uterine segment


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segment

 [seg´ment]
a demarcated portion of a whole. adj., adj segmen´tal.
behavior segment the smallest descriptive unit of a response to a stimulus.
bronchopulmonary s's the smaller subdivisions of the lobe of a lung; each segment is separated from others by a connective tissue septum and supplied by its own branch of the bronchus leading to the particular lobe.
hepatic s's subdivisions of the hepatic lobes based on arterial and biliary supply and venous drainage.
renal s's subdivisions of the kidney that have independent blood supply from branches of the renal artery, including the superior, anterior superior, inferior, anterior inferior, and posterior segments.
uterine segment either of the two portions into which the uterus becomes differentiated early in labor; the upper contractile portion (corpus uteri) becomes thicker as labor approaches, and the lower noncontractile portion (the isthmus) is thin walled and passive in character.

uterine segment

One of the two functional divisions of the uterine musculature during labor. During labor the upper uterine segment forcibly contracts, becoming progressively shorter and thicker, exerting traction on the more passive lower segment, and increasing the hydrostatic pressure against the cervix. The combination of forces and traction gradually cause the lower segment to thin, resulting in cervical effacement and dilation. See: physiologic retraction ring
See also: segment
References in periodicals archive ?
Key imaging findings include an empty uterine cavity and cervix, gestational sac in the low anterior uterine segment, and thinned or absent overlying myometrium; MRI may provide useful anatomic information in equivocal cases or for surgical planning.
The definitive resection specimen consisted of a uterus measuring 110 x 87 x 68 mm and weighing 290 g, with a tumor originating in the right lower uterine segment.
An emergency laparotomy was performed and one active bleeding site was found on the visceral surface of the left posterior side of the lower uterine segment.
3 cm size well-defined heteroechoic space-occupying lesion along anterior wall of uterus in lower uterine segment with caesarean scar ectopic and fibroid as being the differentials.
Normal placental implantation is decidual in the upper uterine segment.
Sonographic evaluation of the lower uterine segment in patients with previous cesarean delivery.
4 However recently the locked single-layer closure method of the lower uterine segment incision has been often preferred by surgeons to provide hemostasis.
3 cm occupying the lower uterine segment and cervical region extending down into the vagina, most likely fibroid.
8 cm cystic area in relation to the anterior aspect of lower uterine segment with arterial channels around it.
68% patients of incomplete abortion, retained products of conception (POCs) visualized in lower uterine segment / cervical canal, a collection of blood / placental remnants in the shape of irregular mass.
The intervening midline vertical septum between the uterus, cervix, and upper vagina is resorbed segmentally beginning in the lower uterine segment and progressing in both directions, (1) as the current case illustrates (Figure 1 and 2).
7,8] Some risk factors have been advocated for the development of VUF, such as an inadequate reflection of the bladder from lower uterine segment, excessive intra-operative bleeding, severe dystocia, forceps delivery, obstetrical vacuum, manual removal of the placenta, placenta percreta, uterine rupture, previous Cesarean section and dilatation and curettage.