Three parts of the Axial skeleton

1.The Skull
2.The Vertebral Column
3.The Thoracic Cage

Cranial Bones

-encloses and protects the fragile brain tissue

Facial Bones

-supports the eyes and position them anteriorly
-provides attachment sites for facial muscles

All but one of the bones of the skull are joined by interlocking joints called ____________.

Sutures

The mandible, or lower jawbone is attached to the rest of the skull by a _______________.

freely movable joint

Cranial Vault/Calvaria

-the superior, lateral, and posterior walls of the skull

Cranial Base

-forms the skull bottom

What are the three distinct depressions of the cranial base?

1.Anterior cranial fossae
2.Middle cranial fossae
3.Posterior cranial fossae

Frontal Bone

-anterior portion of cranium
-forms the forehead

Supraorbital foramen (notch)

-opening above each orbit allowing blood vessels and nerves to pass

Glabella

-smooth area between the eyes

Parietal Bone (2)

-posterolateral to the frontal bone, forming sides of the cranium

Sagittal Suture

-midline articulation point of the two parietal bones

Coronal Suture

-point of articulation of parietals with frontal bone

Temporal Bone

-inferior to parietal bone on lateral skull

What are the three major parts of the temporal bone?

1. Squamous part
-border the parietals
2.Tympanic part
-surrounds the external ear opening
3.Petrous
-forms the lateral portion of the skull base and contains the mastoid process

Squamous Suture

-point of articulation of the temporal bone with the parietal bone

Zygomatic Process

- bridgelike projection joining the zygomatic bone (cheekbone) anteriorly

Mandibular Fossa

-rounded depression on the inferior surface of the zygomatic process
-forms the socket for the condylar process of the mandible
-where the mandible joins the lower cranium

External Acoustic Meatus

-canal leading to eardrum and middle ear

Styloid Process

-needlelike projection inferior to external acoustic meatus
-attachment point for muscles and ligaments of the neck

Jugular Foramen

-opening medial to the styloid process through which the internal jugular vein and cranial nerves IX, X, and XI pass

Carotid Canal

-opening medial to the styloid through which the internal carotid artery passes into the cranial cavity

Internal Acoustic Meatus

-opening on posterior aspect (or petrous part) of temporal bone allowing passage of cranial nerves

Foramen Lacerum

-jagged opening between the petrous temporal bone and the sphenoid providing passage for a number of small nerves and for the internal carotid artery to enter the middle cranial fossa

Stylomastoid Foramen

-tiny opening between the mastoid and styloid processes through which cranial nerve VII leaves the cranium

Mastoid Process

-Rough projection inferior and posterior to external acoustic meatus
-attachment site for muscles

Occipital Bone

-most posterior bone of the cranium

Lambdoid Suture

-site of articulation of occipital bone and parietal bones

Foramen Magnum

-large opening in base of occipital, which allows the spinal cord to join with the brain

Occipital Condyles

-rounded projections lateral to the foramen magnum that articulate with the first cervical vertebra (atlas)

Hypoglossal Canal

-opening medial and superior to the occipital condyle through which the hypoglossal nerve pass

External Occipital Crest and Protuberance

-midline prominences posterior to the foramen magnum

Sphenoid Bone

Bat-shaped bone forming the anterior plateau of the middle cranial fossa across the width of the skull.
-articulates with all the other cranial bones

Greater Wings

-portions of the sphenoid seen exteriorly anterior to the temporal and forming a part of the eye orbits

Pterygoid Processes

-inferiorly directed trough-shaped projections from the junction of the body and the greater wings

Superior Orbital Fissures

-jagged openings in orbits provding passages for cranial nerves III, IV, V, and VI to enter the orbit where they serve the eye

Sella Turcica

- saddle shaped region in the sphenoid midline

Lesser Wings

-bat shaped portions of the sphenoid bone anterior to the sella turcica

Optic Canals

- openings in the bases of the lesser wings through which the optic nerve (cranial nerve II) enter the orbits to serve the eyes

Foramen Rotundum

- opening lateral to the sella turcica providing passage for a branch of the fifth cranial nerve

Foramen Ovale

opening posterior to the sella turcica that allows passage of the fifth cranial nerve.

Foramen Spinosum

opening lateral to the foramen ovale which the meningeal artery passes

Ethmoid Bone

irregularly shaped bone anterior to the sphenoid

Crista Galli

vertical projection providing a point of attachment for the dura meter, helping to secure the brain within the skull

Cribriform Plates

bony plates lateral to the crista galli through which olfactory fibers pass to the brain

Perpendicular Plate

inferior projection of the ethmoid bone that forms the superior part of the nasal septum

Lateral Masses

irregularly shaped and thin-walled bony regions flanking the perpendicular plate laterally

Mandible

the lower jawbone, which articulates with the temporals in the only freely movable joints of the skull

Mandibular body

horizontal portion; forms the chin

Mandibular Ramus

vertical extension of the body on either side

Condylar Process

articulation point of the mandible with the mandibular fossa of the temporal bone

Coronoid Process

jutting anterior portion off the ramus
-site of muscle attachment

Mandibular Angle

posterior point at which ramus meets the body

Mental Foramen

-prominent opening on the body that transmits the mental blood vessels and nerve to the lower jaw

Mandibular Foramen

-permis passage of the nerve involved with tooth sensation

Alveolar Process

superior margin of the mandible, contains sockets in which the teeth lie

Maxillae

-two bones fused in a median suture
-forms the upper jawbone and parts of the orbits

Palatine Processes

-from the anterior hard palate; meets medially in the intermaxillary suture

Infraorbital Foramen

-opening under the prbit carrying the infraorbital nerves and blood vessels to the nasal region

Lacrimal Bone

-fingernail sized bones forming part of the medial orbit walls between the maxilla and the ethmoid bone

Palatine Bone

-paired bones posterior to the palatine processes