Carpal Tunnel Syndrome

Carpal Tunnel Syndrome Description

In the wrist there is a sheath of tough connective tissue which envelopes and protects one nerve (median nerve) and tendons, which attach your muscles to the wrist and hand bones. The carpal tunnel is the space between this sheath (above) and the bones (below) making up the wrist and hand (carpal bones). The term 'carpal tunnel' is also used quite commonly to refer to 'carpal tunnel syndrome' which is a condition where the median nerve is pinched within the tunnel and causes pain and/or numbness of the wrist/hand, typically as a result of repetitive motion such as painting or typing.

Medical/Anatomical definition
The carpal tunnel is a fibro-osseous tunnel on the palmar surface of the carpal bones which transmits a number of tendons and the median nerve from the forearm into the hand.

Surface markings are, proximally, the distal wrist crease; distally, the hook of the hamate bone.

The recurrent thenar branch of the median nerve, the motor branch to the thenar eminence, leaves the median nerve in or beyond the carpal tunnel, then curves back over the flexor retinaculum to reach the thenar eminence. It is endangered in carpal tunnel surgery if the incision over the carpal tunnel is made too far laterally (thumb side).

Recommended reading: How To Cure Your Carpal Tunnel

Boundaries
The base and walls of the carpal tunnel are a concave bony channel formed by the carpal bones.

The flexor retinaculum, or transverse carpal ligament, forms the roof of the carpal tunnel. It attaches to the scaphoid tubercle and ridge of the trapezium laterally, and to the pisiform and hook of the hamate medially.

From superficial to deep, the structures encountered in exposing the carpal tunnel, are:

Skin
Palmaris longus tendon merging with palmar aponeurosis
Palmaris brevis muscle
Flexor retinaculum
The median nerve is located deep to the flexor retinaculum.

The carpal tunnel transmits:

Flexor pollicis longus tendon,
Median nerve
Flexor digitorum superficialis (flex. dig. sublimis) tendons to the four fingers. All four tendons travel in a common synovial sheath. The tendons to the middle and ring fingers lie superficial to the tendons to the index and little fingers
Flexor digitorum profundus tendons, lying side-by-side. The index finger tendon is separate; the others lie close together.

Relevance
The carpal tunnel is important because the median nerve can be compressed in cases such as the following:

Carpal tunnel syndrome
Wrist dislocations
Fractures around the wrist

Carpal Tunnel Signs & Symptoms

Tingling or numbness in your fingers or hand, especially your thumb, index, middle or ring fingers, but not your little finger. This sensation often occurs while driving a vehicle or holding a phone or a newspaper, or upon awakening. Many people "shake out" their hands to relieve their symptoms.

Pain radiating or extending from your wrist up your arm to your shoulder or down into your palm or fingers, especially after forceful or repetitive use. This usually occurs on the front (palm) side of your forearm.

A sense of weakness in your hands and a tendency to drop objects.

Treatment

Most people with carpal tunnel syndrome can be effectively treated with non-surgical methods. A splint that holds your wrist will help relieve nighttime symptoms of tingling & numbness.

Anti-inflammatory drugs will relieve pain from Carpal Tunnel Syndrome. In some instances an injection of Cortisone will relieve any associated pain.

As a last resort surgery may be advised by your doctor.

Prevention

Relax or reduce your grip

Take frequent breaks

Avoid bending your wrists all theway up & down.

Improve your posture. Sagging shoulders can affect your wrists.

Keep your hands warm.

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