Wrist and Hand Functionality

Overview

• The wrist primarily acts as a stabilizer to facilitate finger movement.
• Finger flexors are the prime movers for grasping but are multi-joint muscles that also cross the wrist.
• Wrist muscles, particularly extensors, help stabilize the wrist to allow effective finger movement.

Active Insufficiency

• Describes a condition where muscle strength is insufficient due to improper positioning.
• Example: Radial nerve palsy leads to inactive wrist extensors, causing difficulty in finger flexion and weak grasp strength.

Passive Insufficiency

• Occurs when muscles are stretched to their maximum, affecting movement efficiency.
• Example: When bending the wrist, finger extensors are stretched, reducing grip force.

Tenodesis Grasp

• A technique leveraging passive insufficiency, particularly useful for individuals with spinal injuries at the C6 level.
• Wrist extension passively causes finger flexion, allowing grasp without active finger muscles.
• Wrist flexion helps in releasing the grasp.

Clinical Application

• Enhancing tenodesis grasp and release is crucial for patients with spinal injuries.
• Keep finger flexors short to increase grasp force while ensuring joint health.
• Training involves specific movements to avoid stretching finger flexors but maintain range of motion in the wrist and fingers.
• Techniques include moving the wrist with fingers bent and straightening fingers with the wrist bent.

Key Points

• Wrist stabilizes the hand for effective finger movement.
• Active and passive insufficiency affect grip strength and movement efficiency.
• Tenodesis grasp provides a method for spinal injury patients to grasp and release objects.
• Clinical focus is on optimizing tenodesis while maintaining overall joint health.