Skull and Face

Boonsirm Withyachumnarnkul, M.D., Ph.D.

Department of Anatomy, Faculty of Science

Mahidol University

Bony Landmarks of Skull and Face

• Vertex• Superciliary arch• Zygoma• Mental symphysis• Entrance to orbit• Anterior nasal

aperture

Three foramina vertically alligned

• Supraorbital foramen … for supraorbital nerve

• Infraorbital foramen … for infraorbital nerve

• Mental foramen ... for mental nerve

Muscles of Facial Expression

• Develop from the 2nd branchial arch, thus all are supplied by CN VII.

• Most are thin, originate from facial bones to insert on facial skin, except platysma, and are intermingled at their insertions.

Muscles of Facial Expression

• Muscle of the forehead … frontalis, as part of the occipitofrontalis

• Muscles of the mouth• Muscle of the eyelids• Muscle of the nose• Platysma

Muscles of the Mouth

• Orbicularis oris• Zygomaticus major• Zygomaticus minor• Levator labii superioris• Levator labii superioris alaque nasi• Buccinator• Depressor anguli oris• Depressor labii inferioris• Mentalis• Risorius• Platysma

Muscles of the Mouth

Muscle of the Eyelids

• Orbicularis oculi– Orbital part

– Palpebral part

Buccal Pad Fat

• Between masseter and buccinator muscles

• Brown fat … for heat generation, especially for children

Parotid Duct

• One finger-breadth below zygomatic arch

• Open into the mouth cavity (vestibule) at the level of the 2nd molar tooth (crown)

Facial Nerve

• Comes out from stylomastoid foramen

• Five branches– Temporal

– Zygomatic

– Buccal

– Mandibular

– Cervical

Facial Palcy

• No wrinkle of forehead

• Angle of mouth drops

• Sagging lower eyelid• Other signs relating

to malfunctions of structures innervated by facial nerve

Trigeminal Nerve• Sensory

– Ophthalmic division

– Maxillary division

– Mandibular division

• Motor .. To 1st branchial arch

– Muscles of mastication

• Messeter

• Temporalis

• Medial pterygoid

• Lateral pterygoid

Arteries of the Face(rich, tortuous and highly anastomosed)

• From external carotid artery– Facial artery– Superficial temporal

artery– Transverse facial artery

• From internal carotid artery– supraorbital artery– supratrochlear artery

Veins of the Face

• Two important veins– Facial vein

– Retromandibular vein

• Facial veins have no valves

• Connection of facial veins, pterygoid plexus and cavernous sinus

Lymph Drainage of the Face

• Submental lymph nodes

• Submandibular lymph nodes

• Parotid lymph nodes

Scalp, Cranial Cavity and Venous Sinuses

Boonsirm Withyachumnarnkul, M.D., Ph.D.

Department of Anatomy, Faculty of Science

Mahidol UniversityHead2.ppt in C (Mahidol)

Scalp• Five layers of scalp

– skin– dense subcutaneous tissue– epicranial aponeurosis– loose areolar connective tissue– periosteum

Scalp• Clinical relevance

– infection spreading from loose areolar connective tissue, via emissary veins, to meninges-meningitis

– hematoma

Skull Cap or Calvaria• Suture

– coronal (frontoparietal)• anterior fontanelle

– sagittal (interparietal)– lambdoid (occipitoparietal)

• posterior fontanelle

Skull Cap or Calvaria• Three layers of skull cap

– outer table– diploe– inner table

Cranial Fossae

• Anterior cranial fossa• Middle cranial fossa• Posterior cranial fossa

• Boundaries– lesser wing of sphenoid– superior border of petrous bone

Anterior Cranial Fossa• important landmarks

– crista galli & cribriform plate of ethmoid

– sella turcica• tuberculum sellae• hypophyseal fossa• dorsum sellae

Middle Cranial Fossa• important landmarks

– foramina• superior orbital fissure• foramen rotundum• foramen ovale• foramne spinosum

– groove for middle meningeal artery

Posterior Cranial Fossa• important landmarks

– grooves for transverse & sigmoid sinuses– foramen magnum

Dura Mater

• Outer and inner layers– position of the middle meningeal

artery

Dura Mater• Falx cerebri• Falx cerebelli• Tentorial cerebelli and notch• Diaphragmatic sellae

Intradural Venous Sinuses• Superior and inferior sagittal sinuses• Straight sinus• Transverse and sigmoid sinuses

Intradural Venous Sinuses• Cavernous sinus

– relationship among internal carotid artery, CN III, CN IV, CN V1 and CN VI

– venous connections– clinical relevance

• thrombophlebitis

Orbit and Eye

Boonsirm Withyachumnarnkul, M.D., Ph.D.

Department of Anatomy, Faculty of Science

Mahidol University

•eyelids•palpebral fissure•plica semilunaris•caruncle•lacrimal puncta•cornea•sclera •conjunctiva

•bulbar•palpebral

•Sty•pterygium

Eye From the Outside

Bony Parts of the Orbit

Entrance of the Orbit•frontal bone•zygomatic bone•maxillary bone

More Bones Inside•ethmoid bone•greater and lesser wing of sphenoid•lacrimal bone

Foramina of the Orbit•optic foramen (canal)

•optic n.•ophthalmic a.

•superior orbital fissure•all other nerves•superior ophthalmic vein

•inferior orbital fissure•infraorbital n. & a.•inferior ophthalmic v.

•infraorbital groove & foramen•zygomatic & infraorbital n.

•supraorbital notch & foramen•supraorbital n.

Eyeball

Eyeball

Muscles•Extrinsic (Extra-ocular)•Intrinsic

Levator Palpebrae Superioris

•Supplied by CN III•insert on the upper lid•if paralyzed ptosis

Extra-Ocular Muscles•Superior

Rectus• Inferior

Rectus•Lateral Rectus•Medial Rectus

•Superior Oblique

• Inferior Oblique

Actions of the Extra-Ocular Muscles

• Around vertical axis– medial or adduction– lateral or abduction

• Around horizontal axis– upward or elevation– downward or

depression• Around antero-posterior

axis– medial rotation– lateral rotation

elevate

adduct

medial rotate

Make a 10-15 o with an AP axis

Superior Rectus

depress

adduct

lateral rotate

Inferior Rectus

Medial and Lateral Recti

Medial Rectus•adduction

Lateral Rectus•abduction

•depress•abduction•medial rotate

Superior Oblique

•elevate•abduction•lateral rotate

Inferior Oblique

Periorbita and Orbital Fat

Insertions of the Extra-Ocular Muscles

Nerves of the Extra-Ocular Muscles

• Oculomotor Nerve (CN III)– supplies all except lateral

rectus and superior oblique• Trochlear Nerve (CN IV)

– superior oblique• Abducens Nerve (CN VI)

– lateral rectus

Oculomotor nerve (CN III)

Superior Division• levator palpebrae superioris*• superior rectusInferior Division• inferior rectus• inferior oblique• medial rectus*not an extra-ocular muscle

Functional Tests of the Extra-Ocular Muscle

Principle•align the muscle axis with the eyeball AP axis•contract the muscle

e.g., for Superior Rectus•abduct, first•then, elevateTherefore, test for the superior rectus function is to abduct and elevate

Parts of the Eyeball

•anterior chamber•posterior chamber•cornea•iris•ciliary muscle•suspensory ligament•lens•hyaloid canal•vitreous body•aqueous humor

Three layers•sclera•choroid•retina

•lenticular cataract•glaucoma•Schlemn’s canal•Myopia (near sightedness)•hyperopia (far sightedness)•presbiopia (old-aged sightedness)

Clinical Relevance

Blood Vessels of the Orbit & Eyeball

in the choroid layer

Ophthalmic•Frontal

•anterior & posterior ethmoidal•supraorbital•supratrochlear

•lacrimal•central retinal

Ophthalmoscopic Examination

•optic disc•macula lutea & fovea centralis•retinal vessels in DM & hypertension

•superior & inferior ophthalmic veins•drained to cavernous sinus•connection to pterygoid plexus•connection to facial veins

Veins of the Eyeball

Sensory Nerves of the Eyeball and Orbit

•frontal•supraorbital•supratrochlear

•lacrimal nerve•nasociliary nerve

•anterior ethmoidal•posterior ethmoidal•infratrochlear

Autonomic Nerves of the Eyeball and Orbit

Sympathetic

artery (ophthalmic a) long ciliary n. eyeball

iris (radial fibers)

Parasympathetic

pre-ganglionic parasympathetic fibers (in the nerve to inferior oblique) ciliary ganglion short ciliary n.

Eyeball ciliary muscle & iris (circular fibers)

post-ganglionic sympathetic fibers

Ciliary Ganglion

•Lacrimal puncta•lacrimal canaliculi•lacrimal sac•nasolacrimal duct•opening into the inferior meatus of nasal cavity

Lacrimal Gland and Lacrimal Apparatus

Parasympathetic Supply to the Lacrimal Gland

Preganglionic parasympathetic fibers pterygopalatine ganglionmaxillary n zygomatic branch zygomatico-temporal branch

lacrimal n lacrimal gland

•upper & lower eyelids•conjunctiva•palpebral fissure & palpebral sac•tarsal plates (superior & inferior)•tarsal muscle & nerve (sympathetic n)•tarsal gland & ciliary gland; Meibomitis & sty•attachment of levator palpebrae superioris

Eyelid

Orbital Septum, Medial & Lateral Palpebral

Ligament

Submandibular Region, Nasal Region and Oral Cavity

Boonsirm Withyachumnarnkul, M.D., Ph.D.

Department of Anatomy, Faculty of Science

Mahidol University

Head 6. ppt in C (Mahidol)

Submandibular Region

• Inferior border of mandible• Suprahyoid muscles• Including submandibular triangle• Submandibular gland• Nerves

– lingual– hypoglossal– mandibular branch of CN VII

• Blood vessels– lingual– facial

• Lymph nodes, submandibular lymph nodes

Submandibular Triangle

• Anterior belly of digastric muscle– Origin, digastric fossa of

mandible– Nerve, nerve to mylohyoid (CN V)

• Posterior belly of digastric muscle– Origin, mastoid notch– Nerve, CN VII

• Inferior border of mandible

Actions of Digastric Muscle

• Elevate hyoid bone• Open jaw• Raising floor of mouth for

swallowing reflex

Suprahyoid Muscles• Digastric• Mylohyoid• Geniohyoid• Hyoglossus• Stylohyoid

Mylohyoid Muscle

• Origin, mylohyoid line of mandible• Insertion

– Body of hyoid bone– Median fibrous raphe

• Nerve, nerve to mylohyoid (CN V)

Geniohyoid Muscle• Origin, mental spine• Insertion, hyoid bone• Nerve, C1 spinal nerve

Hyoglossus Muscle

• From hyoid bone to side of the tongue

• Nerve, hypoglossal nerve

Stylohyoid Muscle• Origin, styloid process• Insertion, hyoid bone (two

slips)• Nerve, CN VII

Concerted Action of Suprahyoid Muscles

Elevate floor of mouth for swallowing reflex

Submandibular Gland

• superficial part• deep part• the two parts are separated by

mylohyoid muscle• mixed serous and mucous

gland• submandibular duct

– from deep part– open at sublingual caruncle

Anatomical Relationship

• Hypoglossal and lingual nerves are between mylohyoid and hyoglossus muscles

• Closed relationship between lingual nerve and submandibular duct

Chorda tympani• special sense (taste) from anterior

2/3 of tongue• preganglionic parasympathetic fibers

to submandibular and sublingual gland, via submandibular ganglion

The Nasal Region

• Nostrils• Vestibule• Nasal cavity• Choanae• Nasal septum

– Cartilage, septal cartilage– Bone

•perpendicular plate of ethmoid

•vomer•maxillary & palatine

Lateral Wall of the Nasal Cavity

Chonchae• superior, part of ethmoid• middle, part of ethmoid• inferior, separate bone

Lateral Wall of the Nasal Cavity

Meatuses• sphenoethmoidal recess, opening of

sphenoidal sinus• superior, opening of posterior ethmoidal air

cells• middle

– bulla ethmoidalis, opening of middle ethmoidal air cells

– hiatus semilunaris, opening of• maxillary sinus• anterior ethmoidal air cells• frontal sinus, infundibulum

• inferior, opening of nasolacrimal duct• common meatus

Nerves of the Nasal Cavity

• Special sense, olfactory n. "olfactory mucosa"

• General sense, "respiratory mucosa"– branch of nasociliary n.

• anterior ethmoidal n.– branches of maxillary n.

• nasopalatine n.• posterior superior lateral

nasal n.• posterior inferior lateral nasal

n.• Test of olfactory function

Third Part of the Maxillary Artery

• superior alveolar a.– posterior– anterior, from infraorbital a.

• infraorbital a.• descending palatine a.

– greater palatine a.– lesser palatine a.

• sphenopalatine a.

Blood Supply of the Nasal Cavity

• from sphenopalatine a.– posterior lateral

nasal br.– posterior septal br.

• from ophthalmic a.– anterior and

posterior ethmoidal a

Paranasal Air Sinuses

• Locations– frontal sinuses– ethmoidal air cells

• posterior• middle• anterior

– sphenoidal sinuses– maxilary sinus

• Functions– warm and humidify air– resonance

Maxillary Nerve

• out of the skull through foramen rotundum• branches

– zygomatic n.•zygomaticotemporal n.•zygomaticofacial n.

– infraorbital n., out from the infraorbital foramen

– superior alveolar n.; anterior, middle, posterior

– two small br. to pterygopalatine ganglion

Pterygopalatine Ganglion

In• pterygopalatine br. from maxillary n., general sense• nerve of pterygoid canal

– parasympathetic– sympathetic

Out• pterygopalatine br. to maxillary n., parasympathetic

fibers to lacrimal gland• pharyngeal n.• greater and lesser palatine n.• superior and inferior lateral nasal n.• nasopalatine n

Pterygopalatine Ganglion

All the "out" branches supply• submucosal gland,

parasympathetic• general sense• lacrimal gland,

parasympathetic

Mouth & Lips

• vestibule• oral cavity proper• nasolabial sulcus• philtrum• labial gland• frenulum• palatoglossal arch• palatopharyngeal arch• opening of parotid duct• opening of submandibular & sublingual ducts

The TeethTypes• incisor, 2• canine, 1• premolar, 2• molar, 3Nerves and vessels (to teeth and gingivae)• alveolar

– superior (maxillary n. and a.)• anterior• middle• posterior

– inferior (mandibular n., maxillary a.)• nasopalatine (maxillary n. and a.)• greater palatine (maxillary n. and a.)

The Tongue

• sulcus terminalis• foramen caecum• papillae

– circumvallate– fungiform– filiform– foliform

• lingual tonsil

Muscles of the Tongue

• Intrinsic– longitudinal– transverse– vertical

• Extrinsic– hyoglossus– genioglossus (movement of tongue)– styloglossus– palatoglossus

Artery & Nerves of the Tongue

Artery• lingual a.Nerves• motor, hypoglossal n., except

palatoglossus (vagus n.)• sensory

– general, CN V, IX & X– special, CN VII (anterior

2/3) & CN IX (posterior 1/3), CN X

The Palate• Hard palate• Soft palate, muscles

– tensor veli palatini (CN V)– levator veli palatini (CN X)– musculus uvulae (CN X)– palatoglossus (CN X)– palatopharyngeus (CN X)

• Clinical relevant– openning of auditory tube– test of CN X

Blood Supply of Palatine Tonsil (important for tonsillectomy)from lingual a.

• dorsal lingual a.from facial a.• tonsillar br.• ascending palatine a.from ascending pharyngeal a.• palatine br.lesser palatine a.