Single cancellous osteomas, unlike exostosis, are a relatively rare lesion in the external auditory canal.

单一性瘤，不像外生疣，是一个外耳道较见的病灶。

Blood production —The marrow, located within the medullary cavity of long bones and the interstices of cancellous bone, produces blood cells in a process called haematopoiesis.

造血-髓位于长髓腔间隙内，髓通过造血作用产生血细胞。