Overview
This lecture provides a comprehensive overview of key extraoral and intraoral anatomical landmarks essential for dental hygiene assessments and board exams.
Extraoral Landmarks
- The head and neck are divided into defined regions, each with specific anatomical landmarks.
- Temporal region includes the helix, auricle, external acoustic meatus, tragus, antitragus, intertragic notch, and earlobe.
- Orbital region features include lacrimal gland, pupil, iris, sclera, conjunctiva, lateral and medial canthus, eyelids, and orbital rim.
- Nasal region landmarks: root, bridge, septum, apex, naris (nostril), ala, and nasolabial sulcus.
- Zygomatic, buccal, and infraorbital regions cover the cheekbone, zygomatic arch, angle of mandible, and masseter muscle.
- Frontal region includes frontal eminence, glabella, and supraorbital ridge.
- Mental region covers labiomental groove and mental protuberance (chin).
- Oral region includes philtrum, tubercle, upper/lower lips, vermilion border/zone, and labial commissures.
- The anterior and posterior cervical triangles are separated by the sternocleidomastoid muscle and bordered by the mandible, trapezius, and clavicle.
Intraoral Landmarks
- Maxillary (upper) and mandibular (lower) refer to upper/lower arches; palatal is the roof of the mouth; buccal is towards the cheek; lingual is towards the tongue; labial is near the lips.
- Hard and soft palate separated by the vibrating line; soft palate ends with the uvula.
- Maxillary tuberosity is posterior to the last upper molar; retromolar pad is behind last lower molar.
- Pterygomandibular fold is a key site for local anesthesia.
- Fauces area includes anterior and posterior faucial pillars with palatine tonsils between them.
- Parotid papilla is located near the maxillary molars; buccal and alveolar mucosaes line the cheeks and alveolar ridges.
- Vestibules are spaces between cheeks/lips and teeth/gums; mucobuccal fold is where alveolar and buccal mucosa meet.
- Labial and lingual frena are tissue folds connecting lips/tongue to the gums.
- Attached gingiva (keratinized) and alveolar mucosa (non-keratinized) are separated by mucogingival junction.
- Marginal (free) gingiva surrounds teeth, forming the gingival sulcus (pocket).
- The incisive papilla covers the incisive foramen, crucial for anesthesia.
- Median palatine raphe runs along the midline of the palate; palatine rugae are irregular ridges beside it.
- Hamular notch lies between the maxillary tuberosity and hamular process.
- Dorsal (top), ventral (bottom), and lateral (side) tongue surfaces have specific papillae: filiform (carpet-like), fungiform (mushroom-like), foliate (leaf-like), and circumvallate (large, V-shaped row).
- Floor of mouth includes deep lingual veins, plica fimbriata, retro mylohyoid curtain, sublingual caruncles (opening of submandibular/Wharton's duct), and alveololingual sulcus.
- Mandibular tori are normal bony growths found in some people.
- The pharynx regions are nasopharynx, oropharynx, and laryngopharynx.
Key Terms & Definitions
- Auricle — entire external ear structure.
- Tragus/Antitragus — cartilage projections at the front/back of ear canal.
- Canthus — corner of the eye (medial/lateral).
- Ala — wing-like cartilage on the side of the nose.
- Nasolabial sulcus — groove running from the nose to the corner of the mouth.
- Philtrum — vertical groove above the upper lip.
- Vermilion Border/Zone — red outline/area of the lips.
- Labial Commissure — junction where upper/lower lips meet.
- Sternocleidomastoid — neck muscle dividing cervical triangles.
- Maxillary Tuberosity — bony protrusion behind upper molars.
- Retromolar Pad — tissue behind lower molars.
- Pterygomandibular Fold — mucosal fold for anesthesia landmark.
- Fauces — opening at the back of the mouth; includes faucial pillars and tonsils.
- Frenum — fold of tissue connecting lips/tongue to gums.
- Mucogingival Junction — line where attached gingiva and alveolar mucosa meet.
- Incisive Papilla — tissue over incisive foramen behind upper front teeth.
- Palatine Rugae — ridges on the anterior hard palate.
- Median Palatine Raphe — midline seam of the hard palate.
- Circumvallate Papillae — large taste buds forming a V-shape at tongue base.
- Sublingual Caruncles — small elevations for salivary duct openings under the tongue.
- Alveololingual Sulcus — space between the alveolar ridge and tongue.
Action Items / Next Steps
- Complete and review your guided readings on anatomical landmarks.
- Memorize the key anatomical landmarks, especially those highlighted for local anesthesia and radiology.
- Practice identifying these landmarks on yourself or others.
- Prepare for quizzes/exams by reviewing the anterior and posterior cervical triangle contents.