Chronic Fatigue Syndrome Chronic fatigue syndrome (CFS) involves persistent fatigue

of no known cause that may be associated with impaired memory, sore throat, painful
lymph nodes, muscle and joint pain, headaches, sleep problems, and immune
disorders. The condition often occurs after a viral infection. Epstein–Barr virus (the
cause of mononucleosis), herpesvirus, and other viruses have been suggested as
possible causes of CFS. No traditional or alternative therapies have been consistently
successful in treating CFS. Myasthenia Gravis Myasthenia gravis (MG) is an acquired
autoimmune disease caused by the loss of acetylcholine receptors in the muscle cell
membrane when a person’s immune system mistakenly recognizes these receptors as
foreign and attacks them with antibodies. Without these receptors, the neurons cannot
trigger muscle contraction. There is a progressive loss of muscle power characterized
by chronic muscular fatigue brought on by the slightest exertion. It affects adults and
begins with the muscles of the head. Drooping of the eyelids (ptosis) is a common early
sign. FOCUSSS ON WORDS ON WORDS Some C oolor rfull M in BOX 6-4.) Stress
injuries may involve any muscles or joints, but some common upper extremity
conditions are: ■ Rotator cuff (RTC) injury—The RTC, which strengthens the
shoulder joint, is formed by four muscles, the supra spinatus, infraspinatus, teres
minor, and subscapularis, the “SITS” muscles (FIG. 6-8). Inflammation or tearing of the
RTC can occur in people who repeatedly perform overhead activities, such as
swimming, painting, or pitching. ■ Epicondylitis—The medial and lateral epicondyles
(pro jections) of the distal humerus are attachment points for muscles that flex and
extend the wrist and fingers. Inflammation of these tendons of origin causes pain at
BOX 6 4 Mu usccu olorful Musculoskeletal Terms ulooskeele etal Terrms Some
common terms for musculoskeletal disorders have interesting origins. A charley horse
describes muscular strain and soreness, especially in the legs. The term comes from
com mon use of the name Charley for old lame horses that were kept around for family
use when they could no longer be used for hard work. Wryneck, technically torticollis,
uses the word wry, meaning twisted or turned, as in the word awry (ah-RI), meaning
amiss or out of position. A bunion, technically called hallux valgus, is an enlarge ment
of the first joint of the great toe with bursitis at the joint. It probably comes from the
word bony, changed to bunny, and used to mean a bump on the head and then a
swelling on a joint. A clavus is commonly called a corn because it is a hard ened or
horny thickening of the skin in an area of friction or pressure. 6 200 Part II ■ Body
Systems A Supraspinatus Deltoid (cut) Infraspinatus Teres minor Anterior view B
Supraspinatus Rotator cuff Subscapularis Biceps brachii FIGURE 6-8 Anatomy of the
rotator cuff. Four muscles contribute to the rotator cuff that strengthens the shoulder.
They are the supraspinatus, infraspinatus, teres minor, and subscapularis. Two
adjacent muscles are also shown, the deltoid and biceps brachii. A. Posterior. B.
Anterior. the elbow and forearm on lifting, carrying, squeezing, or typing. These stress
injuries are often sports-related, leading to the terms “golfer’s elbow” and “tennis
elbow” for medial and lateral epicondylitis, respectively. A brace worn below the elbow
to distribute stress on the joint may be helpful. ■ Carpal tunnel syndrome (CTS)—CTS
involves the ten dons of the finger flexor muscles and the nerves that sup ply the hand
and fingers (FIG. 6-9). Hand numbness and weakness are caused by pressure on the
median nerve as it passes through a channel formed by the carpal (wrist) bones. CTS
commonly appears in people who use their Transverse carpal ligament Median nerve
Palmaris longus tendon A Pressure on nerve Median nerve Tendons to flexor and
extensor muscles B FIGURE 6-9 Carpal tunnel syndrome. A. Pressure on the median
nerve as it passes through the carpal (wrist) bones causes numbness and weakness in
the areas of the hand supplied by the nerve. B. Cross-section of the wrist showing
compression of the median nerve. Chapter 6 ■ Muscular System 201 hands and fingers
strenuously, such as musicians and keyboarders. ■ Trigger finger—This is a painful
snapping, triggering, or locking of a finger as it is moved. It is caused by inflam mation
and swelling of the flexor tendon sheath at the metacarpophalangeal joint that prevents
the tendon from sliding back and forth. Some stress injuries that involve the lower
extremities are: ■ Hamstring strain—The hamstring is a large muscle group in the
posterior thigh that extends from the hip to the knee and flexes the knee (see FIG. 6-7).
A “pulled ham string” is common in athletes who stop and start running suddenly. It is
treated with stretching and strengthening activities. ■ Shin-splint—This is pain in the
leg’s anterior tibial region from running on hard surfaces or overuse of the foot flexors,
as in athletes and dancers. Help comes from Terminology good shoes with adequate
support and avoidance of hard surfaces for exercise. ■ Achilles tendinitis—The
Achilles (a-KIL-eze) tendon is a large tendon that attaches the calf muscles to the heel
and is used to plantar flex the foot at the ankle (see FIGS. 6-5 and 6-7). Damage to the
Achilles tendon hampers or prevents walking and running. Treatment Orthopedists
diagnose musculoskeletal disorders by MRI and other imaging techniques, ROM
measurements, and strength testing. Treatment of stress injuries usually begins
conservatively with rest, elevation, ice packs, bracing, and medications, such as
analgesics, anti-inflammatory agents, and muscle relaxants. (The acronym RICE
represents this simple approach—rest, ice, compression, elevation.) Treatment may
progress to steroid injections, ultrasound therapy for deep heat, strengthening
exercises, or even surgery. The terms listed below are emphasized in this chapter.
Knowing them will help you organize and prioritize your learning. amyotrophic lateral
sclerosis (ALS) A disease caused by motor neuron degeneration resulting in muscular
weakness chronic fatigue syndrome (CFS) A disease of unknown cause that involves
persistent fatigue along with muscle and dermatomyositis A disease of unknown origin
involving muscular inflammation as well as fibromyalgia syndrome (FMS) A disorder
associated with widespread muscular aches and stiffness and having no muscular
dystrophy A group of hereditary muscular disorders marked by progressive weakness
and myasthenia gravis (MG) A disease characterized by progressive muscular
weakness; an autoimmune disease polymyositis Tissue damage caused by repeated
motion, usually overuse of the arm or hand in occupational activities such as writing,
typing, painting, or using hand tools; also called repetitive motion injury, cumulative
trauma injury, overuse sprain Injury to a ligament caused by abnormal or excessive
force at a joint, but without strain Trauma to a muscle because of overuse or excessive
stretch; if severe, may involve muscular tearing, bleeding, separation of a muscle from
its tendon, or tendon tendinitis Inflammation of a tendon, usually caused by injury or
overuse; the shoulder, elbow, (continued) 6 202 Part II ■ Body Systems Terminology Key
Terms (Continued) tenosynovitis