HNN Topic 15 - Arm, Pancoast Tumours Flashcards
Describe the staging of Pancoast tumours
Always T3/4
T3 = invade chest wall or sympathetic chain
T4 = invade spine, brachial plexus, blood vessels
Describe the location of the apex of the lung
Extends into root of neck, reaches above the level of the sternal end of the 1st rib
Where does the subclavian artery become the axillary artery?
From outer border of 1st rib
List the strap muscles of the neck
- Sternohyoid muscle
- Omohyoid muscle
- Sternothyroid muscle
- Thyrohyoid muscle
Describe the sympathetic innervation of the eye
- 1st order
- Posterolateral hypothalamus
- Brainstem to spinal cord, terminates at cillospinal centre (C8-T2)
- 2nd order (Preganglionic)
- Exit through T1 root, travel close to apex of lung (ventral ramus), paravertebral sympathetic chain stellate ganglion
- Terminate at superior cervical ganglion
- 3rd order (Postganglionic)
- Exit superior cervical ganglion into carotid canal to form plexus around internal carotid artery
- Plexus ascends into cavernous sinus, runs on CN VI then follows ophthalmic division of CN V to orbit
- Supplies iris dilatory muscles and smooth muscle fibres of upper and lower lid
- Vasomotor and sweat gland fibres follow external carotid artery to supply same side of face
Where is the stellate ganglion?
At level of C7 and neck of 1st rib
Which spinal nerves innervate the scalenus muscles?
C4-6
Define Pancost Tumour
- Malignany neoplasm of the superior sulcus of the lung
- Leads to lesions of the thoracic inlet and involvement of the brachial plexus and cervical sympathetic nerves
What is the clinical significance of the root of the neck?
The subclavian artery and vein and the brachial plexus pass between the thorax and upper limb by passing over the 1st rib and through the axillary inley - close association with the apex of the lung
Which spinal nerves contribute to the phrenic nerve?
C3, 4, 5 - mainly C4
Which areas are drained by the subclavian vein?
Upper limbs
List the branches of the brachial plexus
- Posterior cord - subscapular, thoracodorsal, axillary nerve, contines as radial nerve
- Lateral cord - musculocutaneous, lateral pectoral, median nerve
- Medial cord - medial pectoral nerve, medial cutaneous nerve of forearm + arm, ulnar nerve, median nerve
What is the action of the sternohyoid muscle?
Depresses hyoid bone
Describe the origin and insertion of the omohyoid bone
- Inferior belly - scapula to intermediate tendon
- Superior belly - intermediate tendon to hyoid bone
How are Pancoast tumours diagnosed?
X-Ray, CT, MRI, tissue biopsy
Describe the structure of the brachial plexus
- Roots - C5-T1
- Trunks - superior (C5/6), middle (C7), inferior (C8/T1)
- Divisons - anterior and posterior
- Cords -
- Lateral = anterior divisions of superior and middle trunks
- Posterior = posterior divisions of all 3 trunks
- Medial = continuation of anterior division of lower trunks
- Branches
- Lateral and medial cords join to form median nerve
- Posterior cord continues as radial nerve
- Lateral cord continues as musculocutaneous nerve
- Medial cord continues as ulnar nerve
Where does the radial nerve originate?
- Origin = C5/6, posterior cord
- Exits axilla under teres minor, runs around back of humerus in radial groove w/ arteria profunda brachii, passes down lateral forearm to wrist
Where does the mylohyoid muscle attach?
- Runs from mandible to hyoid bone, forms floor of oral cavity
- Medial fibres of two muscles join at midline raphe
Where is the superior sulcus of the lung?
Apical pleuro-pulmonary groove formed by the subclavian artery as it curves in front of the pleura
Which spinal nerves contribute to the great auricular nerve?
C2/3
What are the potential complications associated with Pancoast tumours?
- Horner’s sydrome
- Superior vena cava syndrome - facial swelling, cyanosis and dilation of veins of head/neck
- Arm oedema secondary to compression of blood vessels
Describe the origin of the internal jugular vein
- Formed by the union of the inferior petrosal and sigmoid sinuses at the jugular foramen
- Retromandibular, facial and lingual veins also drain into internal jugular vein
Describe the origin of the subclavian artery
- Receives blood from the aortic arch
- L directly from aorta
- R from brachiocephalic trunk
Which areas are supplied by the common carotid artery?
Head and neck
Why does arm oedema occur in Pancoast tumours?
- Subclavian vein compressed in axillary inlet - reduced drainage leads to blood pooling
- Reduced sympathetic function (compression of sympathetic ganglion) - reduced vessel tone, worse oedema
What is the function of the axillary nerve?
- Motor - deltoid and teres minor muscles
- Sensory - shoulder
- Cutaneous - shoulder/lateral arm
Define Horner’s syndrome
Condition characterised by miosis (constriction of pupil), ptosis (drooping of eyelid) and anhidrosis (absence of sweating on affected side of face)
Describe the path of the internal jugular vein
Originates at jugular foramen, runs down side of neck lateral to internal (then common) carotid artery, unites with subclavian vein at the root of the neck to form the brachiocephalic vein
List the spinal nerves which form the roots of the brachial plexus
C5, 6, 7, 8 and T1