Neuroanatomy - anatomy session Flashcards
What are the lenticulostriate arteries and why are they important?
Branches of the middle meningeal artery from within the lateral fissure
Supply the thalamus, internal capsule and basal ganglia.
What structure can help identify the middle cerebral artery from a frontal cross section?
Found in the lateral fissure of the brain.
When considering the homoculus map on the pre and post central gyrus what region is supplied by the anterior cerebral artery?
M1 (pre) = toes to trunk
S1 (post) = toes to trunk
What are the potential functional consequences of an occlusion to the anterior cerebral artery?
Contralateral motor/sensory deficits (lower limb focus)
Dyspraxia (basal ganglia)
Abulia (prefrontal cortex)
Emotional changes
What are the potential functional consequences of an occlusion to the middle cerebral artery?
Contralateral motor/sensory loss in the upper limbs, face and bulbar region
Homonymous hemianopia
Eyes deviate to the side of the defect
Aphasia (broccas or wernicks)
What are the functional consequences of damage to the posterior cerebral artery?
Contralateral hemianopia w/ macular sparing
Sensory s/sx if lateral thalamus
What are the functional consequences of basilar artery occlusion?
Quadriplegia “locked in” syndrome (damage to corticospinal and corticobulbar tracts)
No horizontal eye movement (due to loss of supply to abducens nucleus)
Loss of sensation (damage to medial leminuscum for fine touch and proprioception)
What is the functional consequence of occlusion of the anterior spinal artery?
Contralateral paralysis
Tongue deviates to lesion
Loss of proprioception
What is the functional consequence of occlusion of the PICA artery?
Dysphagia/hoarseness (nucleus ambiguous)
Decrease pain temp sense on ipsilateral face contralateral body (trigeminal nerve)
Ipsilateral horner (sympathetic nerve in medulla)
Vertigo, nystagmus and ataxia
What is the functional consequence of an occlusion in the anterior inferior cerebellar artery?
Ipsilateral facial paralysis
Decrease pain/temp ipsilateral face and contralateral body
Decrease lacrimation, salivation, tase of anterior tongue
Vertigo, nystagmus, staxia and dysmetria.
What is the functional consequence of an occlusion in a lenticulostriate artery?
Pure motor stroke, contralateral loss of function.
What artery has been occluded in this image?
What important functional region in the brain will this affect?
Middle cerebral artery (affecting Brocas area)
What are the typical causes of pathology in Brocas area?
Thrombus or emboli in the middle cerebral artery or internal carotid artery
Traumatic brain injury, tumours, brain infection and Alzheimers disease
What are the symptoms of Brocas aphasia?
Expressive aphasia
Non-fluent
Output of spontaneous speech diminished
Loss of normal grammatical structure
Loss use of conjunction (and, or) and prepostions (after, before, under)
Struggle to repeat phrases
However, words that are produced are intelligible and contextually correct.
‘Limited language’ - know what they want to say but unable to produce the words
What is the anatomical relevance of brocas area?
Located in the inferior frontal lobe of the dominant hemisphere
Is lateralised to the left hemisphere in 99% of right handed and 60% of left handed people.
Connected to the frontal lobe, basal ganglia, cerebellum and contralteral hemisphere
How do you diagnose Brocas aphasia?
Diagnosed via fluency tests, ability to name objects, repeat short phases, read and write.
Patient should also be screened for depression
What is the treatment plan for a patient with brocas aphasia?
No standard treatment, care plan is usually developed by a neurologist, neuropsychologist and speech therapist.
What is the key anatomy of the middle meningeal artery?
Is the major human dural artery (runs within the dura)
In almost all cases originates from the internal maxillary artery
May also originate from the internal carotid or the basilar artery.
Must check for this anonymous anatomy before microcatherisationi ntervention to ensure procedure is in the right place.
What is the anatomy underpinning cauda equina syndrome?
Cauda equina consits of lumbar and sacral nerve roots, originating from conus medullaris at base of spinal cord
Begins just below L1
Can arise from injury to L3 to L5 vertebrae damaging L3 to S5 nerve routes
What are the key signs/sympotins for diagnosis for cauda equina syndrome?
Medical emergency - bilateral leg pain, bladder, bowel and sexual dysfunction
MRI is the gold standard diagnostic tool.
What is the clinical associations of the superior sagittal sinus?
Central venous thrombosis - rare stroke, most often in SSS
Decrease CSF drainage and increases Intracranial pressure
Can lead to motor deficits, bilateral deficits and seizures.
Treat with oral anti-cuag often LMWH
Symptoms - headache (acute, severe, thunderclap or could be chronic, pervasive and of lower intensity)
What are the symptoms of a cavernous sinus thrombosis?
Ocular signs (orbital pain, chemosis, proptosis, oculomotor palsy)
What are the signs of a cortical vein thrombosis?
Motor deficits, sensory deficits and seizures
Found in subarachnoid space are superficial veins that supply the brain
What are the clinical indications of sagittal sinus thrombosis?
Motor deficits
Bilateral deficits
Seizures
What are the signs of a lateral sinus thrombosis?
Isolated intracranial hypertension
What is the clinical indication of a left transverse sinus thrombosis?
Aphasia
Affects Brocas area
What are the indications of a deep venous sinus (straight) thrombosis?
Behavioural symptoms
(thalamic lesions)
Identify the labels on this ventral brainstem
Optic chiasm
Mammillary bodies
Basillary pons
Abducens nerve (CN6,7,8 going lateral)
Medullary pyramids
Desiccation of the pyramids
Identify the structures on the dorsal brainstem
Superior and inferior colliculi
Superior middle and inferior peducnles
Floor of the fourth ventricle
Fasciculus cuneus
Fasciculus graciilis
What section of the brainstem is this?
Key identifying features
Is the lower midbrain
Inferior colliculi
Cerebral aqueduct
Peri-aqueduct grey
Red nuclei
Peduncles
Trochlear nucleus
What are the key cross sectional features of the upper midbrain?
Superior colliculi
substantia nigra
Cerebral aqueduct
periaqueductal grey
red nucleus
Oculomotor nucleus
What are the key features of the transverse cross section of the pons?
Desications of fibres in the pontine nuclei (often from cerebellum)
Cerebellar peduncles
Trigeminal nerve
Longitudinal pontine fibres (including the corticopsinal tract)
The floor of the fourth ventricle
What are the key features of the medulla oblongata in transverse cross-section?
Ventral - pyramids = heavily myelin stained (white matter)
Dorsal - cuneate and gracile nuclei.
Medial leminscus
label the key motor nuclei (right) of the brainstem.
Edinger-Westphal nucleus
Oculomotor nucleus
Trochlear nucleus
Trigeminal motor
Abducens nucleus
Facial motor nucleus
Superior and inferior salivatory nucleus
Nucleus ambiggus
Dorsal motor nucleus of vagus
Hypoglossal nucleus
Label the key sensory nuclei of the brainstem
Trigeminal sensory nucleus
Vestibular and cochlear nuclei
Nucleus solitarus
You are examining a patient with a brainstem lesion, and they are
exhibiting the following symptoms:
* Weakness of the face, upper and lower limbs on the right-hand side.
* The left eye is turned “down and out”, and the pupil is dilated.
* Where is the lesion?
Upper and lower limbs on right hand side (damage to left above pons and right from medulla donwards)
Down and out eye - damage to left oculomotor nerve (found in left midbrain)
Weakness of the face - corticobulbar damage - to facial nerve nucleus (pontmoedullary junction) - this is below the level of the midbrain damage - therefore damage to left hand side above damage right hand side face - UMNL
Q1 - damage to left-hand side of the midbrain.
Scenario 2:
* You are examining a patient with a brainstem lesion, and they are
exhibiting the following symptoms:
* Weakness of the left upper and lower limb, with sparing of the face.
* Deviation of the tongue towards the right.
* Loss of vibration and proprioception in the limbs on the left-hand
side.
* Where is the lesion?
Tongue deviates to the right - damage to the right hypoglossal nerve (medulla)
DCML - right side of brain - desciates to left in the medulla.
Weakness of the left upper and lower limb - damage to the right hand side above the desication fo the pyramids.
Sparing of the face - means must be below the level of the facial nerve nucleus - pontomedullary junction
Lesion in the right medulla above level of desication
23M suffered a road traffic accident. what is shown in his CT? What potential treatment could be used?
Epidural bleed (as concave to the brain)
Surgical drain - to remove haematoma
62F, several days post fall with no noted injury to head, presents whilst bending over with severe right sided heachafe, left facial palsy and left-sided weakness. Head MRI:
What is it?
What is alarming?
Right-sided Subdural hematoma (slow-growing hematoma)
Midline shift as space occupying.
What is the difference between the following terminology for haemorrhages?
Epidural
Intracerebral
Subaponeurotic
Subarachnoid
Subdural
Epidrual - between outmost meningeal layer (dural) and innermost skull
Intracerebral - within the brain parenchyma
Subaponeuortic - deep to the aponeuoris and superficial to the skull
Subarachnoid - in the subarchnoic space, superficial to pia mater.
Subdural - deep to dura and superficial to the arachnoid mater.
What neurovascular content is found in the cribiform plate?
The olfactory nerve CN1
What neurovascular content is found in the optic canal?
The optic nerve CN2
The ophthalmic artery
What neurovascular content is found in the superior orbital fissure?
The oculomotor nerve CN3
THe trochlear nerve CN4
The ophthalmic nerve (CNV1)
The abducens nerve CN6
What neurovascular content is found in the foramen rotundum?
The maxillary nerve (CNV1)
What neurovascular content is found in the formane ovale?
CNV3 - the mandibular branch of the facial nerve
The lesser petrosal nerve (PANS to the parotid gland)
What neurovascular content is found in the foramen spinosum?
The middle meningeal artery and vein
What neurovascular content is found in the internal auditory meauts?
The facial nerve 7
The vestibulocochlear nerve 8
The labyrinthine artery
What neurovascular content is found in the jugular foramen?
The glassopharangyeal nerve 9
The vagus nerve 10
The accessory nerve 11
Posterior meningeal artery
Inferior petrosal sinus
What neurovascular content is found in the hypoglossal canal?
The hypoglossal nerve CN12
What neurovascular content is found in the foramen magnum?
The brainstem (medulla oblangata)
The vertebral arteries
Meninges
Spinal roots of the accessory nerve
What is the union of both optic nerves called? In what bony features is it found?
The optic chiasm
The sphenoid bone - just above the pituitary gland in the sella turcica or the hypophyseal fossa.
What muscles does the oculomotor nerve innervate?
The extraocular eye muscles
The Inferior rectus
The middle rectus
The superior rectus
The inferior oblique
The levator palpebrae superioris
What is unusual about the position of origin of the trochlear nerve?
What muscle does it innervate?
Originates dorsally from the midbrain at the level of the inferior colliculus.
Innervates the superior oblique muscle
For the trigeminal nerve, which division carries motor fibres and what muscles are supplied?
Mandibular division of the trigeminal nerve (V3), supplies muscles of mastication (masseter, temporalis, medial and lateral pterygoids)
Abducens - where precisely on the brainstem does it arrive?
What muscle does it innervate?
The pontomedullary junction/caudal pons
The lateral rectus muscle
What are the five motor branches of the facial nerve?
Temporal
Zygomatic,
Buccal
Marginal
Mandibular
Cervical
Through which foramina does the facial nerve enter and leave the skull?
Enters through the internal acoutsic meatus
Leaves through the stylomastoid foramen
Then runs through the parotid salivary gland
What is the function of the vestibulocochlear nerve?
Cochlear nerve - sense of hearing - from the cochlear
Vestibular nerve - sense of balance - from the vestibular system
What pharyngeal arch is the glassopharangyeal nerve association with?
Third
What are the motor and sensory functions of the glassopharangyeal nerve?
Motor - stylopharyngeus muscle of the pharynx
Sensory - 1/3 post tongue taste, palatine tonisls, oropharnyx, muscoa of the middle ear, mastoid air cells, carotid body
Parasympathetic innervation to the parotid gland
What are the sensory/motor /PANSfunctions of the vagus nerve?
Provides motor innervation to the majority of muscles of the pharynx, soft palate and larynx.
Sensory - skin of the external acoustic meatus and larynx, visceral sensation to the heart and abdominal viscera
Parasympathetic - smooth muscle and glands of the pharynx, larynx, thoracic and abdominal organs.
What muscles are innervated by the spinal accessory nerve?
Sternocleidomastoid
Trapezius muscle
What muscles do the hypoglossal nerve innervate?
All intrinsic and extrinsic muscles of the tongue expect palatoglossuls which is innervated by vagus nerve.
Extrinsic = genioglossus, hyoglossus, styloglossus
Where does the oculomotor nerve leave the brain stem?
Midbrain at the level of the superior colliculus
