A pinched nerve and a pulled muscle are two common conditions that come together in any list of differential diagnoses for a localized pain. Differences between these two are of utmost importance to the clinician as well as the patient because the treatment protocols and follow up care differ in many critical ways.
Pinched Nerve
Pinched nerve is a condition where a sensory nerve gets trapped between two segments of tissue. The pressure exerted on the nerve stimulates it. Nervous signals go up the nerve to the brain along the spinal cord to give the sensation of pain arising from the area the nerve innervates. The sensation may be pain or pins and needles. This entrapment can occur at any site where the nerve fibers pass in between two closely situated structures. Common examples for peripheral nerve entrapments are carpal tunnel syndrome, meralgia parasthetica, Saturday night palsy, and post-traumatic. Carpal tunnel is a tunnel made up through a fibrous band of tissue at the wrist called the flexor retinaculum. The median nerve goes through this tunnel. Median nerve supplies the skin over the lateral 2/3rd of the palm, the palmar aspect of thumb, index finger, middle finger and the lateral half of the ring ringer and tips of these fingers. Therefore, the sensation seems to arise from this area in an entrapment at the carpal tunnel. Carpal tunnel syndrome is common in hypothyroidism, pregnancy, and obesity.
Meralgia parasthetica is the entrapment of the lateral cutaneous nerve of the thigh as it passes through the inguinal ligament near the anterior superior iliac spine. There is pins and needles sensation of the lateral aspect of the thigh. This is also common in hypothyroidism. Saturday night palsy is an interesting phenomenon. When people have a good drink at the pub on Saturday night and come back home, they may fall asleep on the armchair. When the person lounges drunken, his arms hang over the two arms of the chair and the arm of the chair may press against the inner aspect of the arm. This exerts pressure directly on the radial nerve. Pressure on the radial nerve at this site presents as painful tingling on the dorsal aspect of the hand with wrist drop. This goes off in a few hours. Similarly, nerves may get trapped by fragments of the fractured bone. This may physically damage the nerve and result in a long lasting weakness. Treating the underlying cause, surgically releasing the trapped nerve and pain relief are the basic principles of management.
Pulled Muscle
Pulled muscle is a sprain due to undue effort on a muscle. Athletes are the usual recipients of such injuries. Muscle fibers or the tendons connecting the muscle to the bone may get damaged. The patient presents with pain while moving the injured area. There may or may not be a wound, but bruising may be evident suggesting undue pressure at the site. Redness, swelling, pain, warmth, and loss of function at the site are the cardinal features of a pulled muscle, and they occur because of the acute inflammation of the area. Resting the muscle, support for weight bearing, pain relief, and treating fractures, wounds etc. are the principles of management.
What is the difference between Pinched Nerve and Pulled Muscle?
• Pinched nerve may occur due to many systemic causes while pulled muscle is always post-traumatic.
• Pinched nerve presents with pain arising from the innervated area with the site of pressure located elsewhere while pulled muscle pain is localized to the damaged site.
• Signs of inflammation may or may not be at sites of nerve entrapment while pulled muscle get inflamed all the time.
• Pulled muscle is a very acute presentation while many nerve entrapments run a chronic cause. Treatment principles of the two conditions also differ.