Anatomy of the Face and Scalp - Lecture 2

These flashcards cover key terms and concepts from the anatomy lecture on the face, scalp, and ear.

Scalp

The soft tissue envelope of the cranial cap consisting of various layers.

Layers of the Scalp

Five layers: Skin, Connective tissue, Aponeurosis, Loose areolar tissue, and Pericranium.

Aponeurosis

A thin, tendon-like structure connecting the occipitalis and frontalis muscles.

Emissary veins

Valveless veins that connect cranial cavity veins with external veins, can spread infection.

Facial Nerve

The 7th cranial nerve responsible for facial expressions, taste, and glandular functions.

Trigeminal Nerve

The 5th cranial nerve that supplies sensory information to the face and has three branches: ophthalmic, maxillary, and mandibular.

Conjunctiva

A clear membrane covering the front surface of the eye and inner eyelids, keeping them moist.

Sclera

The dense connective tissue forming the white part of the eye, providing shape and attachment for muscles.

Cornea

The clear front surface of the eye, responsible for most of the eye's focusing power.

Lens

A flexible transparent tissue behind the iris that helps focus light on the retina.

Cochlea

A component of the inner ear containing receptors for hearing.

Eustachian tube

A canal linking the middle ear to the nasopharynx, helping to equalize pressure.

Bell’s Palsy

A rapid unilateral facial nerve weakness or paralysis of unknown cause.

Oculomotor Nerve

The 3rd cranial nerve innervating most extraocular muscles and controlling eye movements.

Optic Nerve (CN II)

Transmits electrical impulses from the retina to the brain, allowing us to see.

Boundaries of scalp?

• Anterior: Supraorbital margin

• Posterior: External occipital protuberance

• Lateral: Superior temporal line

Layers of scalp (SCALP)?

• S: Skin

• C: Connective tissue

• A: Aponeurosis

• L: Loose areolar tissue

• P: Pericranium

Why wounds of scalp bleed a lot

A: Arteries are fixed in connective tissue → can’t contract → profuse bleeding

Why wounds don’t gap?

First 3 layers attached together

Why aponeurosis wounds gap?

Muscle contraction pulls edges apart

Why loose areolar layer is dangerous?

Emissary veins → infection spreads to cranial cavity

Why does a black eye happen?

Blood spreads from the scalp to the eyelids due to the lack of bony attachment.

Boundaries of the face?

• Superior: Hair margin
• Inferior: Mandible
• Side: Between auricles

Does the face have deep fascia?

No, except for the parotid and buccinator regions.

What type of nerve is the facial nerve (CN VII)?

Mixed (motor, sensory, and parasympathetic).

What is the motor function of the facial nerve?

Controls muscles of facial expression.

What is the sensory function of the facial nerve?

Provides taste sensation to the anterior 2/3 of the tongue.

What is the parasympathetic supply of the facial nerve?

• Lacrimal gland
• Submandibular gland
• Sublingual glands

Does the facial nerve supply the parotid gland?

No, the Glossopharyngeal nerve does.

What are the branches of the facial nerve?

• Temporal
• Zygomatic
• Buccal
• Marginal mandibular
• Cervical

What is the function of the buccal branch of the facial nerve?

Innervates the orbicularis oris and buccinator muscles.

What is Bell’s Palsy?

Sudden unilateral facial paralysis.

What is the difference between an intracranial and extracranial lesion affecting the facial nerve?

• Intracranial: Affects motor, sensory, and parasympathetic functions.
• Extracranial: Affects only motor function.

Function of the trigeminal nerve (CN V)?

Sensory supply of the face.

What are the branches of the trigeminal nerve?

• Ophthalmic (V1)
• Maxillary (V2)
• Mandibular (V3)

Which branch of the trigeminal nerve is motor?

Mandibular (V3) branch.

Where does each branch of the trigeminal nerve exit the skull?

• V1 → Superior orbital fissure
• V2 → Foramen rotundum
• V3 → Foramen ovale

What is the function of conjunctiva?

Provides lubrication and protection for the eye.

What is the function of the sclera?

Maintains the shape of the eye and provides attachment for muscles.

What is the function of the cornea?

Responsible for 75% of the eye's focusing power.

What are the parts of the uvea?

• Iris
• Ciliary body
• Choroid

What is the function of the iris?

Controls the size of the pupil.

What is the function of the pupil?

Allows light to enter the eye.

What is the function of the lens?

Focuses light onto the retina.

What is the function of the retina?

Converts light into electrical signals to be processed by the brain.

What is vitreous humor?

A jelly-like substance that fills the posterior part of the eye.

What is the function of extraocular muscles?

Controls eye movement.

What action does the medial rectus muscle perform?

Adduction of the eye.

What action does the lateral rectus muscle perform?

Abduction of the eye.

What action does the superior rectus muscle perform?

Elevation of the eye.

What action does the inferior rectus muscle perform?

Depression of the eye.

What action does the superior oblique muscle perform?

Medial rotation of the eye.

What action does the inferior oblique muscle perform?

Lateral rotation of the eye.

What is the nerve supply rule for extraocular muscles?

LR6 (lateral rectus innervated by CN VI) and SO4 (superior oblique innervated by CN IV); all others are supplied by CN III.

What is the function of the ear?

Hearing and balance.

What are the parts of the external ear?

• Auricle (pinna)
• External auditory canal
• Tympanic membrane (eardrum)

What are the contents of the middle ear?

• Ossicles: Malleus, Incus, Stapes
• Eustachian tube.

What is the function of the Eustachian tube?

Equalizes pressure between the middle ear and the atmosphere.

What are the parts of the inner ear?

• Cochlea (hearing)
• Vestibule (balance).

What nerve is responsible for the inner ear?

Vestibulocochlear nerve (CN VIII).

What is the pathway of sound?

Canal → Tympanic membrane → Ossicles → Cochlea → Nerve → Brain.