Search results
Results from the WOW.Com Content Network
The function of some dermal bone is conserved throughout vertebrates, although there is variation in shape and in the number of bones in the skull roof and postcranial structures. In bony fish, dermal bone is found in the fin rays and scales. A special example of dermal bone is the clavicle. Some of the dermal bone functions regard ...
There are two principal types of bones: Dermal bone is directly formed in the dermis (skin), usually growing from initially thin plates. Among others, most bones forming the outer surface of the skull and lower jaws are dermal bones. In contrast, endochondral bone is formed from a cartilaginous precursor, which ossifies (turn into bone). [1 ...
The canal of the nutrient foramen is directed away from more active end of bone when one end grows more than the other. When bone grows at same rate at both ends, the nutrient artery is perpendicular to the bone. Most other bones (e.g. vertebrae) also have primary ossification centers, and bone is laid down in a similar manner. Secondary centers
Indirect fracture healing, the most common type of bone repair, [10] relies heavily on endochondral ossification. In this type of healing, endochondral ossification occurs within the fracture gap and external to the periosteum. In contrast, intramembranous ossification takes place directly beneath the periosteum, adjacent to the broken bone’s ...
The bones are derived from dermal bone and are part of the dermatocranium. In comparative anatomy , the term is applied to the whole dermatocranium. [ 1 ] In general anatomy, the roofing bones may refer specifically to the bones that form above and alongside the brain and neurocranium (i.e., excluding the marginal upper jaw bones such as the ...
The dermatocranium is the portion of the cranium that is composed of dermal bone, as opposed to the endocranium and splanchnocranium, which are composed of endochondral bone. The dermatocranium comprises the skull roof, the facial skeleton (usually excluding the dentary), and—in fishes—the opercular bones. [1]
Euteleostomes originally all had an endochondral bone, fins with lepidotrichs (fin rays), jaws lined by maxillary, premaxillary, and dentary bones composed of dermal bone, and lungs. Many of these characters have since been lost by descendant groups, however, such as lepidotrichs lost in tetrapods, and bone lost among the chondrostean fishes ...
Cancellous bone or spongy bone, [12] [11] also known as trabecular bone, is the internal tissue of the skeletal bone and is an open cell porous network that follows the material properties of biofoams. [13] [14] Cancellous bone has a higher surface-area-to-volume ratio than cortical bone and it is less dense. This makes it weaker and more flexible.