Anatomy Flashcards
Mnemonic for cranial nerves
Oh I Olfactory
Oh II Optic
Oh III Oculomotor
To IV Trochlear
Touch V Trigeminal
And VI Abducens
Feel VII Facial
Very VIII Vestibulocochlear
Good IX Glossopharyngeal
Velvet X Vagus
A XI Accessory
H XII Hypoglossal
Mnemonic for cranial nerve functions
Some
Say
Marry
Money
But
My
Brother
Says
Big
Brains
Matter
Most
Trigeminal branches
V1 Opthalmic
V2 Maxillary
V3 Mandibular
What are the ridges and furrows of the brain called?
Ridges: Gyri
Furrows: Sulci
What connects the right and left hemispheres of the brain?
Corpus collosum
What are the 3 parts of the brainstem from superior to inferior?
Midbrain
Pons
Medulla
What structure lies caudal to the diencephalon?
Brainstem
What separates the frontal lobe from the parietal lobe?
Central sulcus
What separates the temporal lobe from the frontal and parietal lobes?
Lateral fissure
What separates the occipital lobe from the parietal lobe?
Parietal-occipital sulcus
Which lobe is present medially in the brain and spans the frontal, parietal, and temporal lobes?
Limbic lobe
Which part of the lateral ventricle lays within the frontal and parietal lobes?
Anterior horn
Which part of the lateral ventricle extends into the occipital lobe?
Posterior horn
Which part of the lateral ventricle extends into the temporal lobe?
Inferior horn
What the lateral ventricles connected to in the midline?
Third ventricle
What connects the third ventricle with the fourth ventricle?
Cerebral aquaduct
What lies on either side of the third ventricle?
Thalamus
What is the benefit of the increased SA d/t gyri and sulci?
Increased volume for neurons.
What makes up the forebrain?
Cerebral cortex and deep nucleii
(Telencephalon and diencephalon)
What makes up the telencephalon?
Cerebral hemispheres and deep structures
What makes up the diencephalon?
Thalamus
Hypothalamus
Subthalamus
What areas make up the limbic lobe?
Cingulate gyrus
Parahippocampal gyrus
What structures facilitate connections between the pons and the cerebellum?
Superior cerebellar peduncle
Middle cerebellar peduncle
Inferior cerebellar peduncle
What produces CSF
Ependymal cells of the choroid plexus
What are the 3 dural layers around the CNS?
Dura - outermost, connected to skull
Arachnoid - middle, tightly attached to dura
Pia - innermost, tightly adhered to brain surface
What two layers make up the dura mater?
Periosteal layer
Meningeal layer
What structure lies along the midline of the superior surface of the brain, formed by the invagination of the meningeal layer of the dura?
Superior sagittal sinus
What are the 2 dural reflections within the brain?
Falx cerebri - runs in longitudinal fissure, separates right and left hemispheres
Tentorium cerebelli - covers upper surface of cerebellum
Specialized portions of arachnoid that protrude into the superior sagittal sinus and are involved in the reabsorption of CSF.
Arachnoid granulations
Potential space between the skull and the periosteal layer of dura.
Epidural space
Potential space between the dura and the arachnoid.
Subdural space
Real space between the arachnoid and pia, filled with CSF.
Subarachnoid space
Clinical features of an epidural hematoma
Accumulation of blood between dura and skull.
Main cause of an epidural hematoma.
Rupture of the middle meningeal artery following fracture of the temporal bone.
Radiological appearance of an epidural hematoma
Lens-shaped biconvex hematoma which does not generally progress past the cranial sutures.
Symptoms of an epidural hematoma
Elevated intracranial pressure and possible brain herniation.
What structures drain the cerebral hemispheres and transverse the subdural space on their way to large dural venous sinuses?
Bridging veins
What can cause rupture of bridging veins?
Shearing forces applied to the head, causing a slow developing subdural hematoma.
What are the 2 types of subdural hematomas?
- Acute - following significant head trauma, generally associated with other serious head injuries.
- Chronic - develops slowly over weeks, no known hx of trauma, more common in elderly; headache, unsteady gait, cognitive impairment.
What suspends vessels within the subarachnoid space?
Arachnoid trabeculae
Rupture of an arterial aneurysm, releasing blood into the subarachnoid space.
Subarachnoid hemorrhage
Clinical features of a subarachnoid hemorrhage.
Accumulation of blood in the CSF-filled subarachnoid space.
Radiological appearance of a subarachnoid hemorrhage.
Blood can be seen tracing down into the sulci and following the contours of the gyri.
What are the 2 types of subarachnoid hemorrhage?
- Non-traumatic (spontaneous) - rupture of arterial aneurysm, worst headache of my life
- Traumatic - bleeding into subarachnoid space following cerebral contusions, also severe headache
Where does the brainstem receive blood from?
Vertebral-basilar system from the vertebral arteries
Where do the cortex and deep structures receive blood from?
Anterior arterial system arising from the internal cartoids.
What is the location of the anastomoses of the vertebral-basilar and anterior systems?
Cerebral arterial circle
What does the basilar artery bifurcate to form?
Posterior cerebral arteries.
What do the internal carotid arteries supply?
Middle cerebral and anterior cerebral arteries.
How does the anterior system join up with the vertebral-basilar system?
Via the posteriorcommunicating arteries.
What components make up the basal ganglia?
Caudate
Thalamus
Putamen
Globus Pallidus
Which portion of the midbrain are an important part of the auditory pathway?
Inferior colliculi
Which portion of the midbrain are an important in visual reflexes?
Superior colliculi
What do the 3 cerebellar peduncles, located in the pons, connect?
Brainstem and cerebellum.
What structures of the caudal medulla carry sensory information about proprioception, fine/discriminative touch, and vibration?
Fasciculus gracilis and fasciculus cuneatus
What separates the fasciculus gracilis and fasciculus cuneatus?
Posterior median sulcus
What do the fasciculus gracilis and fasciculus cuneatus overlie?
Ascending posterior column tracts.
Where does the 4th ventricle lie?
Over the rostral medulla and caudal pons.
Through which structure does the central canal open into the fourth ventricle?
Obex
Which CN does NOT emerge from the brainstem?
CN I
Spinothalamic tract
Pain and temperature.
Enters posterior horn of spinal cord.
Decussate at spinal cord level.
3 neuron chain system;
1 - from receptor to spinal cord
2 - from spinal cord to thalamus
3 - from thalamus to cortex
Posterior column-medial lemniscus pathway
Discriminative touch, vibration, proprioception.
Enters posterior horn of spinal cord.
Decussates in medulla.
3 neuron chain system;
1 - from receptor to medulla
2 - from medulla to thalamus
3 - from thalamus to cortex
What are the 2 sensory input pathways?
Spinothalamic tract - pain and temp.
Posterior column-medial lemniscus pathway - discriminative touch, vibration, proprioception.
Corticospinal tract
Cell body of UMN reside in primary motor cortex.
Pathway: internal capsule to midbrain (cerebral peduncles) to anterior pons to medulla (pyramids).
Decussates at pyramidal decussation in caudal medulla.
Synapses with LMN in anterior horn of spinal cord.
2 neuron chain;
1 - Cortex to spinal cord
2 - Spinal cord to muscle
What is the function of the thalamus regarding incoming information?
Gatekeeper.
Regulates what information reaches the cortex.
Pain almost always is prioritized.
Primary somatosensory cortex
Gathers all raw data from the thalamus.
Sends data to sensory association areas.
Sensory association areas
Help make sense of the data.
Integrates sensory info with visual, auditory, memory, and emotion.
Supplementary motor complex
Association area that helps generate motor plans and patterns.
Role of cerebellum in movement
Fine control and coordination.
Role of basal ganglia in movement
Integrate the sum of all signals into one motor output, or behaviour.
Pyramidal lesion
Lesion to the corticospinal tract (pyramidal system)
Extrapyramidal system
Basal ganglia and cerebelllum.
Systems contolling the UMN.
List the following characteristics of an UMN lesion (pyramidal):
1. Strength
2. Paralysis
3. Rigidity/spacticity
4. Tone
5. Reflexes
- Weakness
- Spastic paralysis
- Spasticity, velocity-dependent resistance, ‘clasp-knife’ phenomenon.
- Hypertonia
- Hyperreflexia
List the following characteristics of a LMN lesion:
1. Strength
2. Paralysis
3. Rigidity/spacticity
4. Tone
5. Reflexes
- Weakness
- Flaccid paralysis
- none
- Hypotonia
- Hyporeflexia
List the following characteristics of a basal ganglia/cerebellar (extrapyramidal) lesion:
1. Strength
2. Paralysis
3. Rigidity/spacticity
4. Tone
5. Reflexes
- No weakness
- No paralysis; slowed or increased involuntary movment
- Rigidity; not velocity-dependent, constant resistance throughout ROM
- Normal tone - basal ganglia, Abnormal tone - cerebellum
- Normal reflexes - basal ganglia, Abnormal reflexes - cerebellum
Cerebral peduncles functions
Carry motor and sensory info between cerebrum and brainstem.
Connect forebrain to spinal cord, cerebellum, and brainstem.
Functions of CN I - XII
CN I - smell
CN II - vision, pupillary light reflexes
CN III - parasympathetic to pupil, motor to most extraocular muscles
CN IV - motor to superior oblique muscle
CN V - Sensory to face, motor to muscles of mastication
CN VI - Motor to lateral rectus muscle (eye movements)
CN VII - motor to muscles of facial expression, parasympathetic to lacrimal gland, taste
CN VIII - balance, hearing
CN IX - sensory and motor to pharynx
CN X - parasympathetic to viscera, sensory and motor to pharynx
CN XI - motor to trap and SCM
CN XII - motor to tongue muscles
What types of fibres interconnect areas on the same side of the brain?
Association fibres
What types of fibres integrate information from one hemisphere with the other?
Commissural fibres.
What types of fibres allow for the connection of the forebrain, midbrain, and spinal cord?
Projection fibres.
What tract is important for the integration of sensory information and connects all 4 lobes on one hemisphere?
Superior longitudinal fasciculus.
What is the name of the subset of fibres within the superior longitudinal fasciculus that connects Broca’s and Wernicke’s areas?
Arcuate fasciculus
What is the largest bundle of commissural fibres?
Corpus collosum.
What structure do the corona radiata fibres converge to form?
Internal capsule.
Which fasciculus connects the frontal and temporal lobes?
Uncinate fasciculus.
What are the 2 limbs of the internal capsule?
Anterior limb.
Posterior limb.
Where do the temporal fibres of one eye and the nasal fibres of the other eye within the optic nerve synapse?
Lateral geniculate nucleus on the ipsilateral side of the temporal fibres A and then project to the primary visual cortex.
A lesion in the temporal lobe affecting Meyer’s loop, will result in a visual deficit in which field?
Upper visual field.
Discuss the primary cortical areas
Areas that receive info from peripheral receptors with little interpretation of meaning.
Primary motor area
Primary somatosensory area
Primary visual area
Primary auditory area
Primary gustatory area
Discuss association areas
Areas that receive input from the primary area and are involved in processing, integrating, and interpreting information.
Usually adjacent to primary areas.
Unimodal or heteromodal.
Unimodal association area
Deals with information from one sense modality.
Heteromodal association area
Manages information from multiple sense modalities.
Location and function of primary motor area.
What tract carries this info from brain?
Located in the precentral gyrus of the frontal lobe.
Motor output to contralateral side of body.
Corticospinal tract carries outflow.
Location of supplementary motor area and premotor association area.
Location is anterior to the primary motor area in the frontal lobe with the supplementary motor area superior to the premotor association area.
Location and function of frontal eye fields
Located in the supplementary motor area.
Involved in eye movements.
What is located just posterior to the frontal eye fields?
Motor-hand area.
Location and function of the somatosensory association area.
Located posterior to the primary somatosensory area in the post central gyrus.
Allows for interpretation of the significance of sensory information.
Location of the primary visual area.
Located on the banks of the calcarine sulcus in the medial occipital lobe.
Discuss the general pathway of visual information.
Fibres from retina travel to the lateral geniculate nucleus of the thalamus, then as optic radiations to the primary visual cortex.
Fibres from the upper visual field travel on the inferior bank of the calcarine sulcus.
Fibres from the lower visual field travel on the superior bank of the calcarine sulcus.
The fovea is represented near the occipital pole.
Location of the visual association area
Surrounding the primary visual cortex on the medial surface of occipital lobe.
Discuss the general pathway of auditory information
Cochlea to the medial geniculate nucleus then to primary auditory area cortex.
Info from cochlea travels both ipsilaterally and contralaterally.
Location of primary auditory area
Heschl’s gyrus deep in lateral fissure and superior surface of superior temporal gyrus in temporal lobe.
Location and general function of insular cortex
Located in the lateral fissure.
Involved in consciousness, emotion, self-awareness, and cognitive function
Location of primary gustatory area
In the insular cortex.
Location and function of prefrontal cortex
Anterior frontal lobe.
Function is executive function, higher order processing, planning, cognitive flexibility, attention, memory, problem solving.
Location and function of parietal association areas
Posterior to primary somatosentory area.
Involved in orienting our attention in time and space.
Location and function of temporal association areas
Located throughout temporal lobe.
Critical for identifying faces or objects and their meaning or identity.
How does the non-dominant hemisphere contribute to language?
Non-verbal language/prosody
Tone
Music perception
Imparting emotional significance
What type of aphasia does damage to Broca’s area result in?
Expressive aphasia.
Impaired naming, repetition, and fluency with normal comprehension.
What type of aphasia does damage to Wernicke’s area result in?
Receptive aphasia.
Impaired comprehension, naming, and repetition with normal fluency.
Damage to the arcuate fascilicus results in what impairments?
Conduction aphasia.
Impaired naming and repetition with normal comprehension and fluency.
What structures do the vertebral arteries arise from?
Subclavian arteries.
What structures does the anterior blood supply to the brain arise from?
Internal carotids.
What area of the cerebrum does the PCA supply?
Inferior and medial temporal lobes and medial occipital cortex.
Deep branches supply the thalamus.
What areas of the cerebrum does the MCA supply?
Superior division:
Frontal and parietal cortex above lateral fissure.
Inferior division:
Temporal and parietal cortex below lateral fissure.
Small portion of the inferior frontal lobe.
Basal ganglia.
Internal capsule.
What is the name of the deep branches of the MCA?
Lenticulostriate arteries.
Supply basal ganglia (caudate nucleus, putamen, globus pallidus) and internal capsule.
What areas of the cerebrum does the ACA supply?
Most of the medial surface of the frontal and parietal lobes.
Inferior surface of frontal lobe.
1-2 cm on lateral surface of frontal and parietal lobes.
Anterior chorodial artery
Travels to the choriod plexus in the lateral ventricle.
Supplies deep structures in temporal and occipital lobes (globus pallidus, putamen, tail of caudate nucleus, posterior internal capsule, hippocampus).
What structure gives rise to the chorodial artery?
Internal carotid.
Vulnerable to hemorrage/aneurysm.
Watershed areas
Where there is little overlap between different arteries.
Vulnerable to severe drops in systemic blood pressure or occlusion resulting in decreased perfusion.
What makes up the basal ganglia?
Caudate
Putamen
Thalamus
Globus Pallidus
List 3 main layers of the eye globe from inwards to outwards.
Retina.
Choroid.
Sclera.
Retina
Neural layer.
Site of phototranscduction.
Choroid
Vascular layer.
Supplies retina with blood.
Sclera
Tough connective tissues that maintains the eye structure.
Connects to optic nerve sheath and cornea.
Fovea
Area of highest visual acuity with tightly packed cones.
Important for sharp central vision.
Macula
Area surrounding fovea.
Important for central visual acuity.
Temporal to the optic disc.
Optic disc
Head of the optic nerve.
Appears slightly raised.
No photoreceptors, creates blind spot.
Discuss pituitary tumor and optic chiasm
The optic chiasm is above the pituitary gland. A tumor would compress the optic chiasm and result in a bilateral hemianopsia
2 types of photoreceptor cells and their functions
Rods:
Dim light
Cones:
Visual acuity in bright light and colour vision.
What is the dual blood supply of the retina?
Ciliary vessels: supply optic nerve head, sclera, conjunctiva.
Retinal vessels: supply the inner retina
Presentation of a pre-chaismal lesion
Monocular deficit.
Vision loss in the ipsilateral affected eye.
Presentation of a chiasmal lesion
Bitemporal.
Vision loss in the temporal region of both eyes.
Presentation of a post-chiasmal lesion
Homonymous deficit.
The same region of the visual field is affected in both eyes.
What is the arterial blood supply to the primary visual cortex?
PCA
What is the blood supply to the occipital pole?
PCA and a deep branch of MCA.
How would a stroke in the PCA or MCA affect vision?
Contralateral homonymous visual field deficit.
Discuss the information flow for higher order visual processing.
Primary visual cortex to
Secondary visual cortex to
Visual association areas through dorsal and ventral streams.
Discuss the dorsal pathway.
Where and how.
Interprets spatial information.
Projects to parietal lobe.
Lesions impact navigation, object manipulation.
Discuss the ventral pathway
What.
Interprets object characteristics; colour, shape, patterns.
Projects to temporal lobe.
Lesions cause issues with object recognition, discrimination, and visual orientation.
