What is a Pinched Nerve?

The term ‘pinched nerve‘ actually refers to any condition where compression of the nerve causes a range of sensory (’feeling’) and motor (’movement’) related symptoms in the affected area. While a pinched nerve if often believed to affect the spinal nerves only, due to compression between parts of the spine, it can actually affect any nerve in the body. The severity of the symptoms will depend on the site that is affected, the extent of the nerve compression, movement or other aggravating factors as well as duration of the compression.

A nerve transmits electrical impulses to and from the brain usually through the main pathway, known as the spinal cord or directly to the brain and brain stem. These nerve impulses carry sensations (pressure, pain, heat) to the brain and signals from the brain causes different actions like muscle movement. Nerves are embedded within the body, surrounded by other structures like bone, muscles, tendons, ligaments and connective tissue. If any of these surrounding structures impinges on the nerve, the compression will distort the signals in the nerve. The nerve compression may occur at the nerve root or along the course of the nerve.

Common Signs & Symptoms of a Pinched Nerve

Symptoms may vary depending on the nerve affected, as well as the site of the compression on the nerve. Some common signs and symptoms include :

• Numbness
• Tingling
• “Pins and needles” sensation
• Pain
• Partial loss of function like muscle weakness or lack of coordination

Paresthesia, a common term for numbness, tingling or the “pins and needles” sensation may be caused by a number of factors and is not always due to a pinched nerve. In the case of a pinched nerves, not all of the above signs and symptoms may be present simultaneously. Symptoms of a pinched nerve may persist even after the cause of the nerve compression has been removed due to inflammation of the nerve.

Diagnosis and Investigation of Pinched Nerves

While the signs and symptoms of a pinched nerve along with a neurological examination may be relevant in diagnosing nerve compression, it is important to consider other diagnostic procedures such as :

• Magnetic Resonance Imaging (MRI)
• Electromyography (EMG) to measure the electrical strength in muscles.
• Nerve conduction study where a mild electrical shock is induced on the skin to test nerve impulses.