Trismus is best defined as which of the following?

Trismus is best defined as which of the following?

• A. Limited opening of the mouth
• B. Swelling of the lips
• C. Pain on chewing
• D. Prolonged toothache

Answer: (A)

Trismus is the restricted ability to open the mouth fully, caused by involuntary contraction or spasm of the jaw muscles. The defining feature is this limited opening, rather than swelling, pain on chewing, or toothache. Clinically, you assess it by measuring how wide the patient can open; a noticeably reduced maximal opening indicates trismus. It can occur after dental injections, trauma, or infection that irritates the muscles of mastication (like the masseter or pterygoids). The other symptoms describe related issues but do not define the restriction in mouth opening that characterizes trismus.

Trismus is the restricted ability to open the mouth fully, caused by involuntary contraction or spasm of the jaw muscles. The defining feature is this limited opening, rather than swelling, pain on chewing, or toothache. Clinically, you assess it by measuring how wide the patient can open; a noticeably reduced maximal opening indicates trismus. It can occur after dental injections, trauma, or infection that irritates the muscles of mastication (like the masseter or pterygoids). The other symptoms describe related issues but do not define the restriction in mouth opening that characterizes trismus.