Mechanism of Injuries in Motorcycle Accidents

People choose to ride motorcycles for several reasons. In general, motorcycles tend to be less expensive than cars in cost, maintenance, and repairs. They also offer better fuel economy than vehicles with standard gasoline-powered engines. Motorcycles also provide riders with a feeling of freedom when they take to the open road since they might feel closer to the surrounding environment and its natural beauty.

Despite the benefits riding motorcycles might offer, they also carry a significant risk of severe injury or death when involved in accidents. According to a 2020 report by the National Highway Traffic Safety Administration (NHTSA) on motorcycle safety, motorcyclists were 28 times likelier to be killed in collisions than the occupants of other types of vehicles and four times likelier to sustain injuries. Here is some information about how injuries happen to motorcyclists and the mechanisms that underly these crashes.

Categories and Mechanisms of Injury

Orthopedic researchers have classified the patterns of injuries motorcyclists tend to suffer in motorcycle accidents into the following four crash types:

• Lowside accidents – Occur when the motorcyclist is turning and falls to the lower side during the turn
• Highside accidents – Occur when the motorcyclist is turning and overcorrects, causing them to fall off the bike on the high side
• Topside accidents – Occur during the sudden deceleration of the motorcycle, causing the cyclist to be thrown off the bike over the handlebars
• Collisions with objects – Happen when a cyclist is struck by or strikes a stationary object, leading to blunt force trauma

Within each of these broad categories of crash types, the researchers identified the following injury mechanisms that resulted in various common types of motorcycle accident injuries:

• Collisions in which the head is leading – Topside or high-side crashes
• Accidents with a direct vertical impact – Collisions with objects
• Wrist radius involvement – Topside or high-side crashes
• Thumb involvement – Collisions with objects
• Fuel tank involvement – Collisions with objects
• Entrapment of limbs – Lowside crashes
• Tire spoke involvement – Lowside crashes
• Hyper-dorsiflexion of the foot – Lowside crashes

Below, we’ll review each of the four main crash types, mechanisms of injuries, and the common types of injuries frequently resulting from motorcycle collisions.

Low-side Accidents and Injury Mechanisms

In a low-side crash, the lower portions of the motorcyclist’s body can become trapped between the bike and the ground while the rider instinctively uses the upper body to brace for impact. This type of crash can result in significant injuries to the lower and upper body on the side of the crash while the other side of the body remains relatively unscathed. Some of the mechanisms of injury that occur during low-side accidents and the injuries that can result are detailed below.

Limb Entrapment Injury Mechanism

When a motorcyclist falls to the side when turning on a motorcycle, their legs can become entrapped between the bike and the pavement. The injuries that result from limb entrapment are among the most common orthopedic injuries that occur in motorcycle collisions. Some of the common types of injuries that happen because of limb entrapment in low-side accidents include the following:

• Fractures of the tibia bone in the lower leg – 20% to 30% incidence in low-side accidents
• Ankle fractures
• Foot injuries

In severe low-side accidents, amputations of the lower limb might occur.

Hyper-dorsiflexion Injury Mechanism

When a motorcyclist anticipates that they will lose control of their bike while turning, they might instinctively extend their leg on that side of the bike to try to stabilize their position and right themselves. This type of movement can lead to a hyper-dorsiflexion injury to the ankle and foot on that side.

A hyper-dorsiflexion injury happens when the muscles, ligaments, and tendons are hyper-extended or overstretched and can result in tears, strains, and sprains. Many cases will involve fractures of the ankle, and some might result in crush injuries to the ankle and foot on that side.

Tire Spoke Involvement Injury Mechanism

In some low-side motorcycle collisions, the rider’s foot can become caught between the spokes of one of the tires. This can result in the following types of common motorcycle accident injuries:

• Severe soft tissue injuries of the muscles, tendons, and ligaments
• Fractures of the heel bone
• Achilles tendon tears and injuries
• Foot amputations

High-side and Top-side Accidents and Injury Mechanisms

In a high-side accident, the motorcyclist is thrown off of the bike at the opposite angle that the bike is leaning. Top-side accidents occur when the rider is thrown over the handlebars of the bike during a collision. Both of these types of crashes result in similar injuries from being thrown from the bike.

Head-Leading Injury Mechanism

When a motorcyclist is leaning forward with their head at the time of a high-side or top-side crash, this can cause serious head trauma when they are thrown from the bike. Head injuries in these types of crashes can be severe and sometimes fatal. Injuries resulting from head-leading top-side and high-side collisions can include the following:

• Facial bone fractures
• Soft tissue injuries of the face
• Depressed skull fractures
• Traumatic brain injuries
• Cervical spine injuries
• Cervical spine fractures
• Brain contusions

Wrist Radius Injury Mechanism

When motorcyclists are thrown from their bikes during a top-side or high-side crash, they might instinctively reach their arms and hands forward to brace themselves. This is known as the crumple zone effect and can result in the hands and lower arms absorbing the brunt of the forces released in the collision and might help to mitigate the severity of the injuries. However, this reaction commonly results in fractures to the radius of the wrists.

Collisions with Objects and Injury Mechanisms

The collision injury mechanism occurs when a motorcycle has a direct impact on a stationary object or motor vehicle. This type of injury accident can involve several types of injury mechanisms and resulting injuries.

Fuel Tank Injury Mechanism

When a motorcycle abruptly comes to a sudden stop during a collision, the rider’s pelvis can be struck by the motorcycle’s fuel tank. This type of mechanism often results in the following types of injuries:

• Pelvic fractures
• Bladder injuries

Bladder injuries typically result from less serious collisions while pelvic fractures from fuel tank impacts often result from severe accidents.

Direct Impact Vertical Injury Mechanism

In some top-side and high-side collisions, the rider’s shoulder might strike a fixed object while traveling at high speeds. An estimated 33% of motorcycle accidents involve this type of injury mechanism and injuries to the upper extremities. Between 15% and 20% of motorcycle crashes involving a direct impact vertical injury mechanism result in the following types of upper extremity injuries:

• Fractures of the clavicle bone
• Brachial plexus injuries
• Fractures of the scapula bone of the shoulder
• Shoulder dislocations

In 10% to 15% of these crashes, motorcyclists suffer fractures to the forearms. Less frequently, motorcyclists might suffer fractures of the wrists and hands in 5% to 10% of the cases.

Motorcycle Thumb Injury Mechanism

When a motorcyclist prepares for an unavoidable and imminent collision, they often tightly grasp the handlebars while locking their elbows to brace for impact. This reaction causes the force of the impact to be directed into the metacarpal bones of the thumb and is involved in 50% of motorcycle collisions. In 20% of the cases, the joint between the ulna of the lower arm and the thumb will be impacted.

Impact of Motorcycle Accidents

It’s important to note that serious motorcycle crashes might involve several types of injury mechanisms and multiple injuries. Because of this, teams of doctors might be necessary to address the various types of injuries and provide appropriate treatment. Motorcycle collisions frequently cause complex injuries that require long periods of recovery, intensive treatment, and rehabilitation. In some cases, people who are severely injured in motorcycle crashes might be left to face permanent and disfiguring injuries that might prevent them from fully returning to the lives they previously enjoyed.

Unfortunately, motorcyclists are much likelier to be killed when they are involved in collisions. Unlike people who occupy cars or trucks, they don’t have safety features or a surrounding metal cage to absorb some of the physical forces of a crash. When a motorcyclist is killed in an accident, the surviving family members might have to contend with significant and unanticipated losses while also dealing with the pain and grief they feel after losing their loved one.

Consult an Experienced Motorcycle Accident Lawyer

If you sustained serious injuries in a motorcycle crash or lost your loved one, you might have legal rights. Speaking with an experienced motorcycle accident attorney about what happened in your case might allow you to understand your legal options and the remedies that might be available. Contact the law office of Steven M. Sweat, Personal Injury Lawyers, APC today for a free consultation at 866.966.5240.