Which cranial nerves are involved in testing oculomotor eye movement and strabismus?

The involvement of cranial nerves in oculomotor eye movement and strabismus is primarily linked to the functions governed by the oculomotor nerve (CN III), the trochlear nerve (CN IV), and the abducens nerve (CN VI).

The oculomotor nerve is responsible for most of the eye's movements, including upward, downward, and medial movements, as well as controlling the pupil and eyelid. The trochlear nerve is specifically involved in the movement of the superior oblique muscle, which helps in turning the eye downward and laterally. The abducens nerve governs the lateral rectus muscle, which moves the eye outward. Abnormalities in these cranial nerves can lead to strabismus, a condition where the eyes do not properly align with each other.

Other cranial nerves listed in the options, such as CN I (olfactory), CN V (trigeminal), CN VII (facial), and CN II (optic), do not play a direct role in eye movement but have other sensory or motor functions. Therefore, recognizing the specific roles of these cranial nerves is critical in assessing eye movement and diagnosing conditions like strabismus.