Head and Neck Regions — Study Notes

Head and Neck Anatomy — Regions and Landmarks (Study Notes)

• Why this is important: oral cancer screenings, radiology, anesthesia, patient comfort and stability during procedures. $2$

Frontal region

• Forehead and area above the eyes
• Supraorbital ridge (eyebrow) – prominent in males
• Glabella – flat in children and adult females
• Frontal Eminence – prominence of the forehead

Parietal and Occipital region

• Covered by the scalp
• Scalp consists of layers of soft tissue overlying the braincase
• Hairline is an important landmark to note during exam

Temporal region

• External Ear
• Auricle – oval flap of ear
• Helix – superior & posterior free margin of the auricle
• Lobule – fleshy protuberance of the earlobe
• External acoustic meatus
• Tragus – flexible when palpated
• Antitragus – opposite tragus
• Inter-tragic notch – deep notch between tragus and antitragus
• (Note: diagram includes additional labeled structures such as Scaphoid fossa, Triangular fossa, Concha, etc.)

Orbital region

• Orbit houses the eyeball and supporting structures
• Eyeball components: Sclera (white of the eye), Iris (colored area), Pupil (black opening in center of iris)
• Lacrimal gland – located below the eyebrow; produces tears (lacrimal fluid)
• Conjunctiva – delicate thin membrane lining inside of eyelids and front of eyeball
• Lateral canthus – outer corner
• Medial canthus – inner angle

Nasal region

• Root of the nose – between the eyes
• Nasion – inferior to glabella
• Bridge of the nose – inferior to the nasion
• Apex – flexible tip
• Naris (Nares) – nostrils; inferior to the apex; $2$ nares
• Nasal Septum – divides the nares
• Ala – winglike edges of the nostrils

Parts of the nose

• Naris
• Position of the nasion
• Root of nose
• Bridge of nose
• Nasal septum (outlined)
• Ala
• Nasolabial sulcus – between the labial commissure and the nose
• Apex

Facial regions (facial aspect)

• Infraorbital region – inferior to the orbital, lateral to nasal
• Zygomatic region – overlies the zygomatic arch
• Temporomandibular joint (TMJ) – upper skull forms a joint with the lower jaw; movement can be felt at the external acoustic meatus
• Buccal region – cheek; formed mainly by the masseter muscle; palpable when clenching; often sore with bruxism
• Angle of the mandible – sharp angle inferior to the ear lobule

Oral region

• Vermilion border outlines the vermilion zone of the lips
• Mucocutaneous junction – transition zone from lips to surrounding skin
• Philtrum – vertical groove between nose and upper lip
• Tubercle of the upper lip – termination point of the philtrum
• Labial commissure – where upper and lower lips meet
• Nasolabial sulcus – groove between the lip and nose
• Labiomental groove – groove separating lower lip from chin
• Upper lip, tubercle, lower lip (key landmarks)

Oral region anatomy — jawbones and mucosa

• Maxilla – upper jaw
• Mandible – lower jaw
• Oral Mucosa – mucous membrane lining the oral cavity
• Labial mucosa – inner parts of the lips
• Buccal mucosa – lining inside of the cheek; protects buccal fat pad
• Lingual – near the tongue
• Palatal – near the palate
• Labial/Facial – near the lips/face
• Buccal – near the inner cheek

Oral cavity directional terms

• Oral cavity
• Buccal
• Facial (labial)
• Maxillary teeth
• Palatal
• Lingual
• Mandibular teeth

Oral cavity landmarks

• Vestibule – horseshoe-shaped space between teeth and cheeks or lips
• Parotid papilla – small elevation in buccal mucosa opposite the maxillary second molar; protects the ductal opening of the parotid gland
• Maxillary tuberosity – elevation on the posterior aspect of the maxilla; distal to the last molar on the maxilla
• Top vestibule; mucobuccal fold
• Retromolar pad – dense pad of tissue distal to the last molar on the mandible
• Labial Frenum – folds/attachments between labial and alveolar mucosa at both maxilla and mandible
• Lingual Frenum – anterior midline fold connecting the ventral surface of the tongue to the floor of the mouth
• Sublingual fold – v-shaped folds on the floor of the mouth; contain openings for the sublingual duct

Oral cavity landmarks (visual reference)

• Parotid papilla, buccal mucosa, labial mucosa, maxillary vestibule, alveolar mucosa, mucobuccal fold, mandible vestibule

Teeth

• Mandibular (lower) teeth – centrals, laterals, canines, premolars, molars
• Maxillary (upper) teeth – centrals, laterals, canines, premolars, molars

Palate

• Hard palate (anterior portion) – firm; contains the median palatine raphe, incisive papilla, palatine rugae
• Median palatine raphe – midline ridge from the uvula to the incisive papilla
• Incisive papilla – small bulge at the most anterior part of the hard palate, lingual to maxillary anterior teeth
• Palatine rugae – firm irregular ridges on the hard palate
• Soft palate (posterior portion) – contains the uvula and the pterygomandibular fold/raphe
• Uvula – muscular structure at the midline of the soft palate
• Pterygomandibular fold/raphe – fold of tissue from the junction of hard and soft palates down to the mandible, just posterior to the second molar line; separates oral palate from pharynx

Tongue anatomy

• Tongue has 3 regions: Pharyngeal (base), Body (anterior 2/3 within the oral cavity), and Apex (tip); $3$ regions
• Apex – tip
• Four surfaces – lateral (sides), dorsal (top), ventral (underneath), and one more surface implied by anatomy
• Base – attaches to the floor of the mouth; considered part of the oral portion of the throat; Lingual tonsil
• Body – anterior 2/3 of tongue; contains various papillae

Tongue anatomy — diagrammatic surfaces and landmarks

• Lingual tonsil – at the base on the dorsal surface
• Circumvallate lingual papillae – large papillae near the sulcus terminalis; contain taste buds
• Filiform lingual papillae – slender, thread-like; numerous on the apex; typically do not contain taste buds
• Fungiform lingual papillae – mushroom-shaped; more numerous on the apex
• Filiform papillae – listed again as a component of the dorsal surface
• Apex of the tongue – the tip
• Palatine tonsil – located near the pharyngeal region
• Foramen cecum – small pit-like depression at the apex of the sulcus terminalis
• Sulcus terminalis – V-shaped groove separating the base from the body
• Median lingual sulcus – midline groove on the dorsal surface

Dorsal surface of the tongue and taste buds

• Lingual papillae – associated with taste buds
• Foliate papillae – on the lateral surface; more prominent in children; associated with vertical ridges
• Fungiform papillae – mushroom-shaped; more numerous on the tongue apex
• Circumvallate papillae – $10-14$; large mushroom-shaped papillae containing taste buds

Locations of papillae on the tongue

• Epiglottis
• Lingual tonsil
• Palatine tonsil
• Foramen Cecum
• Circumvallate Papillae
• Vallate sulcus terminalis (Vallasulcus Terminalis)
• Foliate papillae
• Fungiform papillae

Tongue dorsal architecture

• Sulcus Terminalis – V-shaped groove separating base from body; tissue changes are visible
• Foramen Cecum – at the apex of the sulcus terminalis; small pit-like depression
• Lingual tonsil – irregular lymphoid tissue on the dorsal surface at the base

Ventral tongue architecture

• Contains visibly large lingual veins; run near the surface and are easily seen

Floor of the mouth

• Located inferior to the ventral surface of the tongue
• Lingual Frenum (frenulum) – midline fold between floor of mouth and ventral tongue surface
• Sublingual Fold (plica sublingualis) – V-shaped folds containing openings for the sublingual ducts (sublingual caruncle)

Pharynx

• Muscular tube serving both the respiratory and digestive systems
• Three portions: $3$ portions
• Laryngopharynx – most inferior; not visible during an oral exam
• Nasopharynx – superior to the soft palate; continuous with nasal cavity
• Oropharynx – between the soft palate and the opening of the pharynx; contains the faucial (palatine) tonsils between the faucal pillars
• Fauces are formed laterally by anterior and posterior faucial pillars
• Palatine tonsils are located between the pillars (commonly referred to as “tonsils” by patients)

Clinical application (tonsils)

• Compare differences in tonsil size, color, and shape during assessment

Mental region

• Major landmark = chin
• Mental protuberance – prominence of the chin; more pronounced in males
• Labiomental groove – horizontal groove between the lower lip and chin

Regions of the neck

• Extends from the skull and mandible to the clavicles and sternum
• Sternocleidomastoid – large strap muscle dividing the neck into anterior and posterior cervical triangles
• Thyroid cartilage – “Adam’s apple”; houses vocal cords
• Hyoid bone – suspended in the neck; site of muscular attachment, especially for swallowing

Anterior Cervical Triangle

• Consists of $4$ regions
• Submandibular triangle – formed by the mandible and the anterior and posterior bellies of the digastric muscle
• Carotid triangle / Muscular triangles – inferior parts of the anterior cervical triangle subdivided by the omohyoid muscle
• Submental triangle – formed by the right and left anterior bellies of the digastric muscle and the hyoid bone

Posterior Cervical Triangle

• Two regions
• Occipital triangle – superior to the omohyoid muscle
• Subclavian triangle – inferior to the omohyoid