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1. The act of cutting. 2. A cut or division. 3. A segment or part of any organ or structure delimited from the remainder. 4. A cut surface. 5. A thin slice of tissue, cells, microorganisms, or any material for examination under the microscope. SYN: microscopic s.. [L. sectio, a cutting, fr. seco, to cut]
- attached cranial s. SYN: attached craniotomy.
- axial s. SYN: transverse s..
- cesarean s. incision through the abdominal wall and the uterus (abdominal hysterotomy) for extraction of the fetus.
- classical cesarean s. a cesarean s. in which the uterus is entered through a vertical fundal incision.
- coronal s. a cross s. attained by slicing, actually or through imaging techniques, the body or any part of the body or any anatomic structure in the coronal or frontal plane, i.e., in a vertical plane perpendicular to the median or sagittal plane. Since actual sectioning in the coronal plane results in an anterior and a posterior portion, an anatomic coronal s. may be a two-dimensional view of the cut surface of the posterior aspect of the anterior portion, or of the anterior aspect of the posterior portion. SYN: frontal s..
- cross s. 1. a planar or two-dimensional view, diagram, or image of the internal structure of the body, part of the body, or any anatomic structure afforded by slicing, actually or through imaging (radiographic, magnetic resonance, or microscopic) techniques, the body or structure along a particular plane. Traditionally, “cross s.” referred to views resulting from slicing at right angles to the longitudinal axis of the structure (axial or transaxial), but in contemporary use, the term is applied when the structure is sliced in any given plane; 2. the slice or s. of a given thickness created by actual serial parallel cuts through a structure or by the application of imaging technique.
- detached cranial s. SYN: detached craniotomy.
- diagonal s. SYN: oblique s..
- frozen s. a thin slice of tissue cut from a frozen specimen, often used for rapid microscopic diagnosis.
- Latzko cesarean s. a cesarean s. in which the uterus is entered by paravesical blunt dissection without entering the peritoneal cavity.
- longitudinal s. a cross sectio attained by slicing in any plane parallel to the long or vertical axis, actually or through imaging techniques, the body or any part of the body or anatomic structure. Longitudinal sections include, but are not limited to, median, sagittal, and coronal sections.
- lower uterine segment cesarean s. a cesarean s. in which the uterus is entered in its lower segment by a transperitoneal approach.
- median s. a cross s. attained by slicing in the median plane, actually or through imaging techniques, the body or any part of the body which occupies or crosses the median plane or by slicing any generally symmetrical anatomic structure, such as a finger or a cell, in its midline. Since actual sectioning of the median plane results in a right and a left half, an anatomical median s. may be a two-dimensional view of the cut surface on the medial aspect of either half. SYN: midsagittal s..
- microscopic s. SYN: s. (5).
- midsagittal s. SYN: median s..
- oblique s. a diagonal cross s. attained by slicing, actually or through imaging techniques, the body or any part of the body or anatomic structure, in any plane which does not parallel the longitudinal axis or intersect it at a right angle, i.e., which is neither longitudinal (vertical) nor transverse (horizontal). SYN: diagonal s..
- parasagittal s. SYN: sagittal s..
- perineal s. any s. through the perineum, either lateral or median lithotomy (operations of historical importance) or external urethrotomy.
- pituitary stalk s. transection of the neurovascular connection between the hypothalamus and the pituitary gland.
- Saemisch s. procedure of transfixing the cornea beneath an ulcer and then cutting from within outward through the base.
- sagittal s. a cross s. obtained by slicing, actually or through imaging techniques, the body or any part of the body, or any anatomic structure in the sagittal plane, i.e., in a vertical plane parallel to the median plane. Since actual sectioning in the sagittal plane results in a right and a left portion, an anatomical sagittal s. may be a two-dimensional view of the cut surface on the medial aspect of either portion. SYN: parasagittal s..
- serial s. one of a number of consecutive microscopic sections.
- thin s., ultrathin s. a s. of tissue for electron microscopic examination; the specimen is fixed, typically in glutaraldehyde and/or in osmium tetroxide, embedded in a plastic resin, and sectioned at less than 0.1 μm in thickness with a glass or diamond knife in an ultramicrotome.
- transverse s. a cross s. obtained by slicing, actually or through imaging techniques, the body or any part of the body structure, in a horizontal plane, i.e., a plane which intersects the longitudinal axis at a right angle. Since actual sectioning in the transverse plane results in an inferior and a superior portion, an anatomical transverse s. may be a two-dimensional view of the cut surface on the inferior aspect of the superior portion, or of the superior aspect of the inferior portion. By convention, in medical imaging transverse sections demonstrate the former unless otherwise stated. SYN: axial s..
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sec·tion 'sek-shən n
1) the action or an instance of cutting or separating by cutting esp the action of dividing (as tissues) surgically <nerve \section> <abdominal \section> see CESAREAN SECTION
2) a natural subdivision of a taxonomic group
3) a very thin slice (as of tissue) suitable for microscopic examination
section vt, sec·tioned; sec·tion·ing -sh(ə-)niŋ
1) to divide (a body part or organ) surgically <\section a nerve>
2) to cut (fixed tissue) into thin slices for microscopic examination
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1. n. (in surgery) the act of cutting (the cut or division made is also called a section). For example, an abdominal section is performed for surgical exploration of the abdomen (see laparotomy). A transverse section is a cut made at right angles to a structure's long axis. See also Caesarean section.
2. n. (in imaging) a three-dimensional reconstruction of body scans obtained by computerized tomography or magnetic resonance imaging. These are reconstituted as transverse and sagittal plane sections, less commonly as coronal plane sections.
4. vb. to issue an order for compulsory admission to a psychiatric hospital under the appropriate section of the Mental Health Acts.
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sec·tion (sekґshən) [L. sectio] 1. an act of cutting. 2. a cut surface. 3. a segment or subdivision of an organ; called also sectio [TA]. 4. a supplemental taxonomic category subordinate to a subgenus but superior to a species or series.Medical dictionary. 2011.