headturn

Headturn is the act of rotating the head relative to the trunk to reorient the line of sight or attention. In humans it is typically described as horizontal or vertical movement and may occur with or without concurrent eye movements. A headturn can be voluntary, reflexive, or a combination of both, and it often serves to acquire information from the environment or from a particular stimulus.

Biomechanics and neural control involve the neck muscles, including the sternocleidomastoid, splenius capitis, and other deep cervical muscles. Voluntary movement is planned by the motor cortex and premotor areas, while brainstem circuits coordinate the movement with vestibular and proprioceptive input. The eyes may move independently or accompany the turn, and the vestibulo-ocular reflex helps stabilize the gaze during rapid headmotion.

Functions of headturning include orienting toward sounds, tracking moving objects, scanning environments, and signaling attention or interest in social interactions. In social contexts, turning toward a speaker or an event can communicate engagement. Developmentally, headturning in infants supports joint attention and language learning as gaze shifts link people to objects or events.

Measurement and clinical relevance: headturn range of motion is commonly assessed in cervical spine examinations and can be quantified in degrees of rotation per side using goniometry or motion capture. Abnormalities or asymmetries can accompany neck pain, cervical spine pathology, or injuries such as whiplash, potentially affecting balance and visual-motor tasks.

In other fields, the concept appears in robotics and animation as a mechanism to reorient cameras or avatars, and in linguistics as a way to describe attention and gaze shifts during discourse.