Head and Neck, Session 2 Flashcards Preview

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Flashcards in Head and Neck, Session 2 Deck (86):
1

Why is the left common carotid artery longer than the right?

left derived from arch of aorta, and so courses for about 2cm in superior mediastinum before entering neck, whereas right from brachiocephalic artery where bifurcates behind r sternoclavicular joint

2

what is the course of the common carotid artery defined as?

carotid line: defined by a line beginning below sternoclavicular joint and terminating midway between angle of mandible and mastoid process of temporal bone.

3

where does the external carotid artery divide into maxillary and superficial temporal branches?

at a level behind neck of mandible, within substance of parotid gland
here it is accompanied by the facial nerve and the retromandibular vein

4

reliable anatomical landmark for birfurcation on common carotid artery?

superior border of thyroid cartilage
carotids terminate midway between angle of mandible and mastoid process of temporal bone

5

where does the inferior thyroid artery originate from?

thyrocervical trunk- comes off subclavian artery

6

branches of external carotid artery?

superior thyroid
lingual
facial
ascending pharyngeal
occipital
posterior auricular

terminal: superficial temporal
maxillary

7

clinical relevance of carotid triangle?

carotid pulse
access vagus and hypoglossal (XII) nerves
carotid end arterectomy, surgical approach to carotid artery or IJV
carotid sinus massage e.g. in supraventricular tachycardia

8

why can a cut to the scalp lead to profuse bleeding?

arteries supplying scalp lie in dense CT which is closely attached to the walls of the arteries, limiting their constriction

9

why is scalp bleeding predominantly arterial?

venous pressure extremely low in erect position
arteries have limited ability to constrict when lacerated due to close attachment of their walls with dense CT

10

what is an extradural hamatoma?

bleeding into the extradural space- potential space between dura mater and bone, periosteal layer of dura normally firmly attached to bones surrounding outside of cranial cavity, but can become fluid-filled space with haemorrhage e.g. laceration of middle meningeal artery or a torn dural venous sinus

11

how might an infection of the scalp spread to involve the meninges?

blood can flow from the veins of the scalp into the diploic veins of the skull, and then into the dural venous sinuses, due to emissary veins connecting veins of scalp to diploic veins

12

what does the facial artery supply?

muscles of facial expression and face

13

what does the superior labial artery supply?

upper lip, and side and septum of nose

14

what does inferior labial artery supply?

lower lip

15

what does lateral nasal artery supply?

skin on ala and dorsum of nose

16

what does angular artery supply?

superior part of cheek and inferior eyelid

17

what does occipital artery supply?

scalp of back of head, as far as vertex

18

what does posterior auricular artery supply?

scalp post to auricle and auricle

19

what does superficial temporal artery supply?

facial muscles, and skin of temporal frontal and temporal regions

20

what does the transverse facial artery supply?

parotid gland and duct, muscles and skin of face

21

what does mental artery supply?

facial muscles and skin of chin

22

what does supra-orbital and supratrochlear arteries supply?

muscles and skin of forehead, and scalp and superior conjunctiva

23

which arteries supply blood to the brain?

internal carotid
vertebral

24

what is the carotid sheath made from?

areolar (LCT) tissue

25

what is the carotid sheath derived from?

fusion of prevertebral layer of fascia posteriorlu, pretracheal anteromedially, and superficial layer of cervical fascia anterolaterally

26

where does the sympathetic trunk lie in relation to the carotid sheath?

outside sheath, medially and behind it

27

major source of blood to extra-cranial structures?

external carotid artery

28

where are the superficial cervical LNs situated?

along the course of the EJV

29

LNs in regional group of head and neck?

occipital, retroauricular, submandibular, submental, anterior, cervical, superficial cervical, retropharyngeal, laryngeal and tracheal

30

give examples of 2 deep (terminal) cervical LNs, and what they drain?

jugulo-digastric: located just below and behind angle of mandible, drains tongue and tonsil

jugulo-omohyoid: drainage of tongue, oral cavity, trachea, oesophagus, and thyroid gland

31

what do the efferent lymph vessels from deep cervical nodes join to form?

the jugular lymph trunks

32

what do the jugular lymph trunks join with on the L side?

throacic duct, which enters the L brachiocephalic vein at junction of subclavian and internal jugular vein

33

what do the jugular lymph trunks join with on the R side?

enters venous system at junction between subclavian and IJV via a short right lymphatic duct

34

What does a surgeon do when cervical metastases occur?

performs a block dissection of cervical nodes, removing en bloc the IJV, fascia, LNs and submandibular salivary gland.
Aim to remove all lymph tissues on affected side of enck

35

where is the carotid body located in relation to the division of the common carotid artery?

just posterior to it

36

how specifically can the common carotid artery pulse be felt?

by pressing against the anterior tubercle of transverse process of C6 vertebra.
Also at point of division of artery- vertebral level C4- upper border of thyroid cartilage

Can be felt just medial to SCM

37

why must carotid artery palpation be performed low in neck?

to avoid pressure on carotid sinus which could cause a reflex drop in heart rate and blood pressure

38

Why is the right IJV evaluated rather than the left?

the right is straighter

39

why are pulsations of IJV visible?

transmitted through surrounding tissue

40

worry if sudden occurrence of a stiff neck, with fever and headache?

meningtitis

41

what might neck pain be associated with because of referred pain?

MI or angina, as referred pain from chest

42

muscles derived from first pharyngeal arch?

muscles of mastication- temporalis, masseter, medial and lateral pterygoids
mylohyoid
anterior belly of digastrics
tensor tympani
tensor veli palatine

43

cranial nerve of first pharyngeal arch?

trigeminal (V)- maxillary and mandibular divisions
mandibular branch supplies muscles of arch
principal sensory nerve of head- skin of face, and lining of mouth and nose
motor to muscles of mastication and those derived from mandibular process

44

cranial nerve of second pharyngeal arch?

facial nerve (VII)

45

what does facial nerve pass through?

stylomastoid foramen and parotid gland
supplies muscles of facial expression, and those derived from 2nd pharyngeal arch

46

small sensory component of facial nerve?

taste buds in anterior 2/3 of tongue

47

why might thyroid surgery result in vocal cord paralysis?

damage to recurrent laryngeal nerves

48

name of oblique plane where curvature of aorta starts and ends?

transverse thoracic plane

49

clinical importance of jugulo-omohyoid internal jugular LN which lies above the omohyoid muscle?

can be enlarged in oral cancer

50

why might a patient have difficulty turning their head and shrugging their shoulders if they have had their spinal accessory nodes (part of deep group) removed?

these nodes lie in the posterior triangle of the neck, along course of accessory nerve, and removal due to malignancy may damage the accessory nerve , causing weakness in SCM and trapezius

51

examples of deep cervical LNs?

internal jugular
spinal accessory
supraclavicular

52

where does the thoracic duct arise?

from cisterna chyli in the abdomen at L2, ascends through aortic hiatus at T12 in diaphragm, crosses midline at T5 to the left, post to oesophagus and ascends into superior medistinum

53

where does thoracic duct empty into venous system?

at left venous angle- where union of left internal jugular and subclavian veins
may enter origin of left brachiocepahlic vein
or may empty directly into left subclavian vein

54

how are the pharyngeal clefts and pouches separated?

branchial (pharyngeal) membrane- thin sheet of ectoderm on outside, and endoderm on inside

55

how may branchial cysts in the neck be formed?

A flap of tissue from the second pharyngeal arch grows down to cover the third to sixth arches and clefts, obliterating all other clefts except 1st, creating a space, the Cervical Sinus. This is normally obliterated, but remnants of clefts may persist as branchial cysts in the neck if it is not.

can occur anywhere along A border of SCM- path taken by 2nd pharyngeal arch

56

cranial nerves innervating pharyngeal arches?

CN V, VII, IX and X

57

muscles of 2nd pharyngeal arch?

muscles of facial expression
poster. belly of digastrics
stylohyoid
stapedius

58

nerve of 3rd pharyngeal arch?

glossopharyngeal

59

muscle of 3rd pharyngeal arch?

stylopharyngeus

60

nerve of 4th to 6th pharyngeal arches?

vagus: superior laryngeal to 4th, recurrent laryngeal to 6th

61

muscles of 4th pharyngeal arch?

cricothyroid, levator palatini, constrictors of pharynx

62

muscles of 6th pharyngeal arch?

intrinsic muscles of larynx

63

general and special sensory innervation of glossopharyngeal nerve?

posterior 1/3 of tongue

64

what cells are the skeletal elements of the head and neck derived from?

neural crest cells

65

name of 1st pharyngeal arch cartilage?

Meckel's cartilage

66

derivatives of 1st pharyngeal arch cartilage?

malleus and incus- middle ear bones
sphenomandibular ligament
template for mandible which forms by intramemebranous ossification, so cartilage not converted into bone

67

2nd pharyngeal arch cartilage?

Reichert's cartilage

68

skeletal element derivatives of 2nd pharyngeal arch?

stapes- bones of middle ear
styloid process of temporal bone
stylohyoid ligament
lesser cornu and upper body of hyoid

69

skeletal element derivative of 3rd pharyngeal arch?

greater cornu and part of body of hyoid

70

skeletal element derivatives of 4th and 6th pharyngeal arch catilages?

thyroid, arytenoid and cricoid cartilages of larynx

71

what is the epiglottis derived from?

4th and 6th pharyngeal arch mesenchyme from the pharyngeal floor

72

what provides arterial supply to pharyngeal arches?

aortic arches

73

3rd aortic arch artery?

internal carotid

74

4th aortic arch arteries?

arch of aorta on left, brachiocephalic artery on right

75

6th aortic arch artery?

pulmonary arch
On R, distal part of 6th aortic arch and 5th disappear, so R recurrent laryngeal nerve moves up and hooks around R subclavian vein
L nerve does not move up as distal part of 6th aortic arch persists as ductus arteriosus

76

derivative of 2nd pharyngeal pouch?

palatine tonsils- 2nd pouch epithelial proliferation, followed by colonisation by lymphoid precursors

77

what are the parathyroid glands derived from?

the 3rd (forms inferior) and 4th (forms superior) dorsal pharyngeal pouches

78

what is the thymus gland derived from?

the 3rd ventral pharyngeal pouch

79

1st pharyngeal pouch derivatives?

tympanic cavity and eustachian tube

remember, ossicles= 1st and 2nd arch cartilage bar derivatives

80

outcome of 1st pharyngeal cleft?

external acoustic meatus

81

how are the eyes shifted from sides of head to front?

growth of maxillary prominences towards midline

82

what are the tympanic cavity and eustacian tube of middle ear derived from?

1st pharyngeal pouch

83

how is the facial vein connected to the cavernous sinus?

via the superior opthalmic vein

84

importance of facial vein being valveless?

infection of face can spread to involve venous sinuses, as facial vein connected to cavernous sinus

85

veins which form the external jugular vein?

union of posterior auricular and retromandibular (posterior branch) veins

86

what are the layers of the scalp?

SCALP:skin, CT-vessels and nerve, aponerurosis-epicranial between occipital and frontalis muscles, LCT, periosteum (pericranium)