Anatomy Chapter 6 - The Axial Skeleton

Cranium

Frontal, parietal, temporal, occipital, sphenoid, ethmoid, mandible, maxillae, palatine

Frontal

Forehead and roof of orbitals

• Supraornital foramen

• Lacrimal fossa

• Supraornital margin

Parietal

Superior and lateral surfaces

• Saggital and coronal sutures

• Superior and inferior temportal lines are attachment sites for temporalis muscles which are responsible for closing mouth

Temporal

Lateral and inferior walls, zygomatic arches, articulation with mandible, protect sensory organs of inner ear

• Squamous suture

• Zygomatic process

• Mandibular fossa

• External auditory meatus

• Styloid process

• Mastoid process

• Jugular foramen

• Carotid canal

• Internal acoustic meatus

• Hyoid, toungue, pharnyx, and larynyx

Occipital

Posterior, lateral, and superior surfaces

• Lambdoidal suture - wormian bone

• Formane magnum - Connects cranial and spinal

• Occipital condyles - Articulates with 1st vertebra

• External occipital protuberance - Attachment site for muscles to stabilize head

Sphenoid

Articulates with every cranial bone, connects facial and cranial bones

• Greater wings

• Sella turcica - Pituitary gland

• Hypophyseal fossa - Pituitary gland

• Lesser wings

• Optic canal

• Foramen ovale

Ethmoid

Orbital wall, anteromedial floor of cranium, roof of nasal cavity, part of nasal septum

• Christa galli - Stabilizes brain’s position

• Cribiform complex - Cribiform foramine, olfactory nerves

• Perpendicular plate - Nasal septum

• Lateral masses - Superior and middle nasal concha slow air movement

Mandible

Lower jaw, body, angle, and ramus

• Mandibular condyle - Articulates with temporal bone

• Mandibular notch

• Coronoid process - Temporalis muscle inserts to allow closing of mouth

• Mental foramen - Nerves

• Temperomandibular joint

• Alveolar part - Alveoli and roots of teeth

Maxillae

Upper jar, articulates with all other facial bones except mandible

• Alveolar margin

• Palatine process - Bony roof of mouth

• Orbital rim - Protects eye

• Infraorbital foramen - Nerves

Palatine

L - shaped bones articulate with maxillae to complete posterior portion of bony plate

Facial bones

Zygomatic, lacrimal, nasal, vomer, nasal conchae

Zygomatic

Forms lateral rim of orbit

• Temporal process - Cheek

• Central piece of zygomatic arch

Lacrimal

Medial portion of orbit

• Nasolacrimal groove - Tear duct

Nasal

Articulate with frontal bone

Vomer

Inferior portion of nasal septum

Nasal conchae

Superior and middle located on lateral masses of ethmoid bone

• Inferior paired bones that resemble the others

Paranasal sinuses

Air spaces connected to nasal cavities

Frontal, ethmoidal, sphenoid, maxillary

Hyoid bone

Suspended by stylohyoid ligament, movement of tongue and larynx

Orbit

7 bones - Frontal, maxilla, zygomatic, sphenoid, ethmoid, lacrimal, and palentine

Fetal skull

Allows skull to be distorted during delivery without being damaged

Fontal fontanel - Frontal, sagittal, and coronal suture

Occipital fontanel - Lambdoid and sagittal sutures

Sphenoid fontanel - Squamous and coronal sutures

Mastoid fontanel - Squamous and lambdoid sutures

Fontanel

Fibrous CT

Vertebral column number

24 single, sacrum, coccyx

Vertebral column function

Bears body’s weight and transfer that weight to lower limbs

Protects spinal chord

Vertebral column spinal curvature

Bring weight closer to body’s axis

Cervical curve

Thoracic curve

Lumbar curve

Saccral curve

Vertebral body

Anterior, bears weight, articulates with neighbors separated by vertebral discs

Intervertebral foramen

Passageway of nerves

Vertebral spinous process

Projects dorsally, muscle attachment

Vertebral superior and articular vertebral surfaces

Arise from pedicle/lamina junction

Vertebral foramen

Vertebral arch surrounds spinal chord

Pedicles

Walls

Lamina

Roof

Body

Floor

Transverse process

Extend from pedicle/lamina junction, attachment of muscles, articulation of ribs

Intervertebral discs

Fibrous cartilage, elastic CT ligaments

Cervical vertebra

Atlas - C1

Axis - C2, no intervetebral discs between C1 and C2

C2 - C5 - Transverse foramina

C7 - Vertebral prominens

Thoracic vertebra

T1 - T12

Vertebra articulating with ribs

Lumbar vertebra

L1 - L5

Sacrum

Superior articulating surface, transverse lines of fusion, sacral foramina

Coccyx

3 - 5 fused vertebra

Sternum

Manubrium, sternal angle, xiphoid process

Ribs

Head, tubercle, angle, body - superior surface, costal groove