Other OSCE bits Flashcards
Causes of absent red reflex (fundal reflex) - Adults and Children
- Adults: cataracts, vitreous haemorrhage, and retinal detachment
- Children: congenital cataracts, retinal detachment, vitreous haemorrhage and retinoblastoma
Describe the Snellen chart measurement and how the numbers work - eg. 6/6 (20/20), 6/20 etc. and 6/12 (-2) + what you do if the pt has poor vision
- Visual acuity is recorded as chart distance (numerator) [either 6m or 20ft] over the number as the denominator (which is the distance a ‘normal’ person would be able to see the letter at)
- eg. 6/20 —> pt can see the letters at 6m away the same as normal can see 20m away from chart
- 6/60 = top line
- If they can read the line but get two letters wrong for example it would be 6/12 (-2)
- if the pt gets more than 2 letters wrong then the previous line should be recorded as their acuity
- Poor vision: 6m, then 3m, then 1m, then counting fingers (CF), then hand movements (HM), then perception of light (PL)
Explain these visual field defects
- Bitemporal hemianopia
- Homonymous hemianopia
- Scotoma
- Monocular vision loss
Pathophysiology of RAPD / the pupillary reflex
Cover test - which direction will the eye move relating to the type of strabismus (squint)
Causes of anosmia
- Mucous blockage —> preventing odours from reaching the olfactory nerve receptors
- Head trauma —> can result in shearing of the olfactory nerve fibres
- Congenital anosmia
- Parkinson’s —> anosmia is an early feature
- COVID-19
Actions of extraocular muscles
- Superior rectus: Primary – elevation
- Inferior rectus: Primary – depression
- Medial rectus: Adduction of eyeball
- Lateral rectus: Abduction of eyeball
- Superior oblique: Depresses, abducts and medially rotates
- Inferior oblique: Elevates, abducts and laterally rotates
Trigeminal nerve branches + what does each supply?
- Ophthalmic (V1) —> forehead, upper eyelids, and eyes
- Maxillary (V2) —> middle of face (including cheeks, nose, lower eyelids, upper lip/teeth, and gums)
- Mandibular (V3) —> lower face (including jaws, lower lip/teeth, and gums) + has a motor branch that enables chewing, biting, and swallowing
Facial nerve branches
TZBMC
Facial nerve movements, what muscle is tested in each?
- Raised eyebrows
- Eyes closed
- Blow cheeks out
- Smile (show teeth)
- Purse lips (whistle)
- Raised eyebrows - frontalis
- Closed eyes - orbicular oculi
- Blown out cheeks - orbicularis oris
- Smiling - levator anguli oris and zygomaticus major
- Pursed lips (whistle) - orbicularis oris and buccinator
Causes of sensorineural hearing loss and conductive hearing loss
When testing CN XII (hypoglossal), which side does the tongue deviate in a left-sided lesion?
hypoglossal nerve palsy causes atrophy of the ipsilateral half of tongue and deviation to side of lesion
After completing a cranial nerve examination, what further tests would you do?
- Full neurological examination including the upper and lower limbs
- Neuroimaging (eg. MRI head) —> if concerns about space-occupying lesions or demyelination
- Formal hearing assessment (including pure tone audiometry) —> if there are concerns about vestibulocochlear nerve function
What do you look for on general inspection in a neurological examination (upper/lower limb examination)
In an upper limb neuro examination, what does a +ve pronator drift indicate? + what muscles are involved to cause this?
- +ve if forearm pronates - indicates a contralateral pyramidal tract lesion
- Pronation occurs because, in the context of an UMN lesion, the supinator muscles of the forearm are typically weaker than the pronator muscles.
What scale is used to assess muscle power + details
Power is graded 0 to 5 using the MRC muscle power scale
For each movement - myotome + nerve + muscles involved
- Shoulder abduction
- Shoulder adduction
- Elbow flexion
- Elbow extension
- Wrist extension
- Wrist flexion
- Finger extension
- Finger abduction
- Thumb abduction
- Shoulder abduction (C5 - axillary nerve) - deltoid (primary) and other shoulder abductors
- Shoulder adduction (C6/C7 - thoracodorsal nerve) - teres major, latissimus dorsi, and pectoralis major
- Elbow flexion (C5/C6 - musculocutaneous and radial nerve) - biceps brachii, coracobrachialis, and brachialis
- Elbow extension (C7 - radial nerve) - triceps brachii
- Wrist flexion (C6/C7 - median and ulnar nerve) - flexors of the wrist
- Wrist extension (C6 - radial nerve) - extensors of the wrist
- Finger extension (C7 - radial nerve) - extensor digitorum
- Finger abduction (T1 - ulnar nerve) - First dorsal interosseous (FDI), Abductor digiti minimi (ADM)
- Thumb abduction (T1 - median nerve) - abductor pollicis brevis
For each reflex - nerve root tested + name of tendon
- Biceps reflex
- Supinator
- Triceps reflex
- Biceps reflex (C5/C6) - biceps brachii tendon (medial aspect of antecubital fossa)
- Supinator (C5/C6) - brachioradialis tendon (posterolateral aspect of wrist)
- Triceps reflex (C7) - triceps tendon (superior to olecranon process of the ulna)
What type of reflexes are seen in UMN lesions and LMN lesions? (ie. hyperreflexia or hyporeflexia)
- Hyperreflexia - UMN lesions (eg. stroke, spinal cord injury)
- Hyporeflexia - LMN lesions (eg. brachial plexus pathology or other peripheral nerve injuries)
Testing upper limb dermatomes - where would you touch for each of the dermatomes?
C5:the lateral aspect of the lower edge of the deltoid muscle (known as the “regimental badge”).
C6:the palmar side of the thumb.
C7:the palmar side of the middle finger.
C8:the palmar side of the little finger.
T1:the medial aspect antecubital fossa, proximal to the medial epicondyle of the humerus.
When assessing dermatomes, what tracts/columns are being assessed in:
- light touch
- pin-prick
- vibration sense
- Light touch (dorsal columns and spinothalamic tracts)
- Pin prick (spinothalamic tract)
- Vibration sensation (dorsal columns)
When assessing coordination, what would patients with cerebellar pathology exhibit on:
- finger-to-nose test
- dysdiadochokinesia
Finger-to-nose:
- Dysmetria (over/undershooting the target)
- Intention tremor
Dysdiadochokinesia:
- may struggle to carry out task (movements slow and irregular)
After completing an upper or lower limb neuro examination, what further assessments/investigations would you like to do?
- Full neurological examination (including cranial nerves, lower/upper limbs, and cerebellar assessment)
- Neuroimaging (eg. MRI spine and head)