Which structures in the anterior chamber angle are neural crest-derived?

• A. Trabecular meshwork and Schlemm's canal (and related structures)
• B. Iris sphincter
• C. Ciliary body stroma
• D. Corneal epithelium

Answer: (A)

Neural crest cells migrate into the developing eye and form many parts of the anterior segment. In the anterior chamber angle, the key neural crest–derived structures are the trabecular meshwork and Schlemm’s canal, which together create the conventional aqueous humor outflow system. The trabecular meshwork arises from neural crest–derived mesenchyme that differentiates into its beams and intertrabecular spaces, while Schlemm’s canal forms from neural crest–derived endothelium that shapes the circular canal at the angle. These anatomical origins explain why they’re categorized as neural crest derivatives.

By contrast, tissues like the corneal epithelium come from surface ectoderm, and other structures outside the angle have different embryologic origins, so they aren’t the neural crest-derived structures highlighted in this context.