Lecture 6 Anatomy of Face & Scalp PDF

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Everything mentioned in the lecture is written in red. Lecture notes were taken during class and then once again after class while listening to the recording to make sure everything covered in class was in the notes....

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BISC 3112

HEAD and NECK ANATOMY

ANATOMY OF THE FACE AND SCALP LEARNING OBJECTIVES: 1. 2. 3. 4. 5. 6.

Identify the surface features of the face. List the sensory nerves of the face and scalp. List the five divisions of the seventh cranial nerve. List the cervical nerves which innervate the scalp and face. List the arteries and veins of the face and scalp. List and identify the muscles of facial expression and the action(s) of each muscle.

READING:

I.

Liebgottt Chapter 7 The Head by Regions, pp. 202-219

INTRODUCTION a. Organization of the Face and Scalp into Regions b. External Features

II.

REGIONS and SURFACE ANATOMY OF THE SCALP and FACE a. Face b. Scalp c. Frontal Region – Forehead - runs from the eyebrows to the hairline - features beneath the surface of the skin are frontal eminences, supraorbital margin (bony margin above the orbit), supraciliary arch, and glabella d. Temporal Region / Temples - anterior from the ear - below the surface of the skin are the temporal lines and the temporal fossa - temporal fossa is filled in by the temporalis muscle e. Orbital Region - region around the eye - the eyeball is here - upper eyelid and eyelashes and lower eyelid and eyelashes

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HEAD and NECK ANATOMY - where the upper and lower eyelids meet is the palpebral (eyelid) commissure (medial and lateral) - close to the medial palpebral commissure and on the waterline (on both the upper and lower eyelid), there is a papilla (bump) and punctum (hole on the bump) f.

Infraorbital Region - just below the orbit - under the skin is the infraorbital nerve (nerve comes through infraorbital foramen)

g. Nasal Region / External Nose - skin is very adherent to the wings of the nose - under the skin is the nasal bones and on the inferior aspect of the inferior margin of the nasal bone will be the cartilaginous framework of the bulk of the nose - septal cartilage in the midline and 2 lateral cartilages on either side - alar cartilages make up the wings of the openings of the nasal cavity - actual opening of the nose is the external nares - when you pinch your nose shut, you're pinching the fibroareolar tissue - when you feel like your nose is broken, the lateral cartilages are shoved up into the nasal bone (very rarely is the nasal bone broken) h. Zygomatic / Malar Region - overlies the zygomatic bone - under the skin there is the zygomatic arch, temporomandibular joint, and the masseter muscle

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HEAD and NECK ANATOMY i.

Buccal Region / Cheeks - below the zygomatic region - flesh of the cheek region - posterior aspect of the buccal region is the angle of the mandible

j.

Mouth and Lips - labia = lip - superior and inferior labia - border between the normal skin of the face and the skin of the lips is the vermillion border (vermillion = bright red) - transition zone on the lips where the lips feel dry to where it goes into the oral cavity, there’s a transition from dry mucosa to wet mucosa (from the very thin highly vascularized tissue of the lip to the wet mucosa) - commissures where the upper and lower lip meet (2 lateral commissures and no medial commissure) (also referred to the angle of the oral cavity) - little divet above the oral cavity in the midline of the upper lip is the philtrum and the groove between the lower lip and mental region is the labiomental groove - leading from the lateral aspect of the nasal (where the external nare is) down to the angle of the mouth is the nasolabial groove - becomes more pronounced as we age

k. Mental Region / Chin - the jutting out of the jaw is the mental protuberance l.

External Ear  aka auricle a. The external ear contains the largest amount of elastic cartilage in the body. b. Musculature i. Three muscles innervated by CN VII (can voluntarily be moved) 1. Superior, posterior, anterior auricular muscles

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HEAD and NECK ANATOMY - lobule  where piercings happen - helix  upper curvature of the auricle - tragus  flap of tissue you push on when you plug your ears

III.

SKIN and FASCIA a. Skin - medium to thin in thickness overlying the face - very pliable and movable except to where it is fixed to the ala of the nose and the cartilage of the ear - lots of sweat glands and oily sebaceous glands embedded in the skin of the face b. Superficial Fascia - contains connective tissue and varying amounts of fat underneath the skin - substance of the cheek is the buccal fat pad (buccal fat pad is the last fat reserve that is used) - vessels, nerves, and superficial muscles of expression - some of the muscles insert right into the skin c. Deep Fascia - no discrete layer in the face (once that muscle layer is removed, it’s all bone)

IV.

SENSORY NERVES of the FACE a. Cranial Nerve V – Trigeminal Nerve (aka dentist nerve) - primary nerve of sensation to the anterior portion of the face and a large part of the forehead - can find the trigeminal ganglion on the anterior slope of the petrous ridge in the middle cranial fossa ii. Ophthalmic Division V1  goes through the orbit; some supply aspects of the eye itself, but most go through the orbital cavity and externalize 1. Supraorbital  goes through the supraorbital foramen 2. Supratrochlear 3. Infratrochlear

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HEAD and NECK ANATOMY 4. Lacrimal 5. External nasal iii. Maxillary Division V2 1. Infraorbital  externalizes through the infraorbital foramen a. Inf. palpebral  goes to the lower eyelid b. Lateral nasal  goes to the lateral side of the nose c. Superior labial  goes to the upper lip 2. Zygomaticofacial  comes out of the zygomaticofacial foramen 3. Zygomaticotemporal  comes out of the zygomaticotemporal foramen; goes up the lateral side of the face iv. Mandibular Division V3 1. Auriculotemporal nerve  goes up by the ear and up to the temporal region 2. Buccal nerve (long buccal nerve) 3. Mental nerve (when it goes through the mental foramen)  has individual subbranches - mental  goes to the chin - inferior labial  goes to the lower lip - gingival  goes to the inferior incisors closes to the lip b. Cervical Spinal Nerves i. Great Auricular nerve  supplies the part of skin that is below the ear and just along the lower side of the mandible on either side

V.

ARTERIES of the FACE a. Origin b. Branches of the ophthalmic artery (from internal carotid artery) - ophthalmic is the first branch off the internal carotid and it comes off when the internal carotid is safely in the neurocranium

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HEAD and NECK ANATOMY ii. Supraorbital artery – with supraorbital nerve iii. Supratrochlear – with supratrochlear nerve iv. Dorsal Nasal – with infratrochlear nerve v. Lacrimal – with lacrimal nerve vi. External Nasal – with external nasal nerve vii. Zygomatic – with zygomatic nerve and branches 1. Zygomaticofacial & Zygomaticotemporal c. Branches of external carotid artery i. Branches of the Maxillary artery 1. Infraorbital a. Inferior palpebral b. Nasal c. Superior labial 2. Buccal – with buccal nerve 3. Mental – with mental nerve & branches ii. Branches of the facial artery – different termination point of the major branch off the external carotid 1. Angular branches (no nerve named the same) – goes up from the angle of the face to the angle of the eye 2. Nasal branches – goes to the nose 3. Superior and inferior labial arteries – goes to the inferior and superior lips iii. Superficial Temporal Artery – with auriculotemporal nerve 1. Emerges between TMJ & ear, ascends to scalp a. Transverse facial artery  typically comes off the superficial temporal artery

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HEAD and NECK ANATOMY Veins of the Face

- Veins that are draining the scalp, forehead, and upper lids don’t go all the way down and drain through the facial vein, but instead go deep through the eye and go to the ophthalmic veins, but they can go to the superficial facial veins - 2 drainage options: deep into the orbital cavity or superficial into the facial veins - Midface drainage and lower face drainage can go into the pterygoid plexus of veins which is deep into the structure of the face (for example, infraorbital and mental do so) - Alternate route would be the facial vein which ultimately dumps into the internal jugular - Deep facial vein has a connection to the pterygoid plexus - Deep plexus of veins is where the venous drainage can go and then ultimately end up in the internal jugular b. Most are hard to identify but accompany their companion arteries. c. Veins above the heart lack valves. Blood can flow either to the large veins in the neck, OR to the large venous channels located in the interior of the cranium. d. “Dangerous zone”  the region where the cavernous sinus has a connection with the pterygoid plexus because the pterygoid plexus is superficial in the cheek area and the blood from there can get to the cavernous sinus which is close to the brain e. Veins in the face you should identify (their drainage routes): i. Facial vein  Angular vein  Sup. Ophthalmic vein  Cavernous Sinus - Cavernous sinus has a connection with the pterygoid plexus ii. Nasal veins  infraorbital vein iii. Deep facial vein  pterygoid plexus iv. Superior and inferior labial veins  Infraorbital & mental veins v. Retromandibular vein

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HEAD and NECK ANATOMY MUSCLES of FACIAL EXPRESSION

See Leibgott Table 7-1

a. Development: derived from second branchial arch (all innervated by CN VII) b. Origins: from bone or fascia c. Insertions: into the skin of the face d. Mouth: i. Orbicularis oris 1. Ax: acts as a sphincter; compresses the lips (close your mouth); protrude your mouth ii. Levator anguli oris 1. In: angle of the mouth 2. Ax: elevator of the angle of the mouth (like smiling) iii. Zygomaticus major 1. Or: zygomatic bone 2. In: angle of the mouth 3. Ax: draw up the angle of the mouth iv. Depressor anguli oris 1. In: angle of the mouth 2. Ax: depress the angle of the mouth (like frowning) v. Risorius 1. I: angle of the mouth 2. A: draws the angle of the mouth laterally e. Lips i. Levator labii superioris and Levator labii superioris alaque nasii (LLSAN) 1. In: ala of the nose 2. Ax: elevation of the upper lip; alaque nasii flares the nostrils ii. Zygomatic minor 1. In: substance of the lip 2. Ax: elevates the upper lip iii. Depressor labii inferioris 1. In: lower lip 2. Ax: depress the lower lip

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HEAD and NECK ANATOMY f.

Cheek i. Buccinator (well developed in trumpet players) 1. O: Pterygomandibular raphe, buccal alveolar processes maxilla & mandible 2. In: upper and lower lips 3. Ax: compresses the cheeks against the molar (like sucking), but can cup out when blowing g. Eye i. Frontalis (covers the forehead) 1. O: galea aponeurotica 2. In: skin of the forehead along the supraciliary arch 3. Ax: pulls the scalp up and back; raises eyebrows ii.

Orbicularis oculi Orbital (circular muscle) a. Ax: forceful closing of the eye (scrunching the eye) Palpebral (covers the eyelid) b. Ax: closing the eye gently (blinking)

iii.

Procerus 1. In: skin overlying the glabella 2. Ax: transverse wrinkling in the skin of the nose

iv.

Corrugator 1. In: deep surface of the skin, above the middle of the orbital arch 2. Ax: move eyebrows down and inward toward the nose and the eye; vertical lines in between the forehead when frowning, wrinkling of the skin above the nose

h. Nose and Chin v. Nasalis – compressor, dilator (transverse fibers across the nose) 1. Ax: compresses and dilates the nostrils i.

Mentalis – associated with the chin; under the angular fibers associated with the depressor labii inferioris 1. Or: mandibular fossa 2. In: skin overlying the mandible 3. Ax: puckers the chin and skin when you are protruding; assists the depressor in protruding the lower lip

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HEAD and NECK ANATOMY MOTOR INNERVATION of the FACE a. Cranial Nerve VII – Facial Nerve i. Provides motor fibers to the muscles of the face and scalp ii. 5 major divisions named by areas they serve 1. Temporal  supply forehead and eye muscles 2. Zygomatic  supply muscles below eye area, in zygomatic area 3. Buccal  supply the cheek 4. Mandibular  supply the mandible 5. Cervical  supply the cervical region, platysma, posterior digastric, and stylohyoid TWO ZEBRAS BIT MY CLAVICLE PAINFULLY iii. Identify divisions and named branches to their muscle groups iv. Additional branches of CN VII 1. Posterior Auricular branch: (auricular) muscles of the ear 2. Occipital branch: occipital muscle

IX.

THE SCALP a. Regions of the scalp b. 5 layers -i. Skin – thick, hair follicles, glands - covers scalp - superficial layer of the scalp ii. Connective tissue – thick, dense vascular, innervated, emissary veins

SCALP PROPER

- subcutaneous tissue - anchored to aponeurosis iii. Aponeurosis – galea aponeurotica, tendon of occipitofrontalis muscle (connects the occipital muscle to the frontalis muscle); gaping wounds

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HEAD and NECK ANATOMY iv. Loose Areolar tissue – mobile, transmits bacteria & blood v. Pericranium – adherent to the cranium - horizontal cut on galea will bleed a lot, but vertical cut won’t c. Vascular and Sensory Nerve Supply to the Scalp AR is anterior rami & PR is posterior rami i. Arterial supply: - come from the branches of the ophthalmic or external carotid anterior to the ear - posterior to the ear will be the additional branches off of the external carotid ii. Nerve supply: -

anterior to the ear are all the nerves off of the trigeminal nerve

-

posterior to the ear will be branches off the cervical plexus

d. Motor Nerves of the Scalp – CN VII e. Muscles of the Scalp i. Occipital portion of occipitofrontalis muscle 1. Or: occipital portion originates from the superior nuchal line 2. In: skin overlying the occipital area as well as the epicranium aponeurosis 3. A: slide the scalp back and forth when we do various facial expressions ii. Frontalis 1. Or: epicranial aponeurosis 2. In: skin just above the supraciliary arches...