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ESA 4 > Head and Neck > Flashcards

Head and Neck Flashcards

1
Q

State the innervation of the facial muscles

A
  • Facial Nerve (CN VII) supplies the majority of facial muscles
  • Trigeminal Nerve (CN V) supplies the muscles of mastication
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2
Q

Describe the arterial supply to the face

A
  • Branches of external carotid artery
  • Main artery is facial artery
    • Compress both arteries when lacerated as there are many anastamoses
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3
Q

Describe the venous drainage of the face

A
  • Facial vein drains into internal jugular vein
  • Superficial temporal and maxillary drains into external jugular vein
  • Both drain into subclavian vein
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4
Q

Describe the layers of the deep cervical fascia of the neck

A
  • Investing layer - surrounds whole neck
    • Encloses sternocleidomastoid and trapezius
  • Pretracheal layer
    • Encloses infrahyoid muscles
    • Encloses trachea, oesophagus and thyroid gland
  • Prevertebral layer
    • Encloses vertebrae and associated muscles
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5
Q

What are the functions of the deep cervical fascia?

A
  • Support
  • Limit the spread of abscesses
  • Allows fluidity of structures in the neck - move over one another
    • Swallowing
    • Turning the head and neck
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6
Q

What structures does the carotid sheath contain?

A
  • Common carotid artery
  • Internal jugular vein
  • Vagus nerve (CN X)
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7
Q

Describe the main routes of spread of infection through the neck

A
  • Retropharyngeal space between prevertebral fascia and pharynx fascia
    • Runs to diaphragm
  • Parapharyngeal space - adjacent to carotid sheath
    • More common due to tonsilitis
    • Runs to mediastinum
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8
Q

State the borders of the anterior triangle of the neck

A
  • Roof = Superficial cervical fascia
  • Floor = Pharynx, larynx, thyroid gland
  • Inferior = jugular notch of manubrium
  • Superior = Inferior mandible
  • Medial = Midline
  • Lateral = Anterior sternocleidomastoid
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9
Q

How is the anterior triangle subdivided? What are their main contents?

A
  • Submandibular (digastric) triangle
    • Submandibular gland
  • Submental triangle
  • Carotid triangle
    • Carotid sheath
    • Thyroid gland
    • Pharynx and larynx
    • External carotid artery
  • Muscular (omotracheal) triangle
    • Sternothyroid, sternohyoid, thyroid, parathyroid muscles
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10
Q

What are the borders of the posterior traingle of the neck?

A
  • Roof = Investing layer fascia
  • Floor = Muscles covered by prevertebral layer
  • Superior = Where SCM and trapezium meet (superior nuchal line of occipital bone)
  • Inferior = Middle third of clavicle
  • Anterior = Posterior sternocleidomastoid
  • Posterior = Anterior trapezius
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11
Q

List the suprahyoid muscles and describe their function

A
  • Mylohyoid
  • Geniohyoid
  • Digastric
  • Stylohyoid

Elevate hyoid and larynx during swallowing

Consitute the floor of the mouth

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12
Q

List the infrahyoid muscles and describe their function

A
  • Sternohyoid (superficial)
  • Omohyoid (superficial)
  • Sternothyroid (deep)
  • Thyrohyoid (deep)

Anchor the hyoid, sternum, clavicle and scapula

Depress the hyoid and larynx during swallowing

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13
Q

What is the carotid sinus and why is it clinically relevant?

A
  • The dilation of the internal carotid artery after the carotid bifurcation at superior thyroid cartilage (C4)
  • It contains the baroreceptors that detect changes in arterial blood pressure by detecting stretch
  • Can be used to treat Supra-Ventricular Tachycardia (SVT) by gentle rubbing - carotid massage
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14
Q

What is the carotid body?

A

The location of the peripheral chemoreceptors which detect changes in arterial pO2

It is located at the bifurcation of the common carotid artery at the superior thyroid cartilage (C4)

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15
Q

Why can atheromas in the common carotid artery be dangerous?

A
  • The bifurcation is a common site of atheromas
  • Rupture of the clot can cause an emboli that travels to the brain to cause a TIA or stroke
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16
Q

Describe the main arterial supply of the neck

A
  • No branches of common carotid or internal carotid in neck
  • Subclavian artery gives rise to thryocervical trunk
    • Ascending cervical
    • Inferior thyroid
  • External carotid gives rise to:
    • Superior thyroid
    • Ascending pharyngeal
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17
Q

List the branches of the external carotid artery

A
  1. Stop - Superior thyroid
  2. Alcohol - Ascending laryngeal
  3. Late - Lingual
  4. Friday - Facial
  5. Or - Occipital
  6. Puke - Posterior auricular
  7. More - Maxillary
  8. Saturday - Superficial temporal
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18
Q

Describe the vertebral arteries

A
  • Arise from subclavian arteries
  • Ascend through the transverse foramen of cervical vertebrae 6 to 1
  • Supplies the brain (with the internal carotid artery)
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19
Q

Describe the arterial supply to the scalp

A
  • Internal carotid
    • Supra-orbital
    • Supra-trochlear
  • External carotid
    • Superficial temporal
    • Posterior auricular
    • Occipital

Lies within the dense connective tissue

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20
Q

Describe the blood supply to the dura and skull

A
  • Middle meningeal artery (branch of maxillary)
    • Posterior and anterior branches
  • Fracture at the pterion can rupture the anterior branch to cause an extradural haemorrhage
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21
Q

List the superficial arteries of the face

A
  • Facial artery - supplies mandible
    • Superior and inferior labial - supplies lips
    • Lateral nasal - nose
    • Angular - angle of eye
  • Transverse facial
  • Maxillary
  • Supratrochlear
  • Supraorbital
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22
Q

Describe the venous drainage of the scalp

A
  • Superficial temporal, posterior auricular and occipital accompany corresponding arteries
  • Supraorbital + supratrochlear → angular vein → facial vein
  • Internal jugular vein
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23
Q

What are the dural venous sinuses?

A
  • Enothelium-lined spaces between periosteal and meningeal layers of dura that receive blood from veins of the brain
  • Drain into internal jugular vein
  • Cause of spread of infection from the scalp to the meninges
  • E.g. Transverse, sigmoid, cavernous, superior sagittal
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24
Q

Describe the venous drainage of the face

A
  • Supraorbital, supratrochlear, angular, superior/inferior labial
  • Drains into common facial vein
  • Drains into internal jugular vein
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25
Q

How do you measure JVP?

A
  • Via internal jugular vein
    • Direct communication with right atrium
  • Through sternocleidomastoid
  • Patient at 45º
  • Measure height from sternal angle + 5 cm
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26
Q

What isthe lymphatic system?

A

A series of vessels and lymphoid organs that drain tissue fluid from the extracellular compartment to the venous system. It is driven by breathing and muscle contraction and is a low pressure system

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27
Q

What is the functions of the lymphatic system?

A
  • Return of plasma proteins from extracellular space
  • Immunological function for the body
  • Absorbs/transports fats from the digestive system
  • Regulate fluid balance of the body
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28
Q

List the main regional/superficial lymph nodes of the head and neck

A
  • Occipital
  • Post-auricular
  • Pre-auricular
  • Parotid
  • Submandibular
  • Submental
  • Superficial cervical
    • Along external jugular vein
  • Anterior/posterior cervical chain
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29
Q

List the main terminal/deep lymph nodes of the head and neck

A
  • Deep cervical
    • Follows course of internal jugular vein
  • Jugulo-digastric (tonsillar)
  • Jugulo-omohyoid (lingual)
  • Supraclavicular
    • Including Virchow’s node on the left, associated with gastric cancer
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30
Q

Describe the lymphatic ducts of the body

A
  • Right lymphatic duct
    • Drains the right upper qudrant of body
    • Enters venous system via right venous angle (union of r. internal jugular and r. subclavian)
  • Thoracic duct
    • Drains the rest of the body
    • Enters venous system via left venous angle (union of l. internal jgular and l. subclavian)
    • Crosses from right to left at T5 (sternal angle)
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31
Q

What are the pharyngeal arches?

A

A system of mesenchymal ridges that form in the lateral walls of the embryonic pharynx

  • Covered by ectoderm externally and endoderm internally
  • 5 in total (1-4 and 6)
  • Each arch has an associated artery, nerve and cartilage bar
  • They lie inferior to frontonasal prominence which overlies the developing brain
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32
Q

Describe the devlopment and basic structure of the neural tube

A
  • Forms in week 3
  • Notochord signals overlying ectoderm to thicken to from neurectoderm
  • Edges curl towards each other to create the tube
  • Anterior end forms the brain
    • Forebrain, midbrain and hindbrain
  • Mid and hindbrain give rise to all cranial nerves (apart from CNI and II)
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33
Q

Describe the formation of the facial skeleton

A

Derived from frontonasal prominence and 1st pharyngeal arch

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34
Q

List the muscle derivatives of the pharyngeal arches

A
  • 1st = mastication muscles
  • 2nd = muscles of facial expression
  • 3rd = stylopharyngeus
  • 4th = cricothyroid, levator palantine and pharynx constrictors
  • 6th = intrinsic muscles of larynx
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35
Q

Describe the cartilage derivatives of the pharyngeal arches

A
  • 1st = Meckel’s cartilage
    • Template for mandible and malleus and incus of middle ear
  • 2nd = Reichart’s
    • Stapes of middle ear, styloid process, hyoid bone
    • 3rd = hyoid bone
  • 4th = epiglottis
  • 4th-6th = cartilage of larynx
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36
Q

List the branchial arch derivatives

A
  • 1st and 2nd = arteries regress
  • 3rd = internal carotids
  • 4th = arch of Aorta (L) and braciocephalic (R)
  • 6th = pulmonary arch
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37
Q

List the cranial nerves of the pharyngeal arches and their sensory and motor functions

A
  • 1st = CN V (trigeminal)
    • Sensory - skin of face
    • Motor - muscles of mastication
  • 2nd = CN VII (facial)
    • Sensory - taste buds in anterior 2/3rds of tongue
    • Motor - muscles of facial expression
  • 3rd = CN IX (glossopharyngeal)
    • Sensory - posterior 1/3rd of tongue
    • Motor - stylopharyngeus
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38
Q

Describe what happens to the pharyngeal pouches

A
  • 1st = Eustachian tube and tympanic cavity
    • Connects middle ear to pharynx
  • 2nd = proliferates and colonised by lymphoid precursors to become the palatine tonsil
  • 3rd and 4th pouch divide into dorsal and ventral
    • Dorsal of 3rd and 4th = parathyroid gland
    • Ventral of 3rd = thymus
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39
Q

Describe what happens to the pharyngeal clefts

A
  • 1st cleft remains
  • 2nd arch grows down and obliterates remaining clefts
  • Cysts or fistulae can occur if cervical sinus isn’t obliterated properly
    • Occur along anterior border of sternocleidomastoid
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40
Q

Name the cranial nerves and whether they are sensory, motor or both

A
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41
Q

Describe CN I including function, test and causes of and consequences of trauma

A
  • Olfactory
  • Sensory
  • Sense of smell - supplies left and right nasal cavities
  • Damaged in fractures of cribiform plate of ethmoid bone
  • Trauma causes anosmia
  • Test using specific odours
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42
Q

Describe CN II including function, test and causes of and consequences of trauma

A
  • Optic
  • Sensory
  • Sense of vision
  • Damaged in direct trauma to eye, fracture to optic canal or pressure on optic nerve pathway
  • Trauma causes loss of pupillary constriction and visual fields
  • Test using Snellen plates, Ishihara plates and fundoscopy
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43
Q

Describe CN III including function, test and causes of and consequences of trauma

A
  • Oculomotor
  • Mixed
  • Motor - all extraocular muscles (except LR6 and SO4) ciliary muscles and sphincter pupillae
  • Sensory (parasympathetic) - constrictor pupillae
  • Damaged by fractures of cavernous sinus or aneurysms
  • Trauma causes dilated pupil, ptosis and ‘down and out’ eye due to unooposed action of lateral rectus and superior oblique
  • Test using H test and eye torch
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44
Q

Describe CN IV including function, test and causes of and consequences of trauma

A
  • Trochlear
  • Motor - superior oblique
  • Damaged in orbit fractures
  • Causes inability to look down when eye is adducted
  • Tested with H test
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45
Q

Describe CN V including function, test and consequences of trauma

A
  • Trigeminal
  • Mixed
  1. Opthalmic - sensory sensation of scalp, forehead, upper eylid, dorsum of nose
  2. Maxillary - sensory sensation of lower eyelid, cheek, upper lip, nasal cavity, palate, upper teeth
  3. Mandibular - sensory sensation to lower cheek, anterior 2/3rds of tongue and lower teeth and motor supply to muscles of mastication

Tested by touching with cotton wool and pinprick and by masseter and pterygoids pushing against resistance

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46
Q

Describe CN VI including function, test and causes of and consequences of trauma

A
  • Abducens
  • Motor - lateral rectus
  • Damaged in fractures to orbit or cavernous sinus
  • Causes diplopia on looking laterally
  • Test using H test
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47
Q

Describe CN VII including function, test and causes of and consequences of trauma

A
  • Facial
  • Mixed
  • Motor - muscles of facial expression
  • Secretomotor to lacrimal, submandibular and sublingual glands and mucous membranes of nasopharynx, paranasal sinuses and palates
  • Sensory - taste in anterior 2/3rds of tongue
  • Damaged in laceration in parotid region, fracture of temporal bone or intracranial haematoma
  • Tests by creasing forehead, keeping eyes closed against resistance, puffing out cheeks and revealing teeth
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48
Q

Describe CN VIII including function, test and causes of and consequences of trauma

A
  • Vestibulocochlear
  • Sensory
    • Vestibular - balance
    • Cochlear - hearing
  • Damaged by skull fractures of ear infections
  • Causes unilateral hearing loss/tinnitus/vertigo
  • Test by whispering numbers into ears and Rinne’s (mastoid process) and Weber’s (forehead) test
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49
Q

Describe CN IX including function, test and causes of and consequences of trauma

A
  • Glossopharyngeal
  • Mixed
  • Motor - stylopharyngeus and parotid gland
  • Sensory - Carotid body and sinus, pharynx, middle ear and taste to posterior 1/3rd of tongue
  • Damaged in deep laceration to neck
  • Test using gag reflex (pharyngeal reflex)
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50
Q

Describe CN X including function, test and causes of and consequences of trauma

A
  • Vagus
  • Mixed
  • Motor - muscles of larynx, pharynx and palate and smooth muscles of bronchi and digestive tract
  • Sensory - external ear, auditory canal, ear drum, pharynx, larynx and viscera of thorax and abdomen
  • Damaged by bronchial/carcinoma, aortic aneurysm and thryoidectomy
    • Causes hoarseness of voice (left recurrent laryngeal nere damage)
  • Test by opening mouth and saying ‘ah’ - uvula should be central
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51
Q

Describe CN XI including function, test and causes of and consequences of trauma

A
  • Accessory
    • 2 divisions = cranial and spinal
  • Motor = sternocleidomastoid and trapezius
  • Damaged in lacerations to neck
  • Causes shoulder droop
  • Test by shrugging shoulders against resistance
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52
Q

Describe CN XII including function, test and causes of and consequences of trauma

A
  • Hypoglossal
  • Motor - muscles of tongue
  • Damaged in neck lacerations and fracture to base of skull
  • Causes tongue to deviate to damaged sides
  • Test by sticking tongue out and moving side to side
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53
Q

Describe how the head and neck is innervated by the sympathetic nervous system

A
  • Via sympathetic trunk (paravertebral chain)
  • FIbres ‘hitch-hike’ on the walls of the carotid arteries but lie outside the carotid sheath
  • Preganglionic fibres arise in the first thoracic segment and then synapse in:
    • Superior cervical ganglion (C1-C4)
    • Middle cervical ganglion (C6)
    • Inferior cervical ganglion (C7)
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54
Q

Describe what each of the cervical ganglion innervates in the head and heck and how they travel into that region

A
  • Superior: Internal/external carotid arteries
    • Somatic - sweat glands
    • Visceral - dilator pupillae, nasal and salivary glands, smooth muscle of levator pupillae
  • Middle: Inferior thryoid artery
    • Lower larynx, trachea, hypo-pharynx, upper oesophagus
  • Inferior: Vertebral artery
    • May fuse with thoracic ganglion to form the stellate ganglion
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55
Q

State which cervical nerves each cervical ganglion gives rise to

A
  • Superior = upper 4 cervical nerves
  • Middle = 5th and 6th
  • Inferior = 7th and 8th

All three gives branches to cardiac plexus

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56
Q

State the cranial nerves that provides parasympathic stimulation to the head and neck and which ganglion they synapse with

A
  • CN III (oculomotor) = ciliary ganglion
  • CN VII (facial) = pterygopalatine or submandibular ganglion
  • CN IX (glossopharyngeal) = otic ganglion
  • CN X (vagus) = no discrete ganglion
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57
Q

Describe what parasympathetic stimulation CN III provides and where the preganglionic neurones are located

A
  • Preganglionic neurones in Edinger-Westphal nucleus
  • Postganglionic fibres run with short ciliary nerves to enter eye
  • Supplies sphincter pupillae and ciliary muscles
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58
Q

Describe what parasympathetic stimulation CN VII provides and where the preganglionic neurones are located

A
  • Preganglionic neurones in superior salivatory nucleus
  • Postganglionic fibres supply the:
    • Lacrimal gland and mucous glands of palate and nose via the pterygopalatine plexus (via greater petrosal nerve)
    • Submandibular and sublingual salivary glands via the submandibular plexus (via chorda tympani)
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59
Q

Describe what parasympathetic stimulation CN IX provides and where the preganglionic neurones are located

A
  • Preganglionic neurones in inferior salivatory nucleus
  • Postganglionic fibres supply the parotid gland and oropharynx
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60
Q

Describe what parasympathetic stimulation CN X provides and where the preganglionic neurones are located

A
  • Preganglionic neurones in dorsal vagal motor nucleus
  • Postganglionic fibres synapse in wall of target organs to supply the laryngopharynx, larynx, oesophagus and trachea
    • Hitch-hike on auriculotemporal nerve (Viii)
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61
Q

What is Horner’s syndrome?

A
  • Interruption to cervical sympathetic trunk
  • Causes:
    • Miosis (pupil constriction due to unopposed sphincter pupillae)
    • Ptosis
    • Vasodilation
    • Anhydrosis (lack of sweating)
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62
Q

What is the neural crest?

A

A specialised population of cells that originates within the neroectoderm (lateral border)

The cells become displaced and enter the mesoderm

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63
Q

Describe the components of the primitive face and what structures they give rise to

A
  • Frontal nasal prominence
    • Forehead, nose, philtrum, upper eyelids
  • Stomatadeum
    • Buccopharyngeal membrane - mouth
  • 1st pharyngeal arch
    • Maxillary prominence = middle third of face, cheeks, lateral upper lip and upper jaw
    • Mandibular prominence = lower third of face, lower lip and jaw

Prominences consist of mesenchyme covered by ectoderm

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64
Q

Describe the development of the nose

A
  • Nasal placodes (ecotdermal thickenings) appear on frontonasal prominence
    • Sinks to become nasal pits
  • Medial and lateral nasal prominences develop on either side
  • Nasal prominences are pushed together in the midline when maxillary prominances grow medially
  • Maxillary prominences fuse with medial nasal prominences
  • Medial nasal prominences then fuse in the midline
  • Oronasal membrane disappears
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65
Q

Describe the development of the palate

A
  • Fusion of medial nasal prominences creates the intermaxillary segment
    • Gives rise to philtrum, primary palate and 4 incisors
  • A palatal shelf develops from the maxillary prominence and grows towards the midline
  • It fuses together and with the primary palate to create the secondary palate
    • Separates the oral and nasal cavities
  • Mandible grows large enough to allow tongue to drop out of the way
  • Nasal septum develops as a midline down-growth and fuses with palatal shelves
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66
Q

Describe some conditions that occur in malformation of the palate

A
  • Lateral cleft lip = failure of fusion of medial nasal prominence and maxillary prominence
    • Can involve the primary palate also
  • Cleft lip = failure of the palatal shelves to meet in the midline
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67
Q

Describe the development of the eyes

A
  • 4th week
  • Develop as out-pocketings of forebrain
    • Grow out to make contact with overlying ectoderm to form optic placodes
  • Optic placodes then invaginate and pinch off
  • Retina derived from forebrain
  • The eyes move to the front from the side when the facial prominences grow
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68
Q

Describe the development of the external ear

A
  • External auditory meatus from 1st pharyngeal CLEFT
  • Auricles from proliferation within 1st and 2nd pharyngeal ARCHES
    • 1st = malleus and incus
    • 2nd = stapes
  • Ears grow to the side of the head from the neck when the mandible grows
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69
Q

Describe the development of the inner ear

A
  • Otic placodes develop as thickening of the ectoderm
  • They then sink and invaginate to form the auditory vesicles
    *
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70
Q

What is foetal alcohol syndrome and what are its symptoms?

A
  • Sensitivity to the developing brain to alcohol
  • Causes problems with migration of neural crest cells
  • Alcohol can freely cross the placenta so no known safe levels
  • Symptoms include:
    • Small eye/nose opening
    • Thin philtrum
    • Under developed jaw
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71
Q

What does the infratemporal fossa contain?

A
  • Mandibular nerve and branches
    • Buccal, lingual, inferior alveolar, auriculotemporal
  • Chorda tympani from facial nerve
  • Otic ganglion
  • Lateral and medial pterygoid and inferior temporalis muscles
  • Maxillary, middle meningeal and superficial temporal arteries
  • Maxillary and middle meningeal veins
  • Pterygoid venous plexus
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72
Q

Name some openings in the infratemporal fossa

A
  • Foramen ovale - mandibular nerve
  • Foramen spinosum - middle meningeal artery
  • Alveolar canal
  • Inferior orbital fissure
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73
Q

Describe some clinical relevances involving the infratemporal fossa

A
  • Mandibular nerve block - anaesthetic injected near to foramen ovale
  • Inferior alveolar nerve block - anaesthetic injected around mandibular foramen which affects mandibular teeth and skin and mucous membranes of lower lip
    • Dental procedures
  • Potential space for tumour growth
    • Hard to detect so likely to be advanced
74
Q

What is the temperomandibular joint?

A
  • Modified synovial hinge joint between cranium and mandible
  • It is located anterior and roughly level to the tragus
  • Bilaterally symmetrical
75
Q

Name the articulating surfaces of the temporomandibular joint

A

Superior:

  • Mandibular fossa (posterior and concave)
  • Articular tubercle (anterior and convex)

Inferior:

  • Condyle of mandible

The superior and inferior compartments are created by the articular disc (mensicus)

76
Q

Describe some movements of the temporomandibular joint

A

Mandible always displaces. Movement in superior compartment = gliding and movement in inferior compartment = hinge

  • Flexion (closing mouth)
    • Retraction of mandible by temporalis
    • Elevation of mandible by temporalis, masseter and medial pterygoids
  • Extension (opening mouth)
    • Condyles pulled forwards (gliding) by lateral pterygoids
    • Chin pulled down (hinge) by digastric
  • Gliding (translation)
  • Rotation (pivoting)
77
Q

List the features of the temporomandibular joint

A
  • Modified synovial joint
    • Lined by fibrocartilage and not hyaline
  • Thin and loose fibrous capsule to permit movement
  • Articular disc separates bony surfaces from contact
    • Upper cavity = sliding joint
    • Lower cavity = modified hinge joint
  • Both enclosed by its own synovial cavity
78
Q

Describe some features of the capsule in the temporomandibular joint

A
  • Strengthened by extracapsular ligament
    • 1 lateral (temperomandibular) - strongest
    • 2 medial (accessory ligaments)

Attaches to:

  • Superior - circumference of mandibular fossa and articular tubercle
  • Inferior - neck of the condyle of the mandible
79
Q

Describe the functions of the accessory ligaments

A
  • Sphenomandibular = prevents inferior dislocation
    • Constant in length and tension
  • Stylomandibular = separates parotid gland from submandibular gland
    • Thickening of deep parotid fascia
80
Q

How does the temporomandibular joint remain stable?

A
  • Posterior glenoid tubercle limits posterior displacement
  • Articular tubercle limitis passive anterior displacement
  • Sphenomandibular ligament prevents inferior dislocation
  • Most stable when closed
    • Teeth in occlusal contact
81
Q

Describe some disorders of the temporomandibular joint

A
  • Bruxism = grinding teeth in sleep
  • Temporomandibular Pain Dysfunction Disorders (TPDD) = muscle pain
  • Mal-occlusion syndrome = muscle pain
  • Dislocation = condyle of mandible moves forwards
    • Sideways blow to the chin when open
    • Excessive contraction of lateral pterygoids when eating or yawning
82
Q

Name which bones makes up the borders of the orbit

A
  • Roof = frontal and sphenoid
  • Floor = maxillar, zygomatic (and palatine)
  • Medial = ethmoid, lacrimal and maxilla
  • Lateral = zygomatic and sphenoid
83
Q

Describe common fractures of the orbit and their consequences

A
  • Involves the thinner medial and inferior walls
  • ‘Blow out’ fractures displaces the orbital walls and contents into nearby sinuses
  • Can cause enopthalmus, diplopia and infraorbital bleeding
84
Q

Name some important orbital fissures and what enters/exits through them

A
  • Optic canal - optic nerve (CN II)
  • Superior Orbital Fissure - Lacrimal, Frontal, Trochlear (CN IV) Oculolmotor (CN III) Abducens (CN VI) nerves and opthalmic veins
    • Large French Teenagers Sit Numb In Anticipation Of Sweets (L to M)
  • Inferior Orbital FIssure - infraorbital nerves
85
Q

Describe the optic nerve and clinical importance

A
  • CN II
  • Covered by pia, arachnoid and dura mater and is continuous with the brain
    • Infection can spread backwards into brain
  • Contains a central artery and vein
  • Shows signs of raised ICP, venous engorgement and papilloedema
86
Q

Describe the extraocular muscles of the eye, their action and innervation

A
  • Superior rectus - moves eye up
    • Oculomotor (CN III)
  • Inferior rectus - moves eye down
    • Oculomotor (CN III)
  • Medial rectus - moves eye medially
    • Oculomotor (CN III)
  • Lateral rectus - moves eye laterally
    • Abducens (CN VI)
  • Superior Oblique - moves eye down and in
    • Trochlear (CN IV)
  • Inferior oblique - moves eye up and out
    • Oculomotor (CN III)
87
Q

Describe consequences of palsies to CN III

A
  • CN III (oculomotor)
  • Ptosis of superior eyelid due to paralysis of levator palpabrae superioris and unopposed action to orbicularis oculi
  • Fully dilated pupil due to paralysis of sphincter pupillae and unopposed action to dilator pupillae
  • Eye moves ‘down and out’ due to unopposed action to lateral rectus and superior oblique
88
Q

Describe consequences of palsies to CN IV

A
  • Trochlear nerve damage
  • Paralysis of superior oblique muscle
  • Unable to look down and in
    • Eg. Diplopia when walking down stairs
89
Q

Describe consequences of palsies to CN VI

A
  • Abducens nerve
  • Paralysis of lateral rectus muscle
  • Inability to move eye laterally (abduction)
  • Pupil is fully adducted due to unopposed pull of medial rectus
90
Q

Describe the arterial supply to the eye

A
  • Opthalmic artery (via internal carotid)
    • Through optic canal
    • Gives rise to central artery of retina
    • Short/long ciliary arteries supply external aspect of eye
    • Supraorbital and supratrochlear
  • Infraorbital artery (via maxillary artery via external carotid artery)
91
Q

Describe the venous drainage of the eye and clinical relevance

A
  • Superior/inferior opthalmic veins
    • Medially
    • Drain through superior orbital fissure
  • Danger triangle = communication between facial vein to cavernous sinus via the opthalmic veins
    • Can spread infection
    • Meningitis, brain abscess, cavernous sinus thrombosis
92
Q

What is the function of the eyelids

A
  • Protect from light and injury
  • Prevent cornea drying out by spreading lacrimal fluid
  • Corneal (blink) reflex
    • Controlled by CN Vi and VII
93
Q

Name the muscles that open and close the eye, innervation and consequences of paralysis

A
  • Levator palpabrae superioris = opens eye
    • Oculomotor nerve (CN III)
    • Paralysis leads to complete ptosis
  • Superior tarsal muscles = assists in opening eye
    • Sympathetic nerves (from sympathetic trunk)
    • Paralysis leads to partial ptosis and Horner’s syndrome
  • Orbicularis oculi = closes eye
    • Facial nerve (CN VII)
    • Paralysis leads to Bell’s Palsy (failure to close eyes) loss of blink reflex and dry eyes
94
Q

Describe how lacrimation takes place

A
  • Eyes close laterally to medially
    • Tears accumulate at lacrimal lake (medial canthus)
  • Stimulates by parasympathetic fibres of facial nerve
  • Sensory supply via lacrimal branch of Vi
  • Lacrimal gland → Lacrimal ducts → Lacrimal canaliculi (medial) → Nasolacrimal duct → Inferior nasal meatus
95
Q

Describe a Meibomian cyst, stye and consequences of raised ICP and papilloedema

A
  • Meibomian cyst = blockage of tarsal gland
  • Stye = infection of sebaceous gland at the base of the eylid
  • Raised ICP = Compresses optic nerve and blood vessels in optic nerve to cause blindness
  • Papilloedema = vein is occluded before artery leading to oedema of the retina before blindness
96
Q

What is Horner’s syndrome and describe some common symptoms and causes

A

Damage to the sympathetic trunk

  • Inactivation of dilator pupillae muscle causes miosis
    • Unopposed contrictor pupillae
  • Inactivation of superior tarsal muscle causing ptosis
  • Enopthalmus
  • Anhydrosis
  • Can be caused by congenital, iatrogenic (thyroidectomy) trauma, tumour of thyroid/lung apex
97
Q

Describe the external ear, including blood supply and sensory innervation

A
  • Consists of pinna/auricle + external auditory meatus
  • Elastic cartilaginous skeleton
  • Collects sound and funnels it into the external auditory meatus
  • Blood supply from posterior auricular and superficial temporal arteries (from external carotid)
  • Sensory innervation anterior to EAM is auriculotemporal nerve (from CN Viii)
    • The rest of the ear supplied by great auricular nerve (C2-3)
98
Q

Describe the histology of the external auditory canal

A
  • Outer 1/3 is elastic cartilage
  • Inner 2/3 is tympanic plate of temporal bone
  • Skin lining the outer 1/3 contains hairs, sebaceous glands and ceruminous glands (secrete ear wax)
99
Q

Describe some disorders of the external ear

A
  • Otitis externa = inflammation of external auditory meatus
    • Frequently in swimmers who don’t dry properly
    • Pain and itching
  • Pinna haematoma = haematoma between cartilage and perichondrium
    • Prevents oxygenation = pressure necrosis
    • Tissue undergoes fibrosis = cauliflower ear
  • Physical blockage of external auditory meatus due to excess earwax
  • Congenital - antihelix deformity, pinna malformation
100
Q

What is the middle ear? List the components

A

The narrow air-filled chamber in the petrous part of temporal bone. Divided into tympanic cavity proper and epitympanic recess (superior)

  • Tympanic membrane
  • Ossicles
  • Eustachian tube
  • Muscles
  • Branches of facial and glossopharyngeal nerves
  • Mastoid air cells
  • Respiratory epithelium
101
Q

What is the function of the middle ear?

A

Converts sound into mechanical form

  • Sound waves vibrate tympanic membrane
  • Vibrations transmitted to oval window by ossicles
  • Causes vibrations of vestibular and basilar membranes

Also connected to the nasopharynx via Eustachian tube, which allows the pressure to equalise between the middle ear and the throat

102
Q

Describe the ossicles and their function

A
  • Malleus
    • Handle attached to tympanic membrane
  • Incus
  • Stapes
    • Articulates with oval window
  • Relay vibrations from the tympanic membrane to the inner ear, amplifying and concentrating the sound energy
  • Synovial joints
103
Q

Describe the function of muscles of the ossicles

A
  • Tensor tympani - tenses the tympanic membrane to dampen the vibrations of the malleus
    • Prevents damage to the inner ear from loud noises
  • Stapedius - tightens the anular ligament to prevent excessive movement of the stapes
    • Innervated by facial nerve
104
Q

Describe 2 common infections of the middle ear

A
  • Otitis media = infection of the middle ear
    • Usually strep pneumoniae
    • Secondary to resp infections (Eustachian tube)
    • Inflammatory products can clog up cavity and cause a build up of pressure = perforation
    • More common in children (shorter and more horizontal Eustachian tubes)
  • Mastoiditis = infection of mastoid antrum and mastoid air cells resulting from otitis media
    • Swelling behind ear
105
Q

What is cholesteatoma?

A

A destructive and exanding growth in the middle ear which is formed by a necrotic mass of dead skin cells that have accumulated in pockets formed by negative pressure

  • Pressure build up by blockage of Eustachian tube
  • Erodes middle ear structures via lytic enzymes
106
Q

Describe the causes and consequences of Eustachian tube blockage

A
  • Swelling of mucous membranes due to infection
  • Causes residual air from tympanic cavity to be absorbed into mucosal blood vessels
    • Lowers the pressure in cavity
    • Causes retraction of tympanic membrane = glue ear (treated with gromits)
  • Tympanic membrane can no longer move freely so hearing is affected
  • In children, Epstein-Barr virus can cause adenoidal hypertrophy to block the entrance to ET
107
Q

Describe the causes and consequences of perforation of the tympanic membrane

A
  • Caused by trauma, inserting foreign bodies, otitis media and excessive pressure (scuba diving)
  • Can be central or subtotal
  • Minor ruptures can heal spontaneously
  • Large ruptures require surgical repair
  • Can lead to deafness
108
Q

Describe the components and function of the inner ear

A

Cavity in petrous part of temporal bone

  • Cochlear = organ of hearing
    • Contains cochlear duct and Organ of Corti
  • Organ of Corti = contains receptors of the auditory apparatus
  • Vestibule = bony chamber sensitive to balance
    • Contains saccule and utricle
  • Semi-circular ducts contain receptors that respond to rotational acceleration
    • Communicates with vestibule
109
Q

What is the difference between conductive deafness and sensorineural deafness?

A
  • Conductive deafness = vibrations do not reach cochlear
    • Due to blockage of sound (wax/object)
    • Or interference of movement of the oval or round windows (osteosclerosis etc)
  • Sensorineural deafness = vibrations not perceived in the cochlear
    • Defect in transduction mechanism or nerve
    • Treated with cochlear implant
110
Q

Name the sensory innervation of the tympanic membrane

A
  • External surface innervated by
    • Auriculotemporal nerve (branch of CN Viii)
    • Auricular branch of Vagus nerve (CN X)
  • Internal surface innervated by glossopharyngeal nerve (CN IX)
111
Q

Why do some people cough when sticking things in their ear?

A
  • Stimulation of auricular branch of Vagus nerve (CN X)
  • The Vagus nerve also supplies the throat (pharyngeal and laryngeal branches)
  • This stimulates the cough (sometimes vomit) reflex
    • Arnold’s Cough Reflex
112
Q

Describe the skeleton (and cartilage) of the external nose

A
  • Bones
    • Nasal bones
    • Frontal processes of maxilla
    • Frontal bone
  • Cartilage
    • 2 lateral cartilages
    • 2 alar cartilages
    • 1 septal cartilage
113
Q

Describe the different portions of the nasal septum

A
  • Anterior = cartilagenous
  • Middle = perpendicular plate of ethmoid bone
  • Posterior = vomer
114
Q

What is a conchae? Describe its function

A

Curved shelves of bone that project out of the lateral wall

  • Creates 4 pathways for air to flow through
    • Inferior, middle, and superior meatus
    • Spheno-ethmoidal recess
  • Increases surface area of nasal cavity to increase humidification and warming of air
  • Make air flow slow and turbulent
115
Q

List some functions of the nose

A
  • Olfaction
  • Filter and humidify air
  • Respiration
  • Drain paranasal sinuses
116
Q

Name some openings into the nasal cavity and what vessels exit/enter through them

A
  • Holes in cribriform plate of ethmoid bone - olfactory nerve
  • Sphenopalatine foramen - communication from ptreygopalatine fossa
    • Sphenopalatine artery, nasopalatine and superior nasal nerves
  • Incisive foramen - nasopalatine nerve and greater palatine artery
  • Foramen cecum - nasal veins to superior sagittal sinus
117
Q

Describe the arterial supply to the nasal cavity

A
  • Branches of opthalmic artery (anterior/posterior ethmoidal)
    • from ICA
  • Branches of facial (superior labial) and maxillary arteries (sphenopalatine and greater palatine)
    • from ECA
  • Form anastamoses with eachother in anterior nose = Kiesselbach’s area
118
Q

Describe the venous drainage of the nasal cavity

A

Veins tend to follow arteries and drain into:

  • Pretygoid plexus
  • Facial vein
  • Cavernous sinus
119
Q

Describe the innervation of the nose

A
  • Special sensory = olfactory nerves from olfactory bulb on superior cribriform plate
  • General sensory
    • Nasopalatine N (via maxillary Vii) to posteroinferior nasal mucosa
    • Anterior and posterior ethmoidal N (via opthalmic Vi) to anterosuperior mucosa
  • Trigeminal (infraorbital Vii and external nasal Vi) to external skin
120
Q

What are paranasal sinuses? What is their function?

A

Air filled extensions of the nasal cavity

  • Humidify inspired air
  • Reduce weight of the skull
121
Q

Describe the frontal sinus

A
  • Not present at birth
  • Drains into middle meatus via frontonasal duct
    • Opens out at semilunar hiatus
  • Related to anterior cranial fossa and the orbit
122
Q

Decribe the ethmoidal sinuses

A

Air cells between the orbit and nasal cavity

  • Anterior → middle meatus via infundibulum
  • Middle → ethmoid bulla (into middle meatus)
  • Posterior → superior meatus
123
Q

Describe the sphenoidal sinus

A
  • Present at birth
    • Enlarges after puberty
  • Drains into the sphenoethmoidal recess
  • Important anatomical relationships:
    • Access to pituitary gland during surgery (through sphenoid bone)
    • Cavernous sinus and ICA
    • Posterior cranial fossa and pons
124
Q

Describe the maxillary sinus (including borders)

A
  • Roof = floor of orbit
  • Floor = alveolar part of maxilla
  • Posterior = pterygopalatine and infratemporal fossa
  • Present at birth
    • Enlarges after age 8
  • Drains into middle meatus via maxillary ostium
    • Spread of infection from frontal sinus
125
Q

Name some potential sites of spread of infection from the nasal cavity

A
  • Anterior cranial fossa (via superior openings - foramen cecum, cribriform plate, ethmoidal foramina)
  • Middle ear (via Eustachian tube)
  • Paranasal sinuses
  • Lacrimal apparatus and conjunctiva (via nasolacrimal duct)
126
Q

Describe some disorders of the nasal cavity

A
  • Rhinitis = inflammation of nasal mucosa
    • Viral (adenovirus, rhinovirus), allergic, polyps
  • Nasal polyps = benign swellings in nasal cavity
    • Can cause obstruction → snoring/obstructive sleep apnoea
  • Sinusitis = inflammation of mucosal lining of sinuses
    • Acute/sub-acute/chronic
    • Viral with secondary bacterial (S. pneumoniae or H. influenzae)
127
Q

Describe some disorders and consequences of the paranasal sinuses

A
  • Ethmoidal sinus infection
    • Breaks through medial wall of orbit to damage optic nerve and opthalmic artery
  • Maxillary sinus infection
    • Congestion of mucous membranes in ostia
    • Impossible for drainage when upright
128
Q

Describe the different management steps in epistaxis

A
  1. Compression for 10 minutes - lean forward
  2. Cautery = burning the ends of the blood vessel to close it off
    1. Electro = using a metal probe
    2. Chemical = using silver nitrate
  3. Nasal tampons (covered in alginate)
  4. Posterior packing = occlude the cloacal arch to stop blood trickling inot the nasopharynx
  5. Surgical intervention = ligation of palatine/maxillary /external carotid arteries or radiological embolisation
129
Q

Name some risks that increases the chance of epistaxis

A
  • Trauma
  • Ethanol
  • Coagulation defects
  • Vascular abnormalities
  • Mucosal drying
  • Infections
  • NSAIDs
130
Q

Describe the anataomical journey of the trigeminal nerve

A
131
Q

Describe the general sensation to the face that the trigeminal nerve supplies

A
  • Opthalmic = scalp, forehead, upper eyelid, dorsum of nose, cornea
  • Maxillary = lower eyelid, upper cheek, upper lip, nasal cavity, maxillary sinus
  • Mandibular = temples, lower cheek, chin, lower lip, anterior 2/3rds tongue, external ear
132
Q

Describe the actions of the trigeminal nerve (not including general sensation)

A
  • Motor from mandibular branch - mastication muscles
    • Masseter, pterygoids, temporalis, digastric, mylohyoid
  • Carries sympathetic fibres from superior cervical ganglion
    • Sweating
    • Vasomotor function
133
Q

What is Harlequin Syndrome?

A

Damage to the trigeminal nerve (specifically pre-ganglionic sympathetic fibres)

  • Anaesthesia to face
  • Vasomotor dysfunction
  • Anhydrosis
134
Q

What does the oculomotor nerve supply?

A
  • 4/6 muscles controlling oculomotion
    • Superior, inferior and medial rectus
    • Inferior oblique
  • Levator palpebrae superioris
  • Sphincter pupillae
135
Q

What is the difference between the anatomical and clinical oculomotor nerve?

A
  • Oculomotor nerve proper = anatomical
    • Only motor function to eye muscles and LPS
    • Begins in oculomotor nucleus
    • Does not synapse at ciliary ganglion
  • Oculomotor nerve including parasympathetic fibres from Edinger-Westphal nucleus = clinical
    • Motor function to eye muscles and LPS as well as innervation to sphincter pupillae (via short ciliary nerve)
    • PNS fibres do terminate at ciliary ganglion
136
Q

Describe the consequence of an oculomotor nerve palsy

A
  • Anatomical
    • Down and out position of eye due to unopposed action of LR6 and SO4
    • Complete ptosis due to denervation of levator palpebrae superioris
  • Clinical
    • As above
    • AND with a dilated pupil due to denervation to sphincter pupillae
137
Q

Describe the difference of a proximal and distal palsy of the oculomotor nerve

A
  • Proximal palsy will have loss of motor function as well as a dilated pupil and loss of accommodation
  • Distal palsy will only have loss of motor function with equal pupils
    • Pupil-sparing third nerve palsy
138
Q

Describe the anatomical journey of the oculomotor nerve

A
  • Oculomotor nucleus (+/- fibres from Edinger-Westphal nucleus)
  • Cavernous sinus
  • Uncus
  • Tentorial notch
  • Exits via superior orbital fissure
  • Terminates at/near ciliary ganglion
139
Q

Describe the course of the facial nerve

A
  1. Motor cortex
  2. Pons (facial motor nucleus)
  3. Internal acoustic meatus (petrous temporal bone)
  4. Facial canal
  5. Stylomastoid foramen
  6. Branches to face and neck
140
Q

Name the branches of the facial nerve (motor portion)

A
  • Temporal
    • Occiptofrontalis and superior ocularis oculi
  • Zygomatic
    • Inferior Ocularis oculi
  • Buccal
    • Orbicularis oris, buccinator, zygomaticus
  • Marginal mandibular
    • Mentalis
  • Cervical branch
    • Platysmus

To Zanzibar By Motor Car

141
Q

Describe the functions of each strand of the CN VII

A
  • Facial nerve = facial expression muscles
  • Superior Salivatory Nucleus = visceral efferent parasympathetic to lacrimal, submandibular, sublingual, nasal and palatine glands
  • Nucleus Solitarius = special sensory of anterior 2/3rds of tongue (taste)
  • Geniculate ganglion = general sensory of auricle of ear
142
Q

How can the facial nerve be damaged?

A
  • Forceps delivery
  • Tumours of partoid gland/parotitis/parotidectomy
  • Incision or inflammation of facial nerve
  • Tympanectomy
  • Surgery on infratemporal fossa
143
Q

Describe the consequences of a facial nerve palsy

A
  • Loss of facial expression
  • Loss of lacrimation
  • Loss of secretomotor function in oral and nasal mucosa
  • Loss of action of sphincter muscles
    • Orbicularis oculi = complete ptosis and loss of blink reflex
    • Orbicularis oris = drooling
144
Q

What is the difference between stroke and Bell’s palsy?

A
  • Bell’s palsy causes paralysis of all facial expression muscles
  • Stroke spares the frontal lobe
    • So occipitofrontalis and orbicularis oculi are not paralysed due to bilateral innervation
145
Q

What is the difference between facial nerve palsy and Bell’s Palsy?

A
  • Facial nerve palsy = cause of damage can usually be identified
    • Usually permenant
  • Bell’s Palsy = inflammation of the facial nerve where cause sometimes cannot be identified
    • Usually temporary
  • Both present in the same way
146
Q

Describe the development of the anterior lobe of the pituitary

A
  • Endocrine (from ectoderm)
  • Derived from Rathke’s Pouch (roof of oral cavity)
  • Grows towards infundibulum and differentiates into endocrine cells
  • The connection between the oral cavity regresses but remnants can form cysts
147
Q

Describe the development of the posterior lobe of the pituitary gland

A
  • Neuroendocrine (from neuroectoderm)
  • Derived from the infundibulum (from the diencephalon of the brain)
  • Extends towards oral cavity to meet anterior lobe
  • Connection becomes the pituitary stalk, connecting pituitary to hypothalamus
148
Q

Describe each component of the primitive tongue

A
  • 2 lateral lingual swellings from Ph Arch 1
  • 3 median lingual swellings
    • Ph Arch 1 = tuberculum impar
    • Ph Arch 2, 3 and 4 = cupola
    • Ph Arch 4 = epiglottal swelling
149
Q

Describe the sequence of steps in the development of the tongue

A
  • Lateral lingual sweelings overgrow the tuberculum impar
  • 3rd arch component of cupola overgrows 2nd arch component
  • Extensive degeneration (apoptosis) frees the tongue from the floor of the oral cavity
    • Connected via lingual frenulum
150
Q

List the sensory innervation of the tongue

A
  • General anterior 2/3rds = lingual branch of CN V3 (from PA 1)
  • General posterior 1/3rd = CN IX (PA 3)
  • Special sensory anterior = chorda tympani from CN VII (PA 2)
  • Special sensory posterior = CN IX (PA 3)
151
Q

List the motor innervation of the tongue

A
  • Hypoglossal nerve (CN XII)
  • Myogenic precursors migrate into tongue
  • NB: Palatoglossus = Vagus nerve (CN X)
152
Q

Describe the development of the thyroid gland

A
  • Develops in floor of pharynx between tuberculum and cupola
    • In adult = foramen cecum
  • Bifurcates and descends as a bi-lobed diverticulum
    • Connected by the isthmus
  • Remains connected by the thyroglossal lobe
    • Loses patency after development
153
Q

Describe the origins of the different cells in the thyroid gland

A
  • Follicular cells secrete T3/T4 and are formed from the thyroid diverticulum (Branchial arches 1 and 2)
  • Parafollicular cells secrete calcitonin and are formed from the ultimobranchial body of the 4th pharyngeal pouch
154
Q

Describe some disorders of incomplete thyroid development

A
  • Thyroglossal cyst = remnant of the thyroglossal duct
  • Fistulae = when a thyroglossal cyst is connected to the exterior by a fistulous canal
  • Ectopic thyroid tissue = incomplete descent of the thyroid
155
Q

What is First Arch Syndrome?

A

Spectrum of defects in development of the eyes, ears, mandible and palate thought to result as a failure of colonisation of 1st Arch with neural crest cells

  • Eg: Treacher-Collins Syndrome = hypoplasia of the mandible and facial bones
156
Q

What is Di-George Syndrome?

A

Congenital thymic aplasia and abscence of parathyroid glands due to abnormal development of neural crest cells

  • CATCH 22
    • Deletion of chromosome 22
    • Cardiac abnormality
    • Abnormal facies
    • Thymic aplasia
    • Celft palate
    • Hypocalcaemia/parathyroidism
157
Q

What is CHARGE Syndrome?

A

A CHD7 mutations essentail for production of multipotent neural crest cells

  • Coloboma
  • Heart defects
  • Choanal atresia
  • Growth/development retardation
  • Genital apalsia
  • Ear defects
158
Q

Name the function, boundaries, epithelum and contents of the nasopharynx

A
  • From skull base to soft palate
    • At level of C1
  • Respiratory function
  • Ciliated pseudostratified columnar epithelium (respiratory)
  • Contents = nasopharyngeal tonsil (adenoids) and Eustachian tube orifice
159
Q

Name the function, boundaries, epithelum and contents of the oropharynx

A
  • Digestive function
  • From soft palate to superior epiglottis
    • At level of C2-C3
  • Stratified squamous epithelium
  • Contents = palatine tonsils and tonsillar pillars
    • Tonsils atrophy after puberty
160
Q

Name the boundaries, epithelum and openings of the laryngopharynx

A
  • From superior epiglottis to inferior cricoid cartilage
    • At levels of C3-C6
  • Statified squamous epithelium
  • Opens into oesophagus (posterior) and larynx (anterior)
161
Q

Describe the pharyngeal musculature

A
  • Superior, middle and inferior constrictors
  • Overlap eachother
  • Open anteriorly
  • Attached posteriorly by the median raphne

Walls of pharynx = outer circular and inner longitudinal layer of muscle which shorten and widen the pharynx during swallowing

162
Q

Name the innervation of the pharynx

A
  • Sensory
    • Naso = CN V2 (maxillary of trigeminal)
    • Oro = CN IX (glossopharyngeal)
    • Laryngo = CN XII (hypoglossal)
  • Motor = mainly CN X (vagus) and CN IX (glossopharyngeal)
    • Forms the pharyngeal plexus along with sympathetic fibres from the superior cervical ganglion
163
Q

Describe the phases of swallowing

A
  1. Voluntary phase = bolus pushed from oral cavity to oropharynx by the tongue
  2. Pharyngeal phase = bolus passes into laryngopharynx by aid of middle and inferior constrictor
    • Soft palate elevates to close off nasopharynx
    • Pressure receptors in the palate and pharynx signal to the swallowing centre
    • Tongue and suprahyoids pull hyoid and larynx up
    • Inhibition of breathing
  3. Oesophageal phase = peristaltic wave propels bolus into stomach
    • Upper 3rd is voluntary striated muscle
    • Lower 2/3rds is smooth muscle
164
Q

Describe the arterial and venous supply to the pharynx

A
  • External carotid artery - superior thyroid, ascending pharyngeal, branches of lingual, facial and maxillary
  • Internal jugular vein - pharyngeal venus plexus
165
Q

Describe the adenoids and associated pathologies and management

A

Mass of lymphoid tissue that can enlarge with viral/bacterial infections

  • Nasal obstruction - hyponasal speech, feeding difficulty, obstructive sleep apnoea
  • Eustachian tube obstruction → otitis media → glue ear and conductive hearing loss
  • Managed with adenoidectomy (curettage or suction diathermy)
166
Q

What is Obstructive Sleep Apnoea?

A

Airway obstruction during sleep that creates turbulent airflow and pauses in breathing

  • 30 apnoeic episodes in 7 hours of sleep
167
Q

Describe a test for innervation of the pharynx

A
  • Gag reflex - touching the back of the oropharynx to make the pharyngeal muscles contract
  • Afferent - glossopharyngeal nerve (CN IX)
  • Efferent - vagus nerve (CN X)
168
Q

Describe the complications and management of tonsillitis

A
  • Palatine tonsils = lymphoid tissues covered by squamous epithelium
  • Enlarge with bacterial/viral infection
  • Tonsillectomy if recurrent tonsilitis, carcinoma, abscess os obstructive sleep apnoea
    • Can cause bleeding from external palatine vein
169
Q

What is the pharyngeal pouch?

A

Posterior herniation of pharyngeal mucosa that occurs through Killian’s dehiscence (between inferiior constrictor and cricopharyngeus)

  • Herniates due to weaker area, incoordination of pharyngeal phase of swallowing or cricopharyngeal spasm
170
Q

What is the difference between stridor and stertor

A

Stertor = noisy breathing caused by partial obstruction of the airways ABOVE the larynx

Stridor = noisy breathing caused by partial obstruction to the aiway AT OR BELOW the larynx

171
Q

Describe the causes, signs and management of acute epiglottitis

A
  • Bacterial infection - H. influenzae type B, staph, ß-haemolytic strep
  • Pyrexial (>38), drooling, tripod position
  • Thumb print sign on x-ray
  • Management:
    • Secure airway - extubation
    • Throat swab
    • Broad spectrum antibiotics (ceftriaxone)
    • Steroids
172
Q

Describe the causes, signs and management of croup (laryngotracheobronchitis)

A
  • Initially viral infection - influenza/parainfluenza
  • Presents with stridor and barking cough
  • Infective oedema narrows subglottis
  • Management:
    • Mild - oral antibiotics and steam inhalation
    • Moderate - IV antibiotics, humidified oxygen, nebulised adrenaline
    • Severe - intubation, tracheostomy
173
Q

Name some common sites for food to get stuck in the pharynx larynx

A
  • Piriform fossa - mucosal recess between the ventral larynx and lateral thyroid cartilage
  • Vallecula - mucosal pouch between the base of the tongue and the epiglottis
  • Palatine tonsils
  • Cricopharyngeus
174
Q

List some functions of the pharynx

A
  • Respiration
  • Phonation
  • Protecting the trachea during swallowing
175
Q

Describe the components of the laryngeal skeleton

A
  • Epiglottis = leaf shaped plate of elastic fibrocartilage that prevents the aspiration of food into the trachea during swallowing
  • Thyroid cartilage
  • Cricoid cartilage
    • Completely encircles airway
  • Paired arytenoid cartilage = pyramid-shaped cartilage that artcultes with the cricoid cartilage and allows vocal cord movement
176
Q

Describe the divisions of the larynx and contents of each

A
  • Supraglottis (inferior epiglottis)
    • Vestibular folds
  • Glottis
    • True vocal cords (+1cm inferiorly)
  • Subglottis
    • Down to lower cricoid cartilage
177
Q

Describe the laryngeal muscles

A
  • Extrinsic muscles move the entire larynx
    • Infrahyoids depress
    • Suprahyoids elevate
  • Intrinsic muscles act on the vocal cords and aryepiglottic folds
    • Cricothyroid - stretches/tenses vocal cords
    • Thyroatenoid - relaxes vocal cords
178
Q

Describe the structure of the vocal cords and the muscles that produce movement

A
  • Stratified squamous epithelium → Reinke’s space (fluid) → vocal ligament → vocalis muscle
    • No submucosa
  • Posterior cricoarytenoid = abduction
    • Only muscle to open
  • Lateral cricoarytenoid = adduction
179
Q

Describe the innervation of the larynx

A
  • Superior laryngeal nerve = cricothyroid muscle
    • Deep to carotids
  • Recurrent laryngeal nerve = rest of laryngeal muscles
    • Left - under arch of Aorta
    • Right - under subclavian artery
    • Back through tracheo-oesophageal groove
180
Q

Name the arterial and venous supply of the larynx

A

Arterial - superior and inferior laryngeal arterys

  • External carotid → superior thyoid → superior laryngeal
  • Subclavian → inferior thyroid → inferior laryngeal

Venous - superior and inferior laryngeal veins

  • Superior → superior thyroid vein → internal jugular
  • Inferior → inferior thyroid vein → left brachiocephalic
181
Q

Describe the causes of hoarseness of the voice

A

Pathology in the neck and chest can damage the recurrent laryngeal nerve leading to intrinsic laryngeal muscle weakness

  • Laryngeal cancer
  • Thyroid hyperplasia/cancer
  • Trauma (thyroidectomy etc)
  • Cervical lymphadenopathy
  • Aortic aneurysm
  • Oesophageal cancer
  • Apex of lung cancer
182
Q

Describe some causes of acute airway obstruction and emergency management

A

Causes:

  • Oedema due to infection
  • Inhalation of foreign body
  • Tumour
  • Anaphylaxis

Management:

  • Cricothyroidotomy - piercing through the cricothyroid membrane
  • Tracheostomy

ESA 4 (3 decks)

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