The frontal bone

Frontal bone

The frontal bone is a bone in the human skull that resembles a cockleshell in form, and consists of two portions:* a vertical portion, the squama frontalis, corresponding with the region of the forehead....

 is ossified in membrane from two primary centers, one for each half, which appear toward the end of the second month of fetal life, one above each supraorbital margin. From each of these centers, ossification extends upward to form the corresponding half of the squama

Squama

Squama refers to a structure shaped like the scale of a fish. More specifically, it can refer to:* Squama frontalis* Squama occipitalis* Squama temporalis, the squamous portion of the temporal bone* Squamous cell...

, and backward to form the orbital plate. The spine is ossified from a pair of secondary centers, on either side of the middle line; similar centers appear in the nasal part and zygomatic processes.

At birth the bone consists of two pieces, separated by the frontal suture

Frontal suture

The frontal suture is a dense connective tissue structure that divides the two halves of the frontal bone of the skull in infants and children. It usually disappears by the age of six, with the two halves of the frontal bone being fused together...

, which is usually obliterated, except at its lower part, by the eighth year, but occasionally persists throughout life. It is generally maintained that the development of the frontal sinuses begins at the end of the first or beginning of the second year, but may begins at birth. The sinuses are of considerable size by the seventh or eighth year, but do not attain their full proportions until after puberty

Puberty

Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...

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