Drop wrist means being unable to raise your hand at the back of your wrist without using your other hand to assist. Drop wrist is caused by paralysis of your radial nerve at some point or points along its length. This nerve which originates in your neck, runs down the back of your upper arm bone, under your funny bone and spreads into the forearm muscles which extend your wrist. The medical term for drop wrist is radial nerve palsy.
Drop Wrist Causes
- Neck trauma to the origin of the radial nerve such as a C7/8 spine fracture, disc herniation, or bone spur.
- Shoulder trauma under the clavicle to the radial nerve branch of the brachial nerve plexus will cause drop wrist.
- Injury to the radial nerve where it runs down the back of your arm e.g. fractured humerus.
- Lead poisoning toxicity to the radial nerve.
- Autoimmune disorders which destroy nerves.
- Drop wrist can be caused by prolonged pressure over the radial nerve by leaning on crutches under your arms.
- Falling asleep with your arm draped over the back of a chair or couch can also cause temporary drop wrist by compression injury to the radial nerve under the armpit.
- Leaning on your elbow over the outter funny bone for long periods such as while using a computer or painting, can crush the radial nerve causing drop wrist.
Drop Wrist Symptoms
- Numbness along the path of the radial nerve
- Soreness at the site nerve impingement
- Tingling, pins and needles in fingers
- Able to grasp but not raise hand at the back of the wrist
Drop Wrist Diagnosis
Drop wrist is typically clinically obvious by the fact that you can close your hand and raise your palm, but can't raise your wrist at the back of your hand. An EMG nerve conduction study pinpoints the location of the nerve injury by firing a small current down the length of the radial nerve from nerve to palm and seeing where the current suddenly drops off.
Drop Wrist Treatment
Simple drop wrist without a history of an accident or penetrating injury is often self-limiting much like the pins and needles you get after your leg falls asleep and you uncross it - which is also caused by nerve compression. These simple cases are often managed by splinting, physiotherapy wrist exercises and observation. Serious cases may require surgery to decompress the impinged section of the radial nerve.