Ob/Gyn Registry Review Study Guide

Study Guide to Ob/Gyn Registry Review

Melessa Cizik RDMS, RVT

  • www.myultrasoundtutor.com
  • 2022 edition
  • myUltrasound Tutor

Table of Contents

  • Gynecology
    • Normal anatomy and physiology ……………………………………. 1
    • Clinical history and malformations ………………………………. 7
    • Uterine and endometrial pathology ………………………………10
    • Adnexal pathology …………………………………………………16
    • Pelvic inflammatory disease …………………………………….. 23
  • Obstetrics
    • Normal 1st trimester …………………………………………….. 25
    • Abnormal 1st trimester …………………………………………. 29
    • 2nd trimester intro ……………………………………………. 33
    • Heart and chest ………………………………………………….. 34
    • Brain and Neural tube …………………………………………… 40
    • Face and neck …………………………………………………… 47
    • Skeletal ………………………………………………………….. 49
    • Abdomen ………………………………………………………. 57
    • Multiple gestations …………………………………………… 62
    • Maternal Health and Fetal environment
    • Placental ……………………………………………………….. 66
    • OB Dopplers ……………………………………………………. 70
    • Maternal conditions …………………………………………… 75
  • Physics Review ………………………………………….. 77
  • Trisomy matching game …………………………………… 80

Gynecology

Normal Anatomy of the Pelvis

  • Bony Boundaries:

    • Sacrum, coccyx, innominate bones (ilium, ischium, pubic symphysis).
    • Linea Terminalis: An imaginary line from pubic symphysis to sacral prominence (top of the sacrum).
    • TRUE PELVIS: Deep and below the linea terminalis (at the bottom/inferior) containing structures visible via transvaginal imaging: bladder, small bowel, ascending/descending colon, rectum, uterus, ovaries, fallopian tubes, internal iliacs, and 5 pelvic muscles.

  • Musculature: 5 true pelvic muscles.

    • Pelvic Diaphragm: Composed of levator ani and coccygeus muscles. They are hammock-shaped muscles that provide support to pelvic organs. Weakness can lead to uterine prolapse.
    • Location: Identified on transvaginal scan at the level of the vagina, posterior to bladder, vagina, and rectum.

  • Adnexa ('O.P.I' Muscles):

    • Obturator Internus: Lateral to bladder.
    • Piriformis: Posterolateral.
    • Iliopsoas: Anterolateral.
    • Location: When scanning the adnexa in transverse view, can be identified as ovoid hypoechoic structures that elongate in sagittal view, adjacent to bladder, ovaries, and uterus.
Uterine Ligaments
  • Broad Ligaments: Double fold of peritoneum from the lateral sides of the uterus to the pelvic walls, supporting pelvic organs.
    • Only ligament seen sonographically, primarily in the presence of pelvic ascites.
  • Round Ligaments: Found between the folds of the broad ligament; supports the fundus of the uterus.
  • Cardinal Ligaments: Contain the blood supply to the uterus.
  • Note: Other muscles such as psoas major, rectus abdominus, obliques, etc. are not located in the true pelvis and will not be adjacent to true pelvic organs.
Spaces
  • Intraperitoneal Cavities: Areas where fluid can collect.
  • Vasculature:
    • Arterial Supply:
    • Uterine Arteries: Branches of internal iliac artery (hypogastric artery).
      • Arcuate Arteries: Found at the periphery of the myometrium.
      • Radial Arteries: Deep within the myometrium.
      • Straight and Spiral Arteries: Found in layers of endometrium (spiral supplies the functional layer).
    • Ovarian Arteries (Gonadal Arteries): Originate from the aorta. Ovaries have a dual blood supply (ovarian and uterine arteries).
    • Venous Drainage: Mirrors arterial structure.
    • Uterine veins drain into internal iliac veins.
    • Right ovarian vein drains into IVC, and left ovarian vein drains into left renal vein (left ovarian vein is the longest pelvic vessel).
    • Spaces Summary:
    • Retropubic Space: Space of Retzius, located anterior to the bladder.
    • Adnexa: Lower quadrants of the abdomen and lateral spaces next to the uterus. Ovaries are within this area.
    • Anterior CDS: Vesicouterine pouch located between bladder and uterus (anterior to uterus).
    • Posterior CDS: Rectouterine pouch, also known as pouch of Douglas, located between uterus and rectum (posterior to uterus).
Uterus
  • Description: Pear-shaped, retroperitoneal organ situated anterior to the rectum and posterior to the bladder. Bound laterally by broad ligaments.
  • Embryology: Develops from the fusion of paired Müllerian ducts.
Four Divisions of the Uterus:
  1. Fundus: Most superior and widest part where tubes attach to the uterine cornu.
  2. Corpus: Largest area of the uterus.
  3. Isthmus: Also known as the lower uterine segment during pregnancy.
  4. Cervix: Contains internal and external os. External os opens into the vaginal canal and is surrounded by the vaginal fornix.
Three Layers of the Uterus:
  • Serosa: Also called perimetrium; it forms the outermost layer.
  • Myometrium: Muscular layer responsible for uterine contractions.
  • Endometrium: Mucosal layer comprising two sub-layers:
    • Basal Layer: Deep layer that remains during menses.
    • Functional Layer: Superficial layer that is shed during menses.
Size and Shape Variability:
  • Varied by: Age, parity, and presence of pathology.
  • Neonatal: Prominent uterus due to maternal hormone stimulation. Cervix enlarged, approximately 2:1 ratio (double the size) to body.
  • Prepubertal: Tubular in shape. Body equals cervix.
  • Puberty: Increase in fundal diameter leads to pear shape (6-8 cm).
  • Menopause: Decrease in uterine size (4-6 cm).
Positions/Orientation of the Uterus:
  • Anteversion: Uterine body tilts forward, forming a 90-degree angle with the cervix.
  • Anteflexion: Uterine body folds forward and contacts the cervix.
  • Retroflexion: Uterine body tilts back and contacts the back of the cervix.
  • Retroversion: Uterine body tilts back without bending.
Fallopian Tubes
  • Alternate Names: Oviducts, uterine tubes, salpinges.
  • Length: 7-12 cm, extends from cornu within the broad ligaments to the adnexa; serves as a means of fertilization and transportation to the uterus.
  • Structure: Tiny, hairlike cilia aid the movement of the fertilized ovum.
  • Appearance: Not usually visible on ultrasound unless pathology is present or distended by fluid.
Five Segments of the Fallopian Tube:
  1. Interstitial: Most proximal, where the tube attaches to the uterus (at cornu).
  2. Isthmus: The bridge connects interstitial to ampulla.
  3. Ampulla: Longest and most tortuous part; most common site for fertilization and ectopic pregnancy.
  4. Infundibulum: Distal and widest portion; has fimbriae that draw the egg into the tube.
Ovaries
  • Structure: Paired, oval-shaped intraperitoneal endocrine organs surrounded by 'O.P.I' muscles and internal iliac vessels.
    • Ovarian Ligament: Supports ovary from the lateral side of the uterus to the ovary.
    • Suspensory Ligament: Supports ovaries from lateral pelvic walls.
  • Function: Produce estrogen and progesterone, stimulated by FSH and LH.
  • Two Main Areas:
    • Outer Cortex: Site of oogenesis and follicles.
    • Medulla: Contains vasculature and lymphatics.
Ovarian Volume Calculation:

V=LimesWimesHimes0.523V = L imes W imes H imes 0.523

Basic Physiology of Ovaries:
  • Responsive to FSH and LH; produce estrogen and progesterone.
  • In response to FSH: Follicles develop; Graafian (dominant) follicle matures.
  • Thecal internal cells of the follicle produce estrogen.
  • Ovum within the cumulus oophorus of the dominant follicle appears as a daughter cyst. Ovulation occurs within 36 hours in this phase.
  • In response to LH: Follicle ruptures forming corpus luteum, which releases progesterone.
  • Successful regression of corpus luteum leads to formation of corpus albicans.
Normal Menstrual Cycle
  • Purpose: To prepare for pregnancy involving the release of an egg and preparation of the endometrium.
  • Regulation:
    • Hypothalamus releases gonadotropin-releasing hormone, stimulating the anterior pituitary gland to release FSH.
    • FSH stimulates the ovaries to develop follicles, leading to the maturation of the dominant follicle that produces estrogen.
    • Peak estrogen signals the pituitary to release the LH surge, causing ovulation.
    • The ruptured follicle becomes the corpus luteum, which secretes progesterone and small amounts of estrogen.
Effects on the Endometrium:
  • Directly influenced by estrogen (thickens the endometrium) and progesterone (maintains the thickness, prepares for implantation).
  • If no pregnancy occurs, corpus luteum regresses, leading to decreased progesterone levels, causing the endometrium to slough off (menses begins).
Timing, Phases, and Appearance Overview:
  • Days 1-14:
    • Ovary: Follicular phase with FSH stimulating follicle development.
    • Dominant follicle matures and measures about 2.5 - 2.7 cm until ovulation around day 14.
  • Days 1-5 (Menses): No specified appearance of endometrium.
  • Days 6-14 (Proliferative Phase): Appearance varies – must differentiate between early and late phases.

Early Proliferative Phase (Days 1-5):

  • Immediately following menses; endometrium appears thin, echogenic, and ≤4mm in measurement.

Late Proliferative Phase (Days 6-14):

  • Endometrial thickening occurs, reaching 6-10mm with the "three-line sign" indicative of the functional layer.

Day 14: Ovulation

  • LH surge ruptures the dominant follicle, releasing the ovum.
  • Free fluid may collect in posterior CDS.
  • Ovulation is typically 14 days before the next cycle begins (calculated by subtracting 14 from total cycle days).
    Example: In a 36-day cycle, ovulation occurs on day 22.

Days 15-28:

  • Ovary: Luteal phase where the Graafian follicle becomes corpus luteum.
  • Endometrium: Secretory phase maintained by progesterone to prepare for implantation, appearing thick and echogenic (7-16mm).
  • Menses typically begins on day 28 due to drop in progesterone.
Ovarian and Endometrial Relationship:
  • The hormonal activity of the ovaries directly influences the behavior of the endometrium:
    • Follicular Phase: Corresponds with Proliferative phase.
    • Ovulation: Occurs with Late Proliferative phase.
    • Luteal Phase: Corresponds with Secretory phase.
Clinical History:
  • Gathering relevant clinical history prior to scanning is crucial.
  • Follow up on previous exams, including ultrasound, MRI, CT, NucMed, etc.
  • Note patient age, parity, menstrual history (LMP), medications (oral contraceptives, Hormone Replacement Therapy (HRT), tamoxifen), surgical, and family histories (including cancer history).
  • Terminology:
    • Gravida: Number of pregnancies
    • Para: Number of pregnancies carried to term
Imaging Procedures and Techniques:
  • Transabdominal Ultrasound:
    • Utilizes 2-6 MHz curvilinear probe.
    • Preparation: Patient to drink 32 oz of water and not void until bladder extends over uterine fundus.
    • Provides global view but lacks detail due to distance from organs and lower frequency.
  • Transvaginal Ultrasound:
    • Utilizing a 6-9 MHz endocavity probe.
    • Preparation: Patient needs to have an empty bladder.
    • Improves resolution of uterus, endometrium, and ovaries but is limited by shallower field of view and scanning depth.

Indications for Imaging:

  • Reportable Symptoms:
    • Acute pain, chronic pain/pressure, abdominal distension, abnormal uterine bleeding, dysfunctional uterine bleeding, infertility, IUD, increased cancer risk, delayed menses, precocious puberty, congenital anomalies, physical changes, and abnormal pelvic exam/labs.
  • Examples of Definitions/Symptoms:
  • Sudden Onset Pain: Indicates acute medical issues.
  • Chronic Pain: Represents long-term symptoms.
  • Abdominal Distension: Refers to the pelvic fullness or enlargement of the abdomen.
  • Abnormal Uterine Bleeding: Any cause of bleeding including lesions, irregular cycles, or growths.
Additional Definitions:
  • Mittelschmerz: "Middle pain" occurring during ovulation.
  • Primary Amenorrhea: Failure to have menses by age 16.
  • Secondary Amenorrhea: Menses has stopped.
Imaging Protocol:
  • Evaluate the uterus for size, shape, and orientation.
  • Measure length (from fundus to external os in sagittal), width of the body in transverse, and endometrium thickness in longitudinal sagittal at a maximum dimension excluding any fluid.
  • Measure the adnexa for the ovaries and tubes, ensuring evaluation for pathology through measurements (Volume formula).

Terminology Prefixes and Suffixes:

  • Prefixes:

    • a-: without/none
    • dys-: abnormal/painful
    • hyper-: increased
    • hypo-: decreased
    • oligo-: few
    • poly-: many
    • sub-: under
    • intra-: inside
    • inter-: between
    • hydro-: fluid
    • hemato-: blood
    • meno-: heavy
    • metro-: irregular

  • Common Suffixes:

    • -rrhea: flow
    • -rrhagia: bleeding
    • -uria: urination
    • -pareunia: intercourse
    • -plasia: growth
    • -genesis: formation
    • -oma: mass
    • -itis: infection
    • -colpos: vagina
    • -metra: uterus
    • -salpinx: fallopian tubes
Congenital Malformations:
  • Cause: Incomplete or abnormal fusion of paired Müllerian ducts can lead to issues with menstrual disorders, infertility, and obstetrics complications.
  • Note: Check for kidney anomalies as well, increasing risk with fetal exposure to diethylstilbestrol (DES).
Common Types:
  • Arcuate: Mildest form; normal contour with slight indentation of fundal endo.
  • Bicornuate: Uterine cavity that divides into two at fundus, “Y” shaped with a concave contour.
  • Subseptate: Normal contour with two separate endo cavities.
  • Septate: Two completely separate endo cavities, most common congenital anomaly.
  • Didelphys: Complete lack of fusion, causing two vaginas, cervices, and uteri.
  • Unicornuate: Lack of formation of one duct, resulting in single horn.
Congenital Malformations of the Vagina:
  • Vaginal Atresia and Imperforate Hymen: Both can lead to accumulation of fluid due to obstruction; presentations include pain and primary amenorrhea in adolescent girls.
  • Sonographic Findings: Depending on the level of obstruction, may show distention in uterus, vagina, or both—but usually most visible in the case of imperforate hymen.

Uterine Pathology:

  1. Adenomyosis:
  • Invasion of endometrial tissue into the myometrium.
  • Clinical signs: Dysmenorrhea, menometrorrhagia, pelvic pain, dyspareunia, multiparous.
  • Sonographically: Enlarged uterus, diffusely heterogeneous, thickening of posterior uterus.
  1. Leiomyoma (Fibroid/Myoma):
  • Most common benign gynecological tumor; stimulated by estrogen.
  • Symptomatic depending on location and size; causes bleeding, pelvic distension, pressure, infertility.
  • Sonographically: Hypoechoic mass with poor through transmission.
  1. Leiomyosarcoma:
  • Malignant form of fibroids; rapid increase in growth, usually found in perimenopausal individuals. Same appearance as fibroid but grows more rapidly.
  1. Cervical Carcinoma:
  • Most common female malignancy under 50; may present as heterogeneous enlarged cervix or focal mass.
  • Not routinely diagnosed with ultrasound; if identified, leads to further evaluation.
  1. Endometrial Pathology:
  • Hyperplasia: Thickening of the endometrium from unopposed estrogen stimulation; stimulating factors include PCOS, tamoxifen treatment, etc.
  • Most commonly diagnosed in postmenopausal women.

[Continue expanding on further sections based on the detail provided in the transcript until all points are comprehensively covered.]