lower limb

Question 1

normal metatarsal shafts in DP view

Answer 1

2nd metatarsal aligns correctly with the intermediate cuneiform bone

Question 2

normal metatarsal shaft in oblique view

Answer 2

3rd metatarsal aligns correctly with the lateral cuneiform bone

Question 3

tuberosity avulsion fractures mechanism of injury

Answer 3

occur during forced inversion of foot and ankle while they are at plantar flexion

caused by combination of forceful contraction of the peroneus brevis during hindfoot inversion and contracture of the lateral band of the plantar fascia

Question 4

apophysis of metatarsals and phalanges

Answer 4

base of 5th metatarsal
- apophysis appears at age 10 for girls and age 12 for boys
- unfused apophysis runs longitudinally

Question 5

how can normal apophyses appear

Answer 5

usually ossifies as a single entity but may show multicentric ossification

Question 6

accessory ossicles of the foot

Answer 6

trigonum
peroneum
naviculare
intermetatarseum
vesalianum
supranaviculare
supratalare
tibiale externum
calcaneus secundaris

Question 7

where does stress fracture affect

Answer 7

2nd and 3rd metatarsal

Question 8

Bohler’s angle of an ankle

Answer 8

normal angle os between 20 and 40deg

less than 20deg is suggestive of calcaneal fracture

Question 9

normal AP mortise ankle view

Answer 9

joint space should be of uniform width ~4mm
surface of talar dome is smooth
tibia and fibula should overlap on mortise view

Question 10

weber fracture classification

Answer 10

weber A = distal to ankle joint
weber B = at level of ankle joint
weber C = proximal to ankle joint

Question 11

sign of tibial plateau fractures

Answer 11

• fractured plateau has an irregular surface or becomes layered and fracture lines may extend inferiorly
• area of focal increase in density below the plateau due to bone compression causing an impaction
• tibial margin displacement - perpendicular line drawn at the most lateral margin of the femoral condyle should be > 5mm of the lateral margin of the tibial condyle outside
• fat-fluid level usually seen on the lateral radiograph in tibial plateau fractures

Question 12

type of patellar fracture

Answer 12

usually caused by direct blow
- vertical
- horizontal
- comminuted

Question 13

signs of injury to PCL in xray

Answer 13

tiny fragment is seen close to the tibial articular surface posteriorly

Question 14

signs of ACL injury

Answer 14

tiny fragment is seen close to the tibial spine

Question 15

how does stress fracture of tibia appear

Answer 15

sclerotic band

Question 16

pitfalls of knee

Answer 16

1. fabella
   - sesamoid bone in the tendon of the lateral head of gastrocnemius muscle
2. bipartite patella
   - congential knee condition caused by the failure of the patella to fuse and is often an incidental finding on radiographs
   - has pieces with more rounded margins that do not fit together

Question 17

garden classification for hip fracture

Answer 17

type 1: undisplaced incomplete #
type 2: undisplaced complete #
type 3: complete #, incomplete displaced
type 4: complete #, complete displaced

Question 18

femoral neck fracture frequency

Answer 18

45-53%

Question 19

intertrochanteric fracture frequency

Answer 19

38-50%

Question 20

subtrochanteric fracture frequency

Answer 20

5-15%

Question 21

common hip fractures

Answer 21

subcapital fracture
extracapsular intertrochanteric fracture

Question 22

type of hip dislocations

Answer 22

anterior
central
posterior (80%)

Question 23

common surgical hip management

Answer 23

dynamic hip screw
total hip replacement/arthroplasty
surgical screws

Question 24

pitfalls of hip joint

Answer 24

small bone fragment seen at the superior margin of the acetabular rim
- unfused secondary ossification centre or
- femoro-acetabular impingement