Week 3 Flashcards
What spinal tracts cross over at the medulla oblongata?
Dorsal column and lateral corticospinal tracts
What spinal tract crosses over in the spinal cord?
Spinothalamic tract
What disorders can be caused by incomplete SCI?
Central/anterior/posterior cord syndrome
Brown-Sequard syndrome
Cauda equina syndrome
What is central cord syndrome?
Low velocity hyperextension injury causes damage to the centre of the spinal cord; impairment of sensation mostly in upper limbs; preservation of proprioception/light touch
Why is central cord syndrome more common in elderly patients?
Narrowed cervical canal due to osteophytes
What is Brown-Sequard syndrome?
Penetrating injury causes damage to one side of the spinal cord; results in paralysis (corticospinal) and loss of proprioception/light touch (dorsal column) on same side and pain/temperature (spinothalamic) on opposite side
What is cauda equina syndrome?
Bony compression/disc protrusion in lumbosacral region causes non-specific symptoms (back pain, bowel/bladder dysfunction, leg numbness/weakness, saddle paraesthesia
What is saddle paraesthesia and what disorder is it associated with?
Loss of sensation restricted to the area of the buttocks, perineum area between the anus and scrotum/vulva and inner surface of the thighs
Cauda equina syndrome
How are SCIs immediately managed?
Identify
Immobilise (prevent further damage from movement)
Investigate (injuries, neurological exam, ASIA scale for motor and sensory)
Inform
A SCI above what level will produce significant autonomic disruption and why?
T5
Origin of the majority of sympathetic output
What is spinal shock?
A combination of areflexia/hyporeflexia and autonomic dysfunction that accompanies SCI immediately
Initial hyporeflexia = loss of reflexes below the level of injury
Initial loss of sympathetic outflow = hypotension and bradycardia
Eventual return of reflexes with hyperreflexia
What level of SCI can cause spinal shock?
All levels
How long does spinal shock last?
3 days to 2 weeks; depends on level and severity of injury
Which reflex is the first to return after spinal shock?
Plantar reflex/Babinski’s sign
What is neurogenic shock?
Disruption of the autonomic pathways within the spinal cord, resulting in hypotension, bradycardia and hypothermia
What level of SCI can cause neurogenic shock?
Above T6
What is an upper motor neuron lesion?
Lesion of the neural pathway above the anterior horn cell of the spinal cord or motor nuclei of the cranial nerves
What is a lower motor neuron lesion?
Affects nerve fibres traveling from the anterior horn of the spinal cord or the cranial motor nuclei to the relevant muscle
What are the signs of an UMN lesion?
Muscle weakness
Increased tone
Increased reflexes
What are the signs of a LMN lesion?
Muscle weakness and wasting
Reduced tone
Reduced reflexes
Fasciculations
What are SCI patients at high risk of a week after injury?
DVT
Pulmonary embolism
What additional medical complications can SCI patients experience?
Asensory skin Bladder incontinence Inability to move bowels Pain Erectile dysfunction Autonomic dysreflexia
How is the bladder affected in UMN and LMN lesions?
UMN - spinal reflex will cause bladder to empty spontaneously when full
LMN - spinal reflex will be absent, causing incontinence
What makes up the brainstem?
Medulla, pons, midbrain (inferior to superior)
What are the functions of the brainstem?
CV, respiratory and GI control Cranial nerves Ascending tracts to thalamus/cortex Descending tracts from motor cortex Reticular formation Neurotransmitters Consciousness
What is CN 1 and what is it’s function?
Olfactory
Smell
What is CN 2 and what is it’s function?
Optic
Vision
What is CN 3 and what is it’s function?
Oculomotor
Extrinsic eye muscles, striated eyelid muscle, pupil constriction, accommodation
What is CN 4 and what is it’s function?
Trochlear
Innervates superior oblique muscle
What is CN 5 and what is it’s function?
Trigeminal
Sensory to facial skin/muscle/joints/mouth/teeth (ophthalmic, maxillary and mandibular branches)
Motor to muscles of mastication
What is CN 6 and what is it’s function?
Abducens
Innervates lateral rectus muscle
What is CN 7 and what is it’s function?
Facial
Sensory to skin of external ear and anterior 2/3 of tongue (taste)
Motor to muscles of facial expression
Secretomotor to lacrimal and salivary glands
What is CN 8 and what is it’s function?
Vestibulocochlear
Hearing and balance
What is CN 9 and what is it’s function?
Glossopharyngeal
Swallowing, carotid body, sensory to palate and posterior 1/3 of tongue (taste), parotid salivary gland
What is CN 10 and what is it’s function?
Vagus
Motor parasympathetic, visceral sensation of pharynx/thorax/abdomen, striated muscles of larynx and pharynx (speech)
What is CN 11 and what is it’s function?
Spinal accessory
Trapezius and sternocleidomastoid muscles
What is CN 12 and what is it’s function?
Hypoglossal
Innervates tongue muscles
What position should a muscle be in for testing reflexes?
Under slight tension but not bearing any weight
What tendon reflexes are present in the lower limb?
Knee - patellar tendon
Ankle - Achilles tendon
What tendon reflexes are present in the upper limb?
Biceps
Triceps
Supinator
What is a Jendrassik manoeuvre?
Method of reinforcing tendon reflexes
Upper limb - clench teeth
Lower limb - pull locked hands apart
What tendon reflexes are present in the head?
Jaw-jerk reflex - masseter muscle (not usually visible)
What is the nerve root level of the jaw jerk reflex?
CN 5
What is the nerve root level of the biceps reflex?
C5/6
What is the nerve root level of the triceps reflex?
C6/7/8
What is the nerve root level of the supinator reflex?
C5/6
What is the nerve root level of the knee jerk reflex?
L3/4
What is the nerve root level of the ankle jerk reflex?
S1/2
What reflex is present on the sole of the foot and what does this test?
Plantar response/Babinski’s reflex
Integrity of pyramidal tracts
What is a normal and abnormal plantar response?
Normal adult - downward curling of the toes (plantar flexion; ‘Babinski negative’)
Normal neonate or adult with a lesion of the cortico-spinal projection - the reflex movement is opposite, with withdrawal of the foot and fanning of the toes (‘Babinski-positive’)
What are the 2 methods by which the ball of the thumb has higher sensory innervation than the upper limb?
Distribution of cutaneous receptors - higher density of touch receptors
Two-point discrimination - smaller and closer receptive fields
What is the cranial cavity comprised of?
Anterior, middle and posterior cranial fossa
What route does the internal carotid artery take to supply the brain?
Passes under the dura of the middle cranial fossa to supply the underside of the brain
Through which hole in the skull does the olfactory nerve pass?
Cribiform plate (roof of nasal cavity)
Through which hole in the skull does the optic nerve pass?
Optic foramen
Through which hole in the skull does the oculomotor nerve pass?
Superior orbital fissure
What is the position of the trochlear nerve relative to the oculomotor nerve?
Behind, lateral to and smaller than the oculomotor nerve
Where does the trigeminal nerve arise from?
Pons
Through which holes in the skull do the branches of the trigeminal nerve pass?
Ophthalmic - superior orbital fissure
Maxillary - foramen rotundum
Mandibular - foramen ovale
Which cranial nerve has the longest course in the cranial cavity?
Abducens (CN 6)
Through which hole in the skull does the facial nerve pass and which other nerve passes with it?
Internal acoustic meatus
Vestibulocochlear (CN 8)
Through which hole in the skull does the vestibulocochlear nerve pass and which other nerve passes with it?
Internal acoustic meatus
Facial (CN 7)
In which bone is the internal acoustic meatus found?
Temporal bone
Which nerves exit the skull through the jugular foramen?
Glossopharyngeal (CN 9), vagus (CN 10) and accessory (CN 11)
Through which hole in the skull does the glossopharyngeal nerve pass?
Jugular foramen
Through which hole in the skull does the vagus nerve pass?
Jugular foramen
Through which hole in the skull does the spinal accessory nerve pass?
Jugular foramen
Through which hole in the skull does the hypoglossal nerve pass?
Hypoglossal canal
Through which hole in the skull does the trochlear nerve pass?
Superior orbital fissure
Through which hole in the skull does the abducens nerve pass?
Superior orbital fissure
What cranial nerves pass through the superior orbital fissure?
Oculomotor
Trochlear
Abducens
Trigeminal (ophthalmic branch)
What cranial nerves pass through the internal acoustic meatus?
Facial
Vestibulocochlear
What is the falk cerebri?
A large, crescent-shaped fold of meningeal layer of dura mater that descends vertically in the longitudinal fissure between the cerebral hemispheres of the brain
What is the tentorium cerebelli?
An extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes
What is the function of the falx cerebri and tentorium cerebelli?
Stop the brain from moving excessively
What is the superior sagittal sinus?
Large venous channel running front to back in the midline inside the attached edge of falk cerebri
Drains blood from central part of the forebrain and meets the inferior sagittal sinus to form the great cerebral vein
What do the superior and inferior sagittal sinuses meet to form?
Great cerebral vein
Where does the straight sinus receive blood from and where does it drain to?
Receives blood from the superior cerebellar veins and inferior sagittal sinus
Drains into the confluence of sinuses
Where is the straight sinus found?
Junction between falk cerebri and tentorium cerebelli
Why is there slow blood flow in the cavernous sinus and what is the clinical significance of this?
Meshwork/labyrinth structure
Infection (e.g. from a boil on the skin surface near this area) can cause bacteria to enter the sinus, clot the blood and cause cavernous sinus thrombosis
What is cavernous sinus thrombosis?
Blood clotting in the cavernous sinus prevents blood draining from the eye, causing swelling accompanied by an increased temperature
How might cavernous sinus thrombosis be caused by a dental infection?
Through the sphenoidal emissary vein which connects the back of the teeth to the cavernous sinus
What is the confluence of sinuses?
Where the superior sagittal and transverse sinuses meet
What is the sick role?
A role of sanctioned deviance; outlines rights and responsibilities of those affected by illness
What is illness behaviour?
The way in which symptoms are perceived, evaluated and acted upon by a person wo recognises some pain, discomfort or other signs of organic malfunction
What is the difference between disease and illness?
Disease - disorder of structure and/or function
Illness - expression and experience of ill health; psychological, social and cultural factors
What is the locus of control?
The degree to which the person believes that control to influence events resides with themself or others
What is internal locus of control?
Belief that they have the agency in their behaviour and ability to influence the world about them
What is the external locus of control?
Belief that they have little control over events and that outcomes will be determined by others or by fate
What are some common illness behaviours?
Consulting behaviours Adherence to treatment Health promoting behaviours Avoidance Unhelpful coping strategies – drugs, alcohol
What is secondary gain?
When a patient unconsciously continues illness behaviours because of something which is positive about being ill
What factors are involved in adjustment to illness?
Managing uncertainty about the future/searching for meaning/dealing with loss of control
Having a need for openness
Need for emotional/medical support
What types of behaviour indicate good coping?
Optimal functioning, self-management strategies, reduced co-morbidity, helpful coping behaviours
Optimistic – maintain morale, realistic
Practical – here and now, problem-focused
Willing to consider new strategies – flexible and open to suggestions
Owns own decisions (internal locus of control)
Expresses emotion but avoids extremes
What role do cytokines play in adjustment to illness?
Large number of non-specific symptoms are mediated through cytokines (e.g. weakness, fatigue, lethargy, anorexia)
Pro-inflammatory cytokines (e.g. TNF, interferon) influence psychological symptoms (e.g. MI, diabetes, cancer)
Interventions can target this (e.g. graded exercise, activity scheduling)
How can illness be self-managed?
Understanding illness Diet, exercise, lifestyle Symptom monitoring Decision making Use of medication Concordance with treatment
What psychological interventions are available for adjustment to illness?
CBT
Motivational interviewing
Acceptance and commitment therapy
Mindfulness
In which bone is the foramen rotundum found?
Sphenoid
What does the foramen rotundum transmit?
Maxillary branch of trigeminal nerve
Other than CN 9, 10 and 11, what other structure passes through the jugular foramen?
Internal jugular vein
Where do the first order sensory neurons of the trigeminal nerve synapse with the second order sensory neurons?
Spinal nucleus of the trigeminal
Why is lumbar puncture contraindicated in a person with raised ICP?
Risk of neurological deterioration/herniation – low-pressure shunt is created by LP where CSF can escape which causes CSF pressure to drop and the mass which is causing raised ICP to move towards the site of the LP
What structures pass through the foramen magnum?
Vertebral arteries, spinal cord/brainstem and spinal accessory nerve
Briefly outline the passage of CSF through the ventricular system
Lateral ventricle → interventricular foramen → third ventricle → cerebral aqueduct → fourth ventricle → subarachnoid space of the meninges
Where is CSF resorbed?
In the arachnoid granulations
What are the arachnoid granulations?
Projections of the arachnoid membrane into the dural sinuses which allows CSF to pass from subarachnoid space into venous system
What is the primary blood supply of the visual cortex?
Calcarine branch of the posterior cerebral artery
What does the foramen ovale transmit?
Mandibular branch of the trigeminal nerve
What is a vestibular schwannoma?
Benign primary intracranial tumor of the myelin-forming cells of the vestibulocochlear nerve (8th cranial nerve)
