Which nerve lies superficially to the extensor retinaculum laterally?

The superficial branch of the radial nerve is indeed the correct answer because it typically emerges laterally to the extensor retinaculum and runs over the top of it, primarily supplying sensation to the skin over the dorsum of the hand and the radial aspect of the wrist. This positioning allows it to remain relatively superficial compared to other nerves in the region.

In contrast, the median nerve lies deeper in the carpal tunnel beneath the flexor retinaculum, which makes it less relevant to the question at hand. The ulnar nerve also traverses the wrist area but does so on the medial side and beneath the flexor retinaculum, not superficially on the lateral aspect. The deep branch of the radial nerve is primarily located deeper in the forearm and does not run superficially to the extensor retinaculum, as it innervates the muscles of the posterior forearm rather than providing sensory innervation in the lateral aspect of the wrist.

Thus, the superficial branch of the radial nerve is correctly associated with being the nerve that lies superficially to the extensor retinaculum laterally.