A Lateral Cervicothoracic Projection (Twining Method) with Poor Positioning Demonstrates

question 12

Multiple Choice

A lateral cervicothoracic projection (Twining method) with poor positioning demonstrates the humerus with the greater degree of magnification rotated posteriorly. How was the patient mispositioned for such a projection to be obtained?

• A) The arm situated farther from the IR was rotated posteriorly.
• B) The midcoronal plane was not aligned parallel with the IR.
• C) The arm situated closer to the IR was rotated posteriorly.
• D) The arm situated closer to the IR was not elevated.

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Definitions:

Ratio Schedules

In operant conditioning, schedules that deliver reinforcement after a certain number of responses have been made, either fixed or variable.

Interval Schedules

A type of operant conditioning reinforcement schedule where the first response is rewarded only after a specified amount of time has elapsed.

FR 30 Schedule

A fixed-ratio schedule of reinforcement where a specific behavior is rewarded after it has been performed a fixed number of times, in this case, 30 times.

VR 30 Schedule

A variable ratio reinforcement schedule where a response is reinforced, on average, every thirtieth time it is made.