axial skeleton

axial skeleton

• vertebral column

• sternum

• ribs

vertebral column

• formed by 24 single bones and 2 fused bones

• from skull to pelvis

• axial support

• 5 curvatures

  • cervical

  • thoracic

  • lumbar

  • sacral

  • coccyx

common vertebrae structure

• transverse process

• spinous process

• vertebral foramen

transverse process

• provide attachment sites for muscles

• transverse; protrude out on the sides of the bone

spinous process

• provide attachment sites for muscles

• protrude out on the top of the bone

vertebral foramen

• holes

• provide passageway for spine to go up and attach to the brain stem

vertebral body

• bears our body weight

• varies in shape

  • largest vertebral body on lumbar bones

  • size of vertebral body increases as body weight beared increases

intervertebral foramen

• provides exit passageway for spinal nerves

• in between vertebrae on the lateral side

fibro-cartilage

• in between vertebrae

• holds them together

cervical curvature

• concave/hourglass shape

• contains 7 vertebrae—”breakfast”

• C1-C7

• make the neck

C1 structure

• “atlas” b/c it supports/holds the skull

• responsible for nodding “yes”

• has no spinous process

• has no body

• has facet that articulates with the condyle of the occipital bone

• has a facet that articulates with dens of axis

• transverse foramen: passageway for blood vessels and veins

• features to gaf abt: anterior and posterior tubercles

  • if you’re looking at it normally (from superior view)—the “top” is the posterior tubercle

  • the “bottom” is the anterior tubercle

C2 structure

• “axis”

• has a spinous process

• has a small body

• has dens (odontoid process)

  • provides axis for skull to sit on/pivot on it

• responsible for nodding “no”

• features to gaf abt: dens

C3-C7 structure

• all have the same structure

• have a small body

• spinous process is bifid

  • bifid: spinous process is split in two like antennae

  • absent in C7!!!!

• vertebral foramen: passageway for spine

• transverse foramen: passageway for blood vessels and veins

thoracic curvature

• convex shape

• contain 12 vertebrae—”lunch”

• T1-T12

• help form the ribs

T1-T12 structure

• long and thin spinous processes

• costal facets on sides for tubercle of rib

  • facets is where ribs attach

  • ribs form thoracic cage

• heart shaped and mid-sized body!!!

• features to gaf abt

  • transverse costal facet

  • superior costal facet

lumbar curvature

• concave/hourglass shape

• contains 5 vertebrae—”dinner”

• L1-L5

L1-L5 structure

• thick and shorter spinous processes

• large, oval shaped bodies

• bear most of the weight

sacrum curvature

5 fused bones to form “1 bone/sacrum”

sacrum 1-5

• 5 fused bones, 4 transverse lines/ridges

• crest is where the last L part articulates

• passageways/holes for nerves and blood vessels

• anterior side is smooth

• posterior side is rough

• features to gaf abt:

  • sacral canal

  • sacral haitus

  • ala

  • sacral promontory

thoracic cage

• composed of sternum and ribs

• cartilage lets the thoracic cavity expand

sternum

• contains 3 parts

1. manubrium: superior part, articulates with the clavicles at it’s superior borders and with first pair of ribs

• features of manubrium to gaf abt: jugular notch and clavicular notch

2. body: middle part

• features of body to gaf abt: sternal angle

3. xiphoid process: the inferior part of the sternum

ribs

• 12 pairs of ribs

  • 7 true pairs: connect directly to the sternum

  • 5 false pairs: connect indirectly to the sternum

    • rib pairs 8-10 are connected to rib pair 7

    • rib pairs 11 and 12 are floating ribs b/c they just hang and don’t articulate at all

rib structure

• junction with costal cartilage so it can articulate with the sternum

• body/shaft is most of it

• neck

• head

• facets for articulation with thoracic vertebrae