Bones of the Skull (pg 4)

Bones of the Skull

• Skull contains 22 bones (8 cranial and 14 facial)

Bones of the Skull

• Skull contains 22 bones (8 cranial and 14 facial)

• Cranial bones form the cranial cavity that surrounds and protects the brain

Bones of the Skull

• Skull contains 22 bones (8 cranial and 14 facial)

• Cranial bones form the cranial cavity that surrounds and protects the brain

• Facial bones form the framework of the face, support the entrances to the digestive and respiratory systems, and provide attachment points for the muscles involved in facial expression

Cranial Bones• Frontal (1): Forms the forehead and the roofs

of the eye sockets

Cranial Bones• Frontal (1): Forms the forehead and the roofs

of the eye sockets• Parietal (2): Form the sides and roof of the

cranial cavity.

Cranial Bones• Frontal (1): Forms the forehead and the roofs

of the eye sockets• Parietal (2): Form the sides and roof of the

cranial cavity. • Occipital (1): Forms the back and the base of

the cranium. Contains foramen magnum, the hole through which the spinal cord passes

Cranial Bones• Frontal (1): Forms the forehead and the roofs

of the eye sockets• Parietal (2): Form the sides and roof of the

cranial cavity. • Occipital (1): Forms the back and the base of

the cranium. Contains foramen magnum• Temporal (2): Form the lower sides of the

cranium. Contains the external auditory meatus (ear canal)

Cranial Bones• Frontal (1): Forms the forehead and the roofs

of the eye sockets• Parietal (2): Form the sides and roof of the

cranial cavity. • Occipital (1): Forms the back and the base of

the cranium. Contains foramen magnum• Temporal (2): Form the lower sides of the

cranium. Contains the external auditory meatus (ear canal)

• Sphenoid (1): Spans the width of the cranial floor. Shaped like a butterfly

Cranial Bones• Frontal (1): Forms the forehead and the roofs of the eye

sockets• Parietal (2): Form the sides and roof of the cranial cavity. • Occipital (1): Forms the back and the base of the

cranium. Contains foramen magnum• Temporal (2): Form the lower sides of the cranium.

Contains the external auditory meatus (ear canal)• Sphenoid (1): Spans the width of the cranial floor.

Shaped like a butterfly• Ethmoid (1): Forms most of the bony area between the

nasal cavity and the orbits. 3 parts: Crista galli (triangular upper portion), Cribiform plate (contains olfactory foramina), and Perpendicular plate (forms part of nasal septum)

Cranial sutures

• Sagittal suture: between the parietal bones

Cranial sutures

• Sagittal suture: between the parietal bones • Coronal suture: between the frontal bone and

the parietal bones

Cranial sutures

• Sagittal suture: between the parietal bones • Coronal suture: between the frontal bone and

the parietal bones• Lambdoid suture: between the occipital bone

and the parietal bones

Facial Bones• Maxillae (2): Form the upper jaw, floor of the

orbits, and roof of the mouth. Contains the upper teeth

Facial Bones• Maxillae (2): Form the upper jaw, floor of the

orbits, and roof of the mouth. Contains the upper teeth

• Palatine (2): L-shaped bones behind the maxillae. Form posterior part of hard palate

Facial Bones• Maxillae (2): Form the upper jaw, floor of the

orbits, and roof of the mouth. Contains the upper teeth

• Palatine (2): L-shaped bones behind the maxillae. Form posterior part of hard palate

• Nasal (2): Form the bridge of the nose

Facial Bones• Maxillae (2): Form the upper jaw, floor of the

orbits, and roof of the mouth. Contains the upper teeth

• Palatine (2): L-shaped bones behind the maxillae

• Nasal (2): Form the bridge of the nose• Lacrimal (2): Located in the medial walls of the

orbits (eye sockets)

Facial Bones• Zygomatic (2): Cheek bones. Joins with the

temporal bone to form the zygomatic arch

Facial Bones• Zygomatic (2): Cheek bones. Joins with the

temporal bone to form the zygomatic arch• Inferior nasal conchae (2): Thin, curved bones

that project into the nasal cavity

Facial Bones• Zygomatic (2): Cheek bones. Joins with the

temporal bone to form the zygomatic arch• Inferior nasal conchae (2): Thin, curved bones

that project into the nasal cavity• Vomer (1): Forms part of nasal septum

Facial Bones• Zygomatic (2): Cheek bones. Joins with the

temporal bone to form the zygomatic arch• Inferior nasal conchae (2): Thin, curved bones

that project into the nasal cavity• Vomer (1): Forms part of nasal septum• Mandible (1): Lower jaw. Articulates with the

temporal bone at the temporomandibular (TMJ) joint. Contains the lower teeth and mental foramina

Other bones of the skull

• Auditory ossicles: malleus, incus, and stapes. Tiny bones in the middle ear

Other bones of the skull

• Auditory ossicles: malleus, incus, and stapes. Tiny bones in the middle ear

• Hyoid bone: U-shaped bone in the neck. Functions as a base for the tongue. Only bone in the body that does not articulate directly with another bone

Sinuses

• Air-filled cavities lined with mucous membranes. Reduce weight of skull

Sinuses

• Air-filled cavities lined with mucous membranes. Reduce weight of skull

• Located in the frontal, sphenoid, ethmoid, and maxillary bones