The term “whiplash” has been used to describe a mechanism of injury and the various clinical manifestations as a consequence of the injury [1]. In 1995, the Quebec Task Force (QTF) on whiplash-associated disorders (WADs) adopted the following definition of whiplash: “whiplash is an acceleration-deceleration mechanism of energy transfer to the neck. It may result from rear-end or side-impact motor vehicle collisions, but can also occur during diving or other mishaps. The impact may result in bony or soft-tissue injuries (whiplash-injury), which in turn may lead to a variety of clinical manifestations called Whiplash-Associated Disorders” [2].

Whiplash injury can be defined, in a most wide interpretation, as a noncontact quick (50 ms) acceleration–deceleration head–neck trauma [3, 4] with involvement of the spine as a whole. This interpretation explains how the WADs comprehend symptoms variably combined:

Whiplash injuries vary from minor to severe, and, generally, the evolution of the whiplash is divided into three phases:

Whiplash patients can be classified according to the severity of signs and symptoms. The QTF-WAD classification system consists of five levels:

The most common presenting symptoms following an acute motor vehicle collision are neck pain (88–100 %) and headache (54–66 %). Other symptoms are neck stiffness, shoulder pain, arm pain/numbness, paraesthesia, weakness, dysphagia, visual and auditory symptoms and dizziness. In most cases, WAD resolves quickly; 47 % of injured people return to normal activities within 4 weeks, and only 2 % continue to be absent from pre-accident activities 1 year after injury [5].

Whiplash injury sometimes causes a labyrinth concussion with a consequent otoconia displacement. In these cases, a benign paroxysmal positioning vertigo (BPPV) is provoked: whiplash-associated BPPV (WA-BPPV).

Most cases of WA-BPPV can be treated using physical therapy (see Chap. 8), by means of Epley’s [6] canalith-repositioning procedure (CRP) in the case of canalolithiasis and Semont’s [7] liberatory manoeuvre in the case of cupulolithiasis.

Although both manoeuvres have been shown to have therapeutic benefits, they require sequential procedures involving moving the patient’s head and body into unnatural positions, making them sometime unsuitable for WAD patients with cervical or back disorders, especially for older patients.

In WA-BPPV patients, it is thus better to use more conservative procedures like the supine to prolonged lateral position (SPLP) [8] or the rolling over manoeuvre (ROM) [9].

The pathogenesis of whiplash-associated balance disorders (WABD) not due to a recognizable BPPV is still debated:

Probably, WABD derive from different combinations of different mechanisms. The kinematics of the acceleration–deceleration is different, for example, for the driver who is usually opposite to the trauma by means of her/his arms being on the wheel and the passenger who usually receives completely and passively the impact forces. Differences can be observed if the patient wore or not the safety belts during the impact: with safety belts, the movement of the head and the neck is not sagittal but torsional with a torsion having the mid-thoracic vertebrae (T7–8) as fulcrum. The direction of torsional component is different: counterclockwise for the passenger and clockwise for the driver. Furthermore, rarely the impact is caused by a straight rear-end collision, while, very often, the impact causes a rotational acceleration of the vehicle. Torsional and angular accelerations cause brain microlesions in different parts, and this can lead to different combinations of signs and symptoms [10, 11].

Following whiplash, either for mechanical lesions on cervical dynamic or for central dysfunctions, some modifications of patient posture are usually observed:

Generally speaking, WABD may be considered as the result of desynchronization of the proprioceptive interaction between the so-called special proprioception (from the labyrinths) and general proprioceptions (from spine muscles, ligaments, joints, etc.) [12, 13].

Pathogenesis may be interpreted also under a phylogenetic point of view. The specific posture of the human being is the bipedal upright position with a maintenance of dynamic equilibrium as an inverse pendulum on a relatively restricted support surface area. This kind of posture represents a biomechanical evolution strictly correlated to the evolution of high-level cognitive processes specific for the human beings [14]. In adulthood, maintaining stance is perceived as an easy action to be performed, at least in normal conditions on steady surfaces, but it requires a very high level of sensorimotor control in order to allow a low-effort antigravity alignment of the different body segments [15].

The possibility to increase the perception of the environment is the main positive aspects of a bipedal upright posture: in the horizontal plane, the atlo-occipital joint allows the head to extend the exploration possibilities of the eyes [16]; furthermore, the relatively strict base of support allows rapid turns of the body in order to control also the environment at our back; in the vertical plane, the evolution of the lumbosacral spine allows the extension of the head and the trunk in order to explore, also for a long time, the environment over our head [17]. Thus, we can state that human posture is an evolution of the quadrupedal motion with very high possibilities of exploration of the environment all along the three-space axis.

The implementation of bipedal posture on quadrupedal motor control is relatively recent in the phylogenesis, and it can be retraced observing how the child fights against gravity force in her/his early months of life [15].

This concept may explain the pathogenesis of whiplash-associated disorders (WADs) that very frequently cause impairments not proportionate to the intensity of the impact. The relatively low energy transferred to the body during the accident acts specifically at the two most innovative parts of the humans: the atlo-occipital joint and the lumbosacral spine. In this way, whiplash immediately decreases the ability of the subjects to rotate the head and to extend the head and the trunk; in other words, whiplash brings backs the humans to a primate.

Thus, the key impairment is the biomechanic disruption of head-to-trunk and lumbar-to-gait coordination.

Treatment must be pointed to restore spine mobility as a whole with special regard to atlo-occipital joint and lumbosacral region and thus to: