CYCLISTS AND MOTOR CYCLISTS:

This includes conventional motor cycles, motor scooters, mopeds and pedal cycles. Accidents to cyclists and motor cyclists are commonly caused by turning in front of a vehicle from one side or the other. The cycle is hit and the person is thrown violently to the ground or into some other object or on to the car.

In being thrown, they may injure the groins or legs by protruding objects, such as handlebars or projection levers or mirrors, long tears being common. The handlebar may tear the liver or the spleen and cause massive internal bleeding.

The head or shoulder may hit some object first, or they may be thrown beneath a vehicle and crushed like any pedestrian. Primary impact injuries may be to the leg or to the chest if the victim runs into a stationary vehicle, often causing a ruptured heart or aorta.

Injuries to legs may occur in relatively low speed accidents due to the machine falling heavily on them. Falling from the" vehicle, especially at speed can cause visceral damage, especially rupture of the liver and spleen.

Pillion riders falling off the backs of motor cycles have" a laceration of the back of the head, a fracture of the posterior fossa, counter coups contusions of the frontal lobes and abrasions of the back and elbows.

Crash helmet reduces friction of the head against the ground, and makes deceleration less drastic by allowing the protected head to skid across the ground. When a crash helmet is worn, the crown may be protected. but the whole head may be "egg shelled” on to the base or cervical spine with fracture of the spine.

Occasionally, when the helmet is pinned or crushed, the chin strap may be drawn upwards and strangulation. Although helmets do decrease fatalities, their greatest value is protection at lower speed or tangential impacts. A helmet which shows only glancing linear abrasions indicates the likelihood of a less severe brain injury than one in which there is direct impact imprint.

About fifty percent of helmetless motor cyclists sustain head injury. The person falls head-on into some hard surface, or slides and tears the unprotected brow, face or ears with flattened or depressed fracture of the skull. The brain is crushed or torn and bleeds from multiple sites.

Impact on the crown of the head may produce ring fracture around the foramen magnum. In about 25% of cases cervical spine fractures occur. Severe brain damage may occur even when a helmet is worn. Conical contusions and lacerations are common. Brain tissue may extrude through compound fractures of the skull.

The classical fatal injury in both motor cyclists and pillion passengers is fracture of the skull, usually front secondary impact with ground. Temper parietal fractures are common often with counter coup brain injury. In many types of road accidents or due to a very heavy impact on one side of the head, a fracture is produced across the flour of each middle fossa passing through the pituitary fossa, often associated with fissured fractures passing upwards to the temporal bones. At autopsy, the base of the skull is seen divided into two halves, each moving independently of each other like a hinge, the so-called motor cyclists fracture.

The motor cyclist may drive into the back of a large vehicle, e.g., truck, known as "under-running" or "tail-gating". This may occur due to the sudden and unexpected stoppage of the truck or when the motor cyclist is at high speed in darkness. In such cases, the motor cyclist's head and shoulders are smashed against the tail-board. In extreme cases decapitation may occur.