Things found in past papers Flashcards
Innvervation of 3 salivary glands
- Facial nerve innervates Submandibular gland & Sublingual gland
- Facial nerve exits the skull via the Internal acoustic meatus and via the Stylomastoid foramen and passes under the parotid gland (but does not innervate it), then innervates sublingual & submandibular glands
- (Glossophargyneal nerve exits the skull via the Jugular foramen and innervates the Parotid gland)
Function of sternothyroid
Depresses thyroid cartilage
Test for trochlear nerve
To distinguish its muscle action from inferior rectus, we must first adduct the eye and then move it superiorly
3 spinal curve abnormalities
- Lordosis – excess lumbar curvature
- Kyphosis – excess thoracic curvature
- Scoliosis – lateral deviation of the vertebral column
List two advantages and two disadvantages of MRI over CT for visualising brain structures
Advantages of MRI o No X rays o Excellent soft tissue detail o Multiplanar acquisition Disadvantages o Slow o Expensive o Noisy o Poor bone detail o Contraindications – metal implants, pacemaker
Oculomotor palsy
- Ptosis – droopy eyelid due to loss of Levator palpebrae superioris
- Eye is in the “down & out” position due to opposed actions of LR & SO
Attachments for carpal tunnel
- Medial attachments: Scaphoid, Trapezium
* Lateral attachments: Pisiform, Hamate
What runs in carpal tunnel
- Flexor digitorum superficialis tendons X4
- Flexor digitorum profoundus tendons X4
- Flexor pollicis longus
- Median nerve
The dorsal venous arch of the foot gives rise to which two main superficial veins?
- Medially – Long saphenous vein
* Laterally – Short saphenous vein
Into which vessels do these superficial veins usually drain?
- Long saphenous vein drains into the Femoral vein t the Saphenous opening
- Short saphenous vein drains into the Popliteal vein at the Popliteal fossa
What are relationships of long and short saphenous vein to the malleoli as they cross the ankle?
- Long saphenous vein passes anterior to medial malleolus
* Short saphenous vein passes posterior to lateral malleolus
What is the common consequence of abnormal drainage between superficial and deep veins?
Varicose veins
What is carpal tunnel normally as a result of
Diabetes, High blood pressure, Autoimmune disorders, fractures of the wrist
Pathology of carpal tunnel syndrome
Increased pressure so entrapment of median nerve
What nerve is affected following a blow to the lateral side of the leg, just below the knee?
Common peroneal
Compartments affected and functional problem with damaged superficial peroneal
Lateral compartment: loss of eversion of the foot
Compartments affected and functional problem with damaged deep peroneal
Anterior compartment: loss of dorsiflexion at the ankle joint
Symptom of lateral medullary syndrome and structure associated
Ipsilateral cerebellar ataxia = inferior cerebellar peduncleLoss of sensation of pain and temperature face = spinal trigeminal nucleusLoss of sensation of pain/temp of contralateral body = spinothalamic tractVertigo = vestibular nucleusHorner’s syndrome = sympathetic tractHoarseness and difficulty swallowing = nucleus ambiguus
3 neural components of a saccade
Optic nerve
Superior colliculus
Visual cortex
Cranial nerves and nuclei
3 types of nystagmus
Vestibulo-‐ocular reflex(vestibular nystagmus) driven by vestibular afferents. When the head is rotated the eyes move in the opposite direction (slow component) to maintain the point of visual fixation on the retina. When the limit of movement is reached the eyes flick back (fast component) and maintain a new fixation point. Slow component driven by afferents from labyrinths. If a subject is rotated and then stopped, postrotatory nystagmus occurs owing to displacement of the cupula in the opposite direction due to inertia of fluid in semi-‐circular canals.•Optokinetic nystagmus(ocular nystagmus) driven by retinal afferents. There is a limit to the amount the eyes can be moved in the head to follow an object (slow phase of nystagmus) -‐for example from a moving vehicle [e.g. at a tube station]. When the limit is reached the eyes flick back (quick phase) to a new fixation point.•Physiologic nystagmusalso occurs even when the subject stares at a stationary fixation point. Since the neural connections from the receptors in the eye adapt to the stimulus, physiologic nystagmus repeatedly moves the image to activate new receptors and help overcome the adaptation.ABD
Difference of nociceptors to touch receptors
polymodal; high threshold; all slow adapting; all free nerve endings
How is neuropathic pain different to nociceptive pain
Lesion in nervous system No response to analgesia Noxious stimulus absent Abnormal pathway used Sensation burning and throbbing rather than dull and aching
Loss of sight in one eye
Anopia
How is acuity increased in middle ear
) The lever system of articulated ossicles between the malleus, incus and stapes, therefore the vibration and
conduction between the bones creates a better intensity
b) The ratio of area of tympanic membrane to oval window (17:1), therefore the sound would be mo
A patient had an acoustic schwannoma and has deafness. Describe why, if left untreated, later on the
patient will have ataxia, dizziness, loss of facial sensation and facial movement.
• Growing in the internal acoustic meatus = sensorineural deafness due to pressing
• Growing in the internal acoustic meatus = sensorineural deafness due to pressing on the cochlear part of the
nerve, dizziness due to pressing on vestibular part of CN8
• Ataxia = further growth puts pressure on cerebellum and brainstem, raising the ICP and causing ataxia• Loss of facial sensation = the tumour may grow into the posterior fossa, press on the V nerve which is
responsible for facial sensation
• Loss of facial movement = the tumour stretches the facial nerve which innervates the facial muscles (leaves the
same foramen)
Cranial nerves with parasympathetic association
Occulomotor
Vagus
Facial
Glossopharyngeal
Upper pontine lesion effects
2) Swallowing (no): the nerves that control swallowing are:
a) Glossopharyngeal CN9 (medulla): innervates stylopharyngeus via nucleus ambiguus
b) Vagus CN10 (medulla): innervates muscles of the soft palate, pharynx, larynx, and upper oesophagus for
swallowing
c) NB: chewing would be affected because the trigeminal nerve emerges on the pons and innervates the muscles of
mastication including the masseter, medial and lateral ptergoids and temporalis
3) Horizontal eye movements (yes): the abducens nerve CN6 controls the lateral rectus muscle for horizontal version and
originates at the ponto-medullary junction.
4) Facial expression (yes): the facial nerve CN7 emerges at the pontomedullary junction lateral to CN6 and controls the
muscles of facial expression
Syringomyelia effects
Spinothalamic level: disruption of pain and temperate as the fibres decussate at the level of input - loss of
nociception from the upper limbs à pt presents with cuts on hands disrupts fibres crossing over at the midline
• Severe pain and UMN lesions; disrupted ANS
• Dorsal columns: Joint position and vibration senses are spared
• If enters the brainstem: dysarthria, dysphagia, tongue wasting, ataxia and nystagmus
Structures associated with aggression
Brain stem (PAG)
Hypothalamus
Amygdala
Limbic system affected disorders
Amygdala (aggression, fear, fight, flight) à Kluver Bucy
Hypothalamus (memory and learning) à Alzheimer’s, epilepsy
What are 2 types of relfex seen in knee jerk
Monosynpatic to the same muscle (effector muscle)
Polysynaptic to the antagonist muscle (knee flexor)
Is a postural reflex
Function test and nerve of each ocular muscle
Superior rectus • Movement = elevation and adduction • Superior ramus of CN3 • To test = abduct then elevate Inferior rectus • Movement = depression and adduction • Inferior ramus of CN3 • To test = abduct then depress Medial rectus • Movement = adduction • Inferior ramus of CN3 • To test = adduct Lateral rectus • Movement = abduction • CN6 • To test = abduction Superior oblique • Movement = depression and abduction • Trochlear nerve CN4 • To test = adduct then depress Inferior oblique • Movement = elevation and abduction • Inferior ramus of CN3 • To test = adduction then elevate
Innervation of ciliary muscle, cornea, levator palpebrae and lacrimal gland
. Ciliary muscle – parasympathetic post-ganglionic fibres (short ciliary nerve) from ciliary ganglion. NB: CN3 is the
pre-ganglionic parasympathetic nerve fibre synapsing in the edinger westphal nucleus.
2. Cornea – trigeminal, V1 (nasociliary of ophthalmic branch). NB branches of ophthalmic include: frontal (scalp +
forehead), nasociliary (orbit and nasal mucosa), lacrimal (lacrimal gland)
3. Levator palpebrae superioris – superior ramus of CN3 N.B. the tarsal muscle is innervated by sympathetic fibres of
superior cervical ganglion from T1 [also innervates vascular SM for vasoconstriction and radial muscle for dilation].
4. Lacrimal gland – post-ganglionic parasympathetic fibres from facial nerve (CN7) from pterygopalatine ganglion
(superior salivatory nucleus within the pons). Sensory innervation is via lacrimal nerve of trigeminal V1
Corticospinal pathway
- Sensory input to the Betz cells in layer 5
- Cell bodies arise in layer 5 of the cerebral cortex via Betz cells
- Axons project to white matter below
- Axons project through the posterior limb of the internal capsule
- UMN fibres go to brainstem
- Travel via cerebral peduncles à fibres come together as the pyramids
- 80% of the fibres decussate at the medullary pyramids (those 20% that don’t = anterior corticospinal)
- Synapse in the ventral horn of the spinal cord
- Lower motor neurones innervate voluntary muscles
Where does 4th ventricel receive CSF from
Central canal of spine
Aqueduct
5 components of reflex arc
Sensory receptor – responds to stimulus by producing receptor potential
• Sensory neurone – conducts impulse from receptor to integrating centre
• Central integrating centre: interneurone in spinal cord, relay impulse sensoryàmotor
• Motor neurone: impulse from integrating centreàeffector
• Effector muscle or gland: responds to motor impulse from motor nerve
Diseases which affect motor system and how they do
Motor neurone disease
• Affects the UMN and LMN of the corticospinal tract
• Chromatolysis = disconnection of the neurons from target muscle fibres
• Mosaic patterns with a decrease in myosin ATP
• Muscle atrophy
• Myasthenia gravis
• Antibodies bind to the nicotinic AChR of the neuromuscular junction
Branches of laryngeal nerve and effect of damage
Superior laryngeal nerve à internal and external laryngeal nerves
• Internal à loss of sensation to larynx above the vocal cords
• External à loss of inferior constrictor muscle and cricothryoid (forward and downward rotation of thyroid cartilage
to tense the vocal cords)
Recurrent laryngeal nerve
1. Loss of intrinsic laryngeal muscles excluding the cricothyroid
2. On the LEFT: bronchial or oesophageal tumour/swollen mediastinal lymph nodes can damage recurrent laryngeal
3. Hoarseness, breathlessness, aphonia
How are loud noises dampened down
There is a reflex contraction of the stapedius muscle (attached to stapes) and the tensor tympani muscle (attached
to malleus) to loud noises à reduces leverage through the ossicle bridge.
• NB: swallowing opens up the Eustachian tube which is connected to the nasopharynx à equalises membrane
pressure either side of the tympanic membrane.
What is responsible for auditory reflexes
Inf colliculus
Action and supply of sternothyroid, geniohyoid, digastric, thyrohyoid, mylohyoid and stylohyoid muscles
• Nerve supply = ansa cervicalis (nerve fibres forming a loop from C1-C3 and innervating many infrahyoid muscles)
• Action = depress the larynx bone
• NB: thyroid muscles (sternothyroid and thyrohyoid depress/raise the larynx respectively). The omohyoid and
sternohyoid depress the hyoid bone.
• Anterior belly digastric opens mouth by lowering the mandible.
• Posterior belly digastric pulls hyoid upward and back = facial nerve
• Mylohyoid elevates the hyoid bone = V3
• Stylohyoid elevates hyoid in postero-superior direction = facial nerve
• Geniohyoid pulls mandible downward and inward, or hyoid bone forward if mandible fixed = C1 fibres
Which nerve is at risk when clamping the inferior thyroid vessels for thyroid surgery and what are the likely
consequences of damaging the nerve?
Vagus supplies larynx.
• Superior laryngeal nerve – internal (sensation above cords) and external branches (cricothyroid and inferior
constrictor muscle). Superior thyroid artery from external carotid and runs with internal branch à thyrohyoid
membrane.
• Recurrent laryngeal nerve (sensation below vocal cords, most intrinsic laryngeal muscles). Inferior thyroid artery
from the thyrocervical trunk of subclavian
• Right recurrent laryngeal most vulnerable as it has a direct course (left arches around aorta).
• Consequence = loss of sensation below the vocal cords and paralysis of the ipsilateral laryngeal muscles except
cricothyroid.
• Unilateral = hoarseness; bilateral may mean loss of voice (aphonia) and difficulty breathing
Consequence of poor drainage between superficial and deep veins in leg
Swelling of superficial veins (i.e. varicose veins)
If a deep vein problem à DVT, post-phlebitic syndrome
If superficial à ulcers, superficial thrombophlebitis
What prevents hip from over-extending
All ligaments limit extension
Ischio-femoral ligament = limits medial rotation
Pubofemoral ligament = limits abduction
Iliofemoral ligament = limits lateral rotation
They spiral together and become taut when the hip extends
Minimises energy required to maintain the standing position
Carpal tunnel syndrome
Pins and needles/paraesthesiae in the hand
Weakness of the thumb muscles
Loss of muscle bulk of the thumb muscles
*Sensation preserved as palmar cutaneous branch of median nerve comes off before
*Swelling of the tendons or cysts in the carpal joints (RA, hypothyroid) à pressure on the median nerve
Landmark femoral artery
3-4cms above the mid-point of the inguinal ligament
What does phospholipase A2 break daiglycerol into
arachidonic acid
