Bone development and Aging

Question 1

what are primary ossification centres?

Answer 1

centres present from birth

orderly sequence

form in diaphysis (central bone)

Question 2

what are secondary ossification centres?

Answer 2

appear after birth

form at the ends of long bone (epiphysis)

Question 3

what is ossifcation

Answer 3

process of cartilage being transformed into bone

Question 4

aging changes in the ribcage

Answer 4

sternum develops

xyphoid process fuses with body in middle age

costal cartilage can ossifies in old age (vulnerable to fractures)

Question 5

aging changes in the upper limb bones

Answer 5

scapula can become absorbed and thins out

supraspinous ligament frequently ossifies in elderly

humours grows as superior end

ulna and radius grow at inferior end

Carpal bones slowly develop over 15 ish years

Question 6

aging changes in lower limbs (hips)

Answer 6

hip bone 3 parts

• ilium bone (3rd month)
• ischium bone (4th month)
• pubic bone (5th month)

the 3 fuse 2–25 years

Question 7

aging changes in lower limbs (legs)

Answer 7

rapid grow when children start to walk and pelvis tilts anteriorly

sacrum takes most of the body weight

Question 8

what are clinical conditions for the hip

Answer 8

cartilage wears out with age (causes osteoarthritis)

avoiding stairs can slow effects

also happens in knee

Question 9

changes in foot size

Answer 9

girls 5-10 growth spurt, boys a bit later

Question 10

neonatal skull characteristics

Answer 10

large skull small face (mandible and lack of teeth)

inner & middle ear already adult size

Question 11

Postnatal skull growth

Answer 11

occurs along periphery of the bones - absorbing inner bone layer while depositing on external surface

6th year - frontal hemisphere fuses
7th year - orbital cavity reaches adult size

Question 12

fontanelle closures

Answer 12

posterior - 2nd month
sphenoidal - 3rd month
mastoid - 1st year

Question 13

changes in mastoid process

Answer 13

sternocleidomastoid muscles (neck) attach the mastoid muscle as children begin to lift their heads (3rd month) encouraging mastoid process to protrude

Question 14

adult skull growth

Answer 14

sutures fuse sagittal (22-31y) coronal (24-40y) lambdoid (26-40)

Question 15

teeth development

Answer 15

see lecture 7 for the picture

Question 16

How does the mandible develop?

Answer 16

increase in length (posteriorly), height, thickness (laterally)

Question 17

postnatal mandible development

Answer 17

starts as 2 halves until 2 years when it is fused by a symphysis menti

covers teeth

angle is very obtuse

coronoid process higher than condyloid

alvelar arches elongate to make space for teeth

chewing strengths mandible

Question 18

adult mandible development

Answer 18

angle reduces further until about 110 degrees

both process at similar height

Question 19

elderly mandible development

Answer 19

teeth lose causes absorption of walls of sockets

superior alveolar arches recede

angle drops to 140 degrees & chin becomes prominent