IBS - THE SKULL

Skull is the …

• bony framework of the head

• rests on the superior end of the vertebral column

Cranial bones form…

• the cranial cavity

• encloses and protects the brain

• provides attachments for muscles of head and neck

Facial bones form…

• the framework of the face

• contain cavities for the special sense organs

• provide openings for air and food passages

• secure the teeth

• anchor the facial muscles of expression

Parietal bones…

• paired

• form superior and lateral aspects of the skull

Temporal bones…

• paired

• form inferolateral aspects of the skull and part of the cranial floor

• zygomatic process forms the prominence of the cheek

Frontal bone…

• unpaired

• forms the forehead, roofs of the orbits, part of the cranial floor

• Supraorbital foramina allow the passage of

  arteries and nerves

Occipital bone…

• unpaired

• forms posterior aspect and base of skull

• Foramen magnum allows passage of the spinal cord

Sphenoid bone…

• unpaired

• forms posterior aspect and base of the skull

• keystone of the cranial floor because it articulates with all the other cranial bones - holding them together

• contributes to the middle cranial fossa and orbits

Ethmoid bone…

• unpaired

• delicate bone forms anterior aspect and base of the skull

• major superior supporting structure and forms an extensive surface area in the nasal cavity

• Helps to form the anterior cranial fossa

Mandible…

• unpaired - facial

• largest, strongest facial bone

• only movable skull bone (other than the auditory ossicles)

• articulates with the temporal bone to form the temporomandibular joint (TMJ)

Vomer…

(Hint: Doritos!)

• unpaired - facial

• roughly triangular bone on floor of the nasal cavity

• forms the inferior portion of the bony nasal septum

Maxilla…

• paired - facial

• form the upper jaw and parts of the hard palate, orbits, and nasal cavity wall

• Articulate with every bone of the face EXCEPT the mandible

Zygomatic bones (cheekbones)…

• paired - facial

• form the raised parts of the cheeks and part of the orbits.

• temporal process of the zygomatic bone articulates with the zygomatic process of the temporal bone to form the zygomatic arch

Nasal bones are…

• Small, flattened, rectangular-shaped bones

• Form the bridge of the nose

Lacrimal bones…

(Hint: where do tears accumulate?)

• thin and resemble a fingernail

• smallest bones of the face

• form part of the medial orbit walls

• contain a lacrimal fossa

Palatine bones…

• L-shaped palatine bones

• form posterior part of the hard palate and a small part of nasal cavity and orbit walls

Inferior nasal concha…

• scroll-like bones form part of the lateral walls of the nasal cavity

Orbital cavity:

• Cone-shaped bony cavity and houses the eyes

• Contains muscles for eye movement

• Contains the lacrimal glands, vessels and nerves

Cranial and facial bones that form the orbital cavity:

• Frontal

• Sphenoid

• Zygomatic

• Maxilla

• Palatine

• Lacrimal

• Ethmoid bones

Nasal cavity:

• Constructed of bone and hyaline cartilage

• Contains olfactory epithelium

• Provides passage for the air

Cranial and facial bones that form the nasal cavity:

• Ethmoid

• Palatine bones

• Maxillae

• Inferior nasal conchae

→ nasal cavity is divided into right and left parts

by the nasal septum

Paranasal sinuses are cavities near the nasal cavity.

Air-filled cavities are in the:

➢ Frontal

➢ Sphenoid

➢ Ethmoid

➢ Maxillary

Paranasal cavities are lined with…

▪ mucous membranes

▪ warm and humidify the air

▪ resonance to voice

▪ drain into the nasal cavity

Middle Ear: 3 Tiny bones ~ transmit the sound waves.

These three bones are called:

➢ Malleus

➢ Incus

➢ Stapes (Smallest bone in body)

Sutures are…

Immovable joint that holds skull bones together

Coronal suture…

Unites the frontal bone and both parietal bones

Sagittal suture…

Unites the two parietal bones on the superior midline of the skull

Lambdoid suture…

Unites the two parietal bones to the occipital bone

Squamous sutures…

Unite the parietal and temporal bones on the lateral aspects of the skull

Temporomandibular joint is…

• the only mobile joint in the skull

• present between the mandibular condyle and mandibular fossa of temporal bone