Greifvorgang

Greifvorgang is a term used in biomechanics, neuroscience and robotics to describe the sensorimotor sequence by which an organism reaches for, grasps, and manipulates an object with the hand. It encompasses the coordination of arm transport, hand shaping, finger contact, and subsequent handling or release of the object. In humans and other primates the process is highly adaptable, allowing objects of different sizes, shapes and weights to be acquired safely and efficiently.

The typical sequence of events includes several overlapping phases. First, reach (or transport) brings the hand toward the target under visual guidance. The hand then pre-shapes its aperture and orientation to match the object's properties. Upon contact, grip is established and the fingers close around the object. Depending on the task, the object may be held firmly or minimally secured, and manipulation follows, which can include repositioning, transferring, or placing the object before release.

Neural and perceptual control relies on an integration of visual, somatosensory, and motor information. The dorsal visual stream provides online guidance for action, while circuits in the parietal and frontal cortex (notably areas involved in grasp planning and hand shaping) encode appropriate grip types. The cerebellum and sensorimotor feedback regulate timing and force to adapt to object fragility and dynamic conditions. Common grip classifications include Präzisionsgriff (fingers and thumb) for small or delicate objects and Kraftgriff (whole hand) for larger or heavier items.

Applications of grasp research span rehabilitation, ergonomics, robotics, and prosthetics, informing how machines and assistive devices plan and execute secure, adaptable grasps.