1: Anatomic Sciences

1 Anatomic Sciences

The anatomic sciences portion of the National Dental Boards tests the following: gross anatomy, histology, and embryology. Gross anatomy encompasses a wide range of topics, including bones, muscles, fasciae, nerves, circulation, spaces, and cavities. Details and diagrams will focus on topics emphasized on the National Dental Boards. Since it is out of the scope of this book to cover every detail, it is recommended that you refer to past class notes, anatomy texts and atlases, and old exams for a more thorough understanding of the information discussed. Only a limited number of figures and diagrams are included in this text. It will be helpful to refer to other anatomy texts and atlases for more figures and diagrams.

1.0 GROSS ANATOMY

1.1 Head and Neck

1.1.1 Oral Cavity

Vascular supply

The main blood supply to the head and neck is from the subclavian and common carotid arteries. The origins of these arteries differ for the right and left sides. From the aorta, the brachiocephalic trunk branch off and bifurcate into the right subclavian and right common carotid artery. The left common carotid artery and left subclavian artery branch off separately from the arch of the aorta.

D. External carotid artery

3. Major branches (Figure 1-2):

g. Maxillary artery

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Figure 1-1 Inferior view of the brain: circle of Willis.

(From Moore NA, Roy WA: Gross and Developmental Anatomy, St. Louis, Mosby, 2002.)

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Figure 1-2 Lateral view of arteries of the neck and superficial head.

(Modified from Moore NA, Roy WA: Gross and Developmental Anatomy, St. Louis, Mosby, 2002.)

TABLE 1-1 MAJOR BRANCHES OF THE FACIAL ARTERY AND THE STRUCTURES THEY SUPPLY

BRANCHES STRUCTURES SUPPLIED
Ascending palatine artery Soft palate, tonsils, pharynx
Tonsillar artery Tonsils, tongue
Glandular artery Submandibular gland
Submental artery Submandibular gland, mylohyoid and anterior digastric muscle
Inferior labial artery Lower lip
Superior labial artery Upper lip
Lateral nasal artery Nose
Angular artery Eyelids, nose

TABLE 1-2 BRANCHES OF THE THREE MAJOR DIVISIONS OF THE MAXILLARY ARTERY AND THE STRUCTURES THEY SUPPLY

BRAN CHES OF THE THREE MAJOR DIVISIONS STRUCTURES SUPPLIED
Mandibular division  
Inferior alveolar artery (IAA) branches  
Deep auricular artery Tympanic membrane
Anterior tympanic artery Tympanic membrane
IAA (dental branches) Mandibular posterior teeth and surrounding tissues
Mylohyoid artery Mylohyoid muscle, floor of mouth
Incisive artery Anterior teeth and surrounding tissues
Mental artery Chin, lower lip
Middle meningeal artery Meninges of the brain, dura of bones in the skull
Pterygoid division  
Deep temporal arteries Temporalis muscle
Pterygoid arteries Pterygoid muscles
Masseteric artery Masseter
Buccal artery Buccinator, buccal mucosa
Pterygopalatine division  
Posterior superior alveolar artery Maxillary posterior teeth, maxillary sinus
Infraorbital artery, including anterior and middle superior alveolar, orbital, and facial branches Maxillary anterior teeth, orbital area and lacrimal gland
Greater palatine artery Hard palate, lingual gingiva of maxillary posterior teeth
Lesser palatine artery Soft palate, tonsils
Sphenopalatine artery Nasal cavity

Venous drainage

Deoxygenated blood from the head and neck is drained from the area by a network of veins that eventually terminate in the jugular veins. The blood from the jugular veins is ultimately returned to the heart via the subclavian and brachiocephalic veins, which join to form the superior vena cava.

C. Veins of the face: venous drainage of the face and oral cavity (Figure 1-4).

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Figure 1-3 Dural venous sinuses. Arrows note the direction of blood flow.

(From Moore NA, Roy WA: Gross and Developmental Anatomy, St. Louis, Mosby, 2002.)

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Figure 1-4 Lateral view of veins of the neck and superficial head.

(From Moore NA, Roy WA: Gross and Developmental Anatomy, St. Louis, Mosby, 2002.)

Lymphatic drainage

Deep cervical nodes Occipital nodes Scalp Deep cervical nodes

TABLE 1-4 DEEP LYMPH NODES

  LOCATION STRUCTURES DRAINED
Superior deep cervical lymph nodes Inferior to the anterior border of the sternocleidomastoid muscles

Deep parotid nodes

Deep cervical nodes Retropharyngeal lymph nodes Posterior pharynx, at the level of C1 vertebrae

TABLE 1-6 REFLEXES

  AFFERENT EFFERENT
Corneal (blink) reflex CN V1 CN VII
Gag reflex CN IX CN X
Jaw jerk CN V3 CN V3
Oculocardiac relex CN V1 CN X3

Cranial nerves

E. CN V: Trigeminal nerve

3. V2—maxillary nerve

4. V3—mandibular nerve

G. CN VII: Facial nerve

6. Chorda tympani: the chorda tympani branches from the facial nerve, carrying both sensory fibers for taste and preganglionic parasympathetic fibers. It exits from of the temporal bone via the petrotympanic fissure and joins the lingual nerve (a branch of CN V3) as it courses inferiorly toward the submandibular ganglion (see Figure 1-13). Postganglionic parasympathetic fibers emerge from the ganglion and continue toward the sublingual and submandibular glands (see Figure 1-14). Sensory fibers also branch from the nerve and provide taste sensation to the anterior two thirds of the tongue.

J. CN X: vagus nerve

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Figure 1-6 Optic pathway of CN II.

(Modified from Liebgott B: The Anatomic Basis of Dentistry, ed 2, St. Louis, Mosby, 2001.)

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Figure 1-9 Sensory distribution for the three divisions of the trigeminal nerve.

(Modified from Fehrenbach M, Herring S: Illustrated Anatomy of the Head and Neck, ed 2, Philadelphia, WB Saunders, 2002.)

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Figure 1-10 Branches of the maxillary nerve (CN V2).

(Modified from Liebgott B: The Anatomic Basis of Dentistry, ed 2, St. Louis, Mosby, 2001.)

TABLE 1-9 BRANCHES OF THE MAXILLARY NERVE (CN V2)

V2 BRANCH FUNCTION DISTRIBUTION
Posterior superior alveolar nerve Sensory Maxillary second and third molars
    Maxillary first molar: palatal and distobuccal root
    Maxillary sinus
Middle superior alveolar nerve Sensory Maxillary first and second premolars
    Maxillary first molar: mesiobuccal root
Anterior superior alveolar nerve Sensory Maxillary anterior teeth
Greater palatine nerve Sensory Posterior hard palate
    Lingual gingiva of maxillary posterior teeth
Lesser palatine nerve Sensory Soft palate
Tonsils
Nasopalatine nerve Sensory Anterior hard palate
Lingual gingiva of maxillary anterior teeth
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Figure 1-11 Branches of the mandibular division of the trigeminal nerve (CN V3).

(Modified from Liebgott B: The Anatomic Basis of Dentistry, ed 2, St. Louis, Mosby, 2001.)

TABLE 1-10 BRANCHES OF THE MANDIBULAR DIVISION OF THE TRIGEMINAL NERVE (CN V3)

V3 BRANCH FUNCTION DISTRIBUTION
Long buccal nerve Sensory Cheek
Buccal gingiva of posterior mandibular teeth
Posterior buccal mucosa
Lingual nerve Sensory Lingual gingiva of mandibular teeth
Floor of mouth
Inferior alveolar nerve Sensory Mandibular posterior teeth
Mental nerve Sensory Chin
Lower lip
Anterior labial mucosa
Incisive nerve Sensory Mandibular anterior teeth
Auriculotemporal nerve Sensory TMJ
External auditory meatus
Auricle
Deep temporal nerves, anterior and posterior Motor Temporalis muscle
Masseteric nerve Motor Masseter muscle
Lateral pterygoid nerve Motor Lateral pterygoid muscle
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Figure 1-12 Facial nerve (CN VII): motor branches to the muscles of facial expression.

(Modified from Fehrenbach M, Herring S: Illustrated Anatomy of the Head and Neck, ed 2, Philadelphia, W. B. Saunders, 2002.)

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Figure 1-13 Facial nerve (CN VII) branches: greater petrosal nerve and chorda tympani.

(Modified from Liebgott B: The Anatomic Basis of Dentistry, ed 2, St. Louis, Mosby, 2001.)

Spaces and cavities of the head and neck

Potential spaces, or fascial spaces, of the head and neck region are important for a dentist to know because many of these spaces communicate with the oral cavity. Odontogenic infections can therefore spread to these areas.

B. Spaces of the mandibular region

Jan 5, 2015 | Posted by in General Dentistry | Comments Off on 1: Anatomic Sciences
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