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

单一性疏松骨瘤，不像外生骨疣，是一个外灶。

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-骨髓位于长骨髓腔和松质骨间隙内，骨髓通过造血作用产生血细胞。