Muscle Strength

HO for Orthopedic - Muscular
1)The muscle that runs on a diagonal from the lower ribs to the iliac crest is the:
A)rectus femoris muscle.
B)external abdominal oblique muscle.
C)latissimus dorsi muscle.
D)rectus abdominis muscle.

2)The patient with cerebral palsy was described as having ataxia. This means that the patient:
A)has slow skeletal muscle movements of his upper extremities.
B)has slow, purposeless writhing of his hands.
C)walks with an uncoordinated gait.
D)has muscle jerking and spasms when he attempts movement.

3)The patient was in a coma for a long time in a nursing home. He eventually developed ____________ or abnormal, fixed positions in which his muscles were permanently flexed.
A)contractures B) conductions
C)contusions D) constrictions

4)Torticollis is a condition that occurs in the muscles of the:
A)hand. B) shoulder. C) neck. D) back.

5)A rhabdomyosarcoma is a malignancy of ____________ tissue.
A)tendon B) involuntary muscle
C)striated muscle D) fascicle muscle

6)The large muscle of the buttocks that one sits on is the:
A)gastrocnemius. B) gluteus maximus.
C)rectus femoris. D) peroneal longus.

7)A physiatrist is a ____________ who gains further specialized training that encompasses treatment for sports injuries.
A)physician B) chiropractor
C)physical therapist D) massage therapist

8)A podiatrist would treat an injury of which muscle?
A)flexor hallucis brevis B) deltoiod
C)temporalis D) brachioradialis

9)When a muscle tears away from a tendon or a tendon tears away from a bone it is known as:
A)contracture. B) avulsion. C) spasm. D) contusion.

10)Myoclonus is characterized by muscle:
A)jerking. B) contractures.
C)inflammation. D) wasting.

11)Inflammation of a cordlike band of connective tissue that attaches a muscle to a bone is known as:
A)fascitis. B) bursitis. C) tendonitis. D) myositis.

12)Acetylcholine receptor antibodies are found in patients with:
A)muscle contractures. B) fibromyalgia.
C)myasthenia gravis. D) muscular dystrophy.

13)Which is an incision into the thin connective tissue sheet that wraps around each individual muscle or a group of muscles?
A)bursotomy B) fasciotomy C) myotomy D) tenotomy

14)Moving a body part away from the midline is known as:
A)abduction. B) flexion. C) adduction. D) eversion.

15)A disorder of the hand that creates a flexion deformity of the fingers is called:
A)Dupuytren's contracture. B) pronation.
C)repetitive strain disorder. D) a ganglion.

16)An athletic injury with pain and inflammation of the flexor muscles over the anterior tibia would be found in the:
A)elbow. B) lower leg. C) neck. D) wrist.

17)Trigger points, areas on a patient's body that are tender to touch and feel firm, are indicative of which condition?
A)rhabdomyoma B) muscular dystrophy
C)fibromyalgia D) restless leg syndrome

18)Abnormally slow skeletal muscle movements associated with Parkinson's disease are known as:
A)hyperkinesias. B) bradykinesia.
C)ataxia. D) dyskinesia.

19)A rotator cuff tear occurs at the:
A)knee. B) shoulder. C) wrist. D) hip.

20)An EMG is a:
A)diagnostic procedure used to diagnose nerve damage or muscle disease.
B)series of rehabilitation exercises following a musculoskeletal injury.
C)test that measures motor muscle strength.
D)laboratory test of enzymes that, when elevated, point to muscle damage.

21)Surgical removal of the ____________ gland is sometimes done to alleviate the symptoms of myasthenia gravis.
A)pituitary B) thymus C) thyroid D) adrenal

22)A contusion due to a blunt injury to a muscle causes a condition commonly known as:
A)whiplash. B) shin splint. C) bruise. D) strain.

23)Which is the characteristic symptom of myasthenia gravis?
A)abnormal fatigue involving skeletal muscles
B)sudden, temporary muscle spasms
C)gradual paralysis
D)widespread stiffness and internal pain over certain muscles

24)Which one is not one of the three types of muscles in the body?
A)cardiac B) smooth C) skeletal D) triceps

25)Which type of muscle is involuntary and nonstriated?
A)smooth B) skeletal C) cardiac D) respiratory

26)Which is a cordlike, nonelastic, white fibrous band of connective tissue?
A)muscle B) bursa C) tendon D) joint

27)Which is the large muscle in the buttocks?
A)rectus abdominis B) temporalis
C)gluteus maximus D) brachioradialis

28)Which is the short muscle that flexes the big toe?
A)flexor hallucis brevis B) extensor digitorum
C)gluteus maximus D) brachioradialis

29)Bending a joint to decrease the angle between two bones or two body parts is known as:
A)abduction. B) adduction. C) extension. D) flexion.

30)Which muscle moves the forehead skin to elevate the eyebrows or wrinkle the forehead?
A)masseter B) frontalis
C)orbicularis oris D) temporalis

31)Which muscle bends the lower arm toward the upper arm?
A)biceps brachii B) thenar
C)triceps brachii D) rectus abdominis

32)The gastrocnemius muscle:
A)straightens the lower arm. B) bends the foot downward.
C)bends the upper body forward. D) moves the food into the stomach.

33)The loss of muscle bulk in one or more muscles is known as:
A)avulsion. B) hypertrophy.
C)contracture. D) atrophy.

34)Painful contracture of the muscles on one side of the neck is known as:
A)torticollis. B) repetitive strain injury.
C)myalgia. D) rotator cuff tear.

35)Incoordination of the muscles during movement is known as:
A)ataxia. B) bradykinesia.
C)dyskinesia. D) hyperkinesis.

36)Which is an uncomfortable twitching of the muscles of the legs, particularly the calf muscles, along with an indescribable tingling, aching, or crawling-insect sensation?
A)restless leg syndrome B) muscular dystrophy
C)chronic fatigue syndrome D) myalgia

37)Inflammation and pain of the flexor and pronator muscles of the forearm where their tendons originate on the medial epicondyle of the humerus by the elbow joint is known as:
A)pitcher's elbow. B) golfer's elbow.
C)medial epicondylitis. D) all of the above

38)Which diagnostic procedure is performed to diagnose muscle disease or nerve damage?
A)myelogram B) myoneurogram
C)Tensilon test D) electromyography

39)During a muscle strength test, grip strength measures ____________ strength.
A)hand B) muscle C) bone D) back

40)During a muscle strength test, ____________ strength is measured.
A)reflex B) adaptive C) extension D) motor

41)Which condition is known as housemaid's knee?
A)tremor B) tendonitis C) shin splints D) bursitis

42)A small, involuntary, sometimes jerky back-and-forth movement of the hands, neck, jaw, or extremities is known as:
A)contracture. B) ataxia. C) dyskinesia. D) tremor.

43)Abnormal motions due to difficulty controlling the voluntary muscles are known as:
A)ataxia. B) contracture.
C)hyperkinesis. D) dyskinesia

44)Which is a normal condition of the muscles that occurs several hours after death?
A)cardiac arrest B) atrophy
C)rigor mortis D) bradykinesis

45)Which is another name for repetitive strain injury (RSI)?
A)bursitis B) restless leg syndrome
C)polymyositis D) cumulative trauma disorder (CTD)

46)Which is a painful, but temporary, condition characterized by a sudden, severe, involuntary, and prolonged contracture of a muscle, usually in the legs?
A)fibromyalgia B) muscle sprain
C)muscle spasm D) tendonitis

47)Which medical word means muscle wasting?
A)hypertrophy B) ataxia
C)atrophy D) dyskinesia

48)Which combining form means triangle?
A)maxim/o- B) fasci/o- C) delt/o- D) flex/o-

49)There are approximately how many skeletal muscles in the body?
A)400 B) 500 C) 600 D) 700

50)Which of the following is NOT a type of muscle in the body?
A)polystriated B) smooth C) skeletal D) cardiac

51)Bending a joint to decrease the angle between two bones or two body parts is known as:
A)extension. B) flexion. C) adduction. D) abduction.

52)Moving a body part around on its axis is known as:
A)eversion. B) supination. C) adduction. D) rotation.

53)The intercostal muscles assist what functions?
A)moving the neck B) raising the shoulder
C)coughing and sneezing D) moving the arm

54)Maximus is a word that means:
A)the largest one of a group. B) pertaining to.
C)front or front part. D) fastest.

55)The neurotransmitter that initiates muscle contraction is:
A)buccinator. B) fascicle.
C)aponeurosis. D) acetylcholine.

56)A fluid-filled sac that decreases friction where a tendon rubs against a bone near a synovial joint is a/an:
A)bursa. B) platysma. C) evertor. D) extensor.

57)A crushing injury to the muscles of the leg causes compartment syndrome, which in turn causes all of the following EXCEPT:
A)cardiac arrhythmias.
B)cellular death and nerve damage.
C)pressure within the compartment of the leg.
D)accumulation of blood in the compartment.

58)What type of drug is used to relieve muscle spasm and stiffness?
A)corticosteroid drugs
B)nonsteroidal anti-inflammatory drugs
C)muscle relaxant drugs
D)analgesic drugs

59)Which word means front?
A)dorsal B) posterior C) lateral D) anterior

60)Which word means inactivity or paralysis coupled with continuing nerve impulses, causing a muscle to be progressively flexed and drawn into a position where becomes nearly immovable?
A)atrophy B) fibromyalgia
C)avulsion D) contracture

61)Which word means pain in several muscle groups?
A)RSI B) myasthenia gravis
C)myopathy D) polymyalgia

62)Abnormally slow muscle movements or a decrease in the number of spontaneous muscle movements is called:
A)dyskinesia. B) myoclonus.
C)ataxic. D) bradykinesia.

63)Inflammation of the bursal sac because of repetitive muscular activity or pressure on the bone underneath the bursa is called:
A)ganglion. B) Dupuytren's contracture.
C)restless leg syndrome. D) bursitis.

64)Which diagnostic procedure is used to diagnose muscle disease or nerve damage?
A)tensilon B) DTR C) CPK-MM D) EMG

65)A muscle biopsy is a surgical procedure to:
A)cut the fascia and release pressure from built up blood and tissue fluid in patients with compartment syndrome.
B)suture together the torn ends of a tendon following an injury.
C)make a definitive diagnosis when muscle weakness could be caused by many different muscular diseases.
D)suture together the torn ends of a muscle following an injury.

66)NSAIDs are drugs used to:
A)kill viruses. B) decrease inflammation.
C)kill bacteria. D) relax muscles.

67)The abbreviation ROM means:
A)range of muscle mass. B) range of motion.
C)rate of measure. D) rate of myalgia.

68)Which statement is true about abbreviations?
A)There are no standard abbreviations for medical documentation.
B)Each abbreviation can only have one meaning.
C)It is acceptable medical practice to use any abbreviation in medical documentation.
D)Abbreviations are commonly used in all types of medical documentation.

69)Movement around a central point or axis is known as:
A)extension. B) inversion. C) abduction. D) rotation.

70)All of the following suffixes mean pertaining to EXCEPT:
A)-ary. B) -or. C) -al. D) -ous.

71)The combining form muscul/o- has the same meaning as which combining form?
A)contract/o- B) ten/o- C) malign/o- D) my/o-

72)The suffix -oma means:
A)weakness. B) tumor or mass.
C)contraction. D) muscle.

73)The suffix -ics in orthopedics means:
A)knowledge or practice. B) action or condition.
C)inflammation of. D) the study of.

74)The neck muscle that goes from the ear to the collarbone and sternum is the:
A)gluteus maximus. B) brachioradialis.
C)sternocleidomastoid. D) aponeurosis.

75)Which of the following is classified as a repetitive stress disorder?
A)myasthenia gravis B) tennis elbow
C)rotator cuff tear D) rhabdomyoma

76)Which is the abbreviation for the government organization that educates healthcare professionals about workplace-related injuries?
A)OSHA B) NSAID C) PM&R D) COTA

77)The latissimus dorsi is a muscle of the:
A)upper leg. B) chest. C) back. D) abdomen.

78)When your outstretched arm has the palm down, this is known as:
A)rotation. B) pronation. C) flexion. D) insertion.

79)Skeletal muscles are also known as ____________ muscles.
A)voluntary B) involuntary C) cardiac D) rascial

80)Patients with Parkinson's disease who move with slow, shuffling movements have the muscle condition known as:
A)myalgia. B) contracture.
C)restless legs syndrome. D) bradykinesia.

81)Moving your head to indicate "yes" and then to indicate "no" would correspond to which two movements?
A)flexion and rotation B) supination and extension
C)elevation and circumduction D) contraction and relaxation

82)If you point your toe like a ballet dancer, you would be doing which movement?
A)plantar flexion B) rotation
C)inversion D) abduction

83)The pectoralis major muscle is located in the:
A)buttocks. B) thigh. C) forearm. D) chest.

84)Lateral epicondylitis is a repetitive strain injury known as:
A)deep tendon reflex. B) myasthenia gravis.
C)tennis elbow. D) myositis.

85)Suturing of a cut tendon is a surgical procedure known as:
A)myorrhaphy. B) range of motion.
C)electromyography. D) tenorrhaphy.

86)The inability to coordinate voluntary movements, as found in someone with cerebral palsy, is known as:
A)fascia. B) ataxia.
C)polymyositis. D) supination.

87)A genetic disorder that causes progressive weakness as the muscle tissue turns to fat is known as:
A)muscular dystrophy. B) myalgia.
C)dyskinesia. D) contracture.

88)The intercostal muscles are:
A)across the chest. B) between the ribs.
C)around the femur. D) in the arm.

89)The masseter muscle is used for:
A)chewing. B) leg movements.
C)arm movements. D) breathing.

90)Select the misspelled word.
A)dyskinesia B) tremor
C)ganglian D) rhabdomyosarcoma

91)Hyperkinesia is the opposite of:
A)tremor. B) bradykinesia.
C)bursitis. D) ataxia.

92)An assistive device is one that can help a patient:
A)meet the requirements of ADA. B) perform ADLs.
C)have a positive DTR. D) decrease ROM.

93)A slender, elongated pocket of synovial membrane that contains synovial fluid is known as a/an:
A)tendon. B) fascia. C) bursa. D) fascicle.

94)A flat, wide, white fibrous sheet of connective tissue that attaches a flat muscle to a bone or to deep muscles is known as a/an:
A)ligament. B) tendon.
C)aponeurosis. D) bursa.

95)Muscles get their names from their:
A)size. B) shape.
C)location. D) all of the above

96)A flexed and nearly immovable position of a muscle is known as a/an:
A)avulsion. B) contracture. C) strain. D) contusion.

97)A percussion hammer is used to test:
A)muscle strength. B) deep tendon reflexes.
C)muscle size. D) the presence of a contraction.

98)Suturing the torn ends of a muscle after an injury is termed ____________.

99)A general word for muscle pain is ____________.

100)Bridget's housemaid's knee came from prolonged kneeling, causing ____________, an inflammation of a pocket of synovial fluid near her knee joint.

101)A pulled muscle or muscle ____________ is caused by overstretching a muscle to cause inflammation, pain, and swelling.

102)Loss of muscle bulk is known as muscle wasting or ____________.

103)The medical word for muscle disease is ____________.

104)Because of periodic, involuntary jerking movement of his hands and head, Mr. Jones is being treated with beta blocker for his essential familial ____________.

105)Drugs such as Motrin and Feldene that are used to suppress inflammation and decrease pain are collectively known by the abbreviation ____________.

106)During a car accident when a person's head snaps backward and forward, causing damage to the structures in the neck, the result is known as hyperextension-hyperflexion. The common term for this condition is ____________.

107)Inflammation of a skeletal muscle with localized tenderness and swelling is known as ____________.

108)All of the muscles of the body or in one part of the body are referred to as the ____________.

109)The ____________ is the beginning of a muscle where it is attached to a stationary or nearly stationary bone of the skeleton.

110)A muscle is attached to a bone at its origin or insertion by a ____________.

111)Straightening and extending a joint to increase the angle between two bones or two body parts is known as ____________.

112)Each muscle ____________ is a bundle of individual muscle fibers.

113)When the electrical impulse reaches the end of the nerve cell, the nerve cell releases a neurotransmitter called ____________.

114)A flat, white sheet of fibrous connective tissue that attaches a muscle to a bone or other structure is called a/an ____________.

115)A/an ____________ is a fluid-filled sac that decreases friction where a tendon rubs against a bone near a synovial joint.

116)The ____________ ____________ muscle is the largest muscle in the buttocks that moves the upper leg posteriorly and rotates it laterally.

117)A muscle ____________ is a painful but temporary condition characterized by a sudden severe, involuntary and prolonged contraction of a muscle, usually in the legs.

118)Skeletal muscles are ____________ muscles that contract and relax in response to conscious thought.

119)Skeletal muscles are ____________ , showing bands of color when examined under the microscope.

120)The ____________ or beginning of a muscle is where it is attached to a stationary or nearly stationary bone of the skeleton.

121)The ____________ or ending point is where the muscle attaches to the bone that it moves when it contracts and relaxes.

122)The muscle is attached to the bone at its origin and at its insertion by a ____________.

123)Moving a body part away from the midline of the body is called ____________.

124)Turning the palm of the hand upward is called ____________.

125)Straightening and extending a joint to increase the angle between two bones or two body parts is called ____________.

126)The muscle in the front shoulder, which is shaped like a triangle and raises and lowers the arm is called the ____________.

127)The ____________ muscle bends the lower arm toward the upper arm (flexion).

128)Each muscle ____________ is a bundle of individual muscle fibers.

129)____________ is a chemical messenger that moves across the neuromuscular junction and acts as a key to unlock receptors on the muscle fiber.

130)Vigorous weight training can increase the size of a muscle, which is called muscle ____________.

131)The group of muscles in the anterior and lateral thigh that straightens the lower leg (extension) is called the ____________ ____________ group. This group of muscle includes the rectus femoris, vastus lateralis, vastus intermedius, and vastus medialis muscles.

132)A muscle that produces extension is part of a muscle pair in which the other muscle produces ____________.

133)A muscle that produces eversion is part of a muscle pair in which the other muscle produces ____________.

134)In dorsiflexion, the toes are pointing ____________ , and in plantar flexion, the toes are pointing ____________.

135)The Achilles tendon is located in the ____________.

136)The two muscles of the upper arm that flex and extend the arm are the ____________ brachii and the ____________ brachii.

137)____________ is the medical specialty that studies the anatomy, diseases, and treatment of the bones and muscles.

138)____________ is the common word for torticollis.

139)Pronation means to turn the palm of the hand upward; supination means to turn the palm of the hand down.

140)A rhabdomyoma is a benign tumor that arises from striated or skeletal muscle.

141)Rigor mortis is a reversible condition if it is caught in time.

142)The electromyography is a test done to confirm myasthenia gravis.

143)The beginning of a skeletal muscle where it is attached is known as its origin and the ending point of attachment is known as the inversion.

144)Hamstrings is a collective name for the four muscles on the anterior and lateral aspect of the upper leg.

145)The word used to describe a site for the injection of a drug is intermuscular.

146)Muscular dystrophy is a genetic inherited disease due to a mutation of the gene that makes a muscle protein.

147)The masseter muscle is found in the area of the face.

148)Insertion of a needle to aspirate muscle tissue is known as a closed biopsy.

149)The combining form orth/o- in the word orthopedics means bone.

150)Skeletal muscles are voluntary muscles.

151)The flexor hallucis brevis muscle is a muscle of the hand.

152)The word part brachi/o- means arm and is found in words related to the arm.

153)The word pronation means turning the palm of the hand upward.

154)The orbicularis oculi muscle is a muscle of the head and neck that closes the eyelids.

155)The word hamstrings is a collective name for two muscles on the posterior aspect of the thigh.

156)Muscle fibers contain hundreds of nuclei scattered throughout the length of each fiber.

157)Each muscle fiber contains many muscle cells.

158)Polymyalgia is pain in several muscle groups.

159)When the deep tendon reflexes are tested, the impulse from tapping the patellar tendon goes to the brain and the brain makes a conscious decision to extend the leg.

160)The word rectus in the muscle name rectus abdominis means oblique.

161)Thenar is an adjective that refers to the leg.

162)The suffix -ceps means head.

163)A rhabdomyoma is a benign tumor of the muscle and a rhabdomyosarcoma is a malignant tumor of the tendon.

164)The Tensilon test is used to diagnose Dupuytren's contracture.

165)The size and strength of muscles decrease in older patients.

166)The gastrocnemius muscle propels food through the stomach.

167)Rigor mortis is the medical name for muscle atrophy.

168)Tremors are tiny, involuntary, back-and-forth movements that the patient cannot stop.

169)What is the definition of a ganglionectomy?

170)Explain how the physician would use the results of the lab test CPK-MM to aid in making a diagnosis for a patient.

171)The patient was in an automobile accident and sustained severe crushing injuries and fractures in her right foot. She developed compartment syndrome. How could this condition lead to a loss of the use of her foot?

172)Describe how a contraction differs from a contracture.

173)List and describe the three types of muscles in the human body.

174)Explain how muscle pairs produce movement.

175)Explain how a muscle fiber contracts.

176)Briefly describe the disease muscular dystrophy, including symptoms and signs.

177)What is an electromyography?

1)B

2)C

3)A

4)C

5)C

6)B

7)A

8)A

9)B

10)A

11)C

12)C

13)B

14)A

15)A

16)B

17)C

18)B

19)B

20)A

21)B

22)C

23)A

24)D

25)A

26)C

27)C

28)A

29)D

30)B

31)A

32)B

33)D

34)A

35)A

36)A

37)D

38)D

39)A

40)D

41)D

42)D

43)D

44)C

45)D

46)C

47)C

48)C

49)D

50)A

51)B

52)D

53)C

54)A

55)D

56)A

57)A

58)C

59)B

60)D

61)D

62)D

63)D

64)D

65)C

66)B

67)B

68)D

69)D

70)B

71)D

72)B

73)A

74)C

75)B

76)A

77)C

78)B

79)A

80)D

81)A

82)A

83)D

84)C

85)D

86)B

87)A

88)B

89)A

90)C

91)B

92)B

93)C

94)C

95)D

96)B

97)B

98)myorrhaphy

99)myalgia

100)bursitis

101)strain

102)atrophy

103)myopathy

104)tremor

105)NSAID

106)whiplash

107)myositis

108)musculature

109)origin

110)tendon

111)extension

112)fascicle

113)acetylcholine

114)aponeurosis

115)bursa

116)gluteus maximus

117)spasm

118)voluntary

119)striated

120)origin

121)insertion

122)tendon

123)abduction

124)supination

125)extension

126)deltoid

127)brachioradialis

128)fascicle

129)Acetylcholine

130)hypertrophy

131)quadriceps femoris

132)flexion

133)inversion

134)upward; downward

135)leg

136)biceps; triceps

137)Orthopedics

138)Wryneck

139)FALSE

140)TRUE

141)FALSE

142)FALSE

143)FALSE

144)FALSE

145)FALSE

146)TRUE

147)TRUE

148)TRUE

149)FALSE

150)TRUE

151)FALSE

152)TRUE

153)FALSE

154)TRUE

155)FALSE

156)TRUE

157)FALSE

158)TRUE

159)FALSE

160)FALSE

161)FALSE

162)TRUE

163)FALSE

164)FALSE

165)TRUE

166)FALSE

167)FALSE

168)TRUE

169)Surgical excision of a ganglion. A ganglion is a semisolid or fluid-containing cyst that develops on a tendon, often on the wrist, hand, or foot. It is clearly visible as a rounded lump under the skin that may or may not be painful.

170)CPK-MM is an isoenzyme found in skeletal muscle. It is released from muscle cells when injury or death occurs to these cells. High levels of serum CPK-MM point to diseases like muscular dystrophy in which skeletal muscle tissue is being destroyed.

171)The fascia around the muscle acts like a compartment. When significant amounts of blood build up, the tissues are compressed. If this pressure is not relieved, nerve and blood vessel necrosis will occur destroying these structures and resulting in the loss of function of the foot.

172)A contraction is a normal shortening of a muscle as actin filaments slide between myosin filaments in response to an electrical impulse from a nerve. A contracture is an abnormal, fixed position of a muscle in which it shortens due to inactivity or paralysis.

173)The three types of muscle in the body are skeletal muscle, cardiac muscle, and smooth muscle. Skeletal muscles provides the means by which the body can move. They are voluntary, striated muscles that contract and relax in response to conscious thought. Cardiac muscle is an involuntary muscle that is not under conscious control. Smooth muscles are involuntary, nonstriated muscles. They are found in organs such as the stomach and intestines.

174)Muscles function in pairs to produce movement. When the first muscle contracts, the second muscle relaxes to allow movement in one direction. When the second muscle contracts, the first one relaxes to allow movement in the opposite direction.

175)Each muscle fiber is connected to a single nerve cell at the neuromuscular junction. When the electrical impulse reaches the end of the nerve cell, the nerve cell releases the neurotransmitter acetylcholine. Acetycholine is a chemical messenger that moves across the neuromuscular junction and acts as a key to unlock receptors on the muscle fiber. This changes the permeability of the cell membrane and allows calcium ions to flow into the muscle fiber. Calcium ions cause the thin filaments to slide between the thick filaments, shortening the muscle and producing a muscle contraction.

176)Muscular dystrophy is a genetic inherited disease caused by a mutation of the gene that makes the muscle protein dystrophin. Without dystrophin, the muscles weaken and then atrophy. Symptoms appear in early childhood as weakness first in the lower extremities and then in the upper extremities. Weakness in the extremities is the most visible disability, but weakness of the diaphragm and inability to breathe is the most frequent cause of death.

177)An electromyography is a diagnostic procedure to diagnose muscle disease or nerve damage. A needle electrode inserted into a muscle records electrical activity as the muscle contracts and relaxes. The electrical activity is displayed as waveforms on an oscilloscope screen and permanently recorded on paper as an electromyogram.