Carpal Tunnel Handout

Running head: CARPAL TUNNEL SYNDROME 1

Carpal Tunnel Syndrome

Michelle Stahl

CTU Online

Biology

143

Professor Karim

December 14, 2011

CARPAL TUNNEL SYNDROME 2

Abstract

This article discusses the definition of carpal tunnel syndrome, the anatomy of the arm,

and treatment of carpal tunnel syndrome. The anatomy discussed is skeletal, muscular, and a

brief mention of the brachial plexus and median nerves. It includes images from A&P revealed

3.0. I also go over prevention and carpal tunnel release surgery.


Carpal Tunnel Syndrome

What is Carpal Tunnel Syndrome? Carpal Tunnel Syndrome affects the median nerve

of the brachial plexus as it runs through the carpal tunnel in the wrist. The inflammation of the

nerve and pressure on it by the transverse carpal ligament can cause pain, weakness, or

numbness in the thumb and the first three fingers of the affected hand. Advanced cases of carpal

tunnel syndrome can cause atrophy of the muscles of the thumb. The condition occurs with

repeated trauma to wrists from repetitive movements (flexion) of the wrist (A.D.A.M, 2011).

Anatomy: The brachial plexuses are the anterior branches of the lower four cervical

nerves and the first thoracic nerve (Shier, Butler, & Lewis, 2010). This plexus is deep within the

shoulders between the neck and armpits. The median nerve supplies the muscles of the forearms,

and the skin of the hands with movement and sensation. Pictured below is the brachial plexus

(APrevealed Version 3.0, 2011).


A picture of the median nerve below, notice how it supplies feeling to the thumb and first

three fingers of the hand (APrevealed Version 3.0, 2011).

The upper arm is attached at the pectoral girdle comprised of the scapula and clavicle that

articulate with the Humerus to form the upper arm. The Humerus articulates distally with the

radius and ulna, forming a hinge joint. The radius and ulna then articulate distally with eight

carpal bones, in two rows of four bones each. It is through these carpal bones that the carpal

tunnel carries the median nerve through to innervate the muscles of the hand. Also traveling

through this tunnel is the transverse carpal ligament, and all the associated blood vessels

including arteries and veins. The lowest row of the carpal bones articulate with the metacarpal

bones of the hand, of which there are five. These metacarpals make up the palm of your hand.

The metacarpals articulate distally with the phalanges, there are proximal, median, and distal

phalanges for each finger except the thumb. In the thumb there are distal and proximal


phalanges. It is important to note that the carpal tunnel is just that, a tunnel that runs through the

carpal bones of the wrist. This tunnel is very narrow, so any swelling of the tissue there puts

pressure on the median nerve (APrevealed Version 3.0, 2011).

The muscles of the arm include the coracobrachialis, pectoralis major which flex

the arm. The Teres major and Latissimus dorsi muscles make up the extensor muscles that

extend the arm. The abductor muscles are the Supraspinatus and Deltoid muscles that abduct the

arm and Subscapularis, Infraspinatus, and Teres minor muscles that rotate the arm.

The muscles of the forearm include: Biceps brachii, brachialis, and brachioradialis that

are responsible for flexing the forearm. The Triceps brachii is responsible for extending the

forearm. Finally the Supinator, pronator teres, and pronator quadratus muscles rotate the forearm.

The muscles of the hand include the flexors: flexor carpi radialis, flexor carpi ulanaris,

palmaris longus, and flexor digitorum superficialis. The extensors are comprised of: extensor


carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris, and extensor

digitorium. The muscles of the hand move the wrist and the fingers and are most impacted by

carpal tunnel syndrome.

Causes of Carpal Tunnel Syndrome: As mentioned earlier repetitive motions can cause

trauma to the carpal tunnel inside the wrist. Repetitive flexing of the wrist can occur from typing,

computer work, painting, massage work, using improperly sized hand tools, and bad posture

when doing office work.

Symptoms and Diagnosis of Carpal Tunnel Syndrome: Pain or numbness in the

thumb and first three fingers of the hand, particularly when bending or flexing the wrist. The

pain or numbness seems to worsen at night. With prolonged cases atrophy of the muscles in the

thumb can be seen. Your doctor will do a series of tests to determine if you have carpal tunnel

syndrome. He will flex your wrist for 60 seconds and then check for numbness or pain this is

referred to as Phalen’s sign. He or she may also tap on the median nerve in the forearm; if this

produces pain then this is referred to as Tinel’s sign. Other diagnostic tests such as nerve

conduction or electromyography may also be ordered to determine the extent of the damage to

the median nerve. X-rays may be done to rule out arthritis, or a fracture.

Treatment Options: The patient will be given a splint to rest the wrist and prevent

further trauma for several weeks. This is to relieve the pressure on the median nerve. You may

also be given anti-inflammatories such as ibuprofen, or Aleve. Your doctor may also give you a

corticosteroid injection to ease pain. You may have to change the way you do work, to avoid

further damage. You may need to change your work environment, with furniture or specialized

tools to avoid straining your wrist and aggravating your symptoms. Proper posture when typing

for example can help greatly. You may also need to do physical therapy and take regular short


breaks to stretch your wrists and fingers when doing prolonged repetitive tasks such as typing.

As a final resort your doctor may suggest Carpal Tunnel release surgery.

Carpal Tunnel Release: In carpal tunnel release surgery a small incision is made in the

palm of the hand near the wrist. This allows the surgeon to access the carpal tunnel and cut some

of the traverse carpal ligament to relieve pressure on the median nerve. Sometimes other tissue

may be removed to make more room. The incision is then sutured closed and kept dry until it is

healed. During this time you may have to do finger exercises to increase circulation to the site

(F.A. Davis Company [F.A. Davis], 2005, p. 349). Once pressure from the nerve is released, the

nerve should stop hurting depending on how long it has been pressed upon. This should enable

the nerve to function normally as it once did, restoring feeling and movement; however if

damage has been prolonged, and then the damage may be permanent. With permanent damage

the patient may have pain or weakness in the affected hand permanently.

Prevention: Always check your posture when sitting or working. Improper posture can

cause additional strain on your joints including your wrists. Try to take regular breaks when

doing activities that cause you to bend and flex your wrists repeatedly, such as typing or

gripping. Try stretching your arms, hands and fingers to improve blood flow. Use ergonomic

office furniture and computer supplies to lessen strain. Make sure your furniture including your

keyboard and monitor is adjusted for your height and comfort. Eat a nutritious diet, and get

plenty of exercise to improve your flexibility, and strength. Finally make sure hand tools are

being used properly and are sized for your hand to avoid stressing the wrist.


References

A.D.A.M (2011). Carpal Tunnel Syndrome. In D. Zieve, & D. R. Eltz (Eds.), U.S. National

Libarary of Medicine (Loc. para 1 - 11). Retrieved from

http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001469/

Anatomy & Physiology Revealed 3.0 (Version 3.0) [Computer software]. (2011). Retrieved from

http://www.mhhe.com/sem/apr3/

David, S., Jackie, B., & Lewis, R. (2010). Hole’s Human Anatomy & Physiology (12 ed.). New

York, NY: McGraw-Hill.

F.A. Davis Company. (2005). Carpal tunnel syndrome. In D. Venes, A. Bidderman, E. Adler, B.

G. Fenton, & A. D. Enright (Eds.), Taber’s Cyclopedic Medical Dictionary (20, pp. 348 -

349). Philadelphia, PA: F.A. Davis Company.

Documents

Carpal Tunnel Handout