Axial Skeleton

Question 1

parts of the axial skeleton

Answer 1

skull, vertebral column and bony thorax

Question 2

how many cranial bones are there and what holds them together

Answer 2

8; immovable joints called sutures

Question 3

what is the purpose of sutures

Answer 3

this type of jigsaw piece joining increases surface area which forms strong articulation

Question 4

how many facial bones are there

Answer 4

14

Question 5

what are the paired and unpaired bones of the cranium

Answer 5

paired bones: temporal and parietal
unpaired bones: frontal, occipital, sphenoid and ethmoid

Question 6

what are the 5 cranial sutures

Answer 6

• coronal suture (parietal and frontal)
• squamous suture (parietal and temporal)
• lambdoid suture (parietal and occipital)
• sagittal suture (L and R side of parietal bone)
• occipitomastoid suture (occipital and temporal)

Question 7

what are the paired and unpaired facial bones

Answer 7

paired: maxillae, zygomatic, nasal, lacrimal, palatine and inferior nasal conchae
unpaired: mandible and vomer

Question 8

what is the only moveable facial bone

Answer 8

mandible

Question 9

what bones make-up the hard palate

Answer 9

maxilla and palatine

Question 10

how many vertebrae are there and what are the subdivisions

Answer 10

26; 7 cervical; 12 thoracic; 5 lumbar, sacrum (5 fused vertebrae) and coccyx (4 fused vertebrae)

Question 11

why is the vertebral column curved

Answer 11

provides flexibility and with perfect posture it balances the weight of the head over the pelvis

Question 12

when is the primary curve present

Answer 12

during fetal development, the thoracic and sacral are formed (single curve)

Question 13

when do secondary curves form

Answer 13

cervical forms when infant raises head at 4 months, lumbar forms when infant sits up and begins to walk at 1 year

Question 14

what are intervertebral discs

Answer 14

cushion-like pads between vertebrae, act like shock absorbers and compose about 25% of vertebral column height, composed of nucleus pulposus and anulus fibrosus

Question 15

what is the nucleus pulposus

Answer 15

gelatinous inner sphere of intervertebral disc, enables spine to absorb compressive stresses

Question 16

what is the anulus fibrosus

Answer 16

outer collar of ligaments and fibrocartilage, keeps nucleus pulposus intact and functions to bind vertebrae together, resist tension on the spine and absorb compressive forces

Question 17

what are the 3 ligaments of the spine and their function

Answer 17

ligamentum flava: elastic fibres for recoil
anterior longitudinal ligament: for backwards arching
posterior longitudinal ligament: for forward arching

Question 18

what is a herniated disc and how is it caused

Answer 18

nucleus pulposus leaks out and impedes spinal cord or spinal nerves (loses cushioning properties), anulus fibrosus weakens, may be caused by trauma to spine, aging also

Question 19

herniated disc treatment

Answer 19

discs are fused (cannot have two vertebral bodies resting on each other), but loss of some range of motion

Question 20

what is an articular process and facet

Answer 20

outcropping of bone, facet is smooth

Question 21

what forms from all the vertebral foramen together

Answer 21

spinal canal

Question 22

what is the intervertebral foramen

Answer 22

holes that get created for nerves exiting the vertebral column

Question 23

which vertebrae are the smallest and lightest and why

Answer 23

cervical; only bare the weight of the skull

Question 24

which cervical vertebrae are typical and why

Answer 24

C3 to C7, body is wider laterally, spinous processes are short and bifid (except C7, known as vertebra prominens, looks more thoracic than superior partners), vertebral foramen are large and triangular, transverse processes contain transverse foramina and superior articular facets face superoposteriorly (face up and tipped slightly back)

Question 25

what is C1 called

Answer 25

atlas

Question 26

what is C2 called

Answer 26

axis

Question 27

what is special about C1

Answer 27

lacks body and spinous process, superior articular facet receives occipital condyles to support the skull, allows flexion and extension of neck (nodding "yes")

Question 28

what is special about C2

Answer 28

less specialized than C1, has a body, a spinous process, and a dens (odontoid process) which projects superiorly and articulates with C1, held in place by transverse ligaments and acts as a pivot point for rotation of atlas (shaking head "no")

Question 29

how do the thoracic vertebrae differ from cervical

Answer 29

larger and stronger bodies, spinous processes are long and point inferiorly, longer transverse processes and vertebral foramen are circular

Question 30

what characterizes thoracic vertebrae

Answer 30

by the need to articulate with the ribs

Question 31

how do thoracic vertebrae articulate with the ribs

Answer 31

thoracic vertebrae have facets or demifacets on the body for the head of the rib and facets on transverse processes (T1 to T10) for tubercle of rib

Question 32

which way do superior and inferior articular processes of thoracic vertebrae point and what does this allow

Answer 32

superior articular facet points posteriorly, inferior articular facets points anteriorly, allows rotation and prevents flexion and extension

Question 33

what differentiates lumbar vertebrae and what do they allow

Answer 33

bodies are thick and robust, transverse processes are thin and tapered, spinous processes are thick, blunt and point posteriorly, vertebral foramina are triangular, superior articular facets directed medially and inferior articular facets directed laterally, allow flexion and extension but rotation prevented

Question 34

what characterizes the sacrum

Answer 34

shapes the posterior wall of pelvis, formed from 5 fused vertebrae, superior surface articulates with L5 and inferiorly articulates with coccyx

Question 35

what characterizes the coccyx

Answer 35

"tailbone", formed from 3 to 5 fused vertebrae (we say 4 as the avg), offers only slight support to pelvic organs (sometimes more problematic than useful)

Question 36

what is scoliosis

Answer 36

abnormal lateral curvature in the thoracic region (S-shaped), occurs most often in girls, results from abnormally structured vertebrae, lower limbs of unequal length, non functional muscles or muscle paralysis

Question 37

what is kyphosis

Answer 37

hunchback/exaggerated thoracic curvature, most common in aged women due to spinal fractures following osteoporosis

Question 38

lordosis

Answer 38

sway-back/accentuated lumbar curvature, usually temporary in pregnant women and obese men (to accommodate for extra weight in front)

Question 39

what are the components of the bony thorax

Answer 39

ribs, sternum and costal cartilage

Question 40

what is the function of the bony thorax

Answer 40

forms the framework of the chest, protects thoracic organs, supports pectoral girdle and upper limbs, provides attachment sites for muscles

Question 41

what are the components of the thoracic cage

Answer 41

thoracic vertebrae and bony thorax

Question 42

what are the rib designations

Answer 42

true ribs: 1 to 7, directly attached to sternum via costal cartilage, superior false ribs: 8 to 12, still attached to sternum via costal cartilage but indirectly, inferior floating ribs: 11 and 12, no direct attachment to sternum

Question 43

what are the 3 sections of the sternum

Answer 43

manubrium: superior section, articulates with medial end of clavicles at clavicular notch body: bulk of sternum, sides are notched at articulations for costal cartilage of ribs 2 to 7 xiphoid process: inferior end of sternum, ossifies around age 40, beforehand is cartilage

Question 44

how do the ribs articulate with the thoracic vertebrae

Answer 44

the inferior costal facet on the vertebrae above joins with the superior costal facet on the vertebrae below to create a complete facet for the head of the rib

Question 45

what are the 3 types of skeletal cartilages

Answer 45

hyaline: most widespread supports with flexibility and resilience (seen in trachea and respiratory system) elastic: more flexible fibrocartilage: highly compressible and great tensile strength (seen in knee joint, anulus fibrosus and pubic symphysis)