The external nose

Question 1

what is the external nose?

Answer 1

a visible component of the face, projecting over and allowing entrance into the nasal cavity

Question 2

shape of external nose?

Answer 2

pyramidal shape

Question 3

what is located superiorly on the external nose?

Answer 3

nasal root - continuous with the forehead

Question 4

apex of external nose?

Answer 4

nose ends inferiorly in a rounded ‘tip’

Question 5

between root and apex of external nose?

Answer 5

dorsum of the nose

Question 6

where are nares located?

Answer 6

immediately inferiorly to the apex are the nares

Question 7

what are nares of the nose?

Answer 7

piriform openings into the vestibule of the nasal cavity

Question 8

what are nares bounded by medially and laterally?

Answer 8

medially: nasal septum
laterally: the ala nasi (the lateral cartilaginous wings of the nose)

Question 9

what is the skeleton of the external nose composed of?

Answer 9

both bony and cartilaginous components

Question 10

bony component of external nose?

Answer 10

located superiorly

comprised of contributions from the nasal bones, maxillae and frontal bone

Question 11

cartilaginous component of external nose?

Answer 11

located inferiorly

comprised of the two lateral cartilages, two alar cartilages and one septal cartilage

Question 12

skin overlying nose?

Answer 12

skin over the bony part of the nose is thin

skin overlying the cartilaginous part is thicker with many sebaceous glands

Question 13

where does skin overlying nose extend?

Answer 13

extends INTO the vestibule of the nose via the nares

there are hairs which function to filter air as it enters the respiratory system

Question 14

what can trauma to the external nose result in?

Answer 14

saddle nose deformity

Question 15

what happens in saddle nose deformity?

Answer 15

septal support to the nose is lost

middle part of nose appears sunken

Question 16

what is saddle nose deformity a result of?

Answer 16

direct damage to septal bone / cartilage
OR
consequence of nasal septal haematoma

Question 17

how does saddle nose deformity result from nasal septal haematoma?

Answer 17

cartilage has no blood supply of its own, relies on oxygen and nutrients diffusing from blood vessels in surrounding perichondrium
haematoma between cartilage and perichondrium can result in destruction of septum - therefore deformity

Question 18

where does the skin of the external nose receive its arterial supply from?

Answer 18

branches of the maxillary (V2) and ophthalmic (V1) arteries

Question 19

where else does the septum and alar cartilages receive additional blood supply from?

Answer 19

the angular artery and lateral nasal artery

Question 20

what are angular artery and lateral nasal artery branches of?

Answer 20

the facial artery (derived from the external carotid artery)

Question 21

where does venous drainage of the nose drain into?

Answer 21

into the facial vein, and then in turn into the internal jugular vein

Question 22

Lymphatic drainage from the external nose is via?

Answer 22

superficial lymphatic vessels accompanying the facial vein

Question 23

where do superficial lymphatic vessels accompanying the facial vein drain into?

Answer 23

like all lymphatic vessels of the head and neck, ultimately drain into the deep cervical lymph nodes

Question 24

how is the venous drainage of the nose and surrounding area unique?

Answer 24

result of communication between facial vein and cavernous sinus, via the (superior + inferior) OPHTHALMIC vein
(medial angle of eye)

Question 25

where does the cavernous sinus lie?

Answer 25

within cranial cavity

small area either side lateral to forebrain

Question 26

what does communication between facial veins –> ophthalmic veins to cavernous sinus enable?

Answer 26

infections from the nasal area to spread to the brain

Question 27

what can retrograde spread of infection from the nasal area cause?

Answer 27

cavernous sinus thrombosis,
meningitis,
brain abscess

Question 28

where is Sensory innervation of the external nose derived from?

Answer 28

the trigeminal nerve (CN V)

Question 29

what is the external nasal nerve a branch of?

Answer 29

the ophthalmic nerve (CN V1)

Question 30

what does the external nasal nerve (V1) supply?

Answer 30

the skin of the dorsum of nose, nasal alae and nasal vestibule

Question 31

what supplies the lateral aspects of the nose?

Answer 31

infrorbital nerve, a branch of the maxillary nerve (CN V2)

Question 32

what is the motor innervation to the nasal muscles of facial expression?

Answer 32

via the facial nerve (CN VII)