What causes flexor weakness of the wrist and fingers?

From the Guidelines

Flexor weakness of the wrist and fingers is most likely caused by conditions affecting the flexor tendons, such as tendinopathy or tenosynovitis, which can be identified using ultrasound (US) evaluation.

Possible Causes

• Tendinopathy or tenosynovitis of the flexor tendons, which can be diagnosed using US evaluation 1
• Entrapment of the median or ulnar nerves, which can also be assessed using US 1
• Conditions such as rheumatoid arthritis (RA), which can cause erosions and active synovitis, leading to flexor weakness 1

Diagnostic Evaluation

• US evaluation of the wrist and fingers can be used to identify abnormalities of the flexor and extensor tendons and tendon sheaths 1
• Radiographs, including posterior-anterior and lateral views, can be used to establish a specific diagnosis in patients with arthritis, complications of injury, or other conditions 1
• US can also be used to guide therapeutic intra-articular and other soft-tissue injections 1

From the Research

Causes of Flexor Weakness of the Wrist and Fingers

• Flexor weakness of the wrist and fingers can be caused by various conditions, including:
  • Forearm flexor diseases, such as Volkmann's contracture, pseudo-Volkmann's contracture, and ulnar finger flexion contracture 2
  • Compression of peripheral nerves, such as the median, ulnar, and radial nerves, which can occur in the elbow, forearm, or wrist 3
  • Chronic hand pathologies, including carpal tunnel syndrome, trigger finger, and de Quervain tenosynovitis, which can cause compression of the median nerve at the wrist 4
  • Contracture of spastic finger flexor muscles, which can be a consequence of central nervous system disorders 5
  • Amyotrophic lateral sclerosis (ALS), which can cause split phenomena of antagonistic muscle groups, including preferential wasting of extensor muscles compared to flexor muscles 6

Underlying Conditions

• Central nervous system disorders, such as cerebral palsy or stroke, can cause contracture of the wrist and extrinsic finger flexor and pronator muscles 5
• ALS can cause muscle wasting and weakness, including flexor weakness of the wrist and fingers 6
• Forearm flexor diseases can cause finger flexion contracture, which can lead to flexor weakness of the wrist and fingers 2

Clinical Presentations

• Patients with flexor weakness of the wrist and fingers may present with symptoms such as:
  • Limited range of motion of the wrist and fingers
  • Weakness or paralysis of the flexor muscles
  • Contracture or deformity of the wrist and fingers
  • Pain or discomfort in the wrist and fingers 2, 3, 4, 5, 6