Which law states reciprocal innervation between agonist and antagonist EOMs of the same eye?

• A. Donder's Law
• B. Hering's Law of Equal Innervation
• C. Troxler Effect
• D. Sherrington's Law

Answer: (B)

Sherrington's law of reciprocal innervation explains how, within a single eye, the agonist muscle contracting to move the eye is accompanied by inhibition of its antagonist to allow smooth, coordinated movement. When a muscle like the medial rectus engages to adduct the eye, the lateral rectus relaxes; when the lateral rectus contracts to abduct, the medial rectus relaxes. This reciprocal setup prevents fighting actions between opposing muscles and keeps motion precise. Hering's law concerns equal innervation to yoked muscles in both eyes for coordinated binocular movements, not the within-eye agonist–antagonist pairing. The other options describe different phenomena (perceptual or separate motor principles) and don’t define the reciprocal innervation at the single-eye level.