Carpal tunnel syndrome develops when pressure increases within the carpal tunnel, reducing space and compressing the median nerve. Because the tunnel cannot expand, even slight swelling or structural changes can affect nerve function.
Several contributing factors may increase this pressure. Inflammation from conditions such as arthritis can cause swelling in the wrist. Repetitive movements, poor wrist positioning, forceful gripping, vibration exposure, and prolonged strain may also play a role.
Lifestyle and health factors—such as smoking, obesity, and high caffeine intake—may increase the likelihood of developing CTS. Hormonal changes, particularly during pregnancy, can lead to fluid retention and added pressure within the tunnel.
In some cases, thickening of the tenosynovium leads to increased pressure. Over time, this can reduce blood flow to the nerve, a condition known as ischemia. If prolonged, it may lead to structural changes in the nerve, including scar tissue formation, which contributes to pain, numbness, and weakness.
Trauma, such as wrist fractures or dislocations, can also reduce the space within the tunnel and lead to acute CTS. Other causes may include cysts, tumors, thyroid disorders, or systemic conditions like diabetes.