Thumb Opposition/Open Webspace and Separation of Function of the Two Sides of the Hand

Today I am expanding on the "Secrets to Good Handwriting" post from several weeks back by addressing Thumb Opposition/Open Webspace and Separation of Function of the Two Sides of the Hand.  Remember that developing all of the skills mentioned in that original post (dated 5-28-13) will positively affect your child's fine motor skills. Think of those skills mentioned as the building blocks of fine motor skills.

Thumb Opposition and Open Webspace:
For effective manipulation within the hand, the thumb must be able to move and rotate so that it can touch each fingertip. In doing so, the thumb is able to produce movements for manipulating items and controls the amount of pressure exerted on an object for speed and dexterity.

If kids don’t develop good strength in the thumb area, they often substitute for the weakness by positioning the thumb in against the side of their index finger, closing the webspace (the web space is the open area that runs between the thumb and the index finger).  They might pick up small items in this manner, or, when holding a pencil, this presents as a lateral thumb wrap pencil grasp.  Use of this type of grasp can mean heavy pressure on the pencil/paper, and can result in hand fatigue when writing or coloring (we have all heard kids saying that their "hand hurts" or that they are "tired of writing," or have seen them take a break and shake their hand when writing and coloring).

An example of a lateral thumb wrap pencil grasp

Activities:
-playing with a racquetball or tennis ball promotes an open web space when grasping them
-playing with bulb syringes or eye droppers
-pinching clothespins or clips, playing with tongs and tweezers (make sure that the child is not using a lateral pinch, however)

Separation of Function of the Two Sides of the Hand:
Refinement of movement of the radial (thumb and index index finger) side of the hand happens when the ulnar (ring finger and pinky) side of the hand is stabilized (or still). When the ulnar side of the hand is still, kids have better control of their middle and index fingers and thumb for precise motions.  When a child is holding their pencil with a correct or refined grasp pattern, the 4th and 5th fingers are curled into the palm.  If you wind a small knob, like on a wind up toy, the 4th and 5th fingers should not be moving along with your index and thumb. The movement is separated, and this provides the most stability through the hand while allowing free movement of the thumb, index and middle fingers.

Separation of the two sides of the hand develops early on when an infant crawls and bears weight through their hand while carrying toys with the thumb and index finger.  Because we have different nerve innervation to the fingers on each side of the hand, we are able to learn to not move the ring and pinky fingers while the other fingers are moving. When kids are writing or coloring, this separation is important because it allows them stabilize the side of their hand on the paper or surface that they are working on.  Think about kids who do not stabilize their hand on the desk/table top when using a marker or pencil-  they are not getting separation of the 2 sides of their hand.  Cutting with a scissors also requires separation of the two sides of hand.

This little guy is not resting his forearm on the table top, and has not yet developed a refined grasp pattern.

Activities:
-color, print or draw while laying on the tummy; this requires a child to stabilize the side of their hand on the surface in order to hold themselves up.  Can also do this on a vertical surface.
-string beads
-when writing or coloring, see if your child can hold a penny or a small smooth object in their hand (held against the palm with the ring and pinky fingers curled around it)
-Roll small balls of play dough, putty, aluminum foil, etc with the fingertips
-Tear paper while keeping ring and pinky fingers tucked into palms
-thumbtack designs:  place a simple coloring page on a small cork board, and have them push thumbtacks (pushpins) into the board to trace the design
-play with water guns or squirt bottles with one- or two-finger triggers
-Penny play: pick up pennies and place them into a piggy bank or see how fast they can turn over a row of pennies.  Have them hold a penny or small object in their hand and try to move the penny to their fingertips and place it on a table without using other hand.