Anatomy

• Orbital Cavity


  • Greater wing of sphenoid
  • Frontal process of zygomatic bone
  • Zygomatic process of frontal bone
  • Superior orbital fissure (where roof and lateral wall meet)
  • Inferior orbital fissure (where lateral wall and floor meet)
  • Lesser wing of sphenoid
  • Superior orbital fissure
  • Greater wing of sphenoid
  • Frontal bone
  • Optic canal
  • Ethmoidal foramina
  • Ethmoid bone
  • Zygomatic bone
• Bony orbits: floor


  • Thin orbital floor
  • Maxillary process of zygomatic bone
  • Zygomaticofacial foramen on malar surface
  • Maxilla
  • Maxillary sinus
  • Infraorbital nerve (enters from pterygopalatine fossa through inferior orbital fissure to infraorbital groove then to infraorbital canal then to infraorbital foramen)
• Openings of the orbit


  • Optic foramen (canal)
  • Superior orbital fissure
  • Inferior orbital fissure
  • Nasolacrimal canal
  • Anterior & posterior ethmoidal foramina
• Bony orbits: medial wall


  • Frontal process of maxilla
  • Frontal bone
  • Lacrimal bone
  • Fossa for lacrimal sac (go to nasolacrimal canal then to inferior nasal meatus)
  • Orbital plate of ethmoid (ethmoidal air cells medial to this)
  • Orbital plate of palatine bone
  • Body of sphenoid: completes the lower part of optic canal
  • Optic canal (where roof and medial wall meet)
  • Anterior & posterior ethmoidal foramina (transmitting corresponding vessels (branch of ophthalmic artery) to supply nasal cavity and ethmoidal air cells)
• The two nasal cavities are the uppermost parts of the respiratory tract and contain the olfactory receptors
• Nasal cavity


  • Separated from each other by a midline nasal septum (which is a perpendicular plate formed from ethmoid & vomer bone)
  • Separated from the oral cavity below by the hard palate
  • Separated from the cranial cavity above by parts of the frontal, ethmoid, and sphenoid bones
• Nasal Bones


  • Fused and form bridge of nose
  • Vary in size considerably
  • The point of junction with the frontal bone is the nasion
  • Articulates with 2 cranial and 2 facial bones
• Vomer bone


  • Forms inferosuperior part of nasal septum
  • Deviated nasal septum
  • Depressions for blood vessels
  • Articulates with 2 cranial bones & 4 facial bones
• Lacrimal Bones


  • About the size & shape of a fingernail
  • Lacrimal foramen for tear duct
  • Lie anteriorly on the medial side of orbit
  • Can be seen on PA and lateral projections X-RAY
  • Articulates with 2 cranial bones and 2 facial bones
• Roof of nasal cavity


  • Cribriform plate of ethmoid
  • Frontal & nasal bone (anteriorly)
  • Sphenoid (posteriorly)
• Floor of nasal cavity


  • Anterior 2/3: palatine process of maxilla
  • Posterior 1/3: horizontal plate of palatine
• Lateral wall of nasal cavity


  • Superior: ethmoid (ethmoidal air cells)
  • Inferior: maxilla (maxillary sinus)
  • Posterior: perpendicular plate of palatine
  • Perpendicular plate separates the nasal cavity from pterygopalatine fossa
  • Sphenopalatine foramen opens from nasal cavity to pterygopalatine fossa
  • Further posteriorly, the medial surface of medial pterygoid plate completes the lateral wall
• Palatine Bones


  • Consists of two plates: horizontal plate, perpendicular plate forming L-shape bone
  • Participates in forming the nasal and oral cavities, as well as the pterygopalatine fossa
  • The hard palate separates the oral and nasal cavities, bordering the oral cavity superiorly and forming the roof of the mouth, and the nasal cavity inferiorly, forming its floor
  • Horizontal portion forms posterior hard palate
  • Vertical portion extends between maxillae and pterygoid plate of sphenoid bone
  • Articulates with 2 cranial bones and 4 facial bones
• Maxilla


  • Incisive foramen
  • Palatine process of maxilla
  • Junction of hard palate and soft palate
• Pterygopalatine fossa (PPF)


  A small but complex space of the deep face in the shape of an inverted pyramid located between the maxillary bone anteriorly, the pterygoid process posteriorly and inferior to the orbital apex
• Shells of bones extending into the nasal cavities


  • Superior concha: part of ethmoid
  • Middle concha: part of ethmoid
  • Inferior concha: a separate bone
• Channels in nasal cavity


  • Sphenoethmoidal recess: above superior concha
  • Superior nasal meatus
  • Middle nasal meatus
  • Inferior nasal meatus