Osteology of the scaphoid

Question 1

describe a scaphoid fracture

Answer 1

it is the most common carpal bone fracture caused by a fall on the outstretched hand resulting stiffness of the anatomical snuffbox

Question 2

what can happen if the diagnosis of a scaphoid fracture is delayed

Answer 2

• mal-union which means the bone will heal in an abnormal position
• delayed union meaning the bone heals very slowly
• avascular necrosis meaning the bone dies due to a lack of blood supply
• osteoarthritis

Question 3

how long does it take foir a scaphoid fracture to show on image

Answer 3

about 10 days

Question 4

which 4 projections are sude to view the scaphoid

Answer 4

dp wrist with ulnar deviation
dp obliquie with ulnar deviation
lateral
posterior oblique

Question 5

describe the positioning, centring and collimation of a dp wrist with ulnar deviation

Answer 5

• patient sat woith affected side next to the table with arm extended over the table and the anterior aspect of the wrist in contact with the image receptor
• applied ulnar deviation with no wrist flexion
• centring should be directly over the anatomical snuffbox
• collimation should include the scaphoid, trapezium and radiocarpal joint

Question 6

describe the positioning, centring and collimation required for a DP oblique with ulnar deviation

Answer 6

• patient sat with affected side next to the table withe anterior aspect of the wrist in contact with then image receptor
• wrist is externally rotated so that the anterior aspect of the wrist is at a 45 degree angle from the image receptor
• ulnar deviation is applied
• centring is over the anatomical snuffbox
• collimation should include the scaphoid, trapezium and radiocarpal joint

Question 7

describe the positioning, centring and collimation required for a lateral scaphoid xray

Answer 7

• arm extended over the table withe the medial aspect of the wrist in contact with the image receptor
• centring should be on the anatomical snuffbox with the wrist at a 90 degree angle with the image receptor
• collimatiomn should include the radiocarpal joint , scaphoid, lunate, trapezium, radial and ulnar styloid processes

Question 8

describe the positioning, centring and collimation required for a posterior oblique xray of the scaphoid

Answer 8

patient with arm extended over the table with the posterior aspect of the arm being at a 45 degree angle to the image receptor.

centring should be at the anatomical snuffbox with collumation including the scaphoid, lunate, trapezium and radiocarpal joint.

Question 9

describe the positioning, centring and collumation required for a zitters projection

Answer 9

positioning is the same as dp with ulnar deviation however the xray machine should be angle 30 degrees vertically
centring at the trapezium with collimation including the scaphoid and surrounding joints