Understanding Carpal Tunnel Syndrome

Anatomy of the Carpal Tunnel

The carpal tunnel is a narrow passageway located in the wrist. It is formed by the arched orientation of the carpal bones (8 small wrist bones) and the transverse carpal ligament.

This passageway allows several important structures, including the median nerve, wrist flexor tendons and blood vessels to travel from the arm to supply the hand.

Symptomology

CTS is characterised by;

• Pain
• Numbness
• Tingling
• Pins and needles
• Weakness

Typically, in the thumb, index, middle and half of the ring finger on the palm side of the hand.

These symptoms usually worsen with repetitive hand movements or prolonged wrist flexion (palm toward your forearm). Common in certain industries;

• Manual labourers
• Computer work; extended keyboard and mouse usage

People may also experience “nocturnal symptoms” meaning an exacerbation of symptoms during the night that interrupts their sleep

Why does it happen?

Symptoms of CTS arise from the compression of the median nerve as it travels through the narrow passageway.

This path naturally narrows further when the muscles that flex the wrist and fingers are active. The median nerve is accustomed to this natural narrowing and opening of the carpal tunnel, however when this movement is repetitive the nerve may become irritated and inflamed. Other stimulation such as repetitive vibration (e.g. from power tools) can also induce local inflammation and oedema (swelling).

This inflammation and subsequent swelling further restricts this passageway leading to more consistent compression of the nerve, and therefore symptoms in the area that it supplies (See image on right).

Carpal tunnel syndrome may also arise from other conditions and/or anatomical variations that reduce the carpal tunnel space. Examples might include;

• Genetically smaller than average carpal tunnel size
• Bony changes (e.g. Osteoarthritis)
• Trauma or injury to the wrist (e.g. strains, sprains, breaks or dislocations)
• Systemic inflammatory conditions (e.g. Rheumatoid Arthritis)
• Oestrogen fluctuations (e.g. menopause, pregnancy {particularly in the 3rd trimester})
• Metabolic issues (e.g. untreated hypothyroidism)
• Changes in blood glucose levels (e.g. type 2 diabetes)

Can it Resolve?

Early diagnosis and intervention play a crucial role in the prognosis of Carpal Tunnel Syndrome. With appropriate treatment and management, including manual therapy, activity modification, rehab and splinting many individuals experience significant improvement in symptoms and function. However, in severe cases, surgical decompression of the nerve may be necessary.

If left untreated this compression can cause damage to the median nerve and lead to muscle wasting in the forearm, resulting in significant wrist and hand dysfunction.