Pathology · single question
A 20-year-old reports jaw deviation to the LEFT on opening without pain. Assisted opening reaches 32mm. Which is the MOST likely diagnosis?
Show answer and explanation
Correct answer: B. Left lateral pterygoid myospasm
Deviation to the LEFT without pain + opening correctable with assistance = LEFT lateral pterygoid myospasm pulling the condyle ipsilaterally.
- A. Left closed lock (disc without reduction) would show deflection to the left with limited opening NOT correctable by assistance.
- B. CORRECT. Myospasm of the LEFT lateral pterygoid causes the jaw to deviate to the LEFT. The spastic muscle restricts movement on the affected side. Assisted opening can reach normal range because it is muscular (not mechanical disc) restriction.
- C. Right lateral pterygoid spasm would cause deviation to the RIGHT, not the left.
- D. Right disc displacement would cause deviation/deflection to the RIGHT.