Anatomy 13 #2 The hyoid bone & Orbits and nasal cavitys

Hyoid bone

-Not a bone of skull

-Lies in anterior neck inferior to mandible

-Only bone in body that does not articulate directly with another bone

Anchored by ligaments

-Acts as a movable base for tongue and site of attachment for muscles of swallowing and speech

Orbits

– Cavities that encase eyes and lacrimal glands

– Sites of attachment for eye muscles

– Formed by parts of seven bones

-Frontal, sphenoid, zygomatic, maxilla, palatine, lacrimal, and ethmoid

Nasal cavity

formed by parts of several bones

Where is the nasal cavity

-roof

-lateraal walla

-floor

-nasal septum

Roof

cribriform plates of ethmoid

Lateral walls:

superior and middle conchae of ethmoid, perpendicular plates of palatine and Inferior nasal conchae

-Spaces between conchae called meatuses

-Conchae increase turbulence of air flow

Floor:

processes of palatine and maxillary bones

– Nasal septum

Bony posterior formed by vomer and perpendicular plate of ethmoid

- Anterior formed by septal cartilage

Paranasal sinuses:

formed from five skull bones: frontal, sphenoid, ethmoid, and paired maxillary bones

– All contain mucosa-lined, air-filled spaces

– Functions: Warm and humidify air

Help to lighten skull

Enhance resonance of voice