Updated: Feb 27, 2019
In today’s blog we are going to discuss a particular type of ulnar nerve dysfunction known as handlebar or cyclists palsy. It is a condition in which the ulnar nerve becomes entrapped at the wrist, usually from the pressure exerted through this area when cycling, resulting in altered sensation and power in the 4th (ring) and 5th (little finger) digits.
How does the nerve become entrapped?
The ulnar nerve is a branch of the medial cord of the brachial plexus, which travels along the inside of the arm. It passes behind the medial epicondyle of the elbow (known as the funny bone) and then follows along the inner forearm towards the hand. At the hand the nerve gives off two sensory branches which give sensation to the back half of the hand, the 5th digit, and half the 4th digit. At the wrist, the ulnar nerve enters the hand by passing through ‘Guyon’s Canal’. This tight tunnel is formed between the small hamate and pisiform bones and the pisohamate ligament which helps keep these carpal bones together. Either within or just beyond Guyon's Canal, the ulnar nerve divides again in two motor branches, which give strength to some of the small hand muscles.
How is the nerve damaged?
Cyclist's palsy typically develops during long-distance or prolonged cycling and occurs with both mountain bike and road cyclists, especially when cycling downhill where a lot of the upper body weight is supported by the hands. The position of the hands while holding the handlebar, often in a hyperextended position, puts pressure on the ulnar nerve as it passes through Guyon’s Canal. The combination of the: (1) stretch created by the hyperextended position of the wrist, (2) compression created by holding the handlebars and (3) vibrations from the road or trails can be enough to damage the nerve. Depending on which branch of the nerve is trapped, this causes a temporary loss of motor and/or sensory function due to a blockage of nerve conduction and is similar to your hand “falling to sleep” from laying on it for too long.
What are the signs and symptoms of handlebar palsy?
The exact symptoms of cyclist's palsy vary between people. This depends on the severity of the condition and, more importantly, whether the sensory branch, the deep motor branch or both branches of the ulnar nerve are affected.
Compression of the sensory branch will present itself in sensory disturbances, such as numbness and tingling in the ulnar innervated areas of the affected hand, namely the ring finger and the little finger. These symptoms are easily recognisable and often go away within a day or two.
Compression of the deep motor branch of the ulnar nerve will present with motor or strength deficits, such as weakness, clumsiness and possibly functional limitations due to loss of muscle function in the hand, this usually arises as the condition progresses.
These latter symptoms are often less distinguishable and if no sensory fibres are affected, can go unnoticed such that a client might continue cycling with an on-going compression of the motor branch, not realizing that there is an injury until a more severe lesion develops.
When there is a prolonged interruption to the ulnar nerve and its innervation of the muscles in the hand, the client can develop a 'claw' position with the hand due to flexion (or bending) of the 4th and 5th digit. Correct and timely intervention of this injury is important, and the healing process can take several months.
How is ulnar neuropathy diagnosed and can it be treated?
Clinical diagnosis is made by taking a detailed subjective and objective history of the condition, including how long it has been apparent for and what exacerbates the symptoms. Your clinician will take you through a range of tests designed to provoke the symptoms such as applying pressure to the area to assess if it reproduces the sensory symptoms. In advanced cases, where strength deficits have been found, a thorough strength assessment of the hand is performed.
Ulnar neuropathy can be treated very effectively in a conservative manner. The biggest issue is that the nerve is being compressed, so relief will not be found until the compressive force is removed. In the early stages avoiding activities that cause the compression is essential, so you need to stop cycling until the symptoms reduce to an appropriate level, which will be guided by your therapist. To enhance the healing process, splinting (especially if you have developed claw symptoms) soft tissue work, inflammatory reduction techniques, joint mobilisation, nerve flossing and exercise rehabilitation including stretching and strengthening make up the main course of treatment.
If you are an avid cyclist, then preventing the onset of ulnar nerve compression is much better than trying to cure it later. So here are 4 tips to help you out.
1. Wear protective gloves, which shield the affected areas from compression and provide shock absorption, during long rides.
2. The position of the hands on the handlebars is paramount. Individual sizing/fitting of the handlebar and riding position is crucial for preventing this condition.
3. Regularly change your hand position on the handle bars, to reduce long term compression.
4. Enthusiastic long-distance cyclists should also adopt a comfortable and resilient riding position by strengthening their postural muscles. As the trunk muscles fatigue the hands will invariably bear more weight to stabilize the upper body, increasing the compressive forces through the wrist.
So that’s a brief overview of how handlebar or ulnar nerve palsy can occur, If you have questions or comments feel free to e-mail us at firstname.lastname@example.org and we will be happy to answer them for you.
If you think you may already be suffering from ulnar nerve palsy, then addressing it sooner rather than later is crucial. So, if you want relief now, call us on (08) 9486 8653 and we will arrange an appointment for you.