Chapter 2. Prehension

Table 6.6 Elliott & Connolly (1984) dynamic hand movements organized according to contact
forms. Each is described in terms of oppositions being used to hold the opposition vector. The
type and direction of movement of the opposition vector relative to the palm is shown.
Form Movement Opposition Direction of Relative motion Example
Name Movement of VFs
Fixed contacts Pinch Pad Translation along z axis concurrent removing splinters
Dynamic Pad&Side Translation along x axis concurrent writing with pen
tripod some y axis
Palmar Palm with Translation along x-y plane concurrent removing pen cap
slide either Pad
or Pad&Side
Rock Alternate
Pad and Side
Rotation about Qz concurrent screwing a lid
Rolling contacts Twiddle Alternate Rotation about Qz thumb moves, screwing small nut
Pad and Side index fixed
Radial Side Rotation about Qz thumb fixed, winding a watch
roll index moves
Indexroll F'ad Rotation about Qy concurrent rolling up paper
Full roll Pad with
5 fingers
Rotation about Qy concurrent rotating small mirror
Sliding contacts Linear step Pad Translation along x-y plane concurrent climbing object
SqUeeZe Pad Reduction about Qz wncurrent squeezing syrin8e
Regrasping Rotary step Alternate
Pad and Side
Rotation about Qz mncurrent turning a dial
Interdigital Alternate Rotation about Qz concurrent turning pen over
step Pad and Side
h,
4
h,