1. A condition in which passive flexion of a joint causes increased resistance of the extensors.

This gives way abruptly if the pressure to produce flexion is continued.

2. An initial marked resistance to passive movement, which then suddenly gives way.

This variety of increased muscle tone is characteristic of spasticity as a result of disease or dysfunction of the pyramidal tracts.

A surgical instrument that uses electrical current to produce heat, that incises (cuts into) tissue by cauterization (use of heat to destroy abnormal tissue).

A medical instrument, provided with tips of various shapss, which operate on a high-frequency electric current that divides tissues and provides a degree of hemostasis (stopping bleeding).

A method for destroying deep-seated brain tumors with a focused beam of gamma radiation.

By using three-dimensional stereoscopic techniques to aim the radiation from several angles, it is possible to concentrate the energy on the tumor while minimizing damage to surrounding tissues.

Radiosurgery in which an intracranial target can be destroyed by ionizing beams of radiation that are directed with stereotaxic precision.

A normal surgical incision is not needed. The therapy is used to treat brain tumors and vascular lesions.