus nucleus

Parasympathetic nucleusParasympathetic nucleus: dorsal nucleus : dorsal nucleus of vagusof vagus

Sensory nucleus: Sensory nucleus: solitary nucleussolitary nucleus spinal nucleus of the trigeminal nervespinal nucleus of the trigeminal nerve

Red: motorBrown: parasympathetic nerveBlue: sensory

Muscle innervation: constrictor muscle of pharynx

intrinsic muscle of the larynx

ambiguus nucleus

? Gag reflex? Gag reflex

9 9 進進 10 10 出出

Vocal palsy

Parasympathetic nucleusParasympathetic nucleus

dorsal nucleus of vagusdorsal nucleus of vagus

Sensory component of CN 10Sensory component of CN 10

GVAGVA: : inferiorinferior vagus ganglion vagus ganglion commissural nucleus commissural nucleus

SVA SVA (taste of epiglottis): (taste of epiglottis): inferiorinferior vagus ganglion vagus ganglion

gustatory nucleusgustatory nucleus

GSAGSA: : superiorsuperior vagus ganglion vagus ganglion spine nucleus of spine nucleus of trigeminal nervetrigeminal nerve

(auricular branch: common sensation: outer ear canal, meninges over posterior cranial fossa)

Solitary nucleus

Visceral afferent nucleus:

primary afferents supplying the alimentary tract and respiratory tract

Jugular foramen syndromeJugular foramen syndrome

A B

C D

Vagal trigone