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a part or portion.
middle piece an anterior portion of the tail of the spermatozoon, between the neck and the anulus. See illustration at spermatozoon.
principal piece the main portion of the tail of a spermatozoon, beginning at the anulus and gradually tapering toward the end piece. See illustration at spermatozoon.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
a part of the spermatozoon characterized by an axoneme and by a sheath of mitochondria arranged in a tight helix.
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