One important entity to distinguish from osteochondritis dessicans is normal irregularity of the ossification centers
. Irregular ossification typically affects the posterolateral femoral condyle and usually occurs in children less than 10 years old, although there is slight variation depending on sex.
Scintigraphy study reports no alterations, while magnetic resonance reveals multiple ossification centers
of the femoral head with normal signal intensity and decrease in epiphysis size (6).
(12,13) Type I, or os tibiale externum, occurs when an ossification center
forms a sesamoid bone within the tibialis posterior tendon, near the navicular insertion.
Ebraheim, "Biomechanical rationale of ossification of the secondary ossification center
on apophyseal bony ring fracture: a biomechanical study," Clinical Biomechanics, vol.
The timing of appearance of elbow secondary ossification centers
shows considerable diversity regarding age, gender, and race.
The interscalar septum and the bone between the cochlea and the vestibule develop from the ossification centers
. Partly missing this bone suggests over-resorption, resulting in a defect of the cartilaginous capsule and a failure of ossification .
Our case had similar radiographic findings with at least one missing pedicle at the level of the midcervical spine along with obvious cervical kyphosis and incomplete/absent ossification centers
MMP13 is the major collagenase expressed in the primary and secondary ossification centers
and drives endochondral ossification by degrading major cartilage components, such as type II collagen and aggrecan .
possessed significantly fewer ossification centers
in hindlimb phalanges and caudal vertebra.
The actual etiology of this condition which is thought to arise from defect of fusion of two primary ossification centers
of the clavicula is not known exactly.
It was established that ossification centers
in the cartilaginous anlages of fore limbs appear a day earlier than in the hind ones, and the process of ossification is slower.