The three parts of a tooth are the crown, neck, and root. The crown is the part of the tooth visible above the gum line; it is covered with a very hard, white enamel. The neck is the constricted area just below the crown. The root below the neck is contained within the tooth socket, in the mandible or maxilla.

The dental formula for a modern human adult is 2:1:2:3 in each quadrant: two incisors, one canine, two premolars, and three molar, for a total of 32 adult teeth. There is some variation in this number, as the third molar (also known as the Wisdom Tooth) is not present in all modern human adults.

There are 20 deciduous teeth in children, and 32 permanent teeth in adults. In children, each quadrant is composed of 2 incisors, 1 canine, no pre-molars, and 2 molars. In adults, each quadrant is composed of 2 incisors, 1 canine, 2 premolars, and 3 molars. There is some variation in the adult number, as the third molar, or wisdom tooth, is not present in all individuals.

The first '2' in the 2:1:2:3 modern human adult dental formula refers to incisors. There are two incisors in each of the four quadrants in adult modern humans, situated in the frontmost part of the dental arcade, for a total of eight of this type of tooth per individual. The wisdom tooth is the third molar and is not always present in all individuals nor in all quadrants.

The '1' in the 2:1:2:3 dental formula of a modern human adult refers to canine teeth. There is one canine tooth, situated between the incisors and premolars, in each of the four quadrants of the modern human adult dental arcade, for a total of four canine teeth per individual.

The second '2' in the 2:1:2:3 dental formula of a modern human adult refers to premolars. There are two premolars, situated between the canine and molars, in each of the four quadrants in a modern human adult, for a total of eight of this type of tooth per individual. Primitive mammals have four pre-molars; in the line of evolution leading to humans, the first two premolars were lost, leaving the third and fourth.

The '3' in the 2:1:2:3 dental formula of a modern human adult refers to molars: first, second, and third, or wisdom tooth (even though the wisdom tooth is indeed a molar, it is only one of three molars per quadrant). In some individuals, this third molar is not present in some or all quadrants. These teeth are situated furthest back in the dental arcade, behind the premolars.

The coronal (frontal) suture runs laterally from the top of the cranium and ties together the frontal and two parietal bones.

The sagittal suture runs along the top of the cranium, between the two parietal bones. The lambdoidal suture ties together the occipital and two parietal bones on the posterior cranium. The squamosal suture is the area where the squamosal section of the temporal bone is beveled and overlaps the parietal bone. The basilar suture, also referred to as spheno-occipital synchondrosis, is a suture between the occipital and sphenoid bones.

The squamosal suture is the area where the squamosal section of the temporal bone is beveled and overlaps the parietal bone.

The sagittal suture runs along the top of the cranium, between the two parietal bones. The coronal suture runs laterally from the top of the cranium and ties together the frontal and two parietal bones. The lambdoidal suture ties together the occipital and two parietal bones on the posterior cranium. The basilar suture, also referred to as spheno-occipital synchondrosis, is a suture between the occipital and sphenoid bones.

The sagittal suture is the long suture that runs between the two parietal bones, running antero-posteriorally along the top of the cranium.

The coronal suture runs laterally from the top of the cranium and ties together the frontal and two parietal bones. The lambdoidal suture ties together the occipital and two parietal bones on the posterior cranium. The squamosal suture is the area where the squamosal section of the temporal bone is beveled and overlaps the parietal bone. The basilar suture, also referred to as spheno-occipital synchondrosis, is a suture between the occipital and sphenoid bones.