Head And Neck

Question 1

What is the name of the continuation of the frontal bone and the nasal bone and the articulation of the nasal bone and the maxilla

Answer 1

The Nasion is the connection between the frontal bone and the nasal bone, it is bounded laterally on both ends by the maxilla(bones of the midface)

Question 2

The floor of the orbit consists of which bone of the skul

Answer 2

The maxilla

Question 3

What are the 3 emergence of the Trigeminal nerve of the skull

Answer 3

V1- Supraorbital foramen

V2- Infra-orbital foramen

V3- Mental Foramen

Question 4

What does the anterior inferior part of the skull consists of?

Answer 4

It mainly consists of the Hard Palate of the Maxilla anterior and the Hard palate of the palatine bone posteriorly with the cruxiform suture there are some features of this, and this includes the incisive fossa which forms a connection between the hard palate and the nasal cavities.

• between the palatine bone there is a medial and lateral plate of the pterygoid process which forms the connection to the palatine canals. The lesser palatine foramen also is part of the pyramidal process of the palatine bone which forms the lesser palatine foramen

Question 5

What is the Vomer of the skull

Answer 5

A bone that is placed in the anterior part of the middle part of the skull. It contributes to the boney part of the nasal septum

Question 6

What bones do the sphenoid bones articulate with anteriorly and posteriorlaterally and inferiorly. Discuss the superior surface of the sphenoid bones

Answer 6

The sphenoid bones articulate with the

• volmer
• ethmoid
• palatine bones

posteriolaterally
- temporal bones

inferiorly
-occipital

The sphenoid bones superiorly contain the sella turcica this consists of

• Tuberculum sellae – forms the anterior wall of the sella turcica, and the posterior aspect of the chiasmatic groove.
• Hypophyseal fossa – the deepest part of the sella turcica, where the pituitary gland is located.
• Dorsum sellae – forms the posterior wall of the sella turcica.

-Chiasmatic groove – a sulcus formed by the optic chiasm (where the optic nerves partially cross).

Question 7

What foramens are present in the greater wing of the sphenoid process

Answer 7

• Foramen Rotundum- maxillary nerve (V2)
• Foramen Ovale- mandibular nerve(V3)
• Foramen Spinosum- middle meningeal arteries

Question 8

what is the course of the Tensor veli pelatinii muscle and it’s function

Answer 8

The humulus is the hook of the medial part of the pterygoid process and it runs across this muscle.

Superior to this there is a shallow depression known as the scaphoid fossa for the attachment of the tensor veli pelatinii

Question 9

What structures pass through the foramen lacerum

Answer 9

i. artery of the pterogoid canal
ii. recurrent artery of the foramen lacerum
iii. nerve of pterygoid canal
iv. greater petrosal nerve/deep petrosal nerve
v. ascending pharyngeal artery

Question 10

What are the functions of the foramen cecum?

Answer 10

They allow emmisary veins to connect to the nasal cavity and the superior saggital sinus

Question 11

What is the inferior petrosal sinus

Answer 11

It forms part of the dural venous sinus and it is found on the pterous part of the temporal bone

Question 11

What is the inferior petrosal sinus

Answer 11

It forms part of the dural venous sinus and it is found on the pterous part of the temporal bone

Question 12

What structures pass the internal acoustic meatus

Answer 12

Cranial Nerve VII

Cranial Nerve VIII

Labryntine artery

Question 12

What structures pass the internal acoustic meatus

Answer 12

Cranial Nerve VII

Cranial Nerve VIII

Labryntine artery

Question 13

What structures pass the pars nervosa

Answer 13

Cranial nerve IX

Cranial Nerve X

Cranial Nerve XI

Question 14

What nerve passes through the hiatus of the temporal muscles of the middle cranial fossa

Answer 14

The nerve of the greater petrosal nerve which is a branch of CN IX(Glossopharyngeal nerve). They bring in pre-ganglionic fibres that pierce through the petrous bone. moves anterior-medially to exit via the

Question 15

What are the contents of the superior orbital fissure

Answer 15

Superior Opthalmic vein

The branches of the opthalmic nerve of the trigeminal nerve

• Frontal branch
• Lacrimal branch
• Nasociliairy branch

Superior Branch of Occulomotor(III)
Inferior Branch of Occulomotor(III)
Trochlear nerve(IV)
Abducens nerve(VI)

Question 16

What is the artery supplying the orbital area and it’s branches

Question 17

What is the course of the occulomotor nerve and it’s branches

Answer 17

originates from along the edge of the midbrain and the pons and goes via the interpeduncular fossa in the interior surface of the brainstem.

It goes through the roof of the carvernous sinus the only nerve that does this.
- it moves anteriorly into the orbit and when it enters it splits

• superior
  provides motor innervation to the superior rectus and levator palpabrae superioris.
  Superior rectus – elevates the eyeball
  Levator palpabrae superioris – raises the upper eyelid.

-inferiorly
3 branches
Inferior rectus branch – depresses the eyeball
Medial rectus branch – adducts the eyeball
Inferior oblique branch – elevates, abducts and laterally rotates the eyeball

it also provides pre-ganglionic fibres in the ciliary branch to form the short ciliary nerves
Sphincter pupillae – constricts the pupil, reducing the amount of light entering the eye.
Ciliary muscles – contracts, causes the lens to become more spherical, and thus more adapted to short range vision.

Question 18

What constitutes the carvernous sinus

Answer 18

• Superior middle cerebral vein
• Superior and inferior ophthalmic veins
• Sphenoparietal sinus

Question 19

What is the course of the Trochlear Nerve

Answer 19

The trochlear nerve is the only nerve that originates from the posterior part of the brain @ the midbrain.
It runs anterior-posteriorly in the Subarachnoid space before piercing the dura adjacent the posterior cliniod process of the sphenoid bone.
it follows the cavernous sinus into the superior orbital fissure and enters the orbit via the superior saggital fossa

it supplies the contralateral as it crosses before leaving the midbrain
-superior oblique- that allows depression and inwards looking

Question 20

What is the course of the Abducens Nerve?

Answer 20

The abducens nerve arises from the abducens nucleus in the pons of the brainstem. It exits the brainstem at the junction of the pons and the medulla.

It then enters the subarachnoid space and pierces the dura mater to travel in an area known as Dorello’s canal.

At the tip of petrous temporal bone, the abducens nerve leaves Dorello’s canal and enters the cavernous sinus (a dural venous sinus). It travels through the cavernous sinus and enters the bony orbit via the superior orbital fissure.

• it supplies the lateral rectus muslce

Question 21

What is the course of the trigeminal nerve

Answer 21

The trigeminal nerve starts from the 3 sensory nuclei & one motor nucleus. from the level of the midbrain to the medulla.
in the middle cranial fossa, the sensory and motor roots meet to form a ganglion near the cavernous sinus to form the trigeminal ganglion. this is near a fossa near the temporal bone called the trigeminal cave.

-the ganglion then splits into 3 branches

V1 opthalmic
enters the orbit via the superior orbital fissure
it then gives rise to 3 branches

1.nasolacrimal
- smallest branch of the opthalmic nerve
in the orbit passes ant. to lateral rectus muscle and
-Post ganglionic fibres from the pterygopalatine ganglion (derived from the facial nerve), travel with the zygomatic branch of V2 and then join the lacrimal branch of V1. The fibres supply parasympathetic innervation to the lacrimal gland and lateral part of upper eyelid

2.nasociliary
- it passes between the sup and inf. branches of CN3 thus lies within tendon on zin
- in the orbit, it crosses the superior surf of optic nerve medially below the sup. rectus muscles
gives
1. sensory root to ciliary ganglion- early in its path
2.between sup. oblique and medial rectus giving off a few branches
- long ciliary = sensory to eyeball and may have sympathetic nerves for papillary dilation
- post. ethmoidal nerve- exits via posterior ethmoidal foramen to supply sphenoidal sinus and ethmoidal air cells.
-infratrochlear nerve= upper and lower eyelids lacrimal sac and skin on upper half of nose
-anterior ethmoidal nerve= exits via ant. ethmoidal foramen ant. cranial fossa and skin of lower half of the nose

3. frontal
   - runs anterior to roof of orbit and levator palpebrae superioris; it then branches into terminal branches
   i. supra orbital nerve- exits the orbit via supraorbital foramen to the foreheads and scalp to upper eyes to the vertexii.

supratrochlear nerve more medial and passes trochlear and

• maxillary
  enters the foramen rotundum
• mandibular(only one with motor innervation)
  enters via the foraman ovale

Question 22

Discuss the phrenic nerve

Answer 22

ant surface of scalenius ant. muscle, and surrounded by prevertabral fascia and the great vessels and passes in between subclavian artery and vein into thorax

Question 23

Discuss the course of the recurrent larygneal nerve

Answer 23

Right comes from R) vagus
at the it reaches bottom part of subclavian artery it passes around it and moves upwards and medially around the groove between the ltrechea and the eosophagus and passes into the larynx

Left recurrent branch from L) vagus
- runs initially lateral/anterior to aortic arch and then moves underneath the aortic arch and medially into the groove of the between the trachea and oesophagus into the larynx

Question 24

discuss the sympathethic trunk of the cervical system

Answer 24

consists of the cervical part of the sympathethic trunk
- lies ant to longus coli and longus capitus muscle and behind the common carotid artery in the carotid sheath

• superior cervical ganglion
• around C1/C2 and fibres go to internal and external cartoid arteries to form a plexus
• forms the sup. cardiac nerves
• middle cervical ganglion
  found around c3/c4
  goes to cervical spinal nerves around C5/C6 through the grey rami communicantes and to the heart as the middle cardiac nerve
• inferior cervical ganglion
• can become very large when joins with T1 to form stellate ganglion
• found around transverse process of C7
• becomes a plexus when it forms with the vertebral artery
• can go to the heart to form inferior cardiac nerves

Question 25

contents and boundaries of the anterior triangle

Answer 25

triangle in the front of the neck
inferior to inferior border of the submandibular

boundaries
anterior border of SCM(laterally)
inferior border of mandible(superior)
midline of the neck(medial)

4 subdivisions

1. submandibular triangle
   - superior by the mandible
   - lateral and medially by the ant and post. digastric muscles
   contents:
2. Submental triangle
   - anterior belly of digastric
   - hyoid bone inferiorly
   -midline of the jaw
   contents:
3. Carotid triangle
   - superior belly of omyhyoid
   - stylohyoid and post digastric
   - medial border of SCM
   contents:
4. Muscular triangle
   -hyoid superiorly
   -Medial border of SCM
   - superior belly of omohyoid
   contents:

Question 26

what are the suprahyoid muscle

Answer 26

1. stylohyoid muscles
   - base of styloid process comes anterior-inferior to attach to lateral hyoid bone
   (innervated by CN7)
   - digastric muscle has 2 bellies
   anterior and posterior
   i.posterior attaches to mastoid process and comes from digastric fossa on the inside of the inferior border of mandible and is innervated by CN7.
   ii.anterior belly is supplied by the trigeminal nerve by the mandibular branch as it does not enter the inferior alveolar canal and goes downwards to supply mylohyoid and ant. belly
2. Mylohyoid muscles
   - originates on medial surface of mandible and inserts into hyoid bones
   - connects with contralateral mylohyoid muscles via the ruffae(?) innervated by trigeminal nerve
3. genuhyoid muscle
   - deep to mylohyoid muscle
   - starts from inferior mentle spine of the mandible and runs backwards and downwards and inserts into body of hyoid bone.
   - supplied by ant ramus of C1 by way of CN12

Question 27

what are the infrahyoid muscles

Answer 27

1. sternohyoid muscle

2.

3.

4.

Question 28

At what level does the vertebral artery enter the foramina of the neck

Answer 28

C6

Question 28

At what level does the vertebral artery enter the foramina of the neck

Answer 28

C6

Question 29

What are the branches of the subclavian artery

Answer 29

1. Vertebral Arteries
   - enters at the level of C6 and moves upwards and terminates at C1 where it joins with the contralateral side at the posterior arch and joins and goes up the foramen magnum and becomes basilar artery @ the pons
2. Thyrocervical branch
   - inferior thyroid branch
   superior to thyrocervical branch and supplies the thyroid
   ascending cervical artery and goes up the anterior pre-vertebral muscles

-transverse cervical
crosses anterior to ant. scalen muscles and goes around the phrenic nerve to get into post triangle of the neck
i. superficial
ii. deep

• suprascapular arteries
  runs anterior to the ant. scalene muscles and holds the phrenic nerve and goes into post. triangle of the neck
• enters supraspinatus fossa

3. internal thoracic artery
   - passes post. to clavicle and ant to pleural cavity
4. costocervical trunk
   - R) side comes from 2nd part of subclavian artery
   - L) side from the 1st part of subclavian artery
   - runs up and backwards
5. supreme intercostal artery
6. deep cervical artery
   - runs up and in the back of the neck and anastomose with the descending branch of occipital artery

Question 30

the cervical plexus is made up of nerve roots C1-4 what muscular branches does the ansa cervicalis innervate

Answer 30

I.Superior belly of the omohyoid muscle
II.Inferior belly of omohyoid muscle
III.Sternohyoid
IV.Sternothyroid

Question 31

what is the 5 Nerves that supply the anterior triangle of the neck

Answer 31

1. Facial nerve
   -emerges at stylomastoid foramen
   isupplies post. belly of digastric
   ii stylohyoid
   iii.platysma muscle
2. Glossopharyngeal
   - leaves the jugular foramen and descends via the internal jugular vein and internal carotid artery
   - continues into internal and external carotid arteries and curves into lateral border of the stylopharyngeus muscles and continues deep to the hypoglossal muscles into the tongue.
   - sensory branch to the carotid sinus & pharynx

3.Vagus
also exits via jugular foramen in between glossopharyngeal and accessory nerve
-descends the neck medial to IJV and post to internal carotid and common carotid sheath.
- gives motor branch to the pharynx
- superior laryngeal nerve
-cardiac branch
4.Accessory
- most posterior nerve leaving via jugular foramen
-medial to internal jugular vein and merges at the point of passing the IJV and common carotid artery and crosses the lateral surface @ IJV and goes under the cover of SCM muscle.

5. Hypoglossal nerve
   exits via hypoglossal canal medial to IJV and Internal carotid artery

Question 32

What is the 3 parts of the pharynx

Answer 32

1. nasopharynx
2. oropharynx
3. laryngopharynx

Question 32

What is the 3 parts of the pharynx

Answer 32

1. nasopharynx
2. oropharynx
3. laryngopharynx

Question 33

what is the attachment of the pharynx

Answer 33

anteriorly: post. margin of the medial plate of the pterygoid process of sphenoid bone

starts off at the medial part of the pterygoid plate jumping over the auditory tube and runs down the pterygoid plate until the hamulus

Question 33

what is the attachment of the pharynx

Answer 33

anteriorly: post. margin of the medial plate of the pterygoid process of sphenoid bone

starts off at the medial part of the pterygoid plate jumping over the auditory tube and runs down the pterygoid plate until the hamulus

Question 34

what are the 4 constituents of the superior constrictor muscles

Answer 34

1. superior constrictor
   i. Pterygopharyngeal part
   - originates from the pterygoid hamulus of sphenoid bone
   ii. Buccopharyngeal part
   - originates from the pterygomandibular raphe of buccopharyngeal fascia
   iii. Mylopharyngeal part
   - originates from the mylohyoid line of the mandible
   iv. Glossopharyngeal part
   - originates from the tongue

fans backwards

these will then join to form the superiorlateral pharynx @ the pharyngeal raphe

Question 35

what are the 3 branches of the 1st part of the subclavian artery

Answer 35

1. Thyrocervical branch
2. Internal thoracic branch
3. vertebral branch

Question 36

What are the branches of the 2nd and 3rd part of the subclavian artery

Answer 36

2nd part: costocervical trunk

i. inferior thyroid artery
ii. transverse cervical
iii. superior intercostal arteries

3rd part: dorsal scapular artery

Question 36

What are the branches of the 2nd and 3rd part of the subclavian artery

Answer 36

2nd part: costocervical trunk

i. inferior thyroid artery
ii. transverse cervical
iii. superior intercostal arteries

3rd part: dorsal scapular artery

Question 37

What are the branches of the external carotid artery?

Answer 37

1. Superior thyroid
   - Supplies thyroid gland, larynx, and infrahyoid muscles
2. Ascending pharyngeal
   - Supplies pharyngeal region, middle ear, meninges, and prevertebral muscles
3. Lingual
   - Passes deep to hyoglossus muscle to supply the tongue
4. Facial
   - Courses over the mandible and supplies the face
5. Occipital
   - Supplies SCM and anastomoses with costocervical trunk
6. Posterior auricular
   - Supplies region posterior to ear
7. Maxillary
   - Passes into infratemporal fossa
8. Superficial temporal
   - Supplies face, temporalis muscle, and lateral scalp

Question 38

What are the relations of the thyroid gland

Answer 38

The thyroid gland consists of a pear shaped bilobed structure with an isthmus in the middle, it is surrounded by paratracheal fascia. It is present on the 2,3,4 of the tracheal rings.

It has 3 surfaces:

lateral: under cover of sternothyroid and sternohyoid
medial: lateral side of the larync and tachea, lower pharynx and oseophagus. cricothyroid muscle and inferior constrictor of the pharynx
posterior: medial partof the carotid sheath.

blood supply of the thyroid:

i. Inferior thyroid artery: from a branch thyrocervical branch which is a branch of the 1st part of the subclavian artery.
- Arches upwards and medially behind carotid sheath, then loops downward to lower pole. divides outside the pretrecheal fascia to the lower pole.
- R) Recurrent Laryngeal nerve has a variable relationship with this artery BUT, always BEHIND the pretracheal fascia
- may give ascending cervical branches

ii. Superior thyroid artery: 1st branch of the External carotid artery
- pierces the pretracheal fascia as a single vessel to supply upper pole. May give off a SCM or laryngeal branch prior to piercing fascia. Then splits into
a) Anterior branch: into isthmus
b) Posterior branch: Runs back of the lobe and anastomose with ascending branch on inferior thyroid
- External laryngeal nerve is posterior to this

iii. Thyroidea ima artery from the brachiocephalic trunk or R) common carotid artery and is present in 3% of individuals.

Venous return:

i. Superior thyroid vein-> IJV or Facial Vein
ii. Middle thyroid vein-> IJV
iii. Inf. thyroid vein-> L) Brachiocephalic

Nerve supply:
i. Recurrent laryngeal nerve from the vagus nerve below will then approach the gland from below, it is in front of the groove between the trachea and oesophagus usually L) nerve is behind the inf. thyroid artery. while on right equal chance Nerve is ALWAYS behind pretrecheal fascia, and BEHIND the cricothyroid joint. @ sup isthmus, often divides into 2, ant. branch larger and has motor control

ii. External laryngeal nerve runs down to supply cicothyroid and lies behind the sup. thyroid artery passing medial to upper pole.

Lymph node:
Superior pole: deep cervical lymph nodes
Inferior pole: posterioinferior group of cervical lymph nodes/ pretracheal nodes.

Question 39

Describe the parathyroid gland

Answer 39

The parathyroid gland consists of usually 4 lobes 2 superiorly and 2 inferiorly. lies either within the thyroid capsule or in prevertebral fascia. superior lobes more consistent is location @ the back of the thyroid lobe above the inferior thyroid artery. inferior lobe more variable, usually behind lower pole below inferior thyroid artery & lat. to recurrent laryngeal nerv. unable to find, try to follow branches of the inferior thyroid artery upwards and downwards as that is its blood supply

blood supply:
i. inferior thyroid artery

nerve supply: sympathetic vasocontrictors

Question 40

What are the branches of the external carotid artery

Answer 40

usually bifurcates from the common carotid artery into external and internal artery at the level of C4.
has 6 branches and two terminal branches

3 anterior

i. superior thyroid
ii. lingual
iii. facial

2 posterior

iv. Posterior auricular
v. Occipital

1 Medial
vi. Ascending pharyngeal

2 Terminal:

i. Superficial Temporal
ii. Maxillary

Question 40

What are the branches of the external carotid artery

Answer 40

usually bifurcates from the common carotid artery into external and internal artery at the level of C4.
has 6 branches and two terminal branches

3 anterior

i. superior thyroid
ii. lingual
iii. facial

2 posterior

iv. Posterior auricular
v. Occipital

1 Medial
vi. Ascending pharyngeal

2 Terminal:

i. Superficial Temporal
ii. Maxillary

Question 41

What consists of the Anterior Cranial Fossa

Answer 41

The anterior fossa is bounded by:
i.. The orbital plates of the frontal bone contribute most of the anterior fossa floor

ii.cribriform plate of the ethmoid bone interposed between them in the midline. The crista galli,to which the falx is attached, ascends vertically from the cribriform plate

iii.the lesser wings(posterior border of the lesser wing of the sphenoid lies at the boundary between the anterior and middle cranial fossa where the sphenoparietal sinus drains and acts as the posterior boundary) and anterior part of the body sphenoid.

iv.ethmoidal sinuses and the nose.

From the nose up to the olfactory region is up to 20 olfactory tracts that perforate the dura and arachnoid mater, at the cribiform plate and pass through the Subarachnoid space to enter the olfactory bulb.

The anterior ethmoidal nerve and artery(branch of opthalmic art.) have a very short course in the fossa. Coming in from the orbit they lie beneath the dura at the edge of the cribriform plate, where they run forwards in a slit and pass down into the nose at the side of the crista galli.

In the sphenoparietal sinus, a branch of the middle meningeal artery crosses this area to supply the anterior fossa.

Question 42

What are the boundaries of the middle cranial fossa?

Answer 42

Medially it consists of the sphenoid body

Laterally, it consists of greater wing of the sphenoid bone which act as the floor, the dorsum sella is the posterior boundary of the pituitary fossa and merges laterally with posterior clinoid processes. It also separates the temporal lobe of the brain from the infratemporal fossa below. and the squamous and petrous part of the temporal bone.

The superior border of the petrous temporal bone lies at the boundary between the middle and posterior cranial fossae; the superior petrosal sinus lies here between the two layers of the dura.

Question 43

What are the boundaries of the pituitary fossa and its contents?

Answer 43

The roof is the Diaphragma sellae, Intercavernous sinuses lie in the diaphragma and in the dural floor of the fossa. On each side is a flange of dura mater separating the gland from the upper part of the cavernous sinus.

Below the fossa lies the body of the sphenoid containing the sphenoid air cells

The ptuitary stalk contains two parts-
1.The neurohypophysis , developed as a neuroectodermal downgrowth from the floor of the third ventricle, consists of the pars posterior (nervosa), the infundibular stalk and the median eminence AND
2.The adenohypophysis consists of the pars anterior (distalis), pars tuberalis and the rudimentary pars intermedia.

It is supplied by the hypophyseal artery from the internal carotid artery

Question 44

WHat are the boundaries of the posterior fossa?

Answer 44

Clivus is the anterior boundary, the squamous part of the occipital bone which extends laterally to where the fossa floor is bounded anterolaterally by the petrous and mastoid parts of the temporal bone.
It lodges the convexities of the cerebellar hemispheres as well as the pons and medulla oblongata. In it the fifth to twelfth cranial nerves inclusive pierce the dura mater

Question 45

What are the parts of the temporal bone?

Answer 45

the temporal bone has 4 parts zygomatic process, squamous, petromastoid, and styloid process.

Question 46

What constitutes the clivus?

Answer 46

The clivus (of Blumenbach) is the sloping midline surface of the skull base anterior to the foramen magnum and posterior to the dorsum sellae 1. Specifically, it is formed by the sphenoid body and the basiocciput, which join at the spheno-occipital synchondrosis. At the clivus, the occipital bone has articulations with the petrous part of temporal bone at the petroclival fissure.
Inferiorly, the clivus is flanked by the rounded prominences of the jugular tubercles, which represents the fusion of the basiocciput with the lateral jugular parts of the occipital bone.
At the level of the jugular tubercles, the clivus is occupied by the medulla.
Above the jugular tubercles, the clivus is wider and occupied by the pons.
Anatomically it is also closely related to the basilar venous plexus and pontine cistern.

Question 47

What are the meninges

Answer 47

The cerebral meninges surround the brain and is made up of three layers (from outermost to innermost):

1.dura mater
2.arachnoid mater
3.pia mater
T
he dura mater can also be known as pachymeninx. The arachnoid mater and pia mater are collectively known as the leptomeninges

The meninges function to protect the brain but also provides a framework for blood vessels, nerves, lymphatics and CSF 2.

There are two potential spaces:
1.epidural (extradural) space - between the bone of the cranium and outer layer of the dura mater
2.subdural space - between the two layers of the dura mater
There is one CSF-containing real space, subarachnoid space, between the arachnoid and pia mater.

Question 48

What are the five cutaneous branches of the opthalmic branch of the trigeminal nerve

Answer 48

The lacrimal nerve supplies a small area of skin over the lateral part of the upper lid.

A third of the way lateral to the medial end of the upper margin of the orbit, the supraorbital nerve indents the bone into a notch or a foramen. The nerve passes up, breaking into several branches which radiate out and supply the forehead and scalp up to the vertex.

The smaller supratrochlear nerve passes up on the medial side of the supraorbital nerve to supply the middle of the forehead up to the hairline.

The infratrochlear nerve supplies skin on the medial part of the upper lid and, passing above the medial palpebral ligament, descends along the side of the external nose, supplying skin over the bridge of the nose.

These four branches of the ophthalmic nerve also supply upper lid conjunctiva.

The external nasal nerve supplies the middle of the external nose down to the tip. It emerges between the nasal bone and the upper nasal cartilage.

Question 49

What are the cutaneous branches of the maxillary nerve?

Answer 49

The infraorbital nerve emerges through its foramen and lies between levator labii superioris and the deeper placed levator anguli oris. It is a large nerve that immediately breaks up into a tuft of branches; these radiate away from the foramen to supply the lower eyelid (including conjunctiva), cheek, nose, upper lip and labial gum.

The zygomaticofacial nerve emerges from a foramen on the outer surface of the zygomatic bone; its branches supply the overlying skin.

The zygomaticotemporal nerve emerges in the temporal fossa through a foramen in the temporal (posterior) surface of the zygomatic bone. It supplies a small area of temporal skin.

Question 50

What are the branches of the mandibular branch of the trigeminal nerve?

Answer 50

The auriculotemporal nerve passes around the neck of the mandible and ascends over the posterior root of the zygomatic arch behind the superficial temporal vessels. The auricular part of the nerve supplies the external acoustic meatus, surface of the tympanic membrane and skin of the auricle above this level. The temporal part supplies the hairy skin over the temple.

The buccal nerve gives off cutaneous twigs before it pierces the buccinator muscle to supply oral mucous membrane. They supply a small area over the cheek just below the zygomatic bone, between the areas of the infraorbital nerve and the great auricular nerve

The mental nerve is a cutaneous branch of the inferior alveolar nerve. Like the infraorbital nerve it breaks up into a tuft of branches; these radiate away from the mental foramen to supply the skin and mucous membrane of the lower lip and labial gum from the midline to about the second premolar tooth.

Question 51

What are the layers of the Scalp, and it’s blood supply and nervous supply

Answer 51

The Scalp has 4 layers
S- SKin
C- Connective tissues
A-Aponeuorosis
L- Loose areolar tissue
P- Periosteum
Between the connective tissue is where the blood supply lies.
i.Occipital artery- external carotid
ii. Superficial temporal artery- terminal branch of external carotid vessels
iii.Supra-orbital and Supratrochlear- opthalmic artery

venous drainage is via
i.The supraorbital and supratrochlear veins drain by the angular vein into the facial vein.
ii.The superficial temporal veins run into the retromandibular vein, and
iii.occipital veins reach the plexus around the suboccipital muscles which drains into the vertebral vein.
iv.The posterior auricular vein drains the scalp behind the ear to the external jugular vein; it also receives the mastoid emissary vein from the sigmoid sinus. Sp
v.At the vertex a parietal emissary vein on either side of the midline connects scalp veins with the superior sagittal sinus.

Nerve Supply:
1.Posteriorly the greater occipital and third occipital nerves (posterior rami of C2 and C3 respectively) extend to the vertex and the posterior scalp respectively.
2.The lesser occipital (anterior ramus of C2) supplies skin behind the ear.
3.The temple is supplied by the auriculotemporal and the zygomaticotemporal nerves, and the forehead and front of the scalp by the supratrochlear and supraorbital nerves.