Nasal margin

The nasal or rostral margin (Margo nasalis) of the frontal bone is beveled in the superficial surface to answer to the nasal bone medially and to the lacrimal bone laterally and can have one or two spikes, according to the species:

-one that limits the frontonasal and the frontomaxillary sutures(1),

-and, in certain species (Horses, Men), a frontal spine (Spina frontalis) formed by the interfrontal suture on the median plane, between the nasal bones.

(1) The bulls have a long spike that moves forward between the nasal and lacrimal bone, because the lacrimal bone separates completely the frontal bone from the maxillary bone.