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The foramen magnum holds relevance in multiple scientific disciplines, including forensic and physical anthropology, comparative anatomy, and biology. Surgical considerations involving the foramen and the craniovertebral junction further highlight the clinical importance of this structure. The foramen magnum is the largest aperture of the skull (see Image. Skull Foramina). Located in the inferiormost portion of the cranial fossa, the foramen magnum constitutes part of the occipital bone (see Image. Foramen Magnum, Superior View). Structures traversing this opening include the medulla oblongata, meninges, spinal root of the spinal accessory nerve (cranial nerve XI), vertebral arteries, anterior and posterior spinal arteries, tectorial membrane, and alar ligaments. The foramen magnum defines 2 craniometric points. The basion is situated at the median point of the anterior margin, and the opisthion is located at the corresponding posterior margin. The foramen magnum has critical clinical significance because its anatomy influences the presentation and progression of conditions, such as cerebellar tonsil herniation, Chiari malformations, trauma-related injuries, and vertebrobasilar vascular compromise. The structure's surgical significance arises from its variable size, shape, and surrounding bony structures, which affect access and approach during procedures such as decompressions, tumor resections, and vascular repairs. Detailed knowledge of the foramen magnum's anatomy and function enables clinicians to anticipate potential complications, plan safe surgical interventions, and accurately interpret imaging and physical findings at the craniovertebral junction.