Brainstem nuclei and cranial nerves Flashcards
What CN leaves the cribiform plate?
Olfactory (CN1)
What CN leaves the optic canal?
Optic nerve (CNII)
What CNs leave the superior orbital fissure?
Oculomotor (CNIII), trochlear (CNIV), ophthalmic (CNV1) abducens (CNVI)
What CN leaves the foremen rotundum?
Maxillary nerve (CNV2)
What CN leaves the foremen ovale?
Mandbular nerve (CNV3)
What CNs leave the internal acoustic meatus?
Facial nerve (CNVII), vestibulocochlear (CNVIII)
What CNs leave the jugular foramen?
Glossopharyngeal (CNIX), vagus (CNX), accessory (CNXI)
What CN leaves the hypoglossal canal?
Hypoglossal nerve (CNXII)
What is SSA
Special somatic afferent = special senses related to external environment; sight, balance
What is GSA
General somatic afferent = sensation on skin, mucous membrane; pain, touch, proprioception
What is SVA
Special visceral afferent = primarily with tasye
What is GVA
General visceral afferent = pain in the GIT, heart, lungs, hollow organs
What is GSE
General somatic efferent = skeletal muscles that control specific myotomes
What is SVE
Special visceral efferent = muscles from brachial/pharyngeal embryo logical origins
What is GVE
General visceral efferent = preganglionic fibres of the autonomic nervous system
Type, function and foramen/origin of olfactory CNVI
SVA, smell, cribiform plate/forebrain
Type, function and foramen/origin of optic CNII
SSA, vision, optic canal/forebrain
Type, function and foramen/origin of Oculomotor CNIII
GSE - movement of the eye (all muscles except lateral rectus and superior oblique)
GVE - parasympathetic pupillary constriction and lens accommodation
Superior orbital fissure/midbrain
Type, function and foramen/origin of trochlear CNIV
GSE, movement of the eye (just superior oblique), superior orbital fissure/midbrain
Type, function and foramen/origin of trigeminal CNV
SVE - chewing via muscles of mastication
GSA - general sensation on anterior 2/3 of the tongue, face, gingiva, teeth, scalp, paranasal sinuses
V1 = superior orbital fissure; V2 = foramen rotundum; V3 = foramen ovale (all pons)
Type, function and foramen/origin of abducens CNVI
GSE, movement of the eye (just lateral rectus), superior orbital fissure/pons
Type, function and foramen/origin of facial CNVII
GSA - general sensation on area posterior to the ear and external auditory meatus
GVA - visceral sensation on middle ear, nasal cavity and soft palate
SVA - taste on anterior 2/3 of tongue
GVE - parasympathetic lacrimal glands, mucous secretion and salivary glands (submandibular and sublingual)
SVE - muscles of facial expression
Internal acoustic meatus and facial canal/pons
Type, function and foramen/origin of vestibulocochlear CNVIII
SSA - hearing and equilibrium/balance, internal acoustic meatus/pons
Type, function and foramen/origin of glossopharyngeal CNIX
GSA - general sensation on posterior 1/3 of tongue, soft palate, upper pharynx
GVA - visceral sensation on middle ear, pharynx, tongue, carotid sinus
SVA - taste on posterior 1/3 tongue
GVE - salivation (parotid)
SVE - swallowing
Jugular foramen/medulla oblongata
Type, function and foramen/origin of vagus CNX
GSA - general sensation in area posterior to ear, external acoustic meatus and posterior part of the meninges
GVA - visceral sensation in thoracic and abdominal viscera
SVA - taste on epiglottis
GVE - parasympathetic peristalsis
SVE - phonation - muscles of larynx and pharynx
Jugular foramen/medulla oblongata
Type, function and foramen/origin of accessory CNXI
SVE - phonation (laryngeal muscles), head and shoulder movements (SCM and trapezius)
Foramen magnum/medulla oblongata
Type, function and foramen/origin of hypoglossal CNXII
GSE - tongue movement (muscles of the tongue), hypoglossal canal/medulla oblongata
What happens if there is a lesion in the olfactory nerve
Patient cannot smell
What happens if there is a lesion in the optic nerve?
Patients vision is affected. Specific symptoms occur depending on where the lesion occurs. Lesion 2 occur due to an enlarged pituitary gland and affect the optic chiasm. Lesion 1 causes monocular blindness, lesion 2 causes tunnel vision, lesion 3 causes homonymous hemianopia.
What happens if there is a lesion in the Oculomotor nerve?
Leads to ptosis (drooped eyelid) and the eye pointing down and outwards. Pupil will also dilate in the same eye.
What happens if there is a lesion in the trochlear nerve
Superior oblique affected. Causes eye to point upward and outward causing double vision due to a paralysed superior oblique muscle. Affected eye will be unable to point down and towards the nose.
What happens if there is a lesion in the abducens nerve?
Paralysis of the lateral rectus causing the eye to point inwards leading to double vision (diplopia). The affected eye will be unable to point outward.
What happens if there is a lesion in the trigeminal nerve?
If lesion in the motor aspect, patient will not be able to chew food. If lesion in sensory aspect then the patient will not feel anything in their face. Specific lesions will cause specific areas of the face symptoms.
What happens if there is a lesion in the facial nerve?
Five branches: temporal, zygomatic, buccal, marginal mandibular, cervical. All have contralateral innervation except the temporal which received bilateral innervation. If lesion in the facial motor nucleus then the muscles of facial expression will be affected, however the forehead will be unaffected due to the temporal branch. If sensory aspect is affected then the patient will be unable to taste anything on the anterior 2/3 of the tongue.
What happens if there is a lesion in the vestibulocochlear nerve?
Loss of hearing and diminished ability to maintain balance. Other symptoms may include vertigo and dizziness.
What happens if there is a lesion in the glossopharyngeal nerve?
Death. Sensory info that will be lost includes the baroreceptor reflex, taste in the posterior 1/3 of the tongue and visceral sensation to the pharynx. Afferent innervation that will be affected includes the inability to elevate the pharynx to swallow and inability to secrete saliva from the parotid gland.
What happens if there is a lesion in the vagus nerve?
Inability to raise the soft palate (making breathing and swallowing difficult), loss of the gag reflex, loss of sensation from the pharynx, oesophagus and trachea. Can lead to irregular heartbeat due to a lack of info being sent to the SAN and cardiac ventricular muscles.
What happens if there is a lesion in the accessory nerve?
Inability to talk and make coherent sounds as well as the inability to use the SCM and trapezius muscles. Patient will not be able to turn their head and these muscles will be paralysed.
What happens if there is a lesion in the hypoglossal nerve?
Tongue to point towards the side of the lesion due to a paralysis of the tongue muscles of the contralateral side.
