A color-coded atlas of the cortical surface anatomy of the equine brain

The horse has a highly gyrencephalic cerebrum; however, detailed references of equine cortical surface anatomy remain limited, and terminology inconsistencies continue to complicate comparative, clinical, and educational applications. This research focused on creating a standardized, high-resolution, color-coded atlas of equine brain sulci and gyri, based on the Nomina Anatomica Veterinaria (NAV).

Brains from ten neurologically normal horses were examined. Following fixation and dissection, the sulci and gyri of the lateral, dorsal, rostral, and medial surfaces were documented, color-coded, and labeled according to NAV terminology.

The atlas documented a consistent lateral network dominated by the Sylvian fissure with an accessory Sylvian fissure at its origin, a three-limbed ectosylvian sulcus that subdivides the ectosylvian gyrus, a continuous suprasylvian sulcus, and a distinct oblique sulcus. Dorsally, the coronal, cruciate, and ansate sulci are complemented by a well-developed marginal complex (marginal, ectomarginal, and endomarginal sulci). Medially, the genual region is resolved into genual, endogenual, and ectogenual sulci; the callosal and cingulate sulci run in parallel; and the splenial complex (splenial, endosplenial, and ectosplenial) is consistently identifiable alongside the medial rhinal sulcus. Across specimens, major sulci and gyri were observed, with variation limited primarily to differences in sulcal depth and branching patterns.

This standardized, color-coded surface atlas provides a detailed reference for equine cortical anatomy, facilitates cross-species comparison, and offers a practical anatomical resource for neuroimaging interpretation, anatomical orientation, and veterinary education. The atlas serves as a specimen-based resource that may provide an anatomical framework for future morphometric, developmental, and functional investigations.