Anatomy Topic 3 Case 5 Flashcards
Identify the three components of the brainstem
- Midbrain
- Pons
- Medulla
Name three systems that ascend through the brainstem
- DCML
- Spinothalamic
- Trigeminothalamic
Name a system that descends through the brainstem
- Corticospinal
Name a system that terminates within the brainstem
- Corticobulbar
Identify three roles of the brainstem
- Pain perception
- Consciousness
- Regulation of cardiovascular and respiratory systems
Why is damage to the brainstem is so devastating?
- Structurally compact region
- Damage to which results in large functional deficit
What are the crus cerebri, where are they located and what do they contain?
- Anterior surface of cerebral peduncles
- Anterior surface of midbrain
- Descending fibres
Where do the oculomotor nerve emerge?
- Between the two cerebral peduncles
- Bracketing the mamillary bodies
Where is the tectum located? What is it composed of? Wheres does the trochlear nerve arise in relation to the tectum?
- Posterior and superior surface of midbrain
- Contains superior and inferior colliculi
- Trochlear nerve arises below the inferior colliculi
Which cranial nerves attach to the pons?
- Trigeminal nerve laterally
- Abducens, facial and vestibulocochlear inferiorly (from medial to lateral)
Where are the pyramids located and what do they contain? What occurs at the pyramidal decussation?
- Anterior surface of medulla
- Corticospinal fibres
- Decussation of corticospinal fibres at the pyramidal decussation
Where are the olives located and what is their function?
- Located posterolaterally to the pyramids
- Connections with cerebellum and is involved in control of movement
Which cranial nerve passes between the pyramid and olive?
- Hypoglossal
What is the obex?
- Inferior apex of fourth ventricle
Where is the fourth ventricle located and what is it covered by?
- Posterior surface of pons and medulla
- Cerebellar peduncles
Where are the gracile tubercles and cuneate tubercles located? What do they contain?
- Posterior surface of medulla
- Gracile tubercle overlies the nucleus gracilis medially carrying GSA fibres of the DCML from the lower limb
- Cuneate tubercles overlies the nucleus cuneatus laterally carrying GSA fibres of the DCML from the trunk and upper limbs
Which cranial nerve arises from the first pharyngeal arch?
- Trigeminal
Which cranial nerve arises from the second pharyngeal arch?
- Facial
Which cranial nerve arises from the third pharyngeal arch?
- Glossopharyngeal
Which cranial nerve arises from the fourth pharyngeal arch?
- Superior laryngeal branch of vagus nerve
Which cranial nerve arises from the sixth pharyngeal arch?
- Recurrent laryngeal branch of vagus nerve
What is meant by cranial nerve nuclei?
- Cells groups arranged in longitudinal columns
- Points at which efferent nuclei originate or afferent nuclei terminate
What is carried by general somatic afferent fibres?
- Touch
- Pain
- Temperature
What is carried by general somatic efferent fibres?
- Motor innervation to skeletal muscle
- Excluding motor innervation by cranial nerves that arise from the pharyngeal arches
What is carried by general visceral afferent fibres?
- Sensory input from the viscera
What is carried by general visceral efferent fibres?
- Motor innervation to smooth muscle, heart muscle and glands
What is carried by special afferent fibres?
- Smell
- Taste
- Vision
- Hearing
- Balance
What is carried by branchial efferent fibres?
- Motor innervation to skeletal muscles
- From cranial nerve nuclei that are derived from pharyngeal arches (5, 7, 9 and 10)
What does the trigeminal motor nucleus innervate?
- Branchial efferent
- Tensor tympani
- Tensor veli palatini
- Mylohyoid
- Anterior belly of digastric
What does the facial motor nucleus innervate?
- Branchial efferent
- Muscles of facial expression
- Stylohyoid
- Stapedius
- Posterior belly of digastric
What does the nucleus ambiguus innervate?
- Branchial efferent to muscles of the pharynx
- Superior constrictor
- Middle constrictor
- Inferior constrictor
- Stylopharyngeus
- Salpingopharyngeus
- Palatopharyngeus
What does the oculomotor nuclei innervate
- General somatic efferent
- Levator palpebrae superioris
- Superior rectus
- Medial rectus
- Inferior rectus
- Inferior oblique
What does the trochlear nuclei innervate?
- General somatic efferent
- Superior oblique
What does the abducens nuclei innervate?
- General somatic efferent
- Lateral rectus
What does the Edinger Westphal nucleus innervate?
- General visceral efferent
- Sphincter pupillae
- Ciliary muscle
What does the superior salivary nuclei innervate?
- General visceral efferent
- Submandibular glands
- Sublingual glands
What does the inferior salivary nuclei innervate?
- General visceral efferent
- Parotid glands
What do the vagal nuclei innervate?
- General visceral efferent
- Thoracic viscera
- Abdominal viscera
What does the hypoglossal nuclei innervate?
- General somatic efferent
- Genioglossus
- Styloglossus
- Hyoglossus
What does the trigeminal sensory nucleus innervate?
- General somatic afferent
- Proprioception (mesencephalic)
- Touch and pressure (chief nucleus)
- Pain (spinal nucleus)
What does the nucleus solitarius innervate?
- General visceral afferent
- Lacrimal gland (VII)
- Submandibular gland (VII)
- Sublingual gland (VII)
- Parotid gland (IX)
- Smooth muscle in thoracic viscera (X)
- Smooth muscle in abdominal viscera (X)
Outline the pathway of the olfactory nerve
- Peripheral processes in the roof and upper parts of the nasal cavity
- Central processes enter the cranial cavity through the cribiform plate
- They synapse with secondary neurons in the olfactory bulbs.
- Second order neurons pass through the olfactory tract and lateral olfactory stria
- To terminate in the primary olfactory cortex.
What do the special afferent fibres of the olfactory nerve innervate?
- Smell
Outline a clinical finding of an olfactory nerve lesion and a cause
- Anosmia
Outline the pathway taken by the optic nerve
- Optic nerve passes through optic canal to optic chiasm
- Decussation of nasal fibres at the optic chiasm
- Decussated nasal fibres join temporal fibres at the optic tract
- Optic tract synapses in dorsal lateral geniculate nucleus of the thalamus
- Geniculocalcarine fibres pass by way of the geniculocalcarine tract to the primary visual cortex in the calcarine fissure area of the medial occipital lobe.
What do the special afferent fibres of the optic nerve innervate? (1)
- Vision
Outline two clinical findings of an optic nerve lesion
- Mononuclear field loss
- Loss of pupillary constriction
Outline the pathway of the oculomotor nerve
- Leaves the anterior surface of the brainstem between midbrain and pons.
- Enters the anterior edge of the tentorium cerebelli,
- Pierces the dura mater lateral to the diaphragmatic sellae.
- Continues in anterior direction in lateral wall of the cavernous sinus
- Leaves the cranial cavity through the superior orbital fissure.
What do the general somatic efferent fibres of the oculomotor nerve innervate?
- Levator palpebrae superioris
- Superior rectus
- Medial rectus
- Inferior rectus
- Inferior oblique
What do the general visceral efferent fibres of the oculomotor nerve innervate?
- Ciliary muscle
- Sphincter pupillae
Outline four clinical findings of an optic nerve lesion
- Inability to look superiorly and medially
- Ptosis
- Loss of accommodation reflex
- Loss of pupillary constriction
Outline the pathway taken by the trochlear nerve
- Exits posterior surface of midbrain inferior to inferior colliculus of tectum
- Curves around midbrain
- Pierces cranial dura mater at tentorium cerebelli
- Continues in lateral wall of cavernous sinus
- Enters orbit through the superior orbital fissure
What do the general somatic efferent fibres of the trochlear nerve innervate?
- Superior oblique
Identify a clinical finding of an trochlear nerve lesion
- Inability to look inferiorly and medially
Outline the pathway taken by the trigeminal nerve
- Arises from lateral surface of pons
- Continues forward in posterior cranial fossa into middle
- Expands into trigeminal ganglion in trigeminal depression in trigeminal cave
Outline the pathway taken by the ophthalmic nerve
- Passes through lateral wall of cavernous sinus
- Exits skull through superior orbital fissure
- Enters orbit
Identify the three branches of the ophthalmic nerve
- Frontal
- Lacrimal
- Nasociliary
Outline the pathway taken by the maxillary nerve
- Passes through lateral wall of cavernous sinus
- Exits skull through foramen rotundum
- Enters pterygopalatine fossa
Identify the three branches of the maxillary nerve
- Zygomaticotemporal
- Zygomaticofacial
- Infra-orbital
Outline the pathway taken by the mandibular nerve
- Exits skull through foramen ovale
- Enters infratemporal fossa
Identify the three branches of the mandibular nerve
- Auriculotemporal nerve
- Buccal nerve
- Mental nerve
What do the general somatic afferent fibres of the trigeminal nerve innervate?
- External acoustic meatus
- Tympanic membrane
- Dura mater in anterior and middle cranial fossae
- Skin over scalp, maxilla and mandible
What do the branchial efferent fibres of the trigeminal nerve innervate?
- Tensor tympani
- Tensor veli palatini
- Mylohyoid
- Anterior belly of digastric
Identify two clinical findings of a trigeminal nerve lesion
- Loss of sensation of the skin over the scalp, maxilla and mandible
- Loss of function of muscles of mastication
Outline the course of the abducens nerve
- Arises from anterior surface of pontomedullary junction
- Pierces dura covering the clivus
- Passes forward in dural canal
- Crosses the cavernous sinus
- Enters the orbit through the superior orbital fissure
What do the general somatic efferent fibres of the abducens nerve innervate?
- Lateral rectus
Identify a clinical findings of an abducent nerve lesion
- Inability of lateral eye movement
Outline the course of the facial nerve
- Arises from anterior surface of pontomedullary junction laterally to the abducens nerve
- Leaves cranial cavity through internal acoustic meatus
- Enters facial canal, and enlarges as geniculate ganglion
- Gives off greater petrosal nerve (GVE)
- Gives off chorda tympani (SA) and nerve to stapedius
- Exits skull through stylomastoid foramen
What do the general somatic afferent fibres of the facial nerve innervate?
- Skin over the auricle
- External acoustic meatus
What do the special afferent fibres of the facial nerve innervate? Which nerve is associated with this function?
- Taste to the anterior 2/3 of the tongue
- Chorda tympani
What do the general visceral efferent fibres of the facial nerve innervate? Which nerve is associated with this function?
- Submandibular glands
- Sublingual glands
- Lacrimal gland
- Greater petrosal nerve
What do the branchial efferent fibres of the facial nerve innervate?
- Stapedius
- Stylohyoid
- Posterior belly of digastric
- Muscles of facial expression
Identify three clinical findings of a facial nerve lesion
- Paralysis of facial muscles
- Abnormal taste from anterior 2/3
- Dry conjunctiva
What do the general somatic afferent fibres of vestibulocochlear nerve carry?
- Hearing
- Equilibrium
Outline the pathway taken by the vestibulocochlear nerve
- Arises from anterior surface of pontomedullary junction laterally to the abducens and facial nerves
- Passes through the internal acoustic meatus and crossing the posterior cranial fossa
Identify two clinical findings of a vestibulocochlear nerve lesion
- Unilateral hearing loss
- Tinnitus
What do the general somatic afferent fibres of the glossopharyngeal nerve innervate?
- Posterior third of the tongue
- Palatine tonsils
- Oropharynx
What do the general visceral afferent fibres of the glossopharyngeal nerve innervate?
- Carotid body
- Carotid sinus
What do the special afferent fibres of the glossopharyngeal nerve innervate?
- Taste to posterior third of the tongue
What do the branchial efferent fibres of the glossopharyngeal nerve innervate?
- Stylopharyngeus
What do the general visceral efferent fibres of the glossopharyngeal nerve innervate?
- Parotid gland
Outline the pathway taken by the glossopharyngeal nerve
- Arises from lateral surface of medulla
- Rootlets crosses the posteriorcranialfossa and enter the jugular foramen
- Where they join to form glossopharyngeal nerve
- Gives off two ganglia outside jugular foramen outside the jugular foramen
Identify two clinical features of a glossopharyngeal nerve lesion
- Loss of taste to posterior third of tongue
- Loss of sensation to soft palate
What do the general somatic afferent fibres of the vagus nerve innervate?
- Auricle
- External acoustic meatus
- Larynx
- Laryngopharynx
- Posterior cranial fossa)
What do the general visceral afferent fibres of the vagus nerve innervate?
- Aortic body
- Aortic arch baroreceptors
- Thoracic viscera
- Abdominal viscera
What do the special afferent fibres of the vagus nerve innervate?
- Taste to epiglottis
What do the branchial efferent of the vagus nerve innervate?
- All muscles of soft palate (except for tensor veli palatini)
- All muscles of pharynx (except for stylopharyngeus)
- All muscles of larynx
What do the general visceral efferent fibres of the vagus nerve innervate?
- Smooth muscle of thoracic viscera
- Smooth muscle of abdominal viscera
Outline the pathway taken by the vagus nerve
- Arises from lateral surface of medulla
- Rootlets crosses the posteriorcranialfossa and enter the jugular foramen
- Gives off two nodose ganglia outside jugular foramen
Identify two clinical features of a vagus nerve lesion
- Soft palate deviation with deviation of the uvula to the normal side
- Vocal cord paralysis
What do the general somatic efferent fibres of the accessory nerve innervate?
- Trapezius
- Sternocleidomastoid
Outline the course of the accessory nerve
- Spinal part arises from upper five segments of spinal cord
- Brainstem part arises from lateral surface of medulla
- These fibres join together and continue through posterior cranial fossa and exits through jugular foramen
Identify two clinical features of an accessory nerve lesion
- Paralysis of trapezius
- Paralysis of sternocleidomastoid
What do the general somatic efferent fibres of the hypoglossal nerve innervate?
- Genioglossus
- Styloglossus
- Hyoglossus
Outline the course of the hypoglossal nerve
- Arises from lateral surface of medulla between pyramids and olives
- Passes laterally across posterior cranial fossa
- Exits through hypoglossal canal
- Descends medial to angle of mandible and turns forward
- Passes between mylohyoid and hypoglossus
- Lies lateral to genioglossus
Outline three clinical features of a hypoglossal nerve lesion
- Atrophy of ipsilateral tongue muscle
- Deviation of tongue to affected side
- Speech disturbances
Identify the two cranial nerves involved in the corneal (blink) reflex
- Afferent: Trigeminal nerve
- Efferent: Facial nerve
Identify the two cranial nerves involved in the gag reflex
- Afferent: Glossopharyngeal nerve
- Efferent: Vagus
Identify the two cranial nerves involved in the pupillary light reflex
- Afferent: Optic nerve (direct)
- Efferent: Oculomotor nerve (Consensual)
Outline the pathway of the maxillary nerve once it passes into the pterygopalatine fossa, detailing its terminal branch, including its course, and branches of this nerve
- Gives off its terminal branch, the infraorbital nerve
- Which enters the orbit through the inferior orbital fissure
- Passes out of the orbit on the inferior surface of the orbit
- Gives off palpebral, nasal and labial branches
Identify 5 motor branches of the mandibular nerve
- Nerve to masseter
- Nerve to temporalis
- Nerve to medial and lateral pterygoids
- Nerve to tensor tympani
- Nerve to tensor veli palatini
Identify three sensory branches of the mandibular nerve
- Auriculotemporal nerve
- Buccal nerve
- Mental nerve
Torsional diplopia is caused by damage to which cranial nerve and is especially problematic for the patient when performing what activity?
- Trochlear nerve
- Descending stairs
Hyperacusis is caused by damage to which nerves?
- Mandibular branch of the trigeminal nerve
- Nerve to stapedius
How would a unilateral lower motor nerve lesion of the facial nerve present?
- Bell’s palsy
- Weakness of both upper and lower facial muscles due to contralateral innervation
- Hyperacusis
- Mastoid pain
-
How would a unilateral upper motor nerve lesion of the facial nerve present?
- Weakness in lower facial muscles with sparing of upper facial muscles
- As there is bilateral innervation to upper facial muscles
A unilateral vagus nerve lesion produces what symptom?
- Reduced elevation of soft palate ipsilaterally
A bilateral vagus nerve lesion produces what symptom?
- Dysphagia
- Dysarthria
Which nerve supplies sensation to anterior 2/3 of tongue? Which foramen does it open into?
- Lingual nerve
- Branch of mandibular branch of trigeminal nerve
- Mandibular foramen, into mandibular canal
