sequestrum

A piece of necrotic tissue, usually bone, that has become separated from the surrounding healthy tissue. [Mod. L. use of Mediev. L. s., something laid aside, fr. L. sequestro, to lay aside, separate]

- primary s. a completely detached s..

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se·ques·trum si-'kwes-trəm n, pl -trums also -tra -trə a fragment of dead bone detached from adjoining sound bone

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n. (pl. sequestra)

a portion of dead bone formed in an infected bone in chronic osteomyelitis. It is surrounded by an envelope (involucrum) of sclerotic bone and fibrous tissue and can be seen as a dense area within the bone on X-ray. It can cause irritation and the formation of pus, which may discharge through a sinus, and is usually surgically removed (sequestrectomy).

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se·ques·trum (sə-kwesґtrəm) pl. sequesґtra [L.] 1. any tissue that has become sequestered. 2. a piece of dead bone that has become separated during the process of necrosis from the sound bone.

Formation of a sequestrum: (A), sound bone; (B), new bone; (C), granulations lining involucrum; (D), cloaca; (E), sequestrum.