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

单一性疏松瘤，不像疣，是一个耳道较见的病灶。

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-髓髓腔和松质间隙内，髓通过造血作用产血细胞。