Musculoskeletal
Neuromuscular
P&O
Pediatrics
Electrodiagnostic Medicine
100
20-year-old football player reports anterior shoulder pain during a game. He completes the game, but radiographs after the game revealed a type 2 acromioclavicular (AC) joint sprain. How is a type 2 acromioclavicular (AC) joint injury defined? (a) AC and coracoclavicular (CC) ligaments are both disrupted. (b) AC and CC ligaments are both intact. (c) AC ligament is disrupted, but the CC ligament is intact. (d) AC ligament is intact, and the CC ligament is disrupted.
What is c. AC joint injuries are classified into 6 types according Rockwood classification. A type 1 injury describes a mild injury to the AC joint without disruption of either the AC or the CC ligaments. A type 2 injury describes disruption of the AC ligament, but the CC ligament remains intact. A type 3 injury describes disruption of both ligaments whereas a type 4 injury entails complete disruption of both ligaments with posterior displacement of the distal clavicle into the trapezius muscle.
100
In patients with neuromuscular disease, which measurement is shown to be the most influential in determining the intensity of their aerobic exercise? (a) 70%-85% maximum heart rate (b) 60%-80% of heart rate reserve (c) Borg scale of perceived exertion (d) Delayed-onset muscle soreness
What is d. Thirty-three studies, to date, report absent or negligible adverse effects of exercise in neuromuscular disease patients. Maximum HR and cardiac reserve are the same goals for able bodied and neuromuscular patients. Delayed onset muscle soreness is shown to be the most influential factor for patients to modify their own exercise program.
100
A 60-year-old woman with right medial knee pain has a genu varum deformity that is observed while she is standing and walking. What shoe modification can help her pain? (a) Medial wedge (b) Lateral wedge (c) Rocker bottom (d) Arch support
What is b. Medial compartment osteoarthritis causes a genu varum deformity. Lateral heel wedges can be used for conservative treatment of medial compartment osteoarthritis. A medial wedge would exacerbate the genu varum. An arch support would help with pes planus (flatfoot) which may be helpful for genu valgum deformity. Rocker bottoms may be used to offload pressure from the metatarsal heads.
100
When should one be concerned when observing a child with an asymmetric tonic neck reflex (ATNR,“fencer” position) with neck rotation, relative extension of the limbs on the chin side and flexion of the limbs on the occiput side? (a) In a 3-month-old infant who is able to move out of the “fencer” position (b) In a 5-month-old infant who is unable to move out of the “fencer” position (c) In a 6-month-old infant whose leg response to the stimulus is greater than the arm’s (d) In an infant of any age, since the ATNR is a primitive pathological reflex.
What is b. The ATNR is typically present at birth and integrates between 4 and 6 months of age. An obligatory “fencer” position is abnormal at any age. A persistent or obligatory ATNR may be an early clue that a child has a disorder of motor control, most often cerebral palsy.
100
Which electrodiagnostic feature is more common in type 2 Charcot-Marie-Tooth (CMT) disease than in CMT type1? (a) It is primarly demyelinating. (b) Lower limbs are more affected than upper. (c) Conduction velocity slows. (d) Secondary axonal changes occur over time.
What is b. The type-2 form of Charcot-Marie-Tooth disease (CMT2) tends to affect the LE > UE. In CMT type 1, which is primarily a demyelinating neuropathy, anatomic changes directly affect the myelin sheath, with secondary axonal changes. In areas of focal demyelination, impulse conduction from 1 node of Ranvier to the next is slowed, because current leakage occurs and the time for impulses to reach threshold at successive nodes of Ranvier is prolonged. The prolongation slows CV along the nerve segment. CMT2 is often a clinically less severe disease than CMT1.
200
25-year-old man presents to clinic with an insidious onset of low back pain over the past 6 months. He denies any trauma, but is quite active running and biking. He does not report any leg symptoms. His pain is worse in the morning, but improves with activity and with antiinflammatory medication. What additional information would be most helpful in making the diagnosis? (a) Blood work revealing elevated ESR (b) MRI revealing degenerative disc disease (c) Plain radiograph revealing sacroiliitis (d) PE revealing an absent Achilles DTR
What is Answer: (c) Commentary: This patient presents with a clinical history consistent with ankylosing spondylitis (AS).This spondyloarthropathy is more common in men in their late teenage years to early twenties. It generally presents with morning stiffness in the low back and/or buttocks. Criteria for diagnosis (modified New York classification) include the presence of sacroiliitis on x-ray and 1 of the following: history of inflammatory back, decreased ROM of spine, and limited chest expansion.
200
In a patient with neuromuscular disease, which pulmonary function parameter best represents abdominal and chest wall strength? (a) Tidal volume (b) Maximal inspiratory pressure (c) Peak cough (d) Maximal expiratory pressure
What is d. The maximal inspiratory pressure reflects diaphragm strength and ventilatory ability. Maximum expiratory pressure is indicative of abdominal and chest wall muscle strength and the ability to cough and clear secretions. The Vt represents the normal volume of air displaced between normal inhalation and exhalation when extra effort is not applied. Peak cough flow is a measure of the amount of air flow that a patient can generate during a volitional cough.
200
At mid stance, where is the ground reaction force vector located? (a) Anterior to ankle, posterior to knee (b) Anterior to ankle, anterior to knee (c) Anterior to knee, anterior to hip (d) Posterior to knee, posterior to hip
What is B In mid stance, the ground reaction vector lies anterior to the ankle, anterior to or through the knee axis, and posterior to the hip center. The passive torques created by this vector alignment are ankle DF, knee extension and hip extension.
200
A 1-year-old boy presents with marked weakness. Parents report a weak cry and cough since birth, and the child cannot sit independently. Exam findings include a bell-shaped thorax, hypotonia, some movement of the hands and feet but minimal movement at the hips and shoulders, and there are tongue fasciculations. The diagnosis is best confirmed by (a) genetic analysis. (b) muscle biopsy. (c) electromyography. (d) repetitive nerve stimulation.
What is a. This child’s presentation is typical for spinal muscular atrophy (SMA) type I, also known as Werdnig-Hoffmann disease. SMA is the second most common neuromuscular disease of childhood, occurring with an incidence of 1:6,000. Deletion of the survival motor neuron gene leads to degeneration of anterior horn cells and can be detected in over 90% of children with SMA. Prior to availability of genetic diagnosis, EMG and muscle biopsies were utilized. Repetitive nerve stimulation has been used in the investigation of botulism and congenital MG but is not helpful in SMA.
200
A 37-year-old man is sent to you for electrodiagnostic assessment for right lumbosacral radiculopathy. NCS of the right leg are normal. Needle exam shows the following: NEEDLE ELECTROMYOGRAPHY Muscle Abnml Spon. Act. Recruitment Adductor longus 0 Normal Vastus medialis 0 Normal Tensor fascia lata 1+ Normal Semimembranosus 1+ Normal B. femoris (short head)0 Normal Tibialis anterior 2+ Reduced Medial gastrocnemius 0 Normal Lumbar paraspinals 1+ N/A Which root is most likely injured? (a) L2 (b) L3 (c) L4 (d) L5
What is d. The common root among the affected muscles is L5. It is often difficult to narrow the involvement to a single root level.
300
Which clinical scenario is most consistent with a L4-5 foraminal disc herniation? (a) Weakness of the EHL, decreased sensation of the web space between the first and second toes, absent hamstring reflex (b) Weakness of the gastrocnemius, decreased sensation of lateral foot, absent Achilles reflex (c) Weakness of the anterior tibialis, decreased sensation of the web space between the first and second toes, absent hamstring reflex (d) Weakness of quadriceps and anterior tibialis, decreased sensation of medial lower leg, absent patellar reflex
What is: d. A foraminal disc herniation at L4-5 level would most likely affect the exiting L4 nerve root. A nerve root lesion could result in muscle weakness in the affected myotomes, sensation loss in the affected dermatomes, and deep tendon reflex changes. The PE findings most consistent with a lesion to the L4 nerve root would be weakness of the quadriceps (L2-4), decreased sensation in L4 dermatomes, and decreased or absent patellar deep tendon reflex (L4).
300
Which muscle fiber is characterized by slow-twitch oxidative metabolic properties? (a) Type 2a (b) Type 1 (c) Type 2b (d) Type 3
What is b. There are 2 primary muscle fiber types in humans. They are categorized according to many different characteristics, including speed of contraction and sources of fuel. Type 1 muscle fibers are slow-twitch with oxidative metabolic pathways. Type 2 muscle fibers are fast twitch fibers. The type 2 fibers can then be further divided into fast-twitch glyclolytic, and fasttwitch oxidative glycolytic.
300
Which K level best describes an individual who is able to ambulate within the household, but not out in the community? (a) K 1 (b) K 2 (c) K 3 (d) K 4
What is a. The K level of 1 represents that of a household ambulator; K 2 limited community ambulator; K 3 unlimited community ambulator; K4 a very active community ambulator. The household exception FIM score of 5 indicates a "modified independent" ambulator who can handle household distances (i.e., less than 50 feet) inside or out.
300
A 14-year-old girl with spastic quadriplegic cerebral palsy (CP) has driven a power wheelchair as her primary means of mobility since age 4 years. She recently sustained a fracture of her tibia with no known significant trauma. You anticipate that the bone mineral density (BMD) z score for her distal femur as measured on a dual-energy x-ray absorptiometry (DEXA) scan will be (a) increased relative to peers without spasticity. (b) increased relative to younger nonambulatory children with CP. (c) similar to younger ambulatory children with CP. (d) decreased relative to age-matched peers without CP.
What is d. Children with severe CP develop clinically significant osteopenia. Lower BMD z scores are associated with greater severity of CP as indicated by gross motor function, and these scores decrease with age. Rather than occurring primarily from actual losses in bone mineral, as in aging adults, the decreasing BMD z scores seen in older youths with CP occur because they have a slower rate of growth in bone mineral, relative to their healthy peers.
300
Dorsal ulnar cutaneous nerve conduction studies are most useful in differentiating (a) ulnar neuropathy at the elbow from lower trunk plexopathy. (b) ulnar neuropathy at the elbow from ulnar neuropathy at the wrist. (c) lower trunk plexopathy from medial cord plexopathy. (d) ulnar neuropathy at the cubital tunnel from ulnar neuropathy at the ulnar groove.
What is b. The fibers of the dorsal ulnar cutaneous nerve travel in the lower trunk and the medial cord of the brachial plexus. This nerve travels with the ulnar nerve to the forearm, where it branches off proximal to the wrist and supplies sensation to the ulnar aspect of the dorsum of the hand and wrist. The dorsal ulnar cutaneous sensory nerve action potential amplitude could be decreased with a lesion of the lower trunk, the medial cord, or the ulnar nerve at the elbow or proximal forearm, and would not be useful in differentiating among them. It should be normal in ulnar neuropathy at the wrist.
400
A 50-year-old administrative assistant presents with low back pain. After taking her history, performing a PE, and reviewing her imaging studies, you determine that her pain is likely discogenic. She asks if there are any positions which would be better for her back while at work. Which position exerts the most pressure on the lumbar discs? (a) Standing erect (b) Standing erect and flexed forward (c) Seated in a chair (d) Seated in a chair and flexed forward
What is D. Nachemson measured the relative pressure changes within the third lumbar disc with changes of position. Standing erect was the reference position and pressures decreased with lying supine and increased in the seated position. Seated and flexed forward further increased disc pressures. Several other positions were evaluated.
400
A 56 year old woman with myasthenia gravis is in the intensive care unit with urosepsis. Which antibiotic should be avoided in this patient? (a) Aztreonam (Azactam) (b) Gentamicin (Garamycin) (c) Ceftriaxone (Rocephin) (d) Ciprofloxacin (Cipro)
What is b. For hospitalized patients, therapy consists of parenteral (or PO) ceftriaxone, quinolone, gentamicin (plus ampicillin), or aztreonam until defervescence. Then, an oral quinolone, cephalosporin, or trimethoprim-sulfamethoxazole for 14 days may be added to complete treatment. The aminoglycoside class of antibiotics is contraindicated in patients with myasthenia and other neuromuscular junction disorders. Most aminoglycosides exert their effect through reducing the number of acetylcholine quanta released. Use may lead to a myasthenic exacerbation.
400
The gluteus maximus is primarily active during which part of the gait cycle? (a) Pre swing (b) Loading response (c) Midstance (d) Terminal stance
What is b. The gluteus maximus is primarily active from terminal swing through initial contact and loading response. During midstance, terminal stance, and pre-swing the gluteus maximus is actually silent.
400
Cognitive deficits are common in (a) Duchenne muscular dystrophy. (b) inclusion body myositis. (c) fascioscapulohumeral dystrophy. (d) Becker muscular dystrophy.
What is a. A brain isoform of dystrophin exists and there are documented mildly decreased Intelligence Quotient scores in people with Duchenne muscular dystrophy. These lower scores may be specific to deficits with tasks requiring attention to complex verbal information.
400
Which electrodiagnostic finding is most consistent with neurogenic thoracic outlet syndrome? (a) Small median motor response from the thenar muscles (b) Abnormal response of the lateral antebrachial cutaneous nerve (c) Abnormal median sensory responses (d) Abnormal spontaneous activity in the pronator teres muscle
What is b. Neurogenic thoracic outlet syndrome involves the lower trunk of the brachial plexus; hence, sensory and motor loss develops in the C8–T1 distribution. Thumb abduction is often affected. Sensory changes are usually in the distribution of the ulnar and medial antebrachial cutaneous nerves.
500
A 35-year-old man presents to your clinic with a 3-month history of groin pain exacerbated by activity. He is an avid skier and runner. He has been taking anti-inflammatories with minimal relief. Anteroposterior films of the hip were normal. The MRI of the hip reported a bony prominence at the femoral head-neck junction. What clinical exam finding is most likely to correlate with these radiographic “abnormalities” ? (a) Pain with resisted straight leg raise (b) Pain with hip flexion, external rotation, and abduction (c) Pain with sacral thrust (d) Pain with hip flexion, internal rotation, and adduction
What is D. This patient has radiographic evidence of femoroacetabular impingement (FAI). Two types have been described, cam impingement and pincer impingement. Cam impingement is described more commonly in active males and describes a non-spherical femoral head or osseous abnormalities of the femoral head-neck junction. These bony abnormalities have abnormal contact with the acetabulum in hip flexion, adduction, and internal rotation. Pincer impingement describes abnormal contact between the femur and the acetabulum due to overcoverage of the femoral head from an abnormally deep or retroverted acetabulum.
500
Which symptom of excessive exertion is NOT typical in a person with neuromuscular disease? (a) Paresthesias (b) Hyperthermia (c) Severe muscle cramping (d) Excessive urine output (diuresis)
What is d. Anuria or decreased urine output, rather than diuresis, is common following excessive exercise. The other statements are typical of overexertion and overwork weakness.
500
In a patient with a transfemoral amputation, what is the most likely cause of excessive knee flexion during ambulation? (a) Hip flexion contracture (b) Prosthetic knee alignment in an excessively posterior position (c) Excessive socket extension (d) Too soft a plantar flexion bumper in the heel
What is a. One of the most common gait deviations in patients with transfemoral amputations is abrupt or excessive knee flexion during ambulation. The prosthetic knee joint should normally be stable in extension in stance phase from heel contact to foot flat. This stability is accomplished by aligning the prosthetic knee axis posterior to the trochanteric knee ankle line. Adequate strength and range of motion in hip extension are critical to maintaining this alignment. Thus, weak hip extensors and hip flexion contractures can cause knee instability. Two prosthetic causes of knee instability are (1) knee malalignment in an excessively anterior position relative to the hip and ankle joints, and (2) excessive socket flexion. A plantar flexion bumper that is too stiff, extensive foot dorsiflexion, or a change in shoe heel height from low to high may all promote knee flexion.
500
The most severe form of mental retardation in cerebral palsy occurs in association with (a) spastic diplegia. (b) ataxia. (c) spastic quadriplegia. (d) athetosis.
What is c. Mental retardation is the most common serious associated disability in cerebral palsy. The overall incidence of mental retardation is approximately 30%-50%. Severe mental retardation is present in about one-half of the retarded group. Approximately one-third of cases have mild cognitive deficits. The greatest retardation is seen in rigid, atonic, and severe spastic quadriplegic cerebral palsy.
500
A 40-year-old man sustained an injury to his left arm, 3 weeks ago, when he lost his balance and crashed into a bookshelf. His complaints include left arm pain, weakness with extension of his wrist and fingers, and decreased hand grip. He denies any numbness but has odd sensations over the dorsum of the left hand. Prior to any testing, which problem would you consider as the most likely? (a) Posterior interosseous neuropathy (b) C7 radiculopathy (c) Posterior cord brachial plexopathy (d) Radial neuropathy
What is d. Based on the clinical presentation, radial nerve injury is the most likely cause of the patient’s symptoms. Considering the location of the trauma the other possibilities seem less likely. In a posterior interosseous nerve injury one would not expect any sensory problems.
M
e
n
u