Your fingers tingle at night. You struggle to unscrew a cap or pick up a coin. Your hand goes numb while driving, on the phone, in front of the screen. These signs, often dismissed or attributed to poor circulation, can reveal carpal tunnel syndrome, the most common musculoskeletal disorder of the upper limb.
In France, nearly 130,000 surgical procedures are performed each year for this condition. A figure that reflects only part of the problem: thousands of mild to moderate cases fly under the radar, managed through self-medication or simply endured in silence.
Anatomy of a tunnel under pressure
At wrist level, the median nerve passes through a narrow passage formed by the carpal bones on one side and a thick ligament, the flexor retinaculum, on the other. This tunnel, the size of a finger, also houses nine flexor tendons. The available space is already limited; the slightest inflammation reduces it further.
The median nerve controls sensation in the thumb, index finger, middle finger and part of the ring finger. It also innervates the muscles at the base of the thumb, those that enable fine grip: buttoning a shirt, holding a pen, pinching an object between thumb and index finger.
When pressure inside the canal increases, the nerve is compressed. Its protective sheath gradually deteriorates. The first signs appear: nocturnal tingling, finger numbness upon waking, a sensation of swollen hands. Without treatment, loss of sensation and strength sets in.
Daily gestures that wear out the wrist
Carpal tunnel syndrome is not reserved for manual workers. It also affects, and increasingly so, office professionals. Typing for hours, clicking with an unsupported mouse, using a smartphone in prolonged flexion: these gestures, repeated thousands of times daily, generate chronic tendon friction inside the canal.
Cashiers scanning items, hairdressers wielding scissors, cooks chopping, workers using vibrating tools: all share the same risk factor, repetition. Studies set a critical threshold at four daily hours of repetitive wrist movements.
Recognizing the signs before it’s too late
Carpal tunnel syndrome typically evolves through three stages. Initially, tingling is intermittent, mainly nocturnal. Many patients wake up shaking their hands to relieve the sensation, a gesture so characteristic that doctors call it the “flick sign.”
At the intermediate stage, symptoms become diurnal. Fingertip sensation decreases. Objects slip from hands. Fine motor tasks become clumsy.
At the advanced stage, muscle wasting at the base of the thumb becomes visible to the naked eye. Grip strength drops. At this point, nerve damage may be irreversible.
What can be done before surgery
Early intervention is decisive. A resting splint worn at night keeps the wrist in neutral position and reduces intracanal pressure. Its effectiveness is proven in mild to moderate forms.
Neurogliding exercises, gentle movements that slide the median nerve through the canal, improve nerve mobility and reduce adhesions. Practiced regularly, they can stabilize or even improve symptoms.
Workstation adjustments play an essential role: keyboard at elbow height, adapted wrist rest, ergonomic mouse, regular mobilization breaks. These adjustments reduce daily mechanical strain.
Surgery, which involves cutting the ligament to free the nerve, remains the last resort. It is indicated when sensory or motor deficit is confirmed by electromyography, or when conservative treatment has failed after three to six months.
Preventing rather than enduring
Carpal tunnel syndrome is one of the few MSDs for which individual prevention has proven effective. Varying gestures, alternating tasks, stretching wrists and fingers between typing sessions: these simple reflexes, adopted early, often prevent reaching the surgical stage.