MSK II-First Aid Flashcards
(101 cards)
What clinical tests may be positive in people who receive a blow where the arrow is pointing on the planted leg?
The structures that are commonly subject to injury in a blow of this sort are the unhappy triad: the ACL (anterior drawer/Lachman’s tests), MCL (abnormal passive abduction of leg) and meniscus (lateral more common than medial, McNeemar’s test)
A 24 year old laboring woman tried to go without an epidural anesthetic but has decided labor has become too painful. It is too late to give her an epidural, but you can block a particular nerve for her. How would you find this nerve?
You could block the pudendal nerve by locating it near the ischial spine.
An ice skater tries her triple axle and fails, falling on an outstretch hand. She does not hear or feel anything break, but experiences sudden numbness along her thumb, index and middle fingers. What bone is likely causing these symptoms?
The lunate can dislocate and cause acute carpal tunnel syndrome.
A 28 year old female falls after tripping over a curb and hurts her hand. Upon examination she describes pain on palpation of the anatomical snuffbox. How quickly will she be able to heal from her injury?
The most likely injury here is a fracture to the scaphoid bone. This bone has a recurrent blood supply that gets broken off in a fracture and slows the healing process.
A 19 year old male presents with a humeral fracture after falling off his bicycle. Physical examination reveals inability to abduct his arm to 90 degrees. What nerve was likely affected by this fracture and what muscles are affected?
The axillary nerve, causing a motor deficit in the deltoid.
A 39 year old female presents after a car accident with a mid-shaft humeral fracture. Why might someone just waking up after a long night of drinking have similar symptoms as she does? Why do they have these symptoms?
Both can cause radial nerve palsy. This affects the “BEST extensors” - Brachioradialis, Extensors of wrist and fingers, supinator and triceps. Dennervation of these muscles results in wrist drop and loss in sensation over the dorsum of the hand and posterior arm.
A 44 year old male presents to the ED after getting in a gang fight. He says he was hit just above the elbow with a baseball bat. His x-ray is shown below. What motor tests could you do to assess if nerve damage has also occurred?
The median nerve is subject to injury in this case. You could test thumb abduction, extension and opposition. You could also test wrist flexion and flexion of the index and middle fingers. You should also test for sensory deficit in the distribution of the median nerve.
A 14 year old boy takes a spill at the skatepark and fractures his medial epicondyle. He complains of sensory deficit on the pinky and ring fingers. How do you expect his wrist to move when you ask him to flex it? What else could you test in assessment of nerve damage?
It will deviate radially because the ulnar nerve no longer flexes the flexor carpi ulnaris. You could have him abduct his fingers to assess dorsal interossei function.
A 31 year old female takes a spill while skiing and can’t get up. You see her in the ED laying like this and promptly relocate her hip. What motor tests should you do when assessing her for nerve injury?
She may have injured the superior or inferior gluteal nerve, which is vulnerable in a posterior hip dislocation. This will result in a positive Trendelenberg’s test (superior gluteal nerve injury), an inability to abduct the thigh (superior gluteal nerve injury) or rise from a seated position (inferior gluteal nerve injury).
While doing rounds in the ICU you see a patient who has been laying on his side for hours. He is now complaining of loss of sensation in the anterolateral leg and dorsal foot. What motor tests could you do to assess nerve compression consistent with the sensory deficits presented?
This sounds like common peroneal compression. You would have him dorsiflex and evert the foot. Also, when walking he would have foot drop or steppage gait.
A 23 year old female comes to the ED after a car crash with anterior dislocation of the tibia. After resolving all immediate problems, you decide to test for nerve damage. She has lost all sensation on the sole of her foot. What motor tests do you suspect will be deficient with this information?
This is consistent with a tibial nerve injury. The tibial nerve inverts and dorsiflexes the foot and flexes the toes. She will also not be able to stand on her tip toes.
A patient comes to see you who had two fractures in the last month. He is 58 years old and also complains that his hats don’t fit anymore. You note thicker bones on physical examination. Serum calcium, phosphorus and PTH levels are all normal. He does, however, have increased alkaline phosphatase activity. Why is this patient more prone to bone breaks? Why do you see these results in the blood tests? What neoplasm is this patient at risk for in the future?
He has Paget’s Disease. In this disease, osteoclasts chew up bone, followed by rampant osteoblast activity and deposition of woven bone. Woven bone is not as strong as lamellar bone and he is more prone to bone breaks. Blood tests are mostly normal because osteoclasts and osteoblasts are still using similar amounts of calcium and phosphorus. Osteoblast activity is increased and thus so does ALP. He is at increased risk for osteosarcoma.
A 60 year old female comes to see you concerned about osteoporosis because she has gone through menopause. She insists that you order a bone scan to check, so you do, and you confirm decreased bone density. When considering medications, you decide to give her two, each one affecting progenitor cells. What cells will these drugs act on?
Hematopoietic cells are the precursors to monocytes and osteoclasts, so these may be inhibited. Mesenchymal cells are the precursors to osteoblasts, so these may be induced.
A 46 year old female comes to see you complaining of severe finger pain after opening a jar at her house. You order an x-ray and find that she has a broken femoral head. You order labs and find her PTH levels to be abnormally high. Why would you want to decrease her PTH levels as opposed to eliminating them? What other findings would you expect to see in her bone?
Low levels of PTH actually stimulate osteoblast activity. You would also expect to find brown tumors because rampant osteoclast activity can cause hemorrhaging.
A 71 year old female comes to your clinic after a fall at her house. She suffers from a femoral neck fracture and a Colles’ fracture. Serum calcium and phosphate levels are in their normal range. Why is this woman most likely suffering from these fractures after a simple fall? What medications could you prescribe her?
She no longer has estrogen. Estrogen inhibits apoptosis of osteoblasts and induces apoptosis of osteoclasts. When it is gone, excess bone resorption occurs and puts her at risk for osteoporosis. You could prescribe her SERMs (estrogen specific for bone and nowhere else), bisphosphonates (bind bone and inactivate osteoclasts), dietary calcium and dietary vitamin D. Also, once the fractures have healed you should prescribe regular exercise to encourage healthy bone remodeling.
A 66 year old man is a new father and his child has achondroplasia. Why will this man’s son have a larger head compared to the rest of his body?
In achondroplasia, FGFR3 is constitutively activated and inhibits chondrocyte proliferation. This only affects endochondral ossification and thus longitudinal bone growth, not membranous bone growth which occurs in the skull.
A mother brings her 8 year old boy in to see you because he broke his pelvis. She also says that he has been irritable and suffered from multiple illnesses this year. His x-ray is shown below and physical exam reveals hepatosplenomegaly. What is the most curative form of treatment for this little boy?
Bone marrow transplant to replace defective monocytes and osteoclasts. He is suffering from osteopetrosis, which can be caused by defective carbonic anhydrase II in osteoclasts, leading to defective bone remodeling, loss of bone marrow and extra-medullary hematopoiesis.
An 8 year old child comes to the ER, appear malnourished with bowing bones as seen in the x-ray below. What is this child likely deficient in and how is this contributing to his symptoms?
This poor kid has Rickets (osteomalacia in adults). This is a result of vitamin D deficiency which results in a decrease in serum calcium. The parathyroid senses this and stimulates bone resorption. This results in an overall decrease in mineralization of osteoid and the bones bow outwards.
How do lab values compare between osteoporosis, osteopetrosis, osteomalacia/rickets, osteitis fibrous cystic and Paget’s disease? Values are serum Ca2+, PO4, ALP and PTH.
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A 9 year old female comes to see you complaining of early menses and a disabling fracture of the femur. Physical examination reveals skin marks seen below. What medicine would you prescribe this patient for her bone condition?
This patient has a form of polyostotic fibrous dysplasia called McCune-Albright syndrome. This is characterized by precocious puberty, cafe-au-lait spots and bone lesions from overactive osteoclasts that results in bone replacement with collagen by fibroblasts. You could prescribe bisphosphonates to help her condition.
A 30 year old male presents with knee pain. His radiograph and biopsy are shown below. What is your diagnosis? Prognosis?
Benign giant cell tumor. These often occur in the epiphyseal regions of long bones and have a soap bubble appearance on x-ray. They also demonstrate spindle-shaped cells with multinucleate giant cells on a biopsy.
A 23 year old male presents with an enlarging mass on the side of his knee over the past few months. The biopsy and radiograph are shown below. What is your diagnosis? Prognosis?
Benign osteochondroma. These tumore originate from long metaphysis and are encased by a cartilaginous cap as seen in his biopsy.
A 15 year old male comes to see you complaining of knee pain that has gone on for a few weeks after his hiking trip. His x-ray is shown below. How would you treat this kid?
He most likely has an osteosarcoma, which is the second most common malignant tumor in kids after rhabdomyosarcoma. Note Codmans triangle at the matphysis of the femur, indicating aggressive tumor growth through the bone cortex. I would treat the cancer aggressively as it could metastasize to the lungs.
An 11 year old boy comes to see you complaining of pain in his middle thigh, fatigue and recurrent infection. Biopsy of the lesion and x-ray are shown below. What is the pathophysiology of his condition?
Note the “onion-skin” tumor and the small blue malignant cells. This is Ewing sarcoma. Tumor cells are generated from a translocation t;(11,22).
