Chapter 2. Prehension

28 WHAT IS PREHENSION?
(screwing on a freely moving lid), radial roll (winding a watch), index
roll, and full roll. Sequential patterns include rotary step, interdigital
step (turning a pen end over end), and linear step. The palmar slide is
an example of an action that requires both digital movement and
power, as in separating a pen cap from a pen with one hand. Elliott
and Connolly’s digital manipulative patterns are revisited in discussing
manipulation in Chapter 6.
Figure 2.4. Various postures. A. The adduction grip. B. External
precision grip. C. Internal precision grip. D. Double grip. (A from
Kapandji, 1982; B,C from Patkin, 1981; D from Patkin & Stanley,
1981; reprinted by permission).
2.2.4 The bridge between power and precision: the lateral
pinch
Hand surgeons and occupational therapists at the University of
Iowa developed their own taxonomy with the goal of facilitating uni-
form observations (Skerik, Weiss, and Flatt, 1971). They pointed out
that the use of symbolic terms, such as cylindrical and spherical grips,
is unfortunate since it ‘promotes observation and concern with the
shape of the test object rather than concentration on the hand using the