A large opening in the anterior inferior portion of occipital bone in the cranium that serves an outlet of the spinal cord and medulla to enter from the skull to the vertebral column.
Foramen magnum is one of the largest openings or canals situated at the base of the skull to permit the route of blood vessels, nerves, cerebrospinal fluid and connective tissue into and out of the brain. It also covey the spinal component of the accessory nerve into the cranial fossa and transmits the anterior and posterior spinal arteries, vertebral arteries and alar ligaments.
The foramen magnum in humans are exceptional compare to other mammals since it is frontward in the occipital bone from the back of the skull beneath the center mass of the skull and brain, thus neck muscles of humans need not to be as tough in order to hold the head upright. Unlike in quadriped mammals in order to create better balance the neck bones and muscles are proportionately smaller. On the other hand, head and brains in humans are relatively larger compare to the upper cervical spine, as consequent human are susceptible to slip and fall kinds of injuries.
Word Origin: foramen= “hole” + magnum= “large”
Synonym: great foramen
• cranial bone
• posterior cranial fossa