A topographic quantitative analysis of the Post-Natal bone formation in the auditory ossicles of the dog

Abstract

The amount and distribution of the post-natal bone deposition in the auditory ossicles and in the left tibia of dogs of varying ages were studied by means of alizarin labelling. The relative amount of fluorescent new-formed bone was expressed as a percentage ratio NB/(NB+PB) of new bone (NB) on the pre-existing bone (PB). The result was that the post-natal bone deposition (1) was larger in the tibia than in the incus, malleus and stapes; (2) significantly decreased with age both in the ossicles and in the tibia; (3) in the stapes it stopped at 3 months, while it was present in the tibia, incus and malleus even at 12 months. In the ossicles the post-natal bone deposition takes place both on the periosteal surfaces of the ossicles and on the internal surfaces of the haversian systems. The first process produces an appositional growth that stops in all three ossicles within the 1st month of post-natal life, the second one produces an internal growth that continues until the age of three months in the stapes, while in the incus and malleus it occurs in small amounts, even in the 12th month of life. In the ossicles all the new-formed bone tissue, periosteal and osteonic, is built up by primary bone (addition bone). In the tibia from 50 days of age the primary bone is gradually replaced by secondary haversian systems as a consequence of remodelling processes.

Developmental Anatomy of the Mouse Stapediovestibular and Temporomandibular Joints

“…Rapid connective tissue restoration associated with simultaneous, active synthesis and breakdown of matricial collagen by osteogenic and fibrillogenic remodeling has been demonstrated in the oral tissues and many sutures (Ten Cate 1972, 1976, 1977. The stapes and otic capsule have been compared, and have shown similar remodeling activities as sutures of the skull vault containing essentially membrane bones (Anson et al 1948;Davies 1948;Anson and Davies 1980;Wright 1987).…”

“…Although both the human incudomalleal and incudostapedial synovial joints have been identified to be composed entirely of elastic tissue, while the SVJ is composed of fibrocartilage containing radially arranged medial and lateral fibrous bands, which are partly elastic and partly inelastic, attaching to the stapedial foot plate and chondroid wall of the oval window (Davies 1948;Harty 1953). On the other hand, comparative studies of the histology of the annular ligament have found that the joint of the kangaroo rat was connected solely with fine collagen fibers (Webster 1961 ing ear structure and function in mammals explained the disagreement by differences in the animal species used or in the methods employed (Engstrom 1947;Roberto 1976;Webster 1966). …”

A topographical analysis of the post-natal bone growth in the cochlea of the dog

“…The experiments were performed in the dog because the growth of its skeletal segments is similar to that of the primates (Godina, 1947). Moreover, the modelling processes have already been studied both in the external and inner canal and in the ossicular chain (Roberto, 1976;Roberto and Lozupone, 1987). The bone matrix laid-down after birth was easily identified using the well known technique of intravital staining of bone tissue with tetracycline.…”