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Nerves of the Arms & Hands - Sensory & Motor Tests for Nerve Compression

Major indicators of compression

When a nerve is compressed, it can stop doing what it is supposed to do: providing sensory input (sensation) and/or motor function (instructing the muscle to move)

Sensory

Abnormal sensation, known as “paresthesia”, is a very common symptom of nerve compression.  You have experienced if you have ever had a limb ‘fall asleep’. Paresthesia can present as a decrease in sensation, numbness, tingling (pins and needles), burning, or just feeling ‘strange’. When these symptoms are experienced in the hand, the exact location can provide some information regarding which nerve is being impinged and discussed above. The compression or injury can be at any point along the path of that nerve — ay any point from the spine to hand.

Motor

Impaired ability to flex, extend, or otherwise move specific parts of the body can be an indicator of nerve compression as well. When it comes to these nerves, here are a few motions that can indicate impingement:

  • Radial Nerve — Difficulty extending the hand backwards in a ‘stop’ motion.
  • Ulnar Nerve — Difficulty extending the ring and pinky fingers (referred to as an ‘ulnar claw’).
  • Median Nerve — Difficulty flexing the index and middle fingers (e.g., when making a fist).

There are a few tests that the Top and the bottom can do to help detect nerve compression.

Anatomical diagram showing radial, median, and ulnar nerve pathways through the arm and hand, with color-coded nerve routes and three hand views indicating nerve distribution zones in green, pink, and blue.

Regularly Test for Peripheral Nerve Compression in the Arm

Do this both before the scene and periodically throughout.

Tops:

  • Before the scene, have the bottom grip two of your fingers and squeeze them as hard as they can so you can feel the strength of their grip.  Periodically throughout the scene have them repeat this.  If their grip strength weakens noticeably, they may be having motor issues.
  • Have your partner do the sensory and mobility tests below before the scene so you know what is normal for that person. Having an understanding of what is normal for them (“baseline”) is critical to detecting change. Periodically during the scene, instruct your bottom to do their sensory and mobility checks. If the bottom reports or you detect any changes in their sensation or motor skills, immediately direct your attention to addressing the issue.

Bottoms:

Regularly test your skin sensitivity and motor function throughout the scene.

Sensory Tests

To test for numbness or changes in sensation, run your thumbnail gently against the skin of each of your fingers. Do the same with the fingernail of your first finger along your thumb. Ensure that you are using your nail to complete this action rather than the soft part of your finger.  if the sensations you feel are different than they normally are for you, inform your Top immediately.

Run your thumbnail against the sides and bottoms of your fingers, one-by-one:

Single column tie around extended forearm and hand using white rope, showing parallel wraps from wrist to mid-forearm with fingers extended in a pointing gesture.
White mannequin hand demonstrating a basic single-column tie around two extended fingers using thin white rope, shown in side view with palm facing left.

Run the fingernail of your forefinger against the side and back of your thumb:

White rope wrapped around a wrist in multiple horizontal bands creating a basic single-column tie, with the hand relaxed and fingers slightly curved against a white background.
Purple rope wrapped around individual fingers in a finger bondage technique, showing thumb and two middle fingers bound separately with thin cord against white background.

Motor Tests

Flex all of your fingers into a tight fist, flex your fist downward as if knocking on a door, extend your fist backward, and extend all of the fingers away from the palm. This series of movements tests the motor function of the ulnar, median, and radial nerves.  If you have difficulty doing any of these things the way you normally would, inform your Top immediately.

1. Make a tight fist.

Closed fist shown in profile against white background, demonstrating hand position for rope bondage practice. No rope visible in frame.

2. Extend that fist upward.

Purple rope tied around a closed fist in a decorative knot pattern, showing hand bondage technique with the arm extended horizontally against a white background.

3. Flex that fist downward.

White-gloved hand in a relaxed fist position against white background, demonstrating neutral hand posture without rope application.

4. Extend your finger straight out.

Left hand extended with fingers spread, palm facing viewer, showing white rope wrapped around base of index, middle, and ring fingers in simple horizontal wraps against white background.