Bio210 Lecture 4: The Axial Skeleton

Front 1

The axial skeleton has 3 types of bones

Back 1

The Skull (Cranium and Facial bones)

Thoracic Cage (ribs)

Vertebral Column (cervicals, thoracics, lumbars, sacrum, coccyx)

Front 2

The cranium has how many bones?

Back 2

8: 2 parietal, 2 temporal, 1 frontal, 1 occipital, sphenoid, ethmoid

Front 3

Occipital bone:
foramen magnum

Back 3

the big hole that connects the skull to the first cervical vertebrae

the connection between the brain and spinal cord

Front 4

Parietal bone:
inferior and superior temporal lines

Back 4

frontal sinuses secrete mucous to clean the nasal cavity

low ridges that provide area for muscle attachment to temporalis muscle which closes the mouth

Front 5

Frontal bone:
Supra-orbital margin

Back 5

a thickening of the roof of the orbits on the frontal bones to protect the eye

Front 6

Temporal bone:
zygomatic arch and its two processes

Back 6

temporal bone is aka squamosal

temporal bone is the only articulation with mandible

protect the sense organs of the inner ear

attachment sites for muscles that close jaws and move head

zygomatic process articulates with temporal process of zygomatic bone, forming zygomatic arch = cheekbone

Front 7

Temporal bone cont'd:
mandibular fossa, styloid process

Back 7

mandibular fossa - on the inferior surface, marks the articulation with the mandible

styloid process - near base of mastoid process, attached to ligaments that support the hyoid bones and tendons of several muscles associated with hyoid bone, tongue, pharynx

Front 8

Sphenoid bone:
Pterygoid process

Back 8

sphenoid acts as base for skull, support sides of skull and sphenoid nasal cavity produces mucous to clean nasal cavity

pterygoid process is an area for muscle attachment related to move mandible and soft palate.

Front 9

Ethmoid bone

Back 9

anteromedial base of the skull, roof of nasal cavity forming part of septum, medial orbital wall, mucous secretions from a network of sinuses flush nasal cavities. Where our sense of smell passes.

Front 10

How many facial bones are there?

Back 10

14, major ones to know: maxillary (paired with external and palatal components), palatines, vomer, lacrimal, nasal, zygomatics (jugal), mandible (lower jaw and teeth)

Front 11

Maxillary Bone:
palatine process, inferior orbital fissure

Back 11

maxillary supports upper teeth, inferior orbital rim, upper jaw, forms most of hard palate, maxillary sinuses to flush nasal cavities, largest sinuses and largest facial bones.

palatine processes form most of the hard palate. Cleft palate happens when the maxillary bones fail to meet at the midline of the hard palate.

inferior orbital fissure: lies between maxilla and sphenoid, allows cranial nerves and blood vessels to pass.

Front 12

Palatine Bones

Back 12

form the posterior part of the hard palate and contribute to the floor of each orbit.

Front 13

Vomer

Back 13

forms the inferior version of the bony nasal septum, increases surface area for the nasal cavity and separates nasal and oral cavity.

Front 14

Lacrimal Bones

Back 14

form part of the medial wall of the orbit, smallest facial bones

Front 15

Nasal Bones

Back 15

support superior portion of nose bridge, the distal portion of the nose.

it's connected to the cartilage and soft tissue and extends to the external nares (entrances to nasal cavity)

Front 16

Zygomatic bones

Back 16

contribute to the rim and lateral wall of the orbit, form part of zygomatic arch

Front 17

The Mandible:
coronoid process, condylar process, mental foramina

Back 17

the mandible forms the lower jaw,articulates with mandibular fossa of temporal bone

the condylar process articulates with temporal bone's mandibular fossa (joint called temporomandibular joint)

coronoid process is an area of attachment for temporalis muscle

mental foramina is a passageway for nerves to carry sensory info from lips and chin to the brain.

Front 18

Occipital condyle

Back 18

located on occipital bone, articulation between skull and first vertebra of the neck

Front 19

Jugular Foramen

Back 19

between occipital bone and temporal bone (at the base of the skull), carries the internal jugular vein which carries venous blood from the brain.

Front 20

Foramen Ovale

Back 20

in the sphenoid, carries nerves from lower jaw which carry sensory info from that area and help to move the lower jaw.

Front 21

Optic Canal

Back 21

in the sphenoid, carries the optic nerve which brings info from the eye to the brain.

Front 22

Orbital complex

Back 22

orbits: bony recesses containing eyes

comprised of seven bones: maxillae (inferior orbital rim), lacrimal bones (medial wall), zygomatic bones (lateral wall), frontal bone (roof, superior orbital rim), sphenoid, palatines (floor), ethmoid

Front 23

vertebrae c1: Atlas

Back 23

Named atlas after Greek myth of a god Atlas who holds the world on his shoulders. Atlas c1 holds the/connects the spine to the neck via occipital condyles.

Different from other vertebrae because:
1) no vertebral body or spinous process
2) large vertebral foramen bound by anterior and posterior arches.

allows you to nod up and down ("yes")

Front 24

vertebrae c2: Axis

Back 24

Axis c2 fuses with Atlas c1 as we develop, a dens becomes prominent, where a transverse ligament wraps around it to bind the Axis to the Atlas. This allows the movement of shaking a head left to right ("no")

not completely fused in children therefore can cause damage if shake them hard enough or blow to base of person's skull sends the dens into the base of the brain (fatal)