Pancoast tumour, spinal cord, neck Flashcards
Where would pain be felt if a Pancoast tumour encases the C8 nerve root, and what would happen to the muscles in that area?
Medial two digits of the hand would be painful
The intrinsic muscles of the hand would atrophy
Describe the pain that would be felt if a tumour interferes with the T1 nerve root?
Pain which radiates down the medial aspect of the arm and forearm, stopping at the wrist
If there is a disruption to the sympathetic nerves of the eye, what symptoms occur?
- Ptosis
- Miosis
- Hemi-facial anhidrosis
- Loss of head and neck sympathetic tone
- Enophthalmos (sunken eyeball)
What happens when tumour compresses the recurrent laryngeal nerve?
Hoarse voice and bovine cough
Describe where first-order neuronal fibres arise and end in sympathetic innervation of the eye
Arise from postero-lateral hypothalamus
Descend through brainstem until termination at C8-T2
Describe when second-order neuronal fibres arise and end in sympathetic innervation of the eye
Exit through T1 root, travelling close to lung apex through sympathetic chain and cervical-thoracic ganglion
Terminate in superior cervical ganglion
Describe when third-order neuronal fibres arise and end in sympathetic innervation of the eye
Exit ganglion forming plexus around carotid internal.
Ascending into the cavernous sinus
Runs to eye via long and short ciliary nerves
Describe the superior vena cava syndrome
Obstruction of the superior vena cava by a tumour (mass effect) causes facial swelling, cyanosis and dilatation of the veins of the head and neck
Which fibres of the face cause sweating and tone to occur?
Vasomotor and sweat gland fibres - form plexus around external carotid artery
Which order of neuronal fibres are affected by a pancoast tumour to cause horners syndrome?
Second order neuronal fibres- called a second order neuronal lesion
Are pancoast tumours the only thing that can cause horners syndrome?
No - if any of the orders of neuronal fibres are affected in any way, the syndrome can appear
Why does enopthalmos occur?
Loss of sympathetic supply to the eye causes narrowing of the palpebral fissure, causing the ILLUSION of enopthalmos
How can upper limb swelling and discolouration be caused by a pancoast tumour?
Tumour growth in the lung apex can completely or partially compress the subclavian vein
What problems in the upper limb can be caused by a pancoast tumour - and why?
Upper limb swelling and discolouration Loss of vascular tone (loss of sympathetic innervation) Oedema (failure of venous drainage) Tenderness Erythema Warmth
Which anatomical structures allow the formation of three compartments within the thoracic inlet?
Insertion of the anterior and middle scalene muscle on the posterior scalene muscle (on second rib)
What is found within the anterior compartment of the thoracic inlet?
Subclavian and internal jugular veins
What is found in the middle compartment of the thoracic inlet?
Subclavian artery and some of its branches
What is found in the posterior compartment of the thoracic inlet?
Brachial plexus branches, sympathetic trunk and cervical-thoracic ganglion
What is a Pancoast tumour characterised by?
Malignant neoplasm of the superior sulcus of the lung with destructive lesions of the thoracic inlet and involvement of the brachial plexus and cervical sympathetic nerves
What are the common clinical features of a Pancoast tumour?
- Pain radiating down the arm
- Atrophy of hand and arm muscles
- Horner’s syndrome
- Compression of blood vessels
- Oedema
What type of cancer are Pancoast tumours normally?
Squamous cell carcinomas
Adenocarcinomas
What is a main difference between a Pancoast tumour and classic lung cancers?
No breathlessness or coughing up blood
How would a Pancoast tumour be diagnosed?
- Biopsy - supraclavicular incision
- Bronchoscopy
- X-ray
- CT
- MRI - spread
- PET - lymph node involvement
What is the classical treatment for Pancoast tumours and what is the 5yr survival rate?
Pre-operative radiotherapy
Removal of chest wall, lower brachial plexus and part or the entire lung
Additional chemotherapy 30%
What is the management for disseminated pancoast tumours?
Palliative radiotherapy or surgery
What causes ptosis
Damage or lack of nerve supply to levator palpebrae superioris muscle and superior tarsal muscle
Give cause of miosis
The iris dilator muscle - responsible for dilatation of the pupil loses sympathetic innervation -inactivated
Which two sources do motor neurons receive input from?
Local sources - segmental reflexes
Descending tracts from brain - voluntary movement
Where does the lateral corticospinal tract decussate?
In the medulla
Where does the anterior corticospinal tract decussate?
At the level at which it leaves the spinal cord
Where in the white matter does the lateral corticospinal tract travel?
Immediately lateral to the dorsal horn
Where in the white matter does the anterior corticospinal tract travel?
Lateral to the anterior median fissure
Which two parts of the brain does the corticospinal tract travel through?
Internal capsule
Cerebral peduncle of the midbrain
Where do the axons of the corticospinal tract form ventral bulges, and what are they called?
In the medulla oblongata - known as pyramids
What is the difference in function between the lateral and anterior corticospinal tracts?
- Anterior - control trunk and proximal limb movement
- Lateral - precise, agile and highly skilled movements of hands and feet
What is the function of the corticobulbar pathway?
Controls skeletal muscles of the head
Which two areas of the brain does the corticobulbar tract pass through?
Internal capsule
Cerebral peduncle of the midbrain
Which nine cranial nerve motor nuclei, do axons of the corticobulbar tract terminate in?
- Oculomotor
- Trochlear
- Trigeminal
- Abducens
- Facial
- Glossopharyngeal
- Vagus
- Accessory
- Hypoglossal
What is the function of the tectospinal pathway?
Maintains balance and posture
Which neurons does tectospinal modulate the activity of?
Alpha and gamma motor neurons innervation muscles of the neck
What is the function of the vestibulospinal pathway?
Maintains balance and posture
What are the two parts of the reticulospinal tract?
- Pontine (extensor)
- Medullary (flexor)
What is the function of the reticulospinal tract?
Maintains balance and posture
What is the function of the rubrospinal tract?
Regulates upper limb muscle tone and movement
Where do the upper motor neurons arise in the rubrospinal tract?
The red nuclei of the midbrain
Where do upper motor neurons of the rubrospinal tract decussate?
Midbrain
Where in the White matter of the spinal cord will you find the dorsal column (medial lemniscus pathway)?
Posterior and medial to the dorsal horn
Why is the dorsal column/medial lemniscus path called this?
Dorsal column of the spinal cord
Medial lemniscus of the brainstem
Where do first order neurons of the dorsal column arise from and terminate at?
Arises from sensory receptors in limbs, trunk, neck, etc
Travels into the spinal cord, ascends up the ipsilateral side and terminates at the medulla (still ipsilaterally)
Where are the cell bodies for the first order neurons of the dorsal column found?
Dorsal root ganglion
What are the two dorsal columns in the white matter - and what sensations are carried in each?
Gracile fasciculus - touch, pressure and vibration from lower limbs Cuneate fasciculus - touch, pressure, vibration and conscious proprioception from the upper limbs, trunk and neck
Where do first and second order neurons synapse in the dorsal column?
In either the gracilis or cuneate nucleus
Where do the second order neurons of the dorsal column arise and terminate?
Arise in the cuneate of gracile nucleus, then decussate (in the medulla still) and enters the medial lemniscus Terminates in the ventral, posterior nucleus of the thalamus
Where do tertiary axons of the dorsal column arise and terminate?
Arise in the ventral, posterior nucleus of the thalamus
Terminates in the primary somatosensory area of the cerebral cortex
What sensations does the medial lemniscus pathway transmit?
Tactile sensations Proprioception
Where in the white matter is the spinothalamI c tract located?
Anterio-lateral to the ventral horn
What sensations does the spinothalamic tract carry?
- Pain
- Temperature
- Itch
- Tickle
Where do the first order neurons in the spinothalamic tract arise and decussate?
They arise at the receptor (in trunk, limbs, neck, posterior head)
They terminate in the dorsal horn on the ipsilateral side
Where do the second order neurons in the spinothalamic tract arise and decussate?
They arise in the dorsal horn, and then decussate to the contralateral side They pass up the spinal cord They terminate in the ventral, posterior nucleus of the thalamus
Where do the third order neurons in the spinothalamic tract arise and decussate?
They arise in the ventral, posterior nucleus of the thalamus and travel to the primary somatosensory area (on the same side as the thalamus)
Where are the pre-ganglionic neurons of the sympathetic nervous system located?
Thoracolumbar region - T1-L3
Where are the pre-ganglionic neurons of the parasympathetic nervous system located?
The brainstem - CN III, VII, IX and XSacral region- S2-4
Where are the ganglia of the sympathetic nervous system located?
In the sympathetic trunk - next to the vertebral column from T1 to the coccyx
Where are the ganglia of the parasympathetic nervous system located?
Near the targets organ - in the walls of the viscera they innervate