The hand can be trapped in many different types of machinery, with the type of injuries dependent on the type of forces applied. The author is from the Institute of Reconstructive Surgery in Sofia, Bulgaria.


Forces Applied to Hand

Type of Machine

Injuries to Hand


tangential shearing forces

moving rollers with narrow gap (< 1 cm); belt pulleys

avulsion of distal phalanges, partial or total denudation of skin from hand (degloving)

Type I

crushing, compressing

rollers with wider gap (1 - 3 cm)

crushing with fracture, lacerated wounds with wide flaying of surrounding skin

Type II

multiple cutting surfaces, rapidly moving planes with sharp cutting edges

carding machine

numerous cuts, skin avulsion, often severe mutilation

Type III



(1) loss of blood supply - especially to digits, with mummification

(2) persistent edema

(3) large skin defects

(4) crush injury to bone and soft tissue

(5) amputation


To read more or access our algorithms and calculators, please log in or register.