red marrow is found in heads of long bones.
where is red marrow found in long bones?
heads
hair abnormalities are very prominent in majority of the cases of tdo. kinky/curly hair that is unusually dry and easily sheds is present at birth. in 80% of cases, the hair has a more relaxed appearance by adolescence. the presence of this hair texture type is a defining characteristic between a diagnosis of tdo verses amelogenesis imperfecta with hypomaturation. additionally, in tdo the nails are usually abnormally thin, brittle, and split frequently. cranial deficiencies are marked by the presence of having a long skull relative to its width, or protrusive foreheads due to increased thickness of the cranial bones and premature closing of the associated sutures in the skull. the long bones in the body (arms, legs) are also abnormally long and tend to fracture very easily. osteosclerosis, commonly seen in tdo cases is characterized by an increase in bone density, affecting the skull and the mastoid process located behind the jawbone on the skull, as well as a shortened ramus seen in people with tdo. there are no known pathological problems associated with hair and bone changes in people with this disease. changes in the long bones tend to appear later in development, but changes in the teeth appear once the teeth being to form, called primary dentition. the hair and bone abnormalities are evaluated radiographically during initial diagnosis, and visually during the course of the disease. radiographic exams may be repeated if there is suspect of fracture.
tricho–dento–osseous syndrome
the composition of marrow is dynamic, as the mixture of cellular and non-cellular components (connective tissue) shifts with age and in response to systemic factors. in humans, marrow is colloquially characterized as "red" or "yellow" marrow (, , respectively) depending on the prevalence of hematopoetic cells vs fat cells. while the precise mechanisms underlying marrow regulation are not understood, compositional changes occur according to stereotypical patterns. for example, a newborn baby's bones exclusively contain hematopoietically active "red" marrow, and there is a progressive conversion towards "yellow" marrow with age. in adults, red marrow is found mainly in the central skeleton, such as the pelvis, sternum, cranium, ribs, vertebrae and scapulae, and variably found in the proximal epiphyseal ends of long bones such as the femur and humerus. in circumstances of chronic hypoxia, the body can convert yellow marrow back to red marrow to increase blood cell production.
bone marrow