I just received another referral for a kid with “weak’ hands. Can’t hold a pencil correctly, can’t make a dark enough mark on paper when he writes or colors. But his mom says he has quite a grip on an object when he doesn’t want to hand something over. He plays soccer without problems and otherwise functions well in a regular classroom. Could it be that hypermobility is his underlying problem?
Some children display problems with fine motor skills due to low muscle tone. Many times, their low tone is significant enough to create poor joint alignment and stability, resulting in joint hypermobility as well as low muscle tone. But kids can also have joint laxity with typical muscle tone. Assessing the difference between tone, strength, alignment/stability and endurance is why you get an evaluation from a skilled therapist. And even then, it can be tricky to determine etiology with the youngest children because they cannot follow your directions or answer questions. Time to take out your detective hat and drill down into patient history and do a very complete assessment.
With older kids, both low tone and joint laxity can lead them over time to develop joint deformity and soft tissue damage. Like a tire that you never rotated on your car, inappropriate wear and tear can create joint, ligament, tendon, and muscular imbalance problems that result in even worse alignment, less stability and endurance, and even pain. And yes, weakness is often observed or reported, but it often is dependent on posture and task demands, rather than being consistent or specific to a nerve distribution or muscle/muscle group.
What does the classic hypermobile hand look like? Here are some common presentations:
- The small joints of the fingers and thumb look “swaybacked”, as the joint capsule is unstable and the tendons of the hand exert their pull without correct ligament support. When they slide laterally and the joint is unable to move smoothly, people say that their fingers “lock” or they are diagnosed with “trigger finger”.
- The arches of the hand aren’t supported, so the palm looks flat at rest. By late preschool, the arches of the hand should be evident in both active and passive states.
- The fleshy bases of the thumb and pinky ( the thenar and hypothenar eminences, for all you therapists out there) aren’t pronounced, due to the lack of support reducing normal muscle development during daily use.
- Grasp and pinch patterns are immature and/or atypical. A preschooler uses a fisted grasp to scribble, a grade-school child uses two hands to hold an object that should be held by one hand and uses a “hook” grasp on a pencil.
- Grasp and pinch may start out looking great, and deteriorate with the need for force. Or prehension begins looking poor and improves for a while, until fatigue sets in. This bell-curve pattern of grasp control is often seen with kids that have poor proprioceptive discrimination. As they use their hands they receive more input, but as fatigue sets in, they cannot maintain a mature grasp and good control.
- The typical arches of the hand that create the “cupping” of the palm when pretending to scoop water from a stream, for example, will be somewhat flattened. Unless there is nerve damage, you won’t see the “claw hand” pattern or another atypical posture.
- Fine grasp will often be accomplished with the thumb and third finger to achieve greater stability through the MCP (knuckle) joints and to avoid full opposition of the thumb. Another common compensatory pattern is using digits II and III together to gain greater stability. Some kids can even wrap one digit partially around another to do this. Now that’s hypermobility!
Don’t forget that hypermobility creates poor sensory processing feedback loops. Reduced proprioception and kinesthesia will result in issues when children try to grade force and control movement without compensations such as visual attention and decreased speed. This can result in kids being labeled clumsy or careless.
Looking for ideas to address the difficulties children face when they have hypermobility in their hands? Take a look at For Kids With Sensory Issues and Low Tone, Add Resistance Instead of Hand-Over-Hand Assistance and Does An Atypical Pencil Grasp Damage Joints or Support Function In Kids With Hypermobility?. Depending on the age and skill level of the child, adaptations and education can be just as important as therapeutic exercise. Your pediatric occupational therapist can help with more than pencil grasp; we are able to help with so many real-life issues!