Lumbrical shift syndrome
The lumbricals consist of 4 muscles within the hand, with some unique qualities. They are described as “intrinsic” as they only have attachments within the hand, rather than down the forearm to the elbow like many of our other hand moving muscles.
The lumbricals attach to tendons within the hand which means unlike most muscles which attach more directly to the bone, they are mobile rather than static, however, this means they can move the fingers in more ways than just bending or straightening at one joint.
Injuries frequently occur here, due to the attachment of the lumbricals at the pinky and ring fingers. Unlike the other muscle groups, this region has multiple attachment points on both sides of the muscle which attach to the neighbouring tendons. This is best likened to the barbs of a feather connecting to the central quill. This anatomical design often causes issues when the finger-bending tendons are moved in opposite directions, which is called the “quadriga effect”.
Lumbrical injuries are particularly common in the sport of climbing, mainly occurring when climbing on 2-3 finger pockets or when using a small hold with just 2-3 fingers. These holds or types of hand position cause injury when one or two fingers are extended and the other fingers are flexed causing a sheering force. Injury can range from Grade I (quickly healing microtrauma) to Grade III (musculotendinous disruption) that requires complete withdrawal from climbing and a longer period of Physiotherapy. Strength in the lumbricals isn’t as large as other muscle groups of the hand and forearm, having roughly 10 percent force production. However, they give significant sensory feedback and fine motor control of the fingers.
The lumbricals are used in climbing for a variety of holds from sloping holds and hand jamming to pinching holds.
The lumbricals primary role is sensory feedback from the force generated in the flexor and extensor tendons in the hand. By sensing the discrepancy between the force produced by the flexors vs the extensors, the lumbricals limit the amount of force produced by the flexors to balance these muscle groups therefore reducing risk of injury.
Injury and symptoms
A lumbrical injury usually presents with pain in the palm of the hand at the base of the ring finger. The pain is normally between the tendons of the hand differentiating it from other injuries such as a pulley or tendon strain. Symptoms present mostly as a dull ache but can be intermittently sharp when the lumbricals are directly stressed.
For a rough self-diagnostic test of a potential lumbrical injury, first actively bend the non-injured fingers, then straighten the injured finger. If this doesn’t elicit pain move onto the next test by, actively bending the non-injured fingers then use your other hand to passively straighten the injured finger. If still no symptoms are shown slowly use the other hand to extend the injured finger further while gently trying to actively resist the straightening with the injured finger.
Grades of injury:
(Mild-moderate strain) no tearing: Significant pressure can be applied or a large range of motion of extension achieved before pain is elicited, the strain might be mild with no tearing.
(Moderate strain) low-grade tear: Significant pressure can be applied or the finger can be moved through a large range of movement with minimal pain, the strain might be moderate with low-grade tearing.
(Moderate to severe) moderate tear: If pain is felt simply going through range actively into the test position, then there might be a significant strain and moderate tear.
If major pain and loss of function is experienced the injury should be assessed immediately by a medical professional such as a specialist consultant in A+E, as this may indicate a moderate or significant tear.
Before assessing the severity of the injury rest for 12-24 hours for the initial inflammation and sensitivity to subside, to get a better idea of the damage to the tissues.
Due to the complexity of this injury and the possible differential diagnosis, appropriate assessment and specific treatment are essential. However, some general advice and rehab can be split into : range of movement, stretching, tissue mobility and retraining.
Range of movement:
Tendon glides – follow the 5 stages below!
- Start by opening the hand fully:
- Then bend the knuckles to make a fist:
- Next bend just the ends of your fingers:
- Then open to make a shelf with the fingers straight:
- Finally, open your hand fully.
Stretching of the lumbricals and particularly the injured finger when appropriate. This can be completed by bending the fingers of the affected hand to the palm. Then using the unaffected hand, gently extend the affected finger on the injured side until slight discomfort is felt. Holding this position for 20-30 seconds and repeating 5 times can be sufficient to see positive changes in pain.
Self-massage can generally be completed by pressing and rubbing gently between the bones of the palm of the affected hand. Massage with the finger and thumb gently pinching the point and creating circular movements for 2-3 mins per day.
Start to re-load the tissues in pinch block positions and general climbing, avoiding pockets.
This training starts once full range is reached and gentle stretching and tissue mobility are achieved with no significant pain.
As with a lot of training, it helps to avoid injury. For beginner climbers, as a rule, finger board training is unnecessary but for the intermediate and advanced climber the fingerboard can be a very useful training tool.
For lumbrical injury prevention, light three-finger drag training can assist. This must be a light load with slow progression, as it can be very easy to start the weight too high, or increase the weight too quickly, causing injury to the lumbricals rather than strengthening them. A strength protocol of a 10 second hang and 6 repetitions is a good starting point.
Physiotherapy Treatment and intervention
Physiotherapy intervention should be considered early if pain in the palm of the hand is felt after a climbing or finger board session. Early treatment should be considered especially if the pain is sharp and impacting your climbing or training.
Treatment may include a home exercise prescription and activity modification advice, for example, changing the type of hold or climbing style that you are taking part in for a short period of time.
Hands on treatment as well as ongoing injury prevention advice would be completed in each session.
Towards the end of treatment, advice on return to baseline climbing and training intensity will be completed related to progress and recovery.
For more information on climbing injuries of all sorts, and to make an appointment with our climbing, hand and upper limb specialist Jack, contact us at:
Address: 10 Fawkon Walk, Hoddesdon EN11 8TJ