7:06 periosteum is only absent on articulation part of epiphysis but remaining part of epiphysis contain periosteum. so the statement, "there is no periosteum on epiphysis", is wrong
May I say that certain osteoblasts present in cellular layer of periosteum move down and start producing straight layers of bone matrix which are called as circumstantial lamellae and concentric layers of bone matrix called as concentric lamellae.... around them...while in between circumstantial and concentric lamellae where osteoblasts were secreting bone matrix around them,,,,certain ring shaped spaces left called as lacunae left where these osteoblasts stuck themselves in their own secreted lamellaeof bone matrix ..... and mature themselves there and then they are called as osteocytes
