Thumb - Lateral

Radiographic Positioning

Adult

Other related pages of interest Applied Radiography Radiographic Anatomy Radiographic Protocols

Name of projection	Thumb - Lateral
Area Covered	Distal and proximal first phalanx, metacapal, carpometacarpal joint, trapezium
Pathology shown	Fracture, dislocation, foreign body, infection, tumour, arthritis
Radiographic Anatomy	Hand Radiographic Anatomy
IR Size & Orientation	18 x 24cm Landscape, divided for multiple thumb images, use lead masking for unused area
Film / Screen Combination	Detail (CR and DR as recommended by manufacturer)
Bucky / Grid	No
Filter	No
Exposure	50 kVp 2.5 mAs
FFD / SID	100cm
Central Ray	Directed to first metacarpophalangeal joint Perpendicular to IR
Collimation	Centre: First metacarpophalangeal joint Shutter A: From distal phalanx to trapezium Shutter B: To include soft tissues
Markers	Distal and Lateral Marker orientation AP
Shielding	Gonadal (check your department's policy guidelines)
Respiration	Not applicable
Positioning	Seated at end of table Palmar surface of hand down Flex hand slightly until thumb is in lateral position Thumb against IR Long axis of thumb in line with axis of IR Centre to metacarpophalangeal joint
Critique PACEMAN	Positioning First digit in true lateral position is demonstrated by anterior surface of proximal phalanx is concave posterior surface of proximal phalanx and metacarpal will be slightly convex Thumbnail, if visualised, will be in profile Proximal first metacapal slightly super-imposed by proximal second metacarpal The following joint spaces are open: metacarpophalangeal, interphalangeal, carpometacarpal Long axis of digit is aligned with long axis of IR Centred to metacarpophalangeal joint Area Covered Distal and proximal first phalanx, metacapal, carpometacarpal joint, trapezium Collimation Centred to first metacarpophalangeal joint Opened to include distal phalanx to trapezium and soft tissues Exposure Bony trabecular patterns and cortical outlines are sharply defined Soft tissues are visualised
Special Notes