Neuro Anatomy Flashcards
What is the hindbrain made up of?
- Cerebellum (motor control and muscle and postural tone), pons and medulla.
What is the role of the midbrain?
- Connect the two other sections of the brain
What is the forebrain made up of?
- Outer layer = cerebral cortex and then deep layer = deep nuclei, basal ganglia, thalamus and hypothalamus.
What is grey matter?
- Dendrites and axons with no neuronal cells.
- Schwann cells within the CNS and oligodendrites within the peripheral cells.
What is white matter?
- Cell bodies - this is where metabolic activity takes place.
What are the different meningeal layers?
- Dura, arachnoid, pia
What are the different bones within the skull?
- Frontal, occipital, pariteal and temporal
What are the different lobes of the brain?
- Frontal lobe (contains the primary motor cortex)
- Pariteal lobe (Contains the primary sensory cortex)
- Temporal lobe (Contains primary auditory cortex, Wernickes area and amygalda/hippocampus)
- Occipital lobe (Primary visual cortex)
What are gyri and sulci?
- Gyri are the roles of cerebral cortex and sulcus are the grooves between the two .
What is the central sulcus?
- Separates the frontal and parietal lobes of the brain.
- Primary motor cortex sits directly in front and primary sensory cortex sits directly behind.
What is the longitudinal fissure?
- Seperate the right and left hemisphere
What is the corpus collosum?
- Fibres that connect the two hemispheres within the longitudinal fissure in order to allow communication.
What is the lateral fissure?
- Seperates the frontal and parietal lobes and the temporal lobe
What is found on the inferior surface of the frontal lobe?
- The olfactory tract runs backwards through the inferior surface.
Where are the mammillary bodies found?
- Behind the optic chiasm
- Optic chiasm is found where the optic nerves cross over, they then run backwards to form the optic tracts.
What are the dominant hemispheres within the brain?
- Within right handed people there is 98% left sided dominance
- Within left handed people there is 60% left sided dominance
Which side of the brain is the Wernickes and Brocas area?
- Dominant
What is found on the parietal lobe?
- Contains primary sensory area
- Dominant important for perception, interpreting sensory info and formation of an idea.
What is found on the frontal lobe?
- Contains primary motor area - spontaneity, memory, problem solving
- It contains Broca’s area on the dominant side, which receives signals from Wernicke’s area then interprets in for speech in the larynx.
What is found on the temporal lobe?
- Primary audiatory cortex and Wernicke’s area in dominant area in hemisphere (Analyses speech to send signals to Broca’s area)
What happens if there is a stroke in the dominant area?
- If there is damage to Wernicke’s areas then it can lead to receptive dysphagia.
- If there is damage to Broca’s area lead to loss of speech
What is limbic system?
- Medial margin of the hemisphere
- Hippocampus, fornix and amygalda
- Long term memory, stimuli related to fear, rewards and about initiating pleasure.
- Influences the endocrine and autonomic systems.
What is the dura mater?
- Thick and durable later
- Made up of outer and inner layer
- Contains dural venous sinues where the two layers don’t meet - the most important is the Cavernous sinus - lies lateral to the body of the Sphenoid.
- Venous sinus drain into the internal jugular vein.
What is the falx cerebri?
- Found in the longitudinal fissure
What is the tentorium cerebelli?
- Thick in dura over the posterior cranial fossa and cerebellum
What is arachnoid mater?
- Contains small blood vessels
- There is subarachnoid cisterns between arachnoid and pia which are filled with CSF
What is the pia mater?
- Very thin layer that’s important in the blood brain barrier.
What are the anatomical adjacent in the blood brain barrier?
- Astrocyte feet
- Endothelial cells in the membrane
- Basement membrane
- Alcohol can cross the blood brain barrier as it’s lipid and water soluble.
What extra dural haematoma?
- Skull and dura
- Head injury
- Haemorrhage from meningeal arteries at increase pressures.
What sub dural haematoma?
- Between dura and arachnoid
- Crescent on CT scan
- High impact injury
- Tear of bridging veins, this is under lower pressure.
What is sub arachnoid haemorrhage?
- Between arachnoid and pia
- Head injury
- Berry aneurysm
- Severe headache and really fatal
What does the anterior cranial fossa contain?
- Frontal lobe and the lesser wing of the sphenoid bone
What does the middle cranial fossa contain?
- Temporal, pariteal and occipital lobe and is much deeper.
What does the posterior cranial fossa contain?
- Cerebellar, pons and medulla
What does the carotid foramen contain?
- The internal carotid artery
What does the jugular foramen contain?
- Internal jugular vein
- Glossopharyngeal (9), vagus (10) and accessory (11)
What does the foramen magnum contain?
- Vertebral arteries, spinal cord and anterior/posterior arteries
What does the ethmoid foramen contain?
- Cranial nerve 1 = olfactory nerve
What does the optic canal contain?
- Cranial nerve 2 = optic nerve
What does the superior orbital fissure contain?
- Cranial nerves 3 (ocularmotor), 4 (trochlear), one branch of 5 (opthalmic branch of the trigeminal nerve) and cranial nerve 6 (abbducens)
What does the foramen rotundum contain?
- Olfactory branch of the trigeminal nerve = nerve 5
What does the foramen ovalae contain?
- Mandibular branch of the trigeminal nerve = nerve 5
What does the hypoclossal canal contain?
- Hypoglossal nerve = cranial nerve 12
What does the internal acoustic meatus contain?
- Facial nerve (7) and vestibularcochlear (8)
What is the frontal nerve?
- Innvervates the cornea and comes out just below the eyebrow.
- Branch of the abducens nerve and also branches into the supraorbital and supratrochlear.
What is the lacrimal nerve?
- Branch of the trigeminal nerve that is found in the lateral orbit.
What are the muscles of the eye?
- Levator palpebrae superioris (originates at the common tendinous ring and inserts into the eyelid, runs over the top of superior rectus)
- Superior rectus (originates at the common tendinous ring and runs over the top of the eyelid)
- Inferior rectus
- Medial rectus
- Lateral rectus
- Superior oblique
- Inferior oblique
What is the innervation in the eye?
- Optic nerve at the back of the retina.
- Occulomotor nerve runs to the medial and inferior rectus muscles
- Abducens runs to the lateral rectus muscles
- Trochlear nerve runs over to superior oblique
What is the vasculature of the eye?
- Opthalmic artery and veins which are branches of the interal carotid.
What makes up the structures of the ear?
- External acoustic meatus to the tympanic membrane, then the ear ossicles (malleolus, incus, stapes - which have synovial joints so can be affected by RA), semicircular cancels (involved in acceleration/deceleration - fluid), cohclear and the audiatory tube and internal acoustic meatus
What happens if the facial nerve is damaged within the ear/
- The facial nerve runs over the tympanic membrane if it becomes damaged it can lead to a loss of taste in the anterior 2/3 of the tongue
How is energy transferred through the ear?
- Energy through the external acoustic meatus to the ear drum, through the ear ossicles to the stapes where its low amplitude and high frequency and allows fluid movement in the ear.
What is the brainstem made up of?
- Midbrain, pons and the medulla oblongata (begins at the foramen magnum)
- Cerebellum is where the most information enters and leave the brain and is the most effected by alcohol
What is contained within the midbrain?
- Superior and inferior colliculi
- Superior = eye movement, contains nuclei of 3rd and 4th cranial nerve
- Inferior = acoustic, contains nuclei of 8th cranial nerve, involved in the movement of the body towards load noises and control of the cochlea and semi circular canals.
What is the pineal gland?
- Synthesises melatonin, improves mood and can be affected with SAD
What is contained in the pons?
- Floor of the 4th ventricle
- Tegmentum with nuclei of 5th, 6 th and 7th cranial nerve
What is contain in the medulla
- 85% fibres cross, 15% remain on the same side a supply positional muscle and cross further down.
- Tegmentum with nuceli of 9th, 10th, 11,th and 12th
What are the tracts on the back of the spinal cord?
- Middle two supply the lower limbs
- Outer two supply the upper limbs
What is Bells Palsy?
- Swelling of the facial nerve, leading to unilateral symptoms and signs.
- Can be caused by VSV
What is Bulbar Palsy?
- Occurs in the cerebellum, can affect cranial nerves 9, 10 , 11 and12
- Can be seen in GBS and MND
What is the cerebellum responsible for?
- Largest part of the hindbrain
- Responsible for the coordination of movement and balance
- Joined by a vermis - that control the axial movements.
- Outer layer with grey matter, cortex, inner layer of white matter with deep nuclei
What are the flocculus responsible for?
- Sub conscious control
What is the red nucleus?
- Grey matter within the cerebellum that is found ventro lateral to the cerebral aqueduct
What is the substasia nigra?
- Lateral - black cells.
What are the vertebrae made up of?
- 7 cervical, 12 thoracic, 5 lumbar and 5 sacrum
- Spinal cord and covering contained inside the vertebral canal.
What are the key characteristics of lumbar vertebrae?
- Largest of the vertebrae
- Transverse and articular processes
- Spinous process (non bifid and shorter than thoracic vertebrae)
- Vertebral foramen (triangle)
What are the key characteristics of thoracic vertebrae?
- Medium sized, they range in size from smaller to larger.
- Transverse process
- Longer spinous processes
- Vertebral foramen (round)
What are the key characteristics of cervical vertebrae?
- Smallest size
- Bifid spinous process - C1 doesn’t
- Transverse foraemn for vertebral arteries and vertebral foramen.
- Verebra prominent at C7
- C1 and C2 = axis and atlas
What is the level of the top of the iliac crest?
- L3/L4
What movement can the spine move?
- Forward flexion, lateral flexion and extension (limited within the thoracic spine)
- Rotation (Maximised within the thoracic spine)
What are in intervertebral discs?
- Strong fibrocartilagenous structures that can withstand compression forces but are flexible enough to allow movement between the vertebrae.
- Each disc is made of a nucleus pulposus and annulus fibrosus
What level is the sciatic nerve?
- L5
What is the epidural space?
- Found between the dura and the vertebral bodies
- Contains small arteries that supply the spinal cord and vertebral venous plexus.
How many pairs of spinal nerves are there?
- 31 pairs
- 8 C
- 12 T
- 5 L
- 5 S
- 1 C
What forms a spinal nerve?
- Dorsal root = sensory
- Ventral root = motor
- They join together to form the spinal nerve at the dorsal and ventral ramus.
Why do the the spinal nerves increase in length as they go down?
- This is because the spinal colomun ends at L1/L2
- This creates cauda equina
What does afferent and efferent mean?
- Afferent = taking something away
- Efferent = taking something towards
How are the intravertebral foramen?
- Anteriorly they are connected to the bodies of ajoining vertebrae
- Posteriorly by synovial joints between the 2 suprior and inferior articular processes
What is a lumbar puncture?
- Occurs at L3/L4
- In the subarachnoid space where the CSF is
- Can be used for measuring open pressure, cytology, treatment of IIHT, infectious meniginitis and sub arachnoid haemorrage.
What can be seen in an axial MRI scan?
- The cerebellum is the wiggly lines at bottom, pons in the middle, floor of the 4th ventricle and the amygdala at the top.
Why is it important to think about severe disease progression within the floor of the 4th ventricle?
- Nuclei of the lower cranial nerves are found here.
What is the name of the structure where the floor of the 4th ventricle is found?
- Rhomboid fossa
Where are the obex and area postrema found and what is their importance?
- Found on the inferior part of the rhomboid fossa, important as they have no blood brain barrier and also are the cough / nausea and vomiting centres.
What is the posterior part of corpus callosum called?
- Splenium
Which is thicker the sensory or motor cortex?
- Motor
- More protons in grey than white matter, can be identified on an MRI easier
What happens within the thalamus?
- All information passes that reaches conscious level
What is found in the bottom part of the thalamus?
- The medial (auditory) and lateral (vision) geniculate bodies.
What are the three different fibres within the brain?
- Association Fibres - allow communication between different parts of the same hemispheres
- Commissural Fibres - similar functional areas in the different cerebral hemispheres - corpus colosseum
- Projection Fibres - between areas of the cortex and structures lower down, through the internal capsule.
What is the hippocampus responsible for?
- Part of the limbic system - involved in emotion and olfaction.
What is the cingulate gyrus?
- It is found superior to the corpus callosum - distance and communication.
Where do the motor and sensory pathways cross?
- Motor just above the medulla and the sensory pathways further up.
What is the role of the basal ganglia?
- Extra decision making
- Modifies motor pathways.
Where is the caudate nucleus?
- Within the anterior horn of the lateral ventricles - inferior lateral aspect.
- Connection between lateral horn and amydala
What is the most likely cause of a stroke within the internal capsule?
- Bleed in the lenticular straiterer artery - between middle cerebral artery.
- Leads to massive damage.
What is the internal capsule?
- Carries motor and sensory fibres from the thalamus/cortex to the brain stem.
- The corona radiata: from the internal capsule to the lentiform nucleus
What are the different planes of an MRI
- Sagittal - through the middle
- Coronal - dividing dorsal and ventral
- Axial - horizontal
If a patient has a stroke that is forehead sparing where is the stroke?
- In the cortex
- If it’s in the internal capsule there is complete paralysis
What is the difference in strokes on an MRI?
- Haemorrhage = shows straight away on an MRI
- Emboli = takes a few days
What are the ventricles in the brain?
- Lateral ventricles - connected to the 3rd ventricle via the interventricle foramen , 3rd ventricle to the 4th ventricle via the cerebral aqueduct.
Where is the majority of the CSF created?
- Within the choroid plexus within the lateral ventricles - these are vascular folds of the pia mater.
How do the ventricles supply the sub arachnoid space?
- Via the foramen of magendie and the lateral foramina of luschkisca
- Reabsorption occurs through the arachnoid villi
