Board Review

• Branchial Arches


  Contribute to the development of the head and neck
• Branchial Arches


  • First arch (mandibular arch)
  • Second arch (hyoid arch)
• Mandibular arch


  Forms the middle and lower face

  
• Meckel's Cartilage


  Forms the foundation for the mandible
• Nerve supply of the first arch

  Becomes the 5th cranial nerve

  
• First arch


  Contributes to the muscles of mastication
• Hyoid arch


  Contributes to the muscle of facial expression

  
• Reichert's cartilage


  Cartilage in the hyoid arch
• The Developing Face (weeks 6-10)

  1. Mandibular processes merge at the midline to form the rudimentary mandible, the lower lip and the lower part of the face

  2. Maxillary processes form the midface, cheeks and zygoma

  3. Maxillary process forms the lateral part of the upper lip

  4. Frontonasal process contributes to the forehead, part of the nose and through the nasal placodes the primary palate and filtrum

  5. Medial nasal process on the inner side of each nasal pit merge into the intermaxillary segment (globular process) and form the upper lip, crest, and tip of the nose

  6. Lateral nasal process from each side merge to form the alae of the nose

  
• The Palatal Development (weeks 6-11)

  1. The palate is formed when the primary and secondary palates fuse

  2. The secondary palate is formed from the maxillary process

  3. The point of fusion between the primary and secondary palates is between the lateral and canine teeth

  
• Tongue Development (Weeks 4-8)


  1. Formed from first 4 branchial arches

  2. Body formed from first branchial arch
• The Developing Tongue Details

  • The tongue is derived from the first, second, third, and fourth branchial arches
  • The body of the tongue (The anterior 2/3) is developed from the first branchial arch
  • The base of the tongue is developed from the 2-4 branchial arches
  • During the development of the body of the tongue a median swelling called the tuberculum impar develops at the base of the stomodeum
  • Two lateral lingual swellings develop on each side of the tuberculum impar and grow over and cover it
  • The body of the tongue is separated from the primitive mouth by cell degeneration (Lingual frenum remains in the adult)
  • The base of the tongue (the poster 1/3) begins to form at the appearance of the copula, swellings behind the fused anterior swellings
  • The copula develops from the 3rd and 4th arches
  • The copula overgrows the 2nd branchial arch and forms the base of the tongue which is the posterior 1/3 of the tongue
  • The sulcus terminalis is where the body and the base of the tongue fused
  • The foramen cecum is at the center of the sulcus terminalis and is the remnant of the opening to the thyroid duct (where the thyroid gland descended into the neck)
• Osteology of the Palate-Important Terms

  • Palatine process of the maxilla
  • Horizontal plate of the palatine bone
  • Incisive foramen
  • Greater palatine foramen (In the palatine bone)
  • Lesser palatine foramen
  • Median palatine suture

  
• The floor of the nasal cavity is formed by the Maxillary and palatine bones

  
• TEMPORAL BONE


  • Styloid Process
  • Interior and exterior acoustic meatus
  • Carotid canal
  • Stylomastoid foramen (CN VII exits here)

  
• Zygomatic Arch


  Union of the zygomatic process of the temporal bone and of the temporal process of the zygomatic bone

  
• Cranial Nerves


  • Cribriform Plate-CN I
  • Optic Foramen-CN II
  • Superior Orbital Fissure-CN III, IV, V-1, VI
  • Foramen Rotundum-CN V-2
  • Foramen Ovale-CN V-3
  • Internal Auditory Canal (Internal Acoustic Meatus)-CN VII, VIII
  • Jugular Foramen-CN IX, X, XI
  • Hypoglossal Canal-CN XII

  
• Cranial Nerves Mnemonic


  Oh Oh Oh to touch and feel very good velvet Ah
• Cranial Nerve V Innervations

  • Olfactory (I)
  • Optic (II)
  • Oculomotor (III)
  • Trochlear (IV)
  • Trigeminal (1-3) (V)
  • Abducens (VI)
  • Facial (VII)
  • Vestibulocochlear (VIII)
  • Glossopharyngeal (IX)
  • Vagus (X)
  • Accessory (XI)
  • Hypoglossal (XII)

  
• V1-Ophthalmic Nerve Branches (Superior Orbital Fissure)

  • Frontal Nerve
  • Lacrimal Nerve
  • Nasocillary Nerve

  
• V2-Maxillary Nerve Branches (Foramen Rotundum)

  • Infraorbital Nerve
  • Anterior Superior Alveolar
  • Middle Superior Alveolar
  • Posterior Superior Alveolar
  • Greater Palatine Nerve
  • Lesser Palatine Nerve
  • Nasopalatine Nerve

  
• V3-Mandibular Nerve Branches (Foramen Ovale)

  • Auriculotemporal Nerve
  • Motor Branches
  • Inferior Alveolar Nerve
  • Incisive Nerve
  • Mental Nerve
  • Long Buccal Nerve
  • Lingual Nerve
  • Mylohyoid Nerve

  
• The Seventh Cranial Nerve Review

  • The VII cranial nerve (Facial) derives from the Hyoid Arch (2nd Branchial arch)
  • The seventh cranial nerve has both afferent and efferent fibers
  • The motor part and sensory part of the facial nerve enters the petrous part of the temporal bone through the internal auditory meatus (Along with CN VIII)
  • Before exiting the skull through the styomastoid foramen CN VII gives off two important branches: The Greater Petrosal Nerve and the Chorda Tympani Nerve
  • The Chorda Tympani Nerve provides parasympathetic efferent fibers to the sublingual and submandibular glands and afferent-taste fibers to the body of the tongue
  • Though CN VII passes through the parotid gland, it does not innervate the gland (This is the responsibility of cranial nerve IX, the glossopharyngeal nerve)
  • The Facial nerve innervates the muscles of facial expression (efferent branches)

  
• Major Branches of CN VII

  • Temporal Branch
  • Zygomatic Branch
  • Buccal Branch
  • Mandibular Branch
  • Cervical Branch
• The Chorda Tympani (Branch of CN VII)

  • Afferent taste branches to body of tongue
  • Efferent parasympathetic branches to the sublingual and submandibular salivary glands
• Bell's Palsy


  Unilateral paralysis of the facial nerve
• The Tongue Innervation


  • CN V3 Trigeminal-Sensory to anterior 2/3 of tongue (Lingual Branch)
  • CN VII Facial nerve-Taste to anterior 2/3 of tongue (Chorda Tympani)
  • CN IX Glossopharyngeal- Sensory and taste to posterior 1/3 of tongue
• Branches of the External Carotid Artery Mnemonic

  • Superior Thyroid
  • Ascending Pharyngeal
  • Lingual (and Sublingual)
  • Facial-See handout for the branches
  • Occipital
  • Posterior Auricular
  • Maxillary- See branches
  • Superficial Temporal

  
• The common carotid artery provides the most reliable arterial pulse
• Internal Carotid Artery


  Enters the cranium via the carotid canal and supplies the intracranial structures and branches to the ophthalmic artery which supplies the eye, the orbit and the lacrimal gland
• The Maxillary Artery
• Posterior 1/3 of tongue

  Sensation and Taste: Glossopharyngeal (IX) Sensation –Lingual nerve (V3) Taste-Chorda Tympani (VII)
• Branches of the External Carotid Artery Mnemonic

  • Superior Thyroid
  • Ascending Pharyngeal
  • Lingual (and Sublingual)
  • Facial-See handout for the branches
  • Occipital
  • Posterior Auricular
  • Maxillary- See branches
  • Superficial Temporal

  
• Internal Carotid Artery


  • Enters the cranium via the carotid canal
  • Supplies the intracranial structures and branches to the ophthalmic artery which supplies the eye, the orbit and the lacrimal gland
• The Maxillary Artery


  1. Gives off many branches in the pterygo-palatine fossa

  2. The main branches include the middle meningeal, the inferior alveolar, the muscle branches, the posterior superior alveolar, the infraorbital, the sphenopalatine and branches of the descending palatine (greater and lesser palatines)

  3. The middle meningeal branch enters the foramen spinosum on its way to the cranium

  4. The inferior alveolar branch will branch again to form the mylohyoid artery

  5. The inferior alveolar artery enters the mandibular foramen and canal and branches to the mental artery

  6. The mental artery exits the mental foramen

  7. The inferior alveolar artery continues on to become the incisive artery

  8. The maxillary artery branches to the muscles of mastication and the buccinator muscle

  9. The infraorbital branch (IO)= enters the orbit via the inferior orbital fissure

  10. The anterior superior alveolar artery branches off of the IO artery

  11. The IO branch of the maxillary artery will exit the IO foramen

  12. The posterior superior alveolar artery branches off the maxillary artery

  13. The descending palatine artery travels down the sphenopalatine canal, becomes the greater and lesser palatine arteries after exiting the greater and lesser palatine foramina

  14. The nasopalatine artery is also known as the sphenopalatine artery (The nosebleed artery)

  15. The nasopalatine artery will eventually go down the incisive canal (and anastomose with the greater palatine artery)

  
• Veins in the head and neck region

  • Generally do not have valves
  • The internal jugular is the larger vein and drains the brain and most other tissues of the head & neck
  • The internal jugular vein originates in the cranial cavity and leaves the skull through the jugular foramen
  • The pterygoid plexis of veins is a massive collection of anastomosing veins in the infratemporal fossa
  • The cavernous venous sinus communicates with the pterygoid plexus
  • Veins of the head region can drain into the cavernous venous sinus and can carry infection to this region
  • The retromandibular vein is formed from the superficial temporal and maxillary veins

  
• Muscles of Mastication


  • Innervation by CN V mandibular division (V3)
  • Masseter-Superficial Head (Enlarges during bruxism)
  • Masseter-Deep Head
  • Temporalis
  • Medial Pterygoid
  • Lateral Pterygoid-Superior and Inferior Heads

  
• Sternocleidomastoid Muscle


  • Origin: The sternum and the clavicle
  • Insertion: The mastoid process of temporal bone
  • Action: Contraction of one side bends the head
  • Action: Contraction of both sides "bows the head"
  • Innervation: CN XI (Accessory nerve)

  
• Trapezius Muscle


  • Action: Contraction causes the shoulders to shrug
  • Innervation: CN XI (Accessory nerve)
• Suprahyoid Muscles (Raise the hyoid bone)


  • Digastric
  • Mylohyoid
  • Stylohyoid
  • Geniohyoid