Ossification of Frontal Bone

The frontal bone 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, 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, 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.

This article incorporates text from a public domain edition of Gray's Anatomy.

Embryology of bones, joints, and muscles (GA 2.80, TE E5.0-2)
Upper limb
  • Ossification of humerus
  • Ossification of ulna
  • Ossification of radius
Lower limb
  • Ossification of tibia
  • cranium: Ossification of occipital bone
  • Ossification of frontal bone
  • Ossification of temporal bone
  • Ossification of sphenoid
  • Ossification of ethmoid
  • facial bones: Ossification of vomer
    • Sutura vomerina
    • Foramen vomerinum
    • Meatus vomerinus
    • Fissura vomerina
  • Ossification of maxilla
  • Ossification of mandible
  • Ossification of scapula
  • Limb development: Limb bud
  • Apical ectodermal ridge/AER
  • Zone of polarizing activity
  • Sclerotome/Myotome
  • Septum transversum


anat (c/f/k/f, u, t/p, l)/phys/devp/cell

noco/cong/tumr, sysi/epon, injr

proc, drug (M5)


anat (h/c, u, t, l)/phys

noco (arth/defr/back/soft)/cong, sysi/epon, injr

proc, drug (M01C, M4)


anat (h/n, u, t/d, a/p, l)/phys/devp/hist

noco (m, s, c)/cong (d)/tumr, sysi/epon, injr

proc, drug (M1A/3)

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