Neck Anatomy 1.5

Question 1

What does the trigeminal nerve do?

Answer 1

• carrying sensation from its frontal division and its lacrimal division
• lacrimal part of the nerve also receives some fibres which supply the lacrimal gland

Question 2

What is a branch of the ophthalmic division of the trigeminal nerve?

Answer 2

nasociliary branch of the ophthalmic division of the trigeminal nerve

Question 3

What is the ciliary ganglion?

Answer 3

an autonomic ganglion of the third or ocular motor nerve through which autonomic parasympathetic fibers get to the eye itself and serve functions such as changing the diameter of the pupil, and changing the thickness of the lens

Question 4

What is the cavernous sinus?

Answer 4

-an important structure, as it contains many structures passing through it, and it’s clinically relevant because of the spread of infection through this to the cranial cavity from for example injuries to the face.

Question 5

What is the cavernous sinus?

Answer 5

• The cavernous sinus receives blood not only from cerebral veins, but also from ophthalmic veins, and these connections between the external world and the cranial cavity, provide a route for infection to pass from outside to within the cranial cavity.
• Also because structures passing through the cavernous sinus passing the walls, they are vulnerable to both traumatic injury and inflammation.

Question 6

What is the lacrimal system?

Answer 6

This is a system involved in the production, movement and drainage of fluid from the surface of the eye

Question 7

Where is the lacrimal gland?

Answer 7

-The lacrimal gland is located in the supra lateral quadrant of the orbit here, and fluid is drained medially by apparatus located here. The lacrimal system, is made up of the lacrimal gland and its ducts, the lacrimal sac, and the nasolacrimal duct, which empties into the nasal cavity

Question 8

How is the lacrimal glad controlled?

Answer 8

receives parasympathetic secretor motor fibers via the cranial nerve number 7, the facial nerve

Question 9

How does excess fluid drains into he nasal cavity?

Answer 9

Via the nasolacrimal duct

Question 10

What are the nasal cavities?

Answer 10

two wedge-shaped cavities that are the uppermost part of the respiratory tract

Question 11

How are the nasal cavities separated?

Answer 11

by a midline septum and from the oral cavity below by the hard palate, and from the cranial cavity above, by parts of a number of bones including the frontal, ethmoidal and sphenoid bone

Question 12

What cranial nerves innervate the nasal cavities?

Answer 12

1. the olfactory nerve, cranial nerve number one for olfaction, the sense of smell,
2. the trigeminal nerve, cranial nerve number five which provides general sensation to the nasal cavity via the ophthalmic division v1 for the more anterior region of the nasal cavities, and the maxillary division of the trigeminal nerve, v2 for the more posterior regions of the nasal cavity.
3. The facial nerve supplies parasympathetic fibers to the glans of the nasal cavities.

Question 13

What supplies the vascular smooth muscle of the nasal cavities?

Answer 13

there are sympathetic fibers from the t1 spinal level of the spinal cord

Question 14

What does the rich blood supply in the nasal cavities help with?

Answer 14

aid in humidifying and changing the temperature of the respired air

Question 15

What is the arterial supply like to the nasal cavities?

Answer 15

via the internal carotid artery, and branches of the external carotid artery

Question 16

What are some issues with the arterial supply to the nasal cavities?

Answer 16

1. There is a great degree of anastomoses between the arteries supplying the nasal cavities, hence it is susceptible to nosebleeds or epistaxis.
2. Additionally, there is a risk of infection being taken from the nasal cavity, into the cranial cavity.
3. This is because some of the blood vessels which drain the nasal cavity, pass through the cavernous sinus as mentioned, and into the cranial cavity, as shown here.

Question 17

How many paranasal sinuses are in the skull? How are they named?

Answer 17

4 and named by the bones in which they are sounds

Question 18

What are the four paranasal sinuses?

Answer 18

1. Frontal sinuses
2. The ethmoidal air cells
3. The sphenoid sinuses
4. Maxillary sinuses

Question 19

What do the paranasal sinuses do?

Answer 19

1. They help reduce the weight of the skull and they also act as crumple zones in the case of facial trauma.
2. They also help to increase the resonance of the voice and humidifying and heating inhaled air.
3. They’re mucous secreting sinuses they’re clinically relevant as they can also become infected.

Question 20

How does the sinuses receive sensory innervation?

Answer 20

innervation by way of branches of the trigeminal nerve

Question 21

Where do the frontal sinuses receive innervation?

Answer 21

V1 or ophthalmic division

Question 22

Where do the ethmoid air cells receive sensory innervation?

Answer 22

via the ophthalmic and maxillary divisions

Question 23

Where do the sphenoid sinuses receive sensory innervation?

Answer 23

via opthalamic and maxillary

Question 24

Where do the maxillary sinuses receive sensory innervation?

Answer 24

second division of trigeminal nerve, the maxillary sinus

Question 25

Where does the sphenoid sinus drain?

Answer 25

• We can see at the top here, this is the sphenoid sinus, in the sphenoidal bone.
• This drains into this sphenoidal recess, superior to the superior concha.

Question 26

What is inferior to the sphenoid sinus and inferior to the superior concha?

Answer 26

• the opening of the ethmoidal cells into the lateral wall of the superior meatus
• Inferior to this, is the opening of the ethmoidal cells
• Anterior to that is the opening or drainage point of the frontal sinus, and the anterior ethmoidal cells.
• Inferior to this, is the opening of the maxillary sinus, in the floor of this half-moon shaped or semilunar hiatus.

Question 27

What is under the inferior concha?

Answer 27

Opening of the nasolacirmal duct

Question 28

What happens in the nasolacrimal duct?

Answer 28

Where excess fluid from lacrimal system is drained

Question 29

What is posterior to the opening of the nasolacrimal duct?

Answer 29

opening of the fringo tympanic tube.

Question 30

What is the oracle?

Answer 30

-We can see the oracle on the outside which has this rim called the helix, and the centre is known as the concha.

Question 31

What is anterior to the canal?

Answer 31

-There’s a flap of cartilage anterior to the canal, known as the tragus and here is the opening of the external acoustic meatus

Question 32

What is the purpose of the external ear?

Answer 32

to transmit sound towards the tympanic membrane or the eardrum

Question 33

What is the tympanic membrane?

Answer 33

has small ossicles or bones attached to it, which transmits sound into the inner ear

Question 34

What is the inner ear?

Answer 34

-The inner ear, or internal part of the ear is where the sense organ for both hearing, the cochlea and balanced, the semicircular canals are located

Question 35

What are the associated nerves with the ear?

Answer 35

• The associated nerves, which are the vestibulocochlear nerve which take respectively, signals relating to balance and orientation from the vestibular system, that’s the vestibular part of the eighth nerve, and the hearing part of the eighth nerve, the cochlear part is bringing information about sound
• Additionally running and closely associated with the ear, is the facial nerve which runs through the middle ear

Question 36

What is middle ear continuous with?

Answer 36

an opening into the nasal cavity, the fringo tympanic tube

Question 37

What is the fringe typanic tube?

Answer 37

equalises the pressure between the middle ear and the atmosphere, and this often is apparent when landing in an aeroplane, pressure is equalised by chewing or swallowing, for example

Question 38

What does the facial nerve do?

Answer 38

• It is a very large nerve which supplies all of the muscles of facial expression, but additionally supplies a very small muscle in the ear stapedius, and also a muscle mentioned previously the digastric muscle
• It also supplies a small muscle called stylohyoid.

Question 39

What is the sensory component of the facial nerve?

Answer 39

• It has a sensory component, which is smaller, which supplies fibers that give rise to the sensation of taste from the anterior two-thirds of the tongue, contains parasympathetic fibers which go to the lacrimal glands and the mucous glands of the nasal cavity and hard and soft palates, and the saliva glands the sublingual and submandibular glands
• It also provides some general sensation from the external acoustic meatus, the ear canal and deeper parts of the auricle.

Question 40

Where does the facial nerve emerge from?

Answer 40

• stylomastoid foramen, and here is a very small branch which is carrying information about taste from the anterior two thirds of the tongue
• Here is this very small branch, that is supplying motor fibers to the stapedius muscle, and here we can see the nerve traversing through and emerging through the internal acoustic meatus, in the temporal bone