The foramen magnum is a large opening at the base of the skull. It serves as the passageway for the spinal cord to connect with the brain. This structure is crucial for the central nervous system, allowing communication between the brain and the rest of the body. In humans and other vertebrates, the position of the foramen magnum can indicate posture and locomotion. For example, in bipedal species like humans, it is located more centrally, reflecting an upright walking stance. In contrast, in quadrupedal animals, it is positioned further back, aligning with their horizontal body structure.