Clinical case 1: Judy is a 29-year-old secretary who has had diabetes since childhood, went to the ER as it looked like she was having a stroke. She presents with her left face drooping and inability to close her left eye which also felt dry. Physical examination reveals facial weakness: Left eye would not close completely and appeared to droop slightly Only the right side of her mouth was elevated when she was asked to smile Only the right eyebrow was elevated when she was asked to wiggle her eyebrows 1) What is your preliminary diagnosis?

1. Injury to left facial nerve (unilateral) --\> muscles of facial nerve not working 1. Obicularis oculi not working 2. Dilators of mouth not working 3. Occipitofrontalis not working

Head and Neck Practical 2 Flashcards by Esme Cosham

How many terminal branches does the facial nerve have?

5 that innervate the muscles of facial expression

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How does the facial nerve enters/leave the skull?

Enters - internal acoustic canal in temporal bone

Exits - stylomastoid foramen

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Motor branches of facial nerve

Ten Zebras Bit My Clavicle

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How many bellies does the occipitofrontalis have?

2 - one in frontal region and one in occipital region

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Action of 2 bellies of occipitofrontalis?

Frontal part: pulls scalp forward, wrinkles forehead and elevates eyebrows
Occipital part: retracts scalp

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What circular muscle is being pointed to? Function?

Orbicularis oculi - closes eyelids (sphincter)

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What muscle is this? Function?

Orbicularis oris - sphincter of mouth (closing lips - ‘kissing muscle’)

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What is the action of orbicularis oris opposed by?

A number of muscles that dilate the mouth –> dilators of mouth

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Function of buccinator? Location?

Lateral to corner of mouth and anterior to masseter
Contracts and keeps cheeks taut when whistling, talking etc and presses cheek against teeth when eating

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What duct is buccinator pierced by?

The parotid duct

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What gland is being pointed to?

Paired parotid gland (anterior to ear)

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Where does parotid gland enter into mouth?

At level of upper 2nd molar tooth

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What muscle is being pointed to? Function?

Platysma (flat and thin) - tenses skin of neck

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What nerve is this?

Temporal branches of facial nerve

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What nerve is this? What does it innervate?

Zygomatic branch of facial nerve
Innervates the orbicularis oculi

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What nerve is this?

Buccal branch(es) of facial nerve

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What nerve is this?

Marginal mandibular branch of facial nerve

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What nerve is this? What does it innervate?

Cervical branch of facial nerve
Innervates platysma

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Within the parotid gland, the facial nerve terminates by splitting into five branches. Does it innervate the parotid gland?

No - only provides motor innervation to the muscles of facial expression.

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Clinical case 1:

Judy is a 29-year-old secretary who has had diabetes since childhood, went to the ER as it looked like she was having a stroke.

She presents with her left face drooping and inability to close her left eye which also felt dry.

Physical examination reveals facial weakness:

Left eye would not close completely and appeared to droop slightly
Only the right side of her mouth was elevated when she was asked to smile
Only the right eyebrow was elevated when she was asked to wiggle her eyebrows

1) What is your preliminary diagnosis?

Injury to left facial nerve (unilateral) –> muscles of facial nerve not working
1. Obicularis oculi not working
2. Dilators of mouth not working
3. Occipitofrontalis not working

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What level does common carotid artery bifurcate?

Between C3 and C4

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Describe course of internal carotid artery

Travels more posterioly - gives off no branches in neck/face but goes straight to supply brain

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Describe course of external carotid

More anterior to internal, gives off branches to supply face

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What is the 1st branch of the external carotid?

Superior thyroid artery - goes to supply thyroid gland

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What is the 2nd branch of the external carotid? What does it supply?

Lingual branch - goes to supply floor of mouth

What is the 3rd branch of the external carotid?

Facial artery (very tortuous)

What are the 2 terminal branches of the external carotid?

* Superficial temporal artery * Maxillary artery

What artery is this? What does it supply?

Superficial temporal artery - generally supply superficial areas of the face.

What artery is this? What does it supply?

Maxillary artery - supplies the deep structures of the face

What pulse is being felt here? How can it be found?

Carotid pulse - identify laryngeal prominence and make your way laterally

What pulse is being felt here?

Facial pulse (near angle of mandible)

What pulse is being felt here?

Temporal pulse (superfical temporal artery)

What nerve is this? Course?

Hypoglossal nerve CN VII - Descends down neck then makes a 90 degree turn around the external and internal carotid arteries to make its way towards area of tongue (motor)

Which foramen transmits the middle meningeal artery and middle meningeal vein into the skull?

The foramen spinosum

Where is the foramen spinosum located?

located in the posteromedial part of greater wing of sphenoid bone (posterolateral to foramen ovale)

Grooves of middle meningeal artery and its branches

Diagram of tentorium cerebelli (protrusion of dura mater)

How is the dura mater related to the skull?

Firmly attached - can only become a space in: * Pathological situations e.g. bleeding * Post mortem (chemicals) Is a **potential space**

What is bleeding between the skull and dura mater called?

Epidural/extradural haemorrhage

What would an epidural bleed in the anterior cranial fossa compress?

The frontal lobe

What do the lateral pterygoid plates of the sphenoid bone form important attachment sites for?

The muscles of mastication

What is being pointed to? (sphenoid bone from inferior view)

Lateral pterygoid plate (on one each side)

What is being pointed to? (inferior view of spheniod)

Medial pterygoid plate (paired)

Space between the medial and lateral pterygoid plates of sphenoid bone

The lateral pterygoid plate of the sphenoid bone has an internal and external aspect. What do these form attachment points for?

Lateral and medial pterygoid plate --\> N.B. both of these muscles attach to the **lateral pterygoid plate**

How can the orientation of the temporal bone be established?

Mastoid process posteriorly and zygomatic process anteriorly

What part of the temporal bone is being pointed to?

Zygomatic process

What part of the temporal bone is being pointed to?

Mastoid process

Where does masseter originate from?

Zygomatic process of temporal bone

Which muscles attach to the mastoid process of the temporal bone?

Sternocleidomastoid and posterior belly of digastric

What is being pointed to? What articulates here?

Mandibular fossa of temporal bone - for articulation with the mandible at TMJ

Picture of mandible

Unpaired

What part of the mandible is being pointed to?

Ramus - has an internal and external surface

What does the external aspect of the mandibular ramus form an attachment point for?

Masseter muscle of mastication

What does the internal aspect of the mandibular ramus (near angle of mandible) form an attachment point for?

Medial pterygoid muscle

What part of the mandible is being pointed to?

Condyloid process / condyle (paired)

What part of the mandible is being pointed to? What muscle attaches here?

* Coronoid process of mandible * Temporalis muscle attaches here

What is the temporal fossa?

fossa (shallow depression) on the side of the skull bounded by the temporal lines and terminating below the level of the zygomatic arch.

Which muscle does the temporal fossa provide attachment for?

Temporalis muscle of mastication

What muscle is being pointed to? Origin and insertion?

Temporalis: * Origin: the temporal fossa * Inserts: It condenses into a tendon, which inserts onto the coronoid process of the mandible.

What muscle is being pointed to? Origin and insertion?

Masseter: Origin: the zygomatic arch of the temporal bone. Inserts: ramus and angle of the mandible.

Picture of temporalis - fan shaped muscle

N.B. zygomatic arch has been removed

What muscle is being pointed to? Origin and insertion?

Lateral Pterygoid: Origin: external/lateral aspect of lateral pterygoid plate of the sphenoid Inserts: condyloid process of mandible

What muscle is being pointed to? Origin and insertion?

Medial pterygoid muscle: Origin: medial aspect of the lateral pterygoid plate of the sphenoid bone. Inserts: ramus of the mandible near the angle of mandible (internally)

What are the 4 muscles of mastication?

* Masseter * Temporalis * Lateral pterygoid * Medial pterygoid

What is the highlighted muscle?

Masseter (mandible has been faded out)

What is the highlighted muscle?

The medial pterygoid (the masseter and medial pterygoid sandwich the mandible either side)

What is the highlighted muscle?

Lateral pterygoid

Function of the superior rectus muscle (extraocular)?

Pulls eyeball superiorly (look up)

Function of the medial rectus muscle (extraocular)?

Contracts to adduct the eyeball (look medially)

Function of the superior oblique muscle (extraocular)?

Depresses, abducts and medially rotates the eyeball.

Function of the lateral rectus muscle (extraocular)?

Contracts to pull eyeball laterally (abducts)

What is this gland?

Lacrimal gland

Function of the inferior rectus muscle (extraocular)?

Helps to look down

Which cranial nerve is most likely to have been damanged if someone cannot move the right eye to look laterally?

**Ab**ducens (as this nerve innervates lateral rectus which **ab**ducts the eyeball)

Innervation of extraocular muscles?

**LR6 SO4** * Lateral rectus - 6 (abducens nerve CN VI) * Superior oblique - 4 (trochlear nerve CN IV) Everything else innervated by CN III oculomotor nerve

A 34-year-old man is hit in the head with a heavy object that was thrown out of a window under which he was walking. He was taken to the ER, given a MRI scan, and 36 hours later, regained consciousness. Several days later, the patient reported **difficulty in following a moving object presented within his visual field** and also felt **little or no sensation of the forehead** after a mild pinprick administered to that region. The MRI provided evidence that the head injury most likely caused damage to: a) Peripheral fibres of the facial nerve b) Central processes of the trigeminal nerve c) Nerve fibres in the superior orbital fissure d) Nerve fibres passing through the jugular foramen

Nerve fibres in the superior orbital fissure (oculomotor nerve passes through here)

Which cranial nerve is responsible for moving the muscles of the tongue?

CN XII Hypoglossal

Which cranial nerve is responsible for sensation to the face?

CN V trigeminal

Which cranial nerve is responsible for motor function of muscles of facial expression?

CN VII Facial nerve

Which cranial nerve is responsible for supplying the muscles of mastication?

Mandibular branch of the trigeminal ( CN V₃)

Which cranial nerve is responsible for moving the eyeballs medially?

CN III oculomotor

Which cranial nerve is responsible for closing the eyelids (orbicularis oculi)?

CN VII facial nerve