Final answer:
The middle meningeal artery enters the skull through the foramen spinosum, a crucial pathway that supplies blood to the brain's outer covering layers.
Step-by-step explanation:
The middle meningeal artery enters the skull via the foramen spinosum. This small opening is situated posterior-lateral to the foramen ovale and serves as a crucial entry point for the artery that supplies blood to the dura mater, the outer covering layer of the brain. The middle meningeal artery's branching pattern creates grooves on the internal surface of the skull, traceable back to the foramen spinosum.