Acceleration injury is Brain injury caused when the moving head strikes a stationary surface, or the stationary head is struck by a moving object in a way that causes the head to move quickly from its resting position. Linear acceleration injury is caused by forces that propel the head on a linear path. Angular acceleration injury is caused by forces that propel the head at an angle from the path of the impact and cause it to rotate. (See also Coup injury, Contrecoup injury, Diffuse axonal injury, Translational trauma.)

Reference: Introduction to Neurogenic Communication Disorders (Eighth Edition) – Robert H. Brookshire [Book Pg. No. 450]