Obstetric Anatomy and Prenatal Nursing

Comprehensive vocabulary flashcards covering obstetric pelvic anatomy, fetal skull landmarks and diameters, presentation and attitude, stations of labor, confirmation signs of pregnancy, and maternal physiological changes.

Linea Terminalis

An imaginary anatomical line that divides the false pelvis from the true pelvis.

False Pelvis

The superior half of the pelvis that supports the uterus during the late months of pregnancy and aids in directing the fetus into the true pelvis for birth.

Coccyx

The bone structure located just below the sacrum, composed of $5$ small bones fused together.

Pelvic Outlet

The inferior portion of the pelvis whose greatest dimension is the anteroposterior diameter.

Pelvic Cavity

The curved passage located between the pelvic inlet and outlet that functions to slow and control the speed of birth.

Anteroposterior Diameter (Pelvic Inlet)

The distance between the pubic symphysis and the sacral promontory, measuring approximately $11\,\text{cm}$.

Platypelloid Pelvis

A flattened pelvis type characterized by a smoothly curved oval inlet.

Cranium

The uppermost portion of the skull composed of eight bones, four of which (frontal, two parietal, and occipital) are superior and clinically important during childbirth.

Biparietal Diameter

The transverse diameter of the fetal skull, measuring approximately $9.25\,\text{cm}$.

Suboccipitobregmatic Diameter

The smallest anteroposterior diameter of the fetal skull, measuring approximately $9.5\,\text{cm}$.

Occipitomental Diameter

The widest anteroposterior diameter of the fetal skull, measuring approximately $13.5\,\text{cm}$.

Occipitofrontal Diameter

An anteroposterior diameter of the fetal skull measuring approximately $12\,\text{cm}$.

Submentobregmatic Diameter

An anteroposterior diameter of the fetal skull measuring approximately $9.5\,\text{cm}$.

Suboccipitofrontal Diameter

An anteroposterior diameter of the fetal skull measuring approximately $10.5\,\text{cm}$.

Fetal Presentation

The body part of the fetus that first contacts the cervix or is born first, determined by the combination of fetal lie and attitude.

Cephalic Presentation

The most frequent fetal presentation where the head presents first, classified into vertex, sinciput, brow, and face types.

Breech Presentation

A presentation in which the buttocks or feet contact the cervix first, categorized into complete, frank, and footling types.

Shoulder Presentation

A presentation where the fetus lies horizontally in the pelvis, with presenting parts including the acromion process, iliac crest, hand, or elbow.

Fetal Attitude

The degree of flexion a fetus assumes during labor or the spatial relationship of the fetal parts to each other.

Military Position

A fetal attitude of moderate flexion where the head is held straight and the chin does not touch the chest.

Caput Succedaneum

An edematous swelling of the fetal scalp that develops during labor from sustained pressure of the presenting skull against the cervix.

Engagement

The settling of the presenting part of the fetus far enough into the pelvis that it rests at the level of the maternal ischial spines.

Fetal Station

The measurement of the descent of the presenting part relative to the ischial spines ($0$ station), where negative numbers ( $-1$ to $-4\,\text{cm}$ ) indicate position above the spines and positive numbers ( $+1$ to $+4\,\text{cm}$ ) indicate position below.

Crowning

The point during labor at $+3$ or $+4$ station where the presenting fetal part reaches the perineum and is visible upon separation of the vulva.

Presumptive Signs

Subjective symptoms of pregnancy experienced by the woman that cannot be documented by an examiner and do not definitively confirm pregnancy.

Probable Signs

Objective findings experienced by the woman and verifiable by an examiner that strongly suggest but do not definitively diagnose pregnancy.

Positive Signs of Pregnancy

Definitive diagnostic indicators of pregnancy characterized by the acronym FAS: Fetal movement felt by examiner, Audible fetal heart tone, and Sonographic evidence of fetal outline.

Goodell's Sign

A probable sign of pregnancy characterized by increased vascularity, edema, and softening of the cervix.

Operculum

The thick mucus plug that forms within the cervical canal during pregnancy to prevent bacterial invasion.

Chadwick's Sign

A bluish or violet discoloration of the vaginal mucosa resulting from increased vascular congestion during pregnancy.

Hegar's Sign

A probable sign of pregnancy identified by softening of the lower uterine segment.

Supine Hypotension Syndrome

A drop in maternal blood pressure caused by compression of the inferior vena cava by the enlarging uterus when the woman lies flat on her back.

Carpal Tunnel Syndrome (Pregnancy)

Compression of the median nerve in the wrist during pregnancy, often precipitated by the effects of relaxin and repetitive hand motions.

Pyrosis

Heartburn during pregnancy triggered by increased progesterone levels, reduced gastrointestinal motility, and upward displacement of the stomach.

Leukorrhea

A whitish, viscous vaginal discharge produced in response to elevated estrogen levels and increased pelvic blood supply during pregnancy.