introduction to bones

Question 1

what is endochondral ossification and what bones does this happen in

Answer 1

the process in which an initial, small hyaline cartilage version grows and turns in to bone (ossifies)
- happens in long boned like the humerous/femur, not flat bones like that face or the clavicle

Question 2

what does physics mean

Answer 2

growth

Question 3

where does cartilage usually start to ossify from

Answer 3

the centre

Question 4

at each end, what does each bone have (4)

Answer 4

• an epiphysis (end bit)
• an epiphyseal growth plate
• a metaphysics (between epiphysis and diaphysis)
• diaphysis (the shaft)

Question 5

what happens when the growth plate of hyaline cartilage finally ossifies

Answer 5

bone growth ceases

Question 6

what is the outer cortex of a bone

Answer 6

• outer most part of the bone
• dense, strong, heavy
• compact (cortical) bone

Question 7

what is the inner medulla

Answer 7

• the inner more porous, weaker and lighter part
• spongey (trabecullar/cancellous) bone

Question 8

what can the medulla (inner hollow part) contain

Answer 8

bone marrow
- in some bones this is the site of red and white blood cell production

Question 9

what is the periosteum

Answer 9

fibrous connective tissue sleeve that covers the length of the middle of the bone but not the articular cartilage
- vascularised
- well innervated (results in extreme pain during tearing, as occurs during fractures)

Question 10

what nutrient vessels supply the periosteum

Answer 10

• arteries and veins
• carry blood to/from the medullar cavity

Question 11

what covers the top of long bones (bits for the joints)

Answer 11

hyaline (articular) cartilage

Question 12

when do bony features occur and describe the 3 main types of them

Answer 12

they develop during bone growth
- functional (genetic) = best shape for the job
- an adjacent structure supplies a force to a developing bone (tendon of a muscle moves when muscle moves which will apply pressure to the bone so could get a groove, or from blood vessel or nerve)
- an adjacent structure is developing at the same time as the bone (sometimes blood vessels have to go through the bone so will form a hole through it)

Question 13

name the 3 fossae of the cranial cavity

Answer 13

• anterior cranial fossa
• middle cranial fossa
  posterior cranial fossa

Question 14

what is foraminae and what are the ones in the skull used for

Answer 14

• a ‘hole’
• for cranial nerves and the brains blood vessels to pass in to/ out of the cranial cavity

Question 15

how is the cranial cavity shaped

Answer 15

the development of different parts of the brain mould the floor of the cranial cavity in to 3 fossae

Question 16

describe the healing process of a fractured bone (4)

Answer 16

• trauma (fracture)
• initial healing = callus (a lump of soft bone that attempts to keep the bone in place) of new bone surrounding fracture line
• callus remodelling (reassuming normal shape)
• healed left bone (more or less normal shape)

Question 17

what does the axial skeleton include

Answer 17

bones in the midline
- bones of the skull
- bones of the neck (including the cervical vertebrae and the hyoid bone)
- bones of the trunk (chest, abdomen and back)

Question 18

what does the appendicular skeleton include

Answer 18

limb bones and bones that connect the limb to the trunk
- bones of the pectoral girdle (connect the upper limbs to the axial skeleton)
- bones of the upper limb
- bones of the pelvic girdle (attaches lower limb to axial skeleton)
- bones of the lower limb

Question 19

what 2 sections are the bones in the skull split in to

Answer 19

• the bones of the facial skeleton (viscerocranium)
• bones of the cranial vault (neurocranium)
• the line that splits them goes from just inferior (below) to just inline/below the eyebrows