Question

Which of the following is the longest extraocular muscle?

• A. Superior rectus (SR)
• B. Medial rectus (MR)
• C. Superior oblique (SO)
• D. Inferior oblique (IO)

Hint:

Which muscle threads through the trochlea, gaining extra length?

Answer 1

The Correct Option is C

Step 1: The superior oblique is the longest and thinnest of the extraocular muscles. It arises near the apex of the orbit and runs forward along the medial wall of the orbit.

Step 2: Its great length comes from its unique course: the muscle ends in a tendon that passes through the trochlea, a fibrous pulley on the upper medial orbital rim, and then turns sharply backward and laterally to insert on the posterolateral sclera under the superior rectus.

Step 3: This long muscle and tendon arrangement is what makes the superior oblique the longest extraocular muscle, so SO is the correct answer.

Step 4: Among the comparisons, the medial rectus is the largest and strongest of the recti, and the inferior oblique is the shortest extraocular muscle, while none of these has the extended tendon of the superior oblique.