Related Experiment Video
Updated: Jul 17, 2026

Dissection of the Auditory Bulla in Postnatal Mice: Isolation of the Middle Ear Bones and Histological Analysis
Published on: January 4, 2017
Too much bone: the middle ear in sclerosing bone dysplasias
Herman Hamersma1, Louis Hofmeyr
1Florida, South Africa.
Abstract:
The middle ear changes in Sclerosteosis and Van Buchem disease are described. Reduced bone resorption occurs due to faulty activity of the sclerostin molecule, a product of the recently discovered SOST gene in chromosome 17. Syndactyly draws attention to scleroteosis, and a conductive hearing loss develops before age six in both conditions. Acute, repeated attacks of facial palsy, similar to Bell's palsy, are usually the first symptoms in both conditions. Total facial nerve decompression can stop the attacks of facial paralysis. The hearing loss is a problem because new bone formation continues up to age 21. Life saving craniectomy becomes necessary when increased intracranial pressure develops, and this may have to repeated. The sclerostin molecule is now of major interest to the researchers who want to develop a treatment for osteoporosis.
Related Concept Videos
Bone Disorders
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
Bone Formation by Endochondral Ossification
Spongy Bone
Spongy bone is more porous, and less dense compared to compact bone. It is composed of concentric lamellae that are arranged irregularly to form the trabecular network. In some bones, the spaces between trabeculae contain red marrow, where...
The Auditory Ossicles
The aptly named stapes look very much like a stirrup. The three ossicles are unique to mammals, and each plays a role in...
Compact Bone
Compact bone, also called cortical bone, is the denser, stronger of the two types of bone tissue. It is found under the periosteum and in the diaphyses of long bones, where it provides support and protection. The microscopic structural unit of compact bone is called an osteon, or haversian system. Each osteon is composed of concentric rings of calcified...
Growth of Cartilage and Bone Tissue

