Axial skeleton

Question 1

Trabecular bone

Answer 1

• Found on the inside of mature bone
• Especially at the ends of long bones where compressive forces are greatest
• Moulded by mechanical forces & stresses
• Contains red and/or yellow bone marrow

Question 2

Compact bone

Answer 2

• Found on the outside of mature bones
• Solid, hard surface layer
• Thickest around the shaft of long bones where tensile & torsional stresses are greatest

Question 3

Long bones

Answer 3

• Length > breadth
• Tubular in shape – gives the strongest & lightest combination
• Shaft or body (diaphysis, which is usually hollow)
• Two expanded ends for articulation (epiphyses)
• Leavers

Question 4

Short bones

Answer 4

• Cuboid in shape
• Thin layer of compact bone supported by a network of trabecular bone
• Found in the wrist & foot
• Resist compression

Question 5

Irregular bones

Answer 5

*Usually have extensions of bone creating a variety of irregular shapes
* Examples - include facial bones & vertebrae
* Attachment - more SA for muscles

Question 6

Pneumatized bones

Answer 6

• Bones with air-filled cavities
• Present in the skull
• Serves to lighten the skull & add resonance to the voice
• Examples – maxilla, ethmoid
• Dont have bone marrow

Question 7

Flat (squamous bones)

Answer 7

• Two flat laminae of compact bone with spongy bone (& marrow) in between
• Usually protective or reinforcing
• Forms walls of cavities, eg skullcap (calvarial) bones, sternum, scapula

Question 8

Sutural bones

Answer 8

• Small flat ‘biscuit’ like joining bones
• Typically fuse with the larger flat bones of the skull and disappear in adults

Question 9

Sesamoid bones

Answer 9

• Round or oval nodules
• Resemble sesame seeds, hence the name
• Develop in certain tendons (postnatal), where the tendon is exposed to pressure
• Protect tendon from excessive wear
• Can help change the line of pull of muscles, giving them a mechanical advantage
• Example – patella (kneecap) – the largest sesamoid bone
• Looks like sesame seeds - protects tendons

Question 10

Tuberosity

Answer 10

large round elevation (L. lump or swelling), eg deltoid tuberosity

Question 11

Trochanter

Answer 11

large blunt elevation (G. a runner), eg greater trochanter of femur

Question 12

Protuberance

Answer 12

swelling or knob (L. I bulge out), eg mental protuberance

Question 13

Tubercle

Answer 13

small raised eminence (L. small lump or swelling), eg humerus

Question 14

Malleolus

Answer 14

Malleolus = hammerhead-like elevation (L. small hammer), eg medial malleolus of tibia

Question 15

Ridge or line

Answer 15

Ridge or line = linear elevation, eg supracondylar ridge

Question 16

Crest

Answer 16

Prominent ridge, eg iliac crest

Question 17

Spine or spinous process

Answer 17

sharp elevation or projecting part (L. thorn), eg SP of
vertebra

Question 18

Head

Answer 18

rounded articular area, eg head of humerus

Question 19

Condyle

Answer 19

rounded articular area (G. knuckle), eg femoral condyles

Question 20

Epicondyle

Answer 20

prominent process just proximal to a condyle (G. epi=upon) eg elbow

Question 21

Fossa

Answer 21

small hollow (L. ditch), eg radial and coronoid fossae

Question 22

Articular facet

Answer 22

small, smooth flat area for articulation with another bone

Question 23

Foramen

Answer 23

an opening in bone (L. hole) OR a notch that is bridged by a ligament

Question 24

Sulcus

Answer 24

long narrow depression (L. groove), eg sulci on brain

Question 25

Notch

Answer 25

indentation at the edge of a bone, eg trochlear notch

Question 26

Meatus

Answer 26

Canal that enters a structure but does not pass through it (L. passage), eg
external auditory meatus

Question 27

Bones in axial skeleton

Answer 27

80 bones
Skull - 22 ones and 7 associated with skull
Vertebral column - 24 vertebrae, 1 sacrum, 1 coccyx
Thoracic - 24 ribs and 1 sternum

Question 28

Functions of axial skeleton

Answer 28

create a framework that supports and protects organs in the dorsal and ventral body cavities
- house special sense organs for taste, smell, hearing, balance and sight.
- provide an extensive surface area for the attachment of muscles
- permit limited movement
- contain red marrow for blood cell formation

Question 29

Excessive curvature conditions

Answer 29

Scoliosis = lateral
Kyphosis = sagittal, primarily thoracic
Lordosis = sagittal, primarily lumbar

Question 30

Part of vertebrae

Answer 30

Body, pedicle & lamina
Processes -transverse & spinous
Articular processes - superior & inferior
Vertebral foramen
Intervertebral notches - superior & inferior

Question 31

Intervertebral disc

Answer 31

Holds vertebrae together, small amount of movement

Question 32

Cervical

Answer 32

Typical Cervical (L. neck) Vertebrae = C3-6
* Small body
* Transverse processes have anterior & posterior tubercles
* Vertebrarterial foramen (transversarium) for vertebral artery & vein
* Large triangular vertebral foramen (for size of vertebral body)
* Almost horizontal articular facets
* Bifid spinous processes

Question 33

Thoracic

Answer 33

Typical Thoracic (G. chest) Vertebrae = T2-9
* Heart shaped body
* Superior & inferior costal facets on vertebral body – for head of rib
* Round vertebral foramen (small in comparison to vertebral body)
* Articular facets are more vertical
* Costal (L. rib) facet on transverse process – for tubercle on typical rib
* Long sloping spinous process

Question 34

Typical ribs

Answer 34

Ribs 3-9
* Head, neck & body (shaft)
* Tubercle, angle & costal groove
* Articular surfaces – head & articular part of tubercle

Question 35

Lumbar

Answer 35

• Lumbar (L. loin) Vertebrae
• Large kidney-shaped vertebral body
• No ribs => No costal facets
• Triangular vertebral foramen
• Large superior & inferior articular processes
• Broad, quandrilateral spinous process