---

SIZING

 

How to Size Thumb Splint

Use A and B measurements to determine which size splint you should order.

1. Measurement A

Measure to the 1/10th of a centimeter the circumference of the far or distal thumb joint.

2. Measurement B

Measure to the 1/10th of a centimeter the distance on the palm from the distal thumb joint to the center of the wrist crease.

3. Measurement F (only used for custom splints)

Measure from the distal thumb crease to the bottom of the web space.

4. Refer to Chart

On the appropriate chart (see links below), find the the square where Measurement A and Measurement B meet. The square should fall within a bold area corresponding to the correct size. If Neonatal use only Measurement A an Neonatal Sizing and refer to the neonatal chart for neonatal sizing.

Example:

If Measurement A = 5.2 centimeters and Measurement B = 6.0 centimeters, then splint size = P5

To view sizing charts click the links below.

• Adult Sizing Chart →
• Pediatric Sizing Chart →
• Neonatal Size Chart → Use only Measurement A. Refer to the neonatal chart for neonatal sizing.

5. Record Sizes

Note splint size and left or right hand, as this is required when ordering. If ordering offline, the catalog number for the above example would be P5-L (left hand) or P5-R (right hand).

To assure the best fit, use of a sizing kit is recommended. If a sizing kit is unavailable, follow the directions above. Neonatal sizes are suitable for very small or prematurely born infants. Pediatric sizes are suitable for children from about 3 months to 6-10 years. Older children and adults need adult sizes. When figuring sizes, it is important to use a centimeter tape measure.

How to Determine Supinator Size

When figuring sizes, it is important to use a centimeter tape measure. All supinator straps may be shortened.

• X-Small: (7/8 inch x 15 inches) straps are typically needed by infants.
• Small: (1 inch x 18 inches) straps fit toddlers through about 6 years. 
• Medium: (1 1⁄2 inches x 24 inches) straps fit larger children, young teens and smaller adults. 
• Large: (2 inches x 30 inches) straps fits most adults and older teens.

Need Custom Sizing

When hand sizes fall outside the standard sizes provided, you may call or choose the custom options when ordering. To order a custom size we will need measurements A, B & F. Select or specify whether you need a longer strap, larger thumb piece or added reinforcement at the web space. Custom cut longer, larger supinator straps are also available.

---

INSTRUCTIONS

Applying Thumb Splint

Step 1: Put the thumb through the thumb hole. Orient the splint so that the stitching follows the crest of the web between thumb and index finger. Snug to fit comfortably. Draw the strap of the splint at an angle so that it drops below the corner of the palm. (For medical personnel, it sits below the pisiform bone). Pull the split strap so it continues around the back of the hand all the way around again to the palm side.

Step 2: Depending on your intent, you can attach the hook tape in either of 2 ways:

Option A: If you are experiencing thumb pain or arthritis at the base of the thumb (C-M-C joint), direct the pull of the strap up into the base of the thumb metacarpal as illustrated.

Option B: If you are attempting to improve grasp quality, attach the hook tape to put mild pressure on the head of the thumb metacarpal.

---

Applying Supinator Strap - Self-Attachment Above Elbow

Step 1: To attach supinator strap, undo strap from thumb splint. Reattach thumb splint over supinator strap. (figure 3)

Step 2: Wind one turn around forearm, then one turn behind elbow. Attach wider, squared hook tape end of strap to itself above elbow (figure 4). The splint is designed to assist forearm extension, so supinator strap must cut across the back of elbow.

Step 3: Once splint is in place, passively turn forearm palm up (supination) and slightly extend wrist (figure 5). Make any necessary adjustments to supinator strap to ensure a snug fit. The attachment above the elbow, while snug, should be comfortable, balancing good coloration of the hand with some pull from the strap.

Step 4: Finally, check the hand splint and, if necessary, rotate it to ensure the thumb is positioned to oppose fingers.

Always follow precautions on label regarding splint application and wear.

---

Fitting Thumb Splint and Adjustable Supinator Strap

Both the strap of the Thumb Splint and the Adjustable Supinator Strap may be shortened to accommodate different size hands or to compensate for some loss of elasticity in the straps that occurs over time.

Thumb Splint

If after trying the on the splint, the splint strap and velcro protrude beyond the thumb, cut strap and/or hook tape to fit the hand.

Supinator Strap

The squared end of the supinator strap may be cut to fit a shorter or narrower forearm. Attach free piece of hook tape to the squared end of strap.

---

Features and Care

All McKie Thumb Splints and Supinator Straps are made of washable, 1.5 mm fabric-covered neoprene. Outer fabric is looped Nylon which allows attachment of hook tape anywhere on the splints . All splints are available in 6 colors, black, navy blue, red, royal blue, pink and tan. “Decorated” splints are available in sizes P4, P5 and P6.

---

How It Works

Neurological/ Developmental Deficits

• The thumb is drawn into opposition. The splint pulls in the same direction as muscle attached to the thumb.
• Because active, opposed grasp is supported, the potential for acquisition of abnormal, compensatory grasp patterns is diminished.
• The neoprene is only 1.5mm and coverage of the palm is minimal, thus adequate space is left in the hand to manipulate and explore objects.
• Normal hand use and development is thus not thwarted by the splint itself.
• For weakness and hypermobility at the M-P joint, strap placement at the head of the metacarpal will block hyperextension.

Arthritis/Injury

• The splint provides light compression.
• It cushions the thenar eminence and reduces joint play.
• At the C-M-C joint, the splint strap can be attached to provide lift to the thumb metacarpal and increase joint space.
• For weakness and hypermobility at the M-P joint, strap placement at the head of the metacarpal will block hyperextension.

Supinator Strap Features

Supination is the forearm motion that turns the palm up. Whether child or adult, it is needed for most activities of daily living including eating, cup holding, dressing, bathing, combing hair, brushing teeth and holding a pencil. Control of supination develops very early when infants begin to explore all sides of objects. It can be lost or fail to develop as a result of neurological injury.

How It Works: Supinator Strap

• Attaches to the back of the splint to aid radial deviation and wrist extension.
• It wraps around the forearm to pull the hand into supination.
• When self-attached above the elbow, facilitates elbow extension.
• The strap can also be attached to promote forearm pronation

Who Can Benefit from Supination?

• Adults with Stroke or Neurological Injury
• Children with Cerebral Palsy who have impaired reach and weight bearing of the upper limb
• Children with Brachial Plexus Injury
• Children with Arthrogryposis

---

ABOUT MCKIE SPLINTS

McKie thumb splints are compassionately designed and handmade in the USA. We are a company with an emphasis focusing on helping people live their best lives. Our splints are prescribed, recommended, and distributed by Occupational Therapists and other medical professionals around the world. For more information about McKie Splints please visit our About Us page. Thank you for visiting our website and have a wonderful day!