Yoke muscle pair –
**Core Concept**
Yoke muscle pairs refer to the coordinated movement of two or more muscles that work together to produce a specific movement or action. These pairs are essential in various physiological functions, including eye movements, speech, and respiration.
**Why the Correct Answer is Right**
In the context of eye movements, yoke muscle pairs are critical for conjugate eye movements. When one eye moves laterally, the yoke muscle pair on the other eye moves in the opposite direction to maintain binocular vision. This coordination is achieved through the innervation of extraocular muscles by the oculomotor (III), trochlear (IV), and abducens (VI) nerves. The yoke muscle pair for lateral rectus (abducens nerve) is medial rectus (oculomotor nerve), while for inferior oblique (oculomotor nerve) it is superior rectus (trochlear nerve).
**Why Each Wrong Option is Incorrect**
* **Option A:** This is not a correct yoke muscle pair. However, it is essential to note that the yoke muscle pair for superior oblique (IV nerve) is inferior rectus (III nerve).
* **Option B:** This option does not specify a correct yoke muscle pair. However, it is worth mentioning that the yoke muscle pair for inferior oblique (III nerve) is superior rectus (IV nerve).
* **Option C:** This option is incorrect as it does not specify a correct yoke muscle pair. However, it is crucial to remember that the yoke muscle pair for lateral rectus (VI nerve) is medial rectus (III nerve).
**Clinical Pearl / High-Yield Fact**
A mnemonic to remember the yoke muscle pairs for extraocular muscles is "Look, Look, Look, Look" - lateral rectus (VI nerve) with medial rectus (III nerve), superior rectus (IV nerve) with inferior oblique (III nerve), and inferior rectus (III nerve) with superior oblique (IV nerve).
**Correct Answer: B. Inferior oblique (III nerve) with superior rectus (IV nerve).**