Congenital Limb Deficiency

Question 1

discuss how bone formation occurs

Answer 1

enchondral: mesenchymal cells -> cartilage -> bone
- axial and appendicular skeleton

intramembranous: mesenchymal cells -> bone
- flat bones, skull, clavicle

Question 2

discuss the primary centers of ossification

Answer 2

chondrocytes of long bone from which mag lengthen

occurs 4-8 wks p fertilization kaya limb defects occur at 4-6 wks

in midshaft of long bones

Question 3

discuss the secondary centers of ossification

Answer 3

in chondroepiphysis and appear post natally

distal femur, proximal tibia, calcaneus, talus

Question 4

what are the parts of long bone

Answer 4

epiphysis - secondary ossification center

physis - growth plate at end of bones; discrepancy happens here

metaphysis

diaphysis - shaft

perichondral ring - appositional growth

Question 5

ratio of head height to body height at birth

Answer 5

1:4

Question 6

ratio of head height to body height at maturity

Answer 6

1:7.5

Question 7

height of child at 5 yo

Answer 7

height doubles

60% of adult height

Question 8

height of child at 9 yo

Answer 8

80% of adult height

Question 9

height of child in puberty

Answer 9

inc 1 cm/mo

Question 10

what is congenital amputation

Answer 10

absence of all or part of limb at birth

upper ex more common in general

1st trimester is crucial

Question 11

most common UE congenital ampu

Answer 11

terminal transradial defiency on (L)

Question 12

most common LE congenital ampu

Answer 12

fibular longitudinal deficiency

Question 13

risk factors for congenital ampu

Answer 13

maternal DM

smoking

thalidomide

valproic acid

Ca channel blockers

maternal occupation

uterine abnormalities

Question 14

causes of congenital ampu

Answer 14

vascular disruption - amniotic band syndrome

vascular malformations - poland

genetic - sponty point mutation

unkown

Question 15

genetically determined syndromes

Answer 15

holt-oram and fanconi

Question 16

discuss fanconi syndrome

Answer 16

renal dysfunction

underdeveloped, missing or dupli thumb

shortned or missing radius

shortened or curved FA

hand perpendicular to FA

impaired wrist, finger and elbow movement

Question 17

discuss holt-oram syndrome

Answer 17

heart hand syndrome

UE deformity + congenial heart defect

Question 18

absence of limb (OG)

Answer 18

amelia

Question 19

partial absence of limb (OG)

Answer 19

meromelia

Question 20

flipper like appendages of limb (OG)

Answer 20

phocomelia

Question 21

absence of half limb (OG)

Answer 21

hemimelia

Question 22

absence of hand or foot (OG)

Answer 22

acheira

Question 23

absence of metacarpal or metatarsal (OG)

Answer 23

adactyly

Question 24

absence of finger or toe (OG)

Answer 24

aphalangia

Question 25

ISP classification

Answer 25

transverese level: no distal parts; absent onwards

longitudinal: names bones affected starting from most proximal; has distal parts

Question 26

most common longitudinal upper limb deficiency

Answer 26

radial ray

Question 27

most common longitudinal lower limb deficiency

Answer 27

hypoplasia of fibula