Perichondrial ring is -
The perichondrial ring of La Croix also surrounds the growth plate circumferentially, similar to perichondrial groove. Perichondrial ring extends towards metaphysis and become continuous with periosteum of metaphysis.
With increasing age, perichondrial ring is thinned and its shear resistance (strength) is decreased.
Seen around foramen magnum
Seen around epiphyseal plate
More prominent in adults
Shear strength increases with age