Spine & Extremities Flashcards
What are the names of the soft center and firm outer layer of a vertebral disc?
soft center: nucleus pulposus
firm outer layer: anulus fibrosus
At what vertebral level does the spinal cord end?
T12-L1.
After the spinal cord ends, what does it taper into?
conus medullaris
What is the nerve bundle that extends inferiorly from the spinal cord?
cauda equina
What are the two common sites for spinal fracture?
C6-C7 & T12-L2
What is a sequestered disc? What else is this called?
a portion of a disc’s nucleus completely breaks free and migrates from its normal position; herniated disc
Define spondylosis.
hypertrophy of the facet joints. CAN lead to spinal stenosis
Define spondylolysis.
a defect of the pars interarticularis caused by an osteophyte
Define spondylolisthesis.
anterior “slipping” of a vertebral body over an inferior one. caused by degenerative changes in the facet joints.
What is the recommended slice thickness for the c-, t-, and l-spine?
c-spine: 1-2 mm
t- and l-spine: 3-5 mm
What are the SFOV and DFOV for the spine?
SFOV: large, 48-50 cm
DFOV: small, 10-15 cm
What window levels and widths are used for CT of the spine?
bone: WL 300 & WW 2000
soft tissue: WL 50 & WW 400
When would IV contrast be indicated for CT of the spine? How much and at what flowrate?
metastatic disease, soft tissue mass, infection, and abscess. 100-125 mL at 2-3 mL/sec during the portal venous phase.
What is the most common malignancy of the skeletal system?
Multiple Myeloma; systemic malignancy of the plasma cells of the bone marrow
What is the infection of a bone?
Osteomyelitis
_____-section slices are acquired with at least ___% overlap for muscoskeletal scans.
thin-sections (<1.25 mm); 50% slice overlap
What is the ideal position for scans of the upper extremity?
prone, with affected limb extended over head. hand pronated for hand, wrist, forearm. hand supinated for elbow scans (until humeral epicondyles are parallel with the scan table)
Describe the axial imaging plane for a foot.
leg fully extended with foot flexed and toes pointing up. parallel to the foot’s plantar surface.
Describe the oblique axial imaging plane for a foot.
axial plane parallel to the metatarsals, roughly 20-30 degrees caudal from the direct axial plane. used to assess the tarsal-metatarsal joints
What is best demonstrated by the sagittal plane of the foot?
tarsal and metatarsal bones and joints
Describe the oblique coronal imaging plane for a foot.
scan plane is perpendicular to the long axis of the metatarsals. best shows ankle joint
What is the best plane to image the ankle and hindfoot?
direct coronal, perpendicular to the tibia
What is tarsal coalition?
it is the abnormal union of adjacent bones of the ankle. it is the most common in the talocalcaneal and calcaneonavicular joints
What type of lower leg fracture is best demonstrated by CT over x-ray?
tibial plateau fx
