A medical instrument 50 has a shaft 52 with a jaw head 58. The jaw head has two jaws 60, 62, at least one being pivotable about an axis 78, 80 by an actuator 72, 74. The pivotable jaw has a toothed wheel 66, which meshes with a toothing 70 on the actuator 72, 74. There are controls at the proximal end of the shaft 52. The distal end of the actuator 72, 74 is flexible and can be driven in and out of a hollow space 76 of a jaw 60, 62 in the distal direction from the toothed wheel 66. The space 76 may have a proximal opening (46 fig 3) and the space 76 may enclose the distal end except for the opening (46 fig 3). The space 76 can be in a pivoting or non-pivoting jaw. Both jaws 60, 62 may be pivotable and may be connected to a separate actuator 72, 74 such that each jaw 60, 62 and the entire jaw head 58 can be moved individually. Each jaw 60, 62 may have a separate toothed wheel pivotable about the same axis 78, 80. The controls may be grip parts 86, 90 with finger eyelets and/or a handle 82 or they may be a motorised drive 120.