HNS25 Face And Scalp Flashcards
Face borders
Upper:
Supraciliary arches / upper aspect of eyebrows —> Forehead belongs to Scalp
Lower:
Lower edge of mandible
Posterior:
Front of ear (face does not include ear)
Scalp border
Rest of head and neck (except face)
Auricle / ear not included
Inferior:
Occipital protuberance / Superior nuchal line (margin between head and neck)
Importance of face
- Identity
- Individuality (difference between people)
- shape
- skin colour etc. - Communication
- non-verbal (facial expression)
- verbal (production of speech)
Face shape determination factor
- Underlying bones and cartilages
- Deposition of fatty tissue (children with more buccal fat to suck milk)
- Colour and effects of aging on overlying skin
- Abundance, placement, nature of hair
Features of face: 3 mains areas of face
- Eyes
- Suprapalpebral sulcus
- Infrapalpebral sulcus
- Eyelids
- Palpebral sulcus (眼窿)
- Eyebrows (on Supraciliary arch)
- Epicanthal / Palpebronasal folds - Nose
- Glabella
- Dorsum
- Apex
- Ala
- Naris (opening)
- Nasal septum - Mouth
- Philtrum (人中)
- Lips (upper + lower)
- Labial commissure (嘴角)
- Oral fissure (口窿)
- Vermillion border (嘴唇同皮膚border)
- Mentolabial sulcus
- Mental protuberance (下巴尖)
- Chin
Rest of face: Cheek
Skin of face
- Thick, Elastic, Vascular
- Normally Lax (except nose (securely attached to cartilage))
Structure of scalp
5 layers:
- Skin
- thin
- many sebaceous gland, sweat gland
- hair follicles
- abundant arterial supply
- good venous and lymphatic drainage - Connective tissue
- thick
- richly vascularised ***SC layer
- cutaneous nerves - Aponeurosis
- Epicranial aponeurosis
- broad, strong
- tendinous sheet that covers calvaria
Skin + Connective tissue + Aponeurosis —> Proper scalp
- Loose connective tissue
- allow free movement of layers above - Pericranium
- external periosteum of calvaria
Skeletons of face and scalp
Division: Neurocranium + Viscerocranium
Function:
- House and protect sense organs (eye, nose, mouth)
- Provide a frame on which soft tissues (including muscles of face) can act, teeth can anchor
Classification of muscles of head and neck
Based on anatomical location:
- Face and scalp
- Eye and orbit
- Middle ear
- Soft palate
- Tongue
- Neck
Muscles of face and scalp
Muscles of scalp:
- Epicranial muscles
- Occipitofrontalis (CN7) - Auricular muscles
Muscles of facial expression:
- Orbital group
- Orbicularis oculi (Palpebral part, Orbital part) - Nasal group (relatively unimportant in human)
- Oral group
- Orbicularis oris
- Muscles of upper lip (Levator labii superioris, Levator anguli oris, Zygomaticus minor, Zygomaticus major)
- Muscles of lower lip (Depressor labii inferioris, Depressor anguli oris, Mentalis)
- Risorius
- Buccinator
- Platysma
Epicranial muscles
- Occipitofrontalis (2 bellies: frontal + occipital belly)
- connection: Epicranial aponeurosis
- origin: Superior nuchal line (occipital belly), ***Skin above upper orbital margin (frontal belly) (attach to skin rather than bone —> for facial expression)
- Elevation of eyebrows, Wrinkles the forehead
- Innervated by CN7
Muscles of facial expression
- Small, thin muscle bundles located in SC tissue / Superficial fascia
- NOT covered by own fascia (except buccinators)
- Most attaches to bone / fascia / skin (pull the skin), rest attaches to other muscles
- ALL from 2nd pharyngeal arch
- ALL innervated by CN7 Facial nerve
Functions:
- Sphincters and dilators of facial orifices —> Protection (Primary function) (e.g. eyes)
- Facial expression (Secondary function) —> expression of emotions
- Support food ingestion —> close mouth for swallowing
- Sound production involvement
Orbital group muscles (3 groups)
Main functions of eyelids:
1. Protection of eyeballs from injury / excessive light
2. Spreading tears to keep cornea moist
—> by closing Palpebral fissure (眼窿)
- Orbicularis oculi (sphincter of eye)
- Palpebral part —> closes eyelid gently
- Orbital part —> closes eyelid forcefully
- Lacrimal part (deep)
***Oral group muscles (6 groups)
- Orbicularis oris (sphincter of mouth)
- opening of mouth - Muscles of upper lip
- Levator labii superioris (labii: lip)
- Levator anguli oris (anguli: angle of lip)
- Zygomaticus minor
- Zygomaticus major - Muscles of lower lip
- Depressor labii inferioris
- Depressor anguli oris
- Mentalis (directly attach to skin) - Risorius
- widens mouth opening - Buccinator
- cheek muscles - Platysma (大塊) (also from 2nd pharyngeal arch, also innervated by CN7)
- muscles of neck interwoven with oral group muscles
- **tenses skin over lower face + anterior neck
- **depresses mandible (against resistance)
Receptor on face
- Touch
- Pain
- Temperature
***Dermatomes of head and neck
Face + Anterior scalp: CN5 Trigeminal nerve
- CNV1 Ophthalmic division: Scalp + nose
- CNV2 Maxillary division: Cheek
- CNV3 Mandibular division: Chin + side of face
Posterior scalp + Neck: Spinal nerve
Anterior-Posterior division:
- Anterior ramus (anterior head and neck, including ear)
- Posterior ramus (posterior head and neck)
OR
Superior-Inferior division:
- C2 (posterior head)
- C3 (neck)
- C4 (just above pectoral girdle)
No C1 dermatome (∵ no cutaneous nerve from C1)
***Cutaneous distribution of nerves in head and neck
Anterior:
Ophthalmic nerve (CNV1)
- ***Supraorbital nerve (middle upper lid, forehead, anterior scalp) —> Supraorbital foramen
- Supratrochlear nerve (glabella)
- Infratrochlear nerve (nose dorsum, small part of glabella)
- External nasal nerve (lateral dorsum, apex)
- Lacrimal nerve (lateral upper lid)
Maxillary nerve (CNV2)
- ***Infraorbital nerve (face, upper lip) —> Infraorbital foramen
- Zygomaticotemporal nerve (lateral forehead)
- Zygomaticofacial nerve (lateral face)
Mandibular nerve (CNV3)
- Auriculotemporal nerve (ear, lateral scalp)
- Buccal nerve (cheek)
- Mental nerve (lower lip, chin) —> Mental foramen
Posterior:
Posterior rami of spinal nerve
- Greater occipital nerve (C2) (posterior scalp)
- Third occipital nerve (C3) (posterior neck)
Anterior rami of spinal nerve
- Lesser occipital nerve (C2, C3 —> cervical plexus) (lateral scalp)
- Greater auricular nerve (C2, C3 —> cervical plexus) (anterior neck, angle of mandible, ear)
Posterior rami of spinal nerve —> never form plexuses
Anterior rami of spinal nerve (cervical, lumbar, sacral) —> form plexuses
***Maps can overlap
Region for testing
NOT overlap with other nerves —> Major nerve tested: 1. CNV1 —> Supraorbital nerve 2. CNV2 —> Infraorbital nerve 3. CNV3 —> Mental nerve
Trigeminal neuralgia
- Severe pain in facial area served by >=1 of 3 branches of CN5
- Electric-shock like
- Suicide disease
- Caused by compression of CN5 and at the base of skull (root / entry zone) (e.g tumour)
Original of ALL 3 sensory divisions of CN5
Trigeminal ganglion (Sensory ganglion) (cell bodies of pseudo-unipolar neurons located)
—> Sensory root
—> Brainstem
—> Information about touch
—> Principal Trigeminal sensory nucleus of Trigeminal nerve
***Motor pathway of face: CN7 and effectors (muscles of facial expression)
CN7: Emerge from Stylomastoid foramen
Divides in parotid gland into major branches in face:
- Temporal (auricular muscles, frontal belly of occipitofrontalis)
- Zygomatic
- Buccal
- Marginal mandibular
- Cervical
- Posterior auricular (posterior auricular muscle, occipital belly of occipitofrontalis)
Facial nerve also supples Stapedius, Posterior belly of digastric, Stylohyoid which are NOT muscles of facial expression
Bell’s palsy
Symptoms (temporary):
- Incomplete closure of eye (Orbicularis oculi)
- cause cornea to dry out (exposure keratitis)
- drooping of lower eyelid (ectropion) (vs ptosis: drooping of upper lid) - Drooling
- dribbling saliva and drinks, difficulty in chewing / speaking (Orbicularis oris) - Decrease sense of taste (anterior 2/3 tongue) (Chorda tympani)
- Sensitive to loud noise (hyperacusis) (Stapedius)
Origin of blood supply to face and scalp
Internal carotid artery (NO branch in neck, 1st branch within skull):
—> Orbit, Medial forehead, Dorsum
External carotid artery:
—> Rest of face and scalp (Majority)
***External carotid artery branches (only superficial —> Lingual, Superior thyroid, Ascending pharyngeal not counted)
- Facial artery (main artery of face, hook around inferior mandible, go through face to medial eye)
- ***Angular artery (medial eye) —> Anastomoses with Dorsal nasal artery
- Inferior labial artery
- Superior labial artery
- Lateral nasal branch
- Submental artery - Maxillary artery
- Infraorbital artery (Infraorbital foramen)
- Mental artery - Superficial temporal artery
- Frontal branch
- Parietal branch
- Zygomaticoorbital artery
- Transverse facial artery (on zygomatic arch) - Occipital artery
- Posterior auricular artery
***Internal carotid artery (Anterior and Middle cerebral arteries not counted)
- Ophthalmic artery (go through orbit)
- Supratrochlear (forehead, dorsum)
- ***Dorsal nasal artery (rest of dorsum) —> Anastomoses with Angular artery
- Supraorbital artery (forehead)
- Lacrimal artery
Supraorbital artery vs Infraorbital artery
Supraorbital artery:
- Internal carotid —> Ophthalmic —> Supraorbital artery
Infraorbital artery:
- External carotid —> Maxillary —> Infraorbital artery
(Supraorbital nerve: CNV1
Infraorbital nerve: CNV2)
Scalp anastomoses (Anterior to Posterior) (External + Internal)
Occurs between L/R branches, different branches of same / different origin
External carotid (Posterior)
- Superficial temporal
- Occipital
- Posterior auricular
Internal carotid (Anterior) 4. Upper branches of Opthalmic artery —> Supratrochlear —> Supraorbital —> Zygomatico-temporal branches
Arterial anastomoses in the face
Significant anastomoses may develop between 2 arterial territories: External + Internal carotid arteries
—> provide alternative route for blood flow
e.g. Blockage of internal carotid artery —> External carotid artery —> Facial artery —> ***Angular artery —> ***Dorsal nasal artery —> Ophthalmic artery —> Internal carotid artery (bypass blocked site)
Arterial pulse
- Carotid pulse
- Facial pulse (Facial artery at mandible)
- Temporal pulse (Superficial temporal artery, anterior to auricle as artery crosses zygomatic arch)
Veins of face and scalp
Internal jugular vein (Majority)
External jugular vein (Minor)
***Venous drainage
Face: 1. Facial vein (Main) - Angular vein - External nasal vein - Superior labial vein - Inferior labial vein - Submental vein (also can go anterior cervical vein —> Brachiocephalic) 2. Retromandibular vein 3. Others —> Internal / External jugular vein
Scalp: 1. Occipital (Main) 2. Superficial temporal vein 3. Supraorbital vein 4. Others —> Internal / External jugular vein
***Pterygoid plexus and Cavernous sinus
- Facial vein —> Can go into Deep facial vein —> Pterygoid plexus of veins
- Infraorbital vein —> Pterygoid plexus of veins
- Ophthalmic vein —> Can go into Cavernous sinus (intracranial)
- Angular vein
- Others
Pterygoid plexus connected with Cavernous sinus via Emissary veins
***These veins are valveless —> can drain into Pterygoid plexus —> Emissary veins —> Cavernous sinus —> into Brain
“Danger area of face”
—> bacterial dissemination from mouth / face
—> Cavernous sinus
—> Thrombosis / Cerebral edema / Meningitis
Plastic surgery injecting toxins during plastic surgery: beware of vessel damage
3 major group of Lymph nodes of head and neck
- Submental nodes
- Submandibular nodes
- Parotid nodes
Lymphatic drainage pathway
Submental, Submandibular, Parotid LN
—> Superficial cervical LN
—> Superior deep cervical LN
—> blood supply
Anterior to vertex: Parotid nodes
Posterior to vertex: Mastoid nodes, Occipital nodes
