Under pure torsion (normal stresses in the z- and theta- directions are zero), the principal stresses and the angle alpha_p (with respect to z-theta coordinates) are:
A. s_1,2 = ±s_ztheta = ±Tr/J and alpha_p = 0
B. s_1,2 = ±s_ztheta = ±Tr/J and alpha_p = pi/2
C. s_1,2 = 0 and alpha_p = pi/2
D. s_1,2 = ±s_ztheta = ±Tr/J and alpha_p = pi/4
Answer: D
Learn More :
Biomechanics
- A 59-year- old woman has been told by her orthopedist that the preferred treatment for her debilitating pain in both knees is knee replacement surgery. She agrees to have the surgery in one month when she will have time for rehabilitation. In the interim, the physician prescribes a medication for pain relief and to reduce inflammation. The woman is otherwise healthy, takes no medication, and has no known drug allergies. The physician decides on a nonsteroidal anti- inflammatory drug that has a high affinity for cyclooxygenase-2 (COX-2) and no affinity for COX-1. Compared to other NSAIDs, this drug is less likely to cause:
- A 69-year-old male presents to your office complaining of pain in his neck that extends bilaterally over his shoulders. He also complains of an aching sensation in both of his arms and loss of fine motor control of his hands. This has been progressing over the past six months. He worked in construction and had multiple small neck injuries during college wrestling and football. His overall health is quite good. On X-rays studies of his cervical spine you would expect to find?
- In the most classical presentation of a herniated L4-L5 lateral disk herniation, the most common reflex change present is:
- A 54-year-old male construction worker has had low back pain for about two months. He has had previous episodes of low back pain. Now, the pain is more intense than it was on prior episodes and seems to be getting worse rather than improving over time. He does remember lifting very heavy steel beams and the pain is now unbearable. He complains of numbness in both legs and across his buttocks. He is embarrassed to report that he was incontinent of urine and stool this morning. You should plan on:
- A 25-year-old female medical student comes to your office asking for an MRI of her neck to confirm her suspicion that she has a herniated cervical disc. On exam, her triceps reflex is absent, and she has weakness of elbow extension and numbness on her long finger. You both expect the MRI to reveal a disc herniation at:
- A 57-year-old physician presents to his doctor complaining of neck pain that radiates down the lateral aspect of his right arm. He also complains of numbness in his right thumb with weakness on resisted thumb extension. You suspect a herniated disc compression which nerve root?
- A 54-year-old male construction worker has had low back pain for about two months. He has had previous episodes of low back pain. Now, the pain is more intense than it was on prior episodes and seems to be getting worse rather than improving over time. He does remember lifting very heavy steel beams and the pain is now unbearable. He complains of numbness in both legs and across his buttocks. He is embarrassed to report that he was incontinent of urine and stool this morning. You should plan on:
- A 35-year-old male presents to your office with complaints of back pain and some weakness in his left leg. It has been present for a few weeks and the back and leg pains have been increasing in intensity. You are concerned about a herniated lumbar disc. His left ankle jerk reflex (achilles tendon reflex) is absent and you find numbness on the lateral aspect of the lower leg and sole of his left foot. This is most commonly caused by a:
- A 35-year-old male presents to your office with complaints of back pain and some weakness in his left leg. It has been present for a few weeks and the back and leg pains have been increasing in intensity. You are concerned about a herniated lumbar disc. His left ankle jerk reflex (achilles tendon reflex) is absent and you find numbness on the lateral aspect of the lower leg and sole of his left foot. These findings are typical of compression of:
- A 25-year-old medical student comes to your office asking for an MRI of her neck to confirm her suspicion that she has a cervical disc herniation. On exam, her triceps reflex is absent. She has weakness of elbow extension and numbness on her long finger. You expect the MRI to reveal a disc herniation at at which of the following levels?
- A patient sustained a cervical sprain/strain (somatic dysfunction) secondary to trauma. She complains of non radiating neck pain in absence of shoulder pain. Given this scenerio, which of the following signs/symptoms would more likely be present than any other?
- What is the treatment for pseudoaddiction?
- Which is the most specific of the urine drug tests?
- What are the 4 A's for pain management?
- Which of the following are side effects from chronic opioid use?
- A 42-year-old nurse presents to the office to see if OMM can be helpful for her long-standing foot pain. The patient had sustained her foot injury five years prior when a car ran over her foot while trying to cross the street. She sustained multiple fractures at that time and the injury healed subsequent to multiple surgeries. There is no back pain and no pain in the legs. She is currently on morphine 60mg every twelve hours. Physical examination reveals relatively normal lumbar range of motion, normal straight leg raise, and reveals normal muscle tone, strength and sensation throughout both lower extremities. The foot and ankle are painful to touch on the surface. There is decreased range of motion of the ankle with erythema and skin dystrophic/atrophic changes. Which of the following pain management approaches is indicated:
- A 40-year-old male presents with a one-week history of low back pain without radiation. The symptoms started after he was carrying some luggage. There is no tingling, numbness in the legs, nor any reported weakness. There is minimal spasm in the paravertebral muscles in the lumbo-sacral spine, straight leg raising test is negative and the neurological examination is normal. There are somatic dysfunctions in form of neutral dysfunctions L1-L5 NSleftRright. Which of the following statements is most appropriate?
- Which of the following is correct about the various pain types?
- A 64-year-old school superintendent with known rheumatoid arthritis presents to the office with a recurrent episode of significant hand and wrist pain after having been virtually pain-free for about eight months on DMARD therapy as closely monitored by her rheumatologist. She questions the doctor as to how it could be that she has these painful chronic-recurrent flare-ups alternating with pain-free periods, all the while it seems that the "arthritis is getting better" with the medications. What would be the best explanation, based on the article by D. Marcus: "Treatment of Nonmalignant Chronic Pain?"
- A 56-year-old female with a known history of seropositive rheumatoid arthritis maintained on etanercept injections presents complaining of right knee pain and swelling for two days. She has been in good health otherwise and denies fevers and chills. She reports stiffness in the right knee that lasts for longer than 1 hour. Her other joints are doing well. You perform an arthrocentesis and remove 30cc of clear fluid. You send the sample to the lab, and 24 hours later no organisms are seen. The patient follows up later that day. The best course of management for this patient is:
- A 64-year-old woman diagnosed with gout has been taking chronic treatment for over one year. The prescribed medication enhances the excretion of uric acid. Her physician cautions her to contact him before starting any prescription or nonprescription medication. The antigout medication and many other drugs can compete for tubular transport. Examples include aspirin and other nonsteroidal anti-inflammatory drugs, loop and thiazide diuretics, certain anti-infective medications, and certain diabetes drugs. The chronic antigout medication prescribed for this patient is most likely:
- A 57-year-old man with chronic gout is given a prescription for a uricosuric agent. He is cautioned to avoid aspirin, NSAIDs, and other drugs that are secreted into the proximal tubule. The mechanism of action of the anti-gout medication is most likely direct inhibition of:
- A patient with a history of hyperuricemia and three gouty flares in the past six months is placed on an anti-gout regimen that includes a drug to prevent gouty flare. He is cautioned that nausea, vomiting, abdominal pain, and diarrhea are early signs of drug toxicity; if these symptoms occur, he should stop taking the drug and call the office. The drug produces its action by binding to:
- A 45-year-old patient with a history of HIV/AIDS and mildly impaired renal function presents with signs/symptoms of acute gouty arthritis. His antiretroviral regimen includes a strong inhibitor of CYP3A4. Which one of the following medications is effective in the treatment of the pain and inflammation of acute gouty flare but contraindicated in this patient?
- A patient with a history of hyperuricemia and three gouty flares in the past six months is placed on hypouricemic therapy. He is also prescribed a concomitant oral drug for prophylaxis of gouty flare. The second drug interferes with microtubule and spindle formation but its anti-gout actions are not well defined. One of this drug's early signs/symptoms of toxicity is: