• Skull 
  Cranium
  o    Superior portion formed by the frontal. parietal, and occipital bones
  o    Lateral portions formed by the temporal and sphenoid bones
  o    Cranial base formed by the temporal. sphenoid, and ethmoid bones
  o    Fontanels-soft spots in which ossification is incomplete at birth

  Frontal bone
  o    Forms the forehead
  o    Contains the frontal sinuses
  o    Forms the roof of the orbits
  o    Union with the parietal bones forms the coronal suture

  Parietal bones
  o    Union with the occipital bone forms the lambdoid suture
  o    Union with the temporal bone forms the squamous suture
  o    Union with the sphenoid bone forms the coronal suture

  Temporal bones
  o    Contains the external auditory meatus and middle and inner ear structures
  o    Squamous portion-above the meatus: zygomatic process-articulates with the zygoma
  o    to form the zygomatic arch 

  •    Petrous portion
  o    Contains organs of hearing and equilibrium 
  o    Prominent elevation on the floor of the cranium

  •    Mastoid portion
  o    Protuberance behind the ear

  o    Mastoid process
  •    Glenoid fossa-articulates with the condyle on the mandible
  •    Styloid process-anterior to the mastoid process; several neck muscles attach here
  •    Stylomastoid foramen-located between the styloid and mastoid processes; facial nerve emerges through this opening
  •    Jugular foramen-located between the petrous portion and the occipital bone: cranial nerves IX. X, and XI exit
   

Structure of the Nasal Septum

• This part bony, part cartilaginous septum divides the chamber of the nose into two narrow nasal cavities.
• The bony part of the septum is usually located in the median plane until age 7; thereafter, it often deviates to one side, usually the right.

• The nasal septum has three main components: (1) the perpendicular plate of the ethmoid bone; (2) the vomer, and (3) the septal cartilage.

• The perpendicular plate, which forms the superior part of the septum, is very thin and descends from the cribiform plate of the ethmoid bone.
• The vomer, which forms the posteroinferior part of the septum, is a thin, flat bone. It articulates with the sphenoid, maxilla and palatine bones.

The Orbital Vessels

• The orbital contents are supplied chiefly by the ophthalmic artery.
• The infraorbital artery, the continuation of the maxillary, also contributes blood to this region.
• Venous drainage is through the superior orbital fissure to enter the cavernous sinus.

The Ophthalmic Artery

• This artery arises from the internal carotid artery as it emerges from the cavernous sinus.
• It passes through the optic foramen within the dural sheath of the optic nerve and runs anteriorly, close to the superomedial wall of the orbit.

The Central Artery of the Retina

• This is the one of the smallest but most important branches of the ophthalmic artery.
• It arises inferior to the optic nerve until it approaches the eyeball.
• It then pierces the optic nerve and runs within it to emerge through the optic disc.
• The central artery of the retina spreads over the internal surface of the retina and supplies it.

The Ophthalmic Veins

The Superior Ophthalmic Vein

• The superior ophthalmic vein anastomoses with the facial vein.
• It has no valves and blood can flow in either direction.
• It crosses superior to the optic nerve, passes through the superior orbital fissure and ends in the cavernous sinus.

The Inferior Ophthalmic Vein

• This begins as a plexus on the floor of the orbit.
• It communicates with the inferior orbital fissure with the pterygoid plexus, crosses inferior to the optic nerve, and ends in either the superior ophthalmic vein or the cavernous sinus.

Genioglossus Muscle

• Origin: Mental spine of the mandible.
• Insertion: Dorsum of the tongue and hyoid bone.
• Nerve Supply: Hypoglossal nerve (CN XII).
• Arterial Supply: Sublingual and submental arteries.
• Action: Depresses and protrudes the tongue.

The Hard Palate

• The anterior bony part of the palate is formed by the palatine process of the maxillae and the horizontal plates of the palatine bones.

• Anteriorly and laterally, the hard palate is bounded by the alveolar processes and the gingivae.
• Posteriorly, the hard palate is continuous with the soft palate.

• The incisive foramen is the mouth of the incisive canal.
• This foramen is located posterior to the maxillary central incisor teeth.
• This foramen is the common opening for the right and left incisive canals.
• The incisive canal and foramen transmit the nasopalatine nerve and the terminal branches of the sphenopalatine artery.

• Medial to the third molar tooth, the greater palatine foramen pierces the lateral border of the bony palate.
• The greater palatine vessels and nerve emerge from this foramen and run anteriorly into two grooves on the palate.

• The lesser palatine foramen transmits the lesser palatine nerve and vessels.
• This runs to the soft palate and adjacent structures.