Three medical conditions affecting the fingers, thumb and wrist have been linked to excessive smartphone use, with repetitive movements and prolonged phone handling identified as contributing factors.

The conditions are trigger finger, De Quervain tenosynovitis and carpal tunnel syndrome, which affect the tendons and nerves responsible for hand and finger movements, CNN reported.

Dr Ariel Williams, an orthopaedic surgeon specialising in hand and upper extremity surgery at Yale Medicine, said she had treated an increasing number of patients whose symptoms were aggravated by mobile phone use.

Williams said repetitive movements and maintaining the hands in particular positions for extended periods could increase pressure on bones, joints, ligaments, tendons and nerves.

Prolonged use of phones and computers has also been associated with neck pain, stiffness, headaches, muscle tightness and reduced neck movement.

Ergonomic physical therapist Kelly Robinson said looking down at a phone increases the load on the lower neck, adding that a 30-degree downward head position could increase the pressure on neck structures to approximately 15 to 20 kilogrammes.

Robinson recommended alternating hands when using smartphones, maintaining proper sitting positions, positioning laptop screens at eye level and performing exercises to strengthen the back muscles. She also advised regular stretching to ease tension associated with prolonged desk work.