Nerve Injuries (Neuropraxia, Axonotmesis, Neurotmesis)

Nerve injuries can happen in different ways and are grouped into three main types (Figure 1). The mildest is neuropraxia, where the nerve gets compressed, bruised, or stretched but isn’t permanently damaged, like when your foot “falls asleep” after sitting too long. The second type, axonotmesis, happens when the nerve fibers inside are damaged but the outer covering stays intact, often caused by more serious pressure, stretching, or a crush injury. The most severe is neurotmesis, where the nerve is completely torn or cut, like in deep cuts or serious accidents, and this usually needs surgery to repair. These injuries can lead to numbness, weakness, or even loss of function, depending on how severe they are. Important nerves that may be injured include the median, radial, ulnar, and axillary nerves in the upper extremity and the peroneal nerve in the lower extremity.

Listen to a Podcast on Nerve Injuries

Nerve Anatomy

A nerve is like a highway for messages in your body. It’s made up of bundles of thin fibers called axons, which are covered by a protective layer called myelin that helps messages travel faster (Figure 2). These axons are grouped together and wrapped in layers of tissue, kind of like wires in a cable. Nerves connect your brain and spinal cord (the central nervous system) to the rest of your body, including your muscles, skin, and organs. They carry messages back and forth, letting your brain know what’s happening in your body and helping your muscles move when you decide to act.

Types of Nerve Injuries

Neuropraxia: A Stunned Nerve

Neuropraxia is a mild type of nerve injury where the nerve gets squeezed, bruised, stretched, or slightly damaged, but it doesn’t break or tear. This can happen from something like a hard hit, sleeping in a weird position, or having your arm or leg squeezed for too long. It usually causes temporary numbness, tingling, or weakness in the affected area. Doctors diagnose neuropraxia by asking about your symptoms, checking how your muscles and nerves work, and sometimes using tests like nerve conduction studies to see how well signals travel through the nerve. The good news is that neuropraxia often heals on its own with rest, physical therapy, and sometimes pain medicine if needed. Most people recover fully in a few days to a few months.

Axonotmesis: A Crushed Nerve

Axonotmesis is a more serious nerve injury where the fibers inside the nerve (called axons) are damaged, but the outer covering of the nerve stays intact. This often happens from a crush injury, like when something heavy presses on a limb, or from severe stretching of the nerve. It can cause numbness, weakness, or even paralysis in the affected area. Doctors diagnose axonotmesis by looking at your symptoms, checking your muscle strength and reflexes, and using tests like nerve conduction studies to see how well signals pass through the nerve. Treatment focuses on giving the nerve time to heal, which can take weeks to months. Rest, physical therapy, and sometimes braces to support weak muscles can help recovery. In some cases, if the nerve doesn’t heal well, surgery might be needed.

Neurotmesis: A Cut Nerve

Neurotmesis is the most severe type of nerve injury where the nerve is completely cut or torn, often from a deep cut, a bad accident, or a serious injury like a fracture. This type of damage causes complete loss of feeling and muscle movement in the area the nerve controls. Doctors diagnose neurotmesis by checking for loss of sensation or movement and using tests like nerve conduction studies or imaging scans to see the extent of the damage. Unlike milder nerve injuries, neurotmesis doesn’t heal on its own.

Treatment of a severed nerve (neurotmesis) often involves surgery if the injured nerve performs an important function such as helping to move the hand or foot. Surgery usually involves repairing or reconnecting the damaged nerve. Surgery may include a direct repair of the two cut ends of the nerve. Alternatively, a nerve graft may be required to span the cut and damaged area of the nerve. It takes an extended period for the injured nerve to regrow following a surgical repair. The nerve regrows at approximately 1mm per day.  As an example, a lacerated peroneal nerve at the level of the knee would cause a loss of important movement of the foot. If this nerve was successfully repaired with surgery it would likely take 100-150 days, or longer, to regrow the 10-15 cm required for the branches of this nerve to once again innervated the muscles in the leg that had been affected. Following surgery bracing and physical therapy is often required. Bracing can hold the affected joint in an appropriate position while the nerve heals so that the involved area (ex. Hand or foot) maintains a functional position. Physical therapy is important to minimize stiffness in the affected joints and to help the muscles and nerves recover. Unfortunately, even with optimal surgical treatment, recovery can take a long time and may not always be complete.

Edited by Stephen Pinney MD, August 16th, 2026.