#8 the axial skeleton (vertebral column, thoracic cage)

five regions of the vertebral column

1. cervical

2. thoracic

3. lumbar

4. sacral

5. coccyx

how many vertebrae are found within the cervical region?

7

• smallest and lightest vertebrae

• sensitive area

C1 (cervical region) →

• what does it lack

• what does it articulate with

atlas

• has no body

• has no spinous process (allows you to nod)

• articulates superiorly with the occipital condyle (base of skull)

C2 (cervical region) →

• what components does it have

axis

• contains all typical vertebral components. not as specialized as atlas

• contains the dens, allowing you to shake your head no!

the dens (c2)

knoblike process that projects superiorly from the body of the vertebrae

• aka odontoid process

• pivot for atlas rotation

C3 to C7 (cervical region) →

• what is its distinguishing feature

• transverse foramina: opening where the vertebral arteries pass in order to service the brain

how many vertebrae in the thoracic region

12, labelled T1-12

thoracic region →

• what do the vertebrae articulate with?

• what is the sizes of the vertebrae

• what is its distinguishing feature

• articulate posteriorly with the ribs

• vertebrae increase in size from first to last

• articular facet: used for rib articulation

how many vertebrae are in the lumbar region

5 → L1 to L5

lumbar region →

• vertebrae function?

• what is it commonly referred as

• what kind of body does it contain

• what is the size of its processes

• support the body’s weight

• “small of the back”

• large, thick body

• processes are heavy and rectangular

how many vertebrae in the sacrum

5 fused vertebrae

the sacrum →

• what does it articulate with

• what does it contain

• articulates with the ilium (part of appendicular skeleton), specifically the pelvis

• also articulates with 5th lumbar vertebra superiorly

• contains intervertebral foramina

intervertebral foramina (sacrum)

exit sites for the spinal nerves

coccyx →

• how many vertebrae does it have

• what is it also known as

• what is its function

• 3-5 but usually 4 vertebrae

• known as the tailbone

• generally useless

normal curvature of the vertebral column

• cervical and lumbar sections curved concave posteriorly

• thoracic and sacral sections curved convex posteriorly

scoliosis

spinal column curves laterally

kyphosis

hunchback

• exaggerated thoracic curve which can be caused by osteoporosis

lordosis

• swayback

• caused by an exaggerated lumbar curve which can be caused by pregnancy or pot bellies

what does the thoracic cage consist of

sternum and ribs

sternum

• what is it

• what are its parts and where are they located

• breast bone

• manubrium is superior

• body is the middle portion

• xiphoid process is inferior

how many pairs of ribs are there, what do they articulate with

• 12 pairs

• articulate posteriorly with thoracic vertebrae

true ribs

• attach directly to the sternum via costal cartilage (hyaline cartilage)

• 7 pairs

false ribs

attach either indirectly to the sternum or not at all

where do rib pairs 8-10 attach

attach indirectly to the sternum via costal cartilage

• they piggyback #7

where do rib pairs 11-12 attach

they are not attached. they are embedded in muscle.

• aka floating ribs