C&M Upper limb- control Flashcards
What is the name of the fissure that divides the cerebrum into two hemispheres
Great longitudinal fissure
What does the central sulcus divide
The frontal lobe from the parietal lobe
Pre central gyrus (motor cortex)
Post central gyrus (sensory cortex)
What structure separates the frontal lobe from the temporal lobe
Lateral sulcus
What are the 3 initial swellings in the rostral neural tube
Prosencephalon- forebrain
Mesencephalon- midbrain
Rhombencephalon- hindbrain
What do the 5 swellings become
Telencephalon- cerebral hemispheres Diencephalon- thalamus and hypothalamus Mesencephalon- midbrain Metencephalon- pons and cerebellum Myelencephalon- medulla oblongata
What 2 layers make up the dura mater
Periosteal
Meningeal
Separate at dural venous sinuses
How does the internal carotid artery enter the skill
Carotid Canal
What is craniosynostosis: symptoms and treatment
Premature sutural fusion of the skull
Abnormal head shape, Raise ICP, cognitive deficits
Requires extensive surgical re-modelling of the cranial vault
What structures make up the brainstem
Midbrain
Pons
Medulla Oblongata
Boundaries of the brainstem
Caudally: Medulla continuous with spinal cord
Rostrally: Midbrain continuous with diencephalon
Ventrally: Clivus of occipital bone
Dorsally: Cerebellum
What structure separates the pyramids of the ventral medulla
Anterior Median Fissure
What structure separates the pyramids from the olives on the ventral medulla and what emerges from here
Anterolateral sulcus
Hypoglossal nerve emerges here
What nerves emerge at the posterolateral sulcus dorsal to the olives
Glossopharyngeal (9) and vagus (10)
What structure forms the roof of the 4th ventricle
Superior Cerebellar Peduncle
What structure forms the floor of the 4th ventricle
Rhomboid fossa
Where does the trochlear nerve emerge
Inferior to the inferior colliculi on the dorsal midbrain
What structure runs through the midbrain
Cerebral aquaduct
What are the 3 structures that can be found rostral to the obex at any point in the brainstem cross section
Basal- most anteriorly
Tegmentum- anterior to ventricular system
Tectum (midbrain- colliculi) posterior to ventricular system
What does the tegmentum contain
Cranial nerve nuclei and tract, reticular formation and some
ascending/descending pathways
What does the basal brainstem contain
descending fibres from cerebral cortex (pyramids, cerebral peduncles)
What does the reticular formation in the tegmentum control
Reticular nuclei – give rise to a descending motor pathway (reticulospinal tract)
Vital autonomic centres – eg. respiratory, cardiovascular
Cells giving rise to Ascending Reticular Activating System – pass to the cortex and involved in consciousness (damage = coma)
Modulate pain
Sleep wake cycle
Arousal
Where is the Edinger Westphal Nucleus and what does it control
Midbrain medial to occulomotor nucleus
Sends parasympathetic visceral fibres to sphincter pupillae and ciliary muscles- change pupil size
What are the 4 autonomic ganglia of the head and neck
Cilary
Otic
Pterygopalatine
Submandibular
Function of facial nerve
Muscles of facial expression, taste anterior 2/3rds tongue, parasympathetic to all glands except parotid
Which nerves exit the skull via the jugular foramen
Glossopharyngeal, vagus, accessory
Which nerves exit the skull via the internal acoustic meatus
Facial and vestibulocochlear
Function of glossopharyngeal nerve
Swallowing, parasympathetic to parotid, taste posterior 1/3rd tongue, cutaneous sensation from ear, sensation from carotid body
Function of accessory nerve
Motor to sternocleidomastoid and trapezius
What foramen does the middle meningeal artery travel through the skull
Foramen spinosum
How does the accessory nerve enter and leave the skull
Enters via Foramen magnum
Exits via Jugular foramen
What lies in-between the two thalami
Third ventricle
What is the function of the sub thalamus
Lateral structure
Part of basal ganglia
Involved in motor control
What is the function of the epithalamus
Includes the pineal gland
Secretes melatonin; circadian rhythm maintenance
What does the lamina terminalis form
Corpus callosum and anterior white commissure
Do commissural fibres cross hemispheres
Yes
Corpus Callosum and Anterior Commisure
Do association fibres cross hemispheres
No- communication between gyri in one hemisphere
short and long fibres
What is the internal capsule
A v-shaped bundle of white matter lateral to the thalamus
Contains projection fibres that carry info from thalamus to/from cortex
What makes up the lentiform nucleus
Globus pallidus
Putamen
What is the basal ganglia
Lentiform nucleus + caudate nucleus
Deep grey matter nuclei controlling movement
How does CSF travel from the lateral ventricles to the third ventricle
Interventricular foramen
How does CSF travel from the 3rd ventricle to the 4th ventricle
Cerebral aquaduct
How does CSF leave the 4th ventricle to the subarachnoid spaces
Lateral and median apertures
What produces CSF
Choroid plexus (lining of ventricles) uses plasma from blood to produce approx 500ml/day
How does the CSF leave the subarachnoid space
Through arachnoid villi to dural venous sinuses and into venous circulation (mainly superior saggital sinus)
Which ventricle produces the most CSF
Lateral ventricle choroid plexus
Where is the primary auditory cortex
Superior temporal gyrus (Heschl’s)
What is the function of the cingulate gyrus
Integrating sensation and motor function with memory (associated with hippocampus in the temporal lobe)
Primary olfactory cortex
Uncus (anterior extremity of parahippocampal gyrus)
Primary visual cortex
Striate nucleus either side of calcarine sulcus
Primary gustatory cortex
Inferior post central gyrus
What info does the Lateral VPL nucleus of the thalamus receive
sensory input from leg projects to midline post central gyrus
What info does the medial VPL nucleus of the thalamus receive
sensory input from arm project to lateral post central gyrus
What info does the VPM nucleus receive
sensory input from face projects to lateral post central gyrus
What is agnosia
Damage to secondary sensory areas leads to disorders of understanding
Awareness of sensation persists, but significance of this sensation is lost.
Eg. Eyes closes, handle scissors, can’t recognise
What is apraxia
Damage to secondary motor areas leads inability to carry out purposive movements, although there is no paralysis
Leads to inability to perform learned movements
What is the function of the pre-frontal cortex
Regulates moods and feelings
Involved in higher order cognitive functions
Conceptualisation, planning, judgement
(Phineas Gage)
What is the function of the parieto-temporal cortex
Integrates information of different modalities
Involved in memory
What is Wernicke’s area
Posterior language area
Sensory or receptive
Understanding/association
What is Broca’s area
Anterior language area
Motor or expressive
Production
What is Erb’s palsy
Excessive stretching of the neck during delivery causing damage to C5, C6 nerve roots (common in newborns)
Paralysis of muscles of shoulder/arm supplied by C5, C6
“waiter’s tip” position
What is Klumpke’s palsy
Damage to inferior trunk of brachial plexus (C8, T1 – ulnar nerve)
Less common than Erb’s palsy
Occurs in newborns where the baby’s upper limb is pulled excessively during delivery
Claw hand- Paralysis of the majority of the intrinsic hand muscles (and ulnar flexors of the wrist and digits)
What is Claw hand
Hyperextension at the metacarpophalangeal joints and flexion at the interphalangeal joints
Due to paralysed lumbricals of digits 4 and 5
What condition can Klumpke’s palsy be associated with
Horner’s syndrome: Ptosis, Miosis, Anhidrosis, Vasodilation
Sympathetic neurons supplying the head originate from T1 and may also be damaged by traction
What is cubital tunnel syndrome
Ulnar nerve entrapment in tendinous arch between the humeral and ulnar heads of flexor carpi ulnaris (elbow)
Same symptoms as Klumpke’s palsy + elbow pain (no horner’s)
Treatment initially anti-inflammatories then surgery if unresolved
What is radial nerve palsy
Injury to radial nerve in spiral groove of humerus results in wrist drop
Inability to extend the wrist and metacarpophalangeal joints due to paralysis of extensor muscles of the forearm.
Triceps is usually weakened rather than paralysed
Why are triceps not completely paralysed in radial nerve palsy
Long head triceps branch of radial nerve is given off before the spiral groove so can get some weak elbow flexion.
How can the median nerve be damaged at the elbow
Supra condylar fractures or pronator teres syndrome
What is the hand of benediction
Inability to flex digits 1-3
Weakened flexion of digits 4-5
Two tests for median nerve compression
Tinel’s Test: percuss nerve
Phalen’s Test: compress nerve by acutely bending wrist
