juvenile pelvis


pelvis

 [pel´vis] (L.) 1. any basinlike structure in the body.2. the bony pelvis, the lower (caudal) portion of the trunk of the body, forming a basin bounded anteriorly and laterally by the hip bones and posteriorly by the sacrum and coccyx; it is formed by the sacrum, the coccyx, and the ilium, pubis, and ischium, bones that also form the hip" >hip and the arch" >pubic arch. These bones are separate in the child, but become fused by adulthood. The pelvis is subjected to more stress than any other body structure. Its upper part, which is somewhat flared, supports the weight of internal organs in the upper part of the body. The floor of the pelvis or pelvic floor is the layer of tissue just below the outlet, formed by the coccygeal and levator ani muscles and the perineal fascia.
Pelvic structures in men and women differ both in shape and in relative size. The male pelvis is heart-shaped and narrow and proportionately heavier and stronger than that of the female, so that it is better suited for lifting and running. The female pelvis is constructed to accommodate the fetus during pregnancy and to facilitate its downward passage through the pelvic cavity in childbirth. The most obvious difference between the male and female pelvis is in the shape. A woman's hips are wider and her pelvic cavity is round and relatively large. There are differences in the shape of the female pelvis, which must be taken into account in childbirth. During pregnancy the capacity of the pelvis and the pelvic diameters are measured, so that possible complications during labor can be anticipated.Dynamic pelvic floor imaging using MRI. MR sequences can now be acquired every half-second or so and this rapidity allows functional studies of the gastrointestinal tract to be undertaken. A and B, These sagittal views can be used to measure pelvic floor descent as well as to give valuable information on the local anatomy. C, Diagrammatic baseline sagittal view. (1 = pubococcygeal baseline; 2 = bladder base descent; 3 = uterocervical descent; 4 = anorectal junction descent.) From Aspinal and Taylor-Robinson, 2001.Various types of pelvic inlets.
android pelvis one with a wedge-shaped inlet and narrow anterior segment typically found in the male.anthropoid pelvis one whose anteroposterior diameter equals or exceeds the transverse diameter.assimilation pelvis one in which the ilia articulate with the vertebral column higher (high assimilation pelvis) or lower (low assimilation pelvis) than normal, the number of lumbar vertebrae being correspondingly decreased or increased.beaked pelvis one with the pelvic bones laterally compressed and their anterior junction pushed forward.brachypellic pelvis a short oval type of pelvis, in which the transverse diameter exceeds the anteroposterior diameter by 1 to 3 cm.contracted pelvis one showing a decrease of 1.5 to 2 cm in an important diameter; when all dimensions are proportionately diminished, it is a generally contracted pelvis.cordate pelvis a heart-shaped pelvis.dolichopellic pelvis a long, oval pelvis with the anteroposterior diameter greater than the transverse diameter.extrarenal pelvis see pelvis" >renal pelvis.false pelvis pelvis major.flat pelvis one in which the anteroposterior dimension is abnormally reduced.frozen pelvis a condition, due to infection or carcinoma, in which the adnexa and uterus are fixed in the pelvis.funnel pelvis one with a normal inlet but a greatly narrowed outlet.greater pelvis pelvis major.gynecoid pelvis the normal female pelvis: a rounded oval pelvis with well rounded anterior and posterior segments.infantile pelvis a generally contracted pelvis with an oval shape, a high sacrum, and inclination of the walls; called also juvenile pelvis.pelvis jus´to ma´jor an unusually large gynecoid pelvis, with all dimensions increased.pelvis jus´to mi´nor a small gynecoid pelvis, with all dimensions symmetrically reduced.juvenile pelvis infantile pelvis.kyphotic pelvis a deformed pelvis marked by increase of the conjugate diameter at the brim with decrease of the transverse diameter at the outlet.lesser pelvis pelvis minor.pelvis ma´jor the part of the pelvis superior to a plane passing through the ileopectineal lines. Called also false pelvis and greater pelvis.pelvis mi´nor the part of the pelvis inferior to a plane passing through the ileopectineal lines. Called also lesser pelvis and true pelvis.Nägele's pelvis one contracted in an oblique diameter, with complete ankylosis of the sacroiliac synchondrosis on one side and imperfect development of the sacrum and coxa on the same side.Otto pelvis one in which the acetabulum is depressed, accompanied by protrusion of the femoral head into the pelvis.platypellic pelvis (platypelloid pelvis) one shortened in the anteroposterior aspect, with a flattened transverse, oval shape.rachitic pelvis one distorted as a result of rickets.renal pelvis the funnel-shaped expansion of the upper end of the ureter into which the calices" >renal calices open; it is usually within the sinus" >renal sinus, but under certain conditions a large part of it may be outside the kidney (extrarenal pelvis).scoliotic pelvis one deformed as a result of scoliosis.split pelvis one with a congenital separation at the symphysis pubis.spondylolisthetic pelvis one in which the last, or rarely the fourth or third, lumbar vertebra is dislocated in front of the sacrum, more or less occluding the pelvic brim.true pelvis pelvis minor.

ju·ve·nile pel·vis

a pelvis justo minor in which the bones are slender.

ju·ve·nile pel·vis

(jū'vĕ-nil pel'vis) A pelvis justo minor in which the bones are slender.

pelvis

(pel'vis) (pel'vez?) (pel'vi-sez) plural.pelvespelvises [L. pelvis, basin] 1. A basin-shaped structure or cavity.PELVIS2. The bony compartment comprising the innominate bones, the sacrum, and the coccyx, joined at the symphysis pubis, sacroiliac, and sacrococcygeal articulations by a network of cartilage and ligaments. The structure supports the vertebral column and articulates with the lower limbs. See: illustration3. The cavity encompassed by the innominate bones, the sacrum, and the coccyx.

Anatomy

The pelvis is separated into a false or superior pelvis and a true or inferior pelvis by the iliopectineal line and the upper margin of the symphysis pubis. The circumference of this area constitutes the inlet of the true pelvis. The lower border of the true pelvis, termed the outlet, is formed by the coccyx, the protuberances of the ischia, the ascending rami of the ischia, and the descending rami of the ossa pubis and the sacrosciatic ligaments. The floor of the pelvis is formed by the perineal fascia, the levator ani, and the coccygeus muscles. All diameters normally are larger in the female than in the male.

External Diameters

Interspinous: The distance between the outer edges of the anterosuperior iliac spines, the diameter normally measuring 26 cm (1014 in.). Intercristal: The distance between the outer edges of the most prominent portion of the iliac crests, the diameter normally being 28 cm (11 in.). Intertrochanteric: The distance between the most prominent points of the femoral trochanters, 32 cm (1212 in.). Oblique (right and left): The distance from one posterosuperior iliac spine to the opposite anterosuperior iliac spine, 22 cm (812 in.), the right being slightly greater than the left. External conjugate: The distance from the undersurface of the spinous process of the last lumbar vertebra to the upper margin of the anterior surface of the symphysis pubis, 20 cm (778 in.).

Internal Diameters

True conjugate: The anteroposterior diameter of the pelvic inlet, 11 cm (414 in.), the most important single diameter of the pelvis. Diagonal conjugate: The distance between the promontory of the sacrum to the undersurface of the symphysis pubis, 13 cm (518 in.). Two cm (34 in.) are deducted for the height and inclination of the symphysis pubis to obtain the diameter of the conjugate. Transverse: The distance between the ischial tuberosities, 11 cm (414 in.). Anteroposterior (of outlet): The distance between the lower border of the symphysis pubis and the tip of the sacrum, 11 cm (414 in.). Anterior sagittal: The distance from the undersurface of the symphysis pubis to the center of the line between the ischial tuberosities, 7 cm (234 in.). Posterior sagittal: The distance from the center of line between the ischial tuberosities to the tip of the sacrum, 10 cm (4 in.).

pelvis aequabiliter justo major

A pelvis that is symmetrically larger than the standard in all its dimensions. Synonym: giant pelvis

pelvis aequabiliter justo minor

A pelvis with all its dimensions uniformly smaller than the standard. Synonym: reduced pelvis

android pelvis

The normal shape of the male pelvis. About 30% of women share this bony configuration; however, the heart-shaped inlet, convergent sidewalls, slanted sacrum, and narrow sacrosciatic notch pose problems for childbearing. The narrowed dimensions increase the risk of fetopelvic disproportion, obstructed labor, and cesarean delivery. Synonym: masculine pelvis

anthropoid pelvis

A deviation from the normal gynecoid configuration of the pelvic bones in which the anterior-posterior diameter is greater than the transverse diameter. It is found in approximately 20% of women. Deviations from the normal gynecoid configuration include a long, oval, narrow inlet and narrow sacrum, straight sidewalls, and a wide sacrosciatic notch. The shape increases the potential for fetal posterior positions during childbearing.

assimilation pelvis

A structural abnormality that results from a developmental lumbosacral fusion or from a sacrococcygeal fusion.

beaked pelvis

A pelvis with the pelvic bones laterally compressed and pushed forward so that the outlet is narrow and long. Synonym: rostrate pelvis; triradiate pelvis

bony pelvis

The skeleton of the pelvis, consisting of the right and left hip bones (each made of an ilium, an ischium, and a pubis), the sacrum, and the coccyx.

brachypellic pelvis

An oval pelvis in which the transverse diameter is at least 1 cm longer, but no more than 3 cm longer, than the anteroposterior diameter of the pelvis.

brim of the pelvis

Brim (2).

contracted pelvis

A pelvis in which one or more of the principal diameters is reduced to a degree that parturition is impeded.

cordate pelvis

A pelvis possessing a heart-shaped inlet.

coxalgic pelvis

A pelvis deformed subsequent to hip joint disease.

dolichopellic pelvis

An abnormal pelvis in which the anteroposterior diameter is greater than the transverse diameter.

dwarf pelvis

An unusually small pelvis in which all diameters are symmetrically reduced.

elastic pelvis

Osteomalacic pelvis.

extrarenal pelvis

A renal pelvis located outside the kidney.

false pelvis

The portion of the pelvic cavity that lies above the pelvic brim, bounded by the linea terminalis and the iliac fossae. It supports the weight of the growing uterus during the middle and last trimesters of pregnancy. Synonym: pelvis major

fissured pelvis

A structural malformation in which the ilia are pushed forward to an almost parallel position; caused by rickets.

flat pelvis

A pelvis in which the anteroposterior diameters are shortened.

frozen pelvis

Adhesion of the female reproductive organs to the peritoneum or bowel by cancer, endometriosis, or pelvic infection.

funnel-shaped pelvis

A pelvis in which the outlet is considerably contracted but the inlet dimensions are normal.

giant pelvis

Pelvis aequabiliter justo major.

gynecoid pelvis

A normal female pelvis. Relative to the male pelvis, it has a wider bone structure and a more oval shape.

halisteretic pelvis

A deformed pelvis resulting from softening of bones because of osteomalacia..

infantile pelvis

An adult pelvis that retains its infantile characteristics. Synonym: juvenile pelvis

pelvis justo major

An unusually large pelvis.

juvenile pelvis

Infantile pelvis.

kyphoscoliotic pelvis

A deformed pelvis caused by rickets.

kyphotic pelvis

A deformed pelvis characterized by an increase of the conjugate diameter at the brim with reduction of the transverse diameter at the outlet.

lordotic pelvis

A deformed pelvis in which the spinal column has an anterior curvature in the lumbar region.

pelvis major

False pelvis.

masculine pelvis

A female pelvis that resembles a male pelvis, esp. in that it is narrower, more conical, and heavier-boned and has a heart-shaped inlet. Synonym: android pelvis

pelvis minor

True pelvis.

pelvis obtecta

A deformed pelvis in which the vertebral column extends across the pelvic inlet.

osteomalacic pelvis

A pelvis distorted because of osteomalacia. Synonym: elastic pelvis

Otto pelvis

See: Otto pelvis

platypellic pelvis

A rare structural malformation that resembles a flattened gynecoid pelvis with shortened anteroposterior and wide transverse diameters.

pseudo-osteomalacic pelvis

A rachitic pelvis similar to that of a person with osteomalacia.

rachitic pelvis

A pelvis deformed from rickets.

reduced pelvis

Pelvis aequabiliter justo minor.

renal pelvis

The expanded proximal end of the ureter. It is within the renal sinus of the kidney and receives the urine through the major calyces.

reniform pelvis

A pelvis shaped like a kidney.

Robert pelvis

See: Robert pelvis

rostrate pelvis

Beaked pelvis.

pelvis rotunda

A tympanic depression in the inner wall, at the bottom of which is the fenestra rotunda.

round pelvis

A pelvis with a circular inlet.

scoliotic pelvis

A deformed pelvis resulting from spinal curvature.

simple flat pelvis

A pelvis with a shortened anteroposterior diameter.

pelvis spinosa

A rachitic pelvis with a pointed pubic crest. Synonym: Kilian pelvis

split pelvis

A pelvis with a congenital division at the symphysis pubis.

spondylolisthetic pelvis

A pelvis in which the last lumbar vertebra is dislocated in front of the sacrum, causing occlusion of the brim.

triradiate pelvis

Beaked pelvis.

true pelvis

The portion of the pelvis lying below the iliopectineal line. The dimensions of the true pelvis are of obstetrical significance in determining the success of fetal descent. Synonym: pelvis minor