Safety In Engineering Industry >Chapter 6> Topic – Safety in IT and Electronic Industry and Service Sector > Subtopic- Carpal Tunnel Syndrome (CTS)

Carpal Tunnel Syndrome (CTS)

What is Carpel Tunnel Syndrome ?

Carpal Tunnel Syndrome is a condition affecting the hand and wrist. The carpal tunnel is a space in the wrist surrounded by wrist bones and by a rigid ligament that links the bones together (see Figure 1). 

Figure-01

Through this small tunnel pass the flexing tendons of the fingers and thumb as well as the median nerve (see Figure 2).  These tendons attach muscles to bones in the hand and transfer the movement of the fingers from muscles to bones. The median nerve carries signals from the brain to control the actions of the fingers and hand.

It also carries information about temperature, pain and touch from the hand to the brain, and controls the sweating of the hand.

The thumb, index, middle and ring fingers are under the control of the median nerve (see Figure 2).

Figure-02

Figure 2 - The Carpal Tunnel with Tendon and Median Nerve

In the carpal tunnel, the tendons of the fingers surround the median nerve. Swelling of the tendons reduces the space in the tunnel and squeezes the median nerve which is softer than the tendons. Pressure on this nerve can injure it.

Such injury results in sensations of numbness, tingling, pain, and clumsiness of the hand. This combination of symptoms is called carpal tunnel syndrome. People with carpal tunnel syndrome experience difficulty in performing tasks such as unscrewing bottle tops, fastening buttons, or turning keys.

Hazards causing Carpal Tunnel Syndrome (CTS) 

Carpal tunnel syndrome has been associated with certain tasks including:

• Repetitive hand motions.
• Awkward hand positions.
• Strong gripping.
• Mechanical stress on the palm.
• Vibration.

Those workers performing assembly line work - including manufacturing, finishing, cleaning, and meat/poultry/fish packaging - commonly report this injury. Cashiers, hairdressers, or knitters or sewers are examples of people whose work-related tasks involve the repetitive wrist movements associated with carpal tunnel syndrome. Bakers who flex or extend the wrist while kneading dough, and people who flex the fingers and wrist in tasks such as milking cows, using a spray paint gun, and hand-weeding are other examples. Excessive use of vibrating hand tools may also be related to carpal tunnel syndrome.

A possible link between carpal tunnel syndrome and computer mouse use is uncertain. While keyboarding work is generally not a risk factor for developing carpal tunnel syndrome, it can cause pain and exacerbate symptoms for those who already have the condition.

Table 1 Job tasks and occupations associated with carpal tunnel syndrome
Job Tasks	Occupations
Handling objects on conveyor belts	Assembly-line worker
Pushing down ratchet, using screwdriver	Mechanic
Using spray gun	Painter
Assembling small parts	Electronic industry worker
Wearing poorly fitting gloves which apply external pressure	Agricultural worker, mechanic, factory worker, those working in cold temperatures
Pressing tool into palm	Painter, carpenter, stable hand
Pounding safety lever or stamping machine	Operator
Using air-powered hand tools	Assembly worker, construction worker

Control Measures for the Carpal Tunnel Syndrome- 

1. Engineering Control- Redesigning work stations, tools, or the job. Proper work station design reduces awkward wrist positions and minimizes the stressful effects of repetitive motions. Ergonomically designed work stations can avoid the awkward working position. 

 

2. Administrative Control- Worker training should aim to reduce the number and types of awkward wrist postures and the number of repetitive motions. Informing workers about the risk factors that can contribute to carpal tunnel syndrome is important. Job rotation policy can be effective to avoid the continuous and repetitive work.