Transvaginal Sonography (TVS) - Complete Teaching Guide

What is TVS and Why Use It?

Patient Preparation and Setup

• Position: Dorsal lithotomy (like a pelvic exam), with hips slightly elevated on a pillow or padded stirrups
• Bladder: Should be empty (full bladder displaces and compresses pelvic organs, degrading the TVS image)
• Probe cover: Always use a sterile condom/glove with coupling gel inside and outside the cover
• Chaperone: Required; document consent and the chaperone's presence

The Probe and Probe Orientation

• Sagittal (longitudinal) view: Marker at 12 o'clock (pointing toward the ceiling) - cephalad structures appear on the left side of the screen
• Transverse (coronal) view: Rotate probe 90° counterclockwise - marker at 9 o'clock (patient's right), so the patient's right appears on the left of the screen

Tip: Keep your thumb aligned with the probe indicator throughout the exam - this lets you track probe orientation no matter how much you manipulate it.

Probe Movements - The Four Maneuvers

Step-by-Step Scanning Protocol

Step 1 - Sagittal View of the Uterus

• Anteverted/anteflexed (most common, ~80%): Fundus tips forward toward bladder; on sagittal TVS you see the fundus at the top-left of the image
• Retroverted/retroflexed (~20%): Fundus tips backward; the cervix appears first and you follow it posteriorly to the fundus; repositioning the probe into the posterior fornix helps

• Length: fundus to external cervical os (normal 6-10 cm in reproductive age)
• Anteroposterior diameter: widest AP dimension of the uterine body
• Endometrial thickness: measured bilayer (both layers together) at widest point, excluding fluid

Step 2 - Transverse (Coronal) View of the Uterus

• A round/oval cross-section of the uterus
• The bright endometrial echo in the center
• Both cornua visible when angled superiorly (fundal transverse)
• The "owl face" appearance: two round cornua flanking the central echo

Step 3 - Cervix View

• The cervical stroma (fibrous, intermediate-to-high echogenicity)
• The endocervical canal as a central bright line
• The anterior lip and posterior lip of the cervix
• The external os (V-shaped notch at the bottom)
• The posterior vaginal fornix (inferior to posterior lip)
• Nabothian cysts: small, round, anechoic - benign retention cysts in the cervical stroma

Step 4 - Ovaries

1. Start in the transverse plane (indicator at 9 o'clock)
2. Fan/tilt the probe toward the right iliac fossa (rock the handle to the patient's left to see the right ovary)
3. Follow the ovarian ligament or use the iliac vessels as a guide - the ovary lies just medial to the internal iliac vein

Step 5 - Adnexa and Pouch of Douglas

Summary Image Checklist for a Complete TVS Exam

1. Cervix - sagittal (with endocervical canal)
2. Uterus midline - sagittal (full length with endometrial measurement)
3. Uterine fundus - transverse (with cornua)
4. Right ovary - long axis (with 3-plane measurements)
5. Right adnexa - any abnormality
6. Left ovary - long axis (with 3-plane measurements)
7. Left adnexa - any abnormality
8. Pouch of Douglas - free fluid assessment

Echogenicity Quick Reference

Common TVS Findings and What They Look Like

Key Points to Remember

1. Always do TAS first, then TVS - they are complementary; TAS gives the big picture, TVS gives the detail.
2. Empty bladder for TVS - a full bladder compresses and displaces structures.
3. Probe indicator orientation is everything - lose track of it and your anatomy orientation collapses.
4. Internal iliac vessels are your ovary GPS - find the hypogastric vessels, and the ovary will be nearby.
5. Endometrial thickness changes with the cycle - always correlate with menstrual history.
6. A little free fluid in the POD is normal - especially in the luteal phase; complex or large-volume fluid is not.
7. Normal fallopian tubes are invisible on TVS - if you see a tube, it's pathological.

Real-Time TVS Scan - Frame-by-Frame Walkthrough

Important note: I can't embed live video here, but I've compiled the best real-time video resources + a detailed frame-by-frame simulation with real sonographic images below. Watch the videos alongside this guide for maximum learning.

Best Free Real-Time TVS Video Resources

Real-Time Scan Simulation - Frame by Frame

FRAME 1 - Probe Insertion and First Image

• (a) Probe enters vaginal canal with indicator at 12 o'clock - red arrow shows direction of beam
• (b) Probe rotated 90° (green arrow) for transverse view
• (c) First sagittal TVS image - label: ENDOMETRIUM visible centrally. ANT = anterior, POST = posterior. The bright central stripe is the endometrium. Red arrow = probe artifact at screen bottom
• (d) Transverse view - RT = right, LT = left. Red arrow = probe shadow

• The first thing you see when inserting the probe is the probe itself (bright artifact at the near field/top of image)
• The uterus "falls into view" as a gray pear-shaped structure
• Fan left-right to center the endometrial stripe

FRAME 2 - Sagittal Uterus (The Establishing Shot)

SCREEN LAYOUT - SAGITTAL TVS:
┌─────────────────────────────────────┐
│  PROBE ARTIFACT (near field, top)   │
│─────────────────────────────────────│
│         ┌──────────┐                │
│  BLADDER│  (black) │                │
│         └────┬─────┘                │
│         ┌────▼──────────────┐       │
│         │   UTERINE FUNDUS  │       │
│         │  ┌─────────────┐  │       │
│MYOMETRIUM│  │ENDOMETRIUM  │  │      │
│(gray)   │  │ (bright)    │  │       │
│         │  └─────────────┘  │       │
│         │      CERVIX       │       │
│         └───────────────────┘       │
│    POUCH OF DOUGLAS (posterior)     │
│         RECTUM (posterior)          │
│─────────────────────────────────────│
│ LEFT = cephalad | RIGHT = caudal    │
└─────────────────────────────────────┘

• Fan the probe toward you (handle down) → see the fundus and upper uterus
• Fan away from you (handle up) → see the cervix and lower uterine segment
• The endometrial stripe follows the uterine axis as you sweep

FRAME 3 - Endometrial Stripe Close-Up

FRAME 4 - Rotating to Transverse (The "Owl Face")

SCREEN LAYOUT - TRANSVERSE UTERUS:
┌─────────────────────────────────────┐
│  LEFT of screen = patient's RIGHT   │
│─────────────────────────────────────│
│                                     │
│      ╭──────────────────╮           │
│      │  ●  ENDO   ●     │ ← cornua  │
│      │     (bright)     │           │
│      ╰──────────────────╯           │
│      MYOMETRIUM (gray rim)          │
│                                     │
│─────────────────────────────────────│
│  Fan UP = fundus | Fan DOWN = cervix│
└─────────────────────────────────────┘

FRAME 5 - Cervix View

SCREEN LAYOUT - CERVICAL SAGITTAL:
┌─────────────────────────────────────┐
│  ┌──────────────┐                   │
│  │  UTERINE     │                   │
│  │  BODY        │                   │
│  └──────┬───────┘                   │
│         │ internal os               │
│  ┌──────▼───────┐                   │
│  │   CERVIX     │←─ fibrous,        │
│  │ ─────────── │   intermediate    │
│  │ endo canal   │   echogenicity    │
│  └──────┬───────┘                   │
│         │ external os               │
│  POSTERIOR FORNIX / VAGINA          │
│                                     │
│  RECTUM posterior to cervix         │
└─────────────────────────────────────┘

• The endocervical canal = bright central line within the cervix
• The internal os = where the cervical canal opens into the uterine cavity
• The external os = V-shaped notch at the bottom of the cervix
• Nabothian cysts = small black dots (anechoic) scattered in cervical stroma - benign, ignore

FRAME 6 - Sweeping to Find the Right Ovary

1. Rock the probe handle toward the patient's LEFT (which angles the beam to the patient's RIGHT)
2. Follow the ovarian ligament as it extends laterally
3. Look for the internal iliac vein - a large, oval, anechoic (black) tubular structure near the pelvic sidewall
4. The ovary sits just medial to this vessel

PELVIC SIDEWALL ANATOMY (what you see scanning laterally):

  ←── UTERUS ──── OVARY ──── ILIAC VESSELS ──── PELVIC WALL ──→
                  (find       (your landmark -
                  this!)      find these first)

FRAME 7 - Normal Ovary on Screen

• Oval, homogeneous structure with a slightly darker (hypoechoic) texture than myometrium
• Follicles = small round black (anechoic) dots within the ovary - these are the antral follicles
• Dominant follicle = one large anechoic bubble, up to ~20-25 mm, thin-walled
• Calipers (the dotted blue measurement lines) to measure 3 dimensions: length × width × height
• Ovarian volume = L × W × H × 0.523 (prolate ellipsoid formula)

• Reproductive age: 5-15 mL
• Postmenopausal: < 3 mL

FRAME 8 - Pouch of Douglas Check

POSTERIOR CUL-DE-SAC / POUCH OF DOUGLAS:

  UTERUS ──► posterior wall
                    ↓
             ┌──────────────┐
             │  POD space   │ ← normal: small anechoic sliver of fluid
             └──────────────┘ ← abnormal: large black pool, complex echoes
                    ↓
              RECTUM/BOWEL

Real-Time Scanning Sequence Summary (Checklist)

TVS SCAN SEQUENCE
─────────────────────────────────────────
① INSERT probe, indicator 12 o'clock
   → Sagittal uterus: identify & measure
   → Endometrial stripe measurement
   → Cervix: canal, os, nabothian cysts

② ROTATE 90° CCW → indicator 9 o'clock
   → Transverse uterus: fundus to cervix
   → "Owl face" at fundal level

③ ROCK HANDLE LEFT
   → Find right ovary (near R iliac vein)
   → Measure in 3 planes

④ ROCK HANDLE RIGHT
   → Find left ovary (near L iliac vein)
   → Measure in 3 planes

⑤ RETURN to sagittal midline
   → Pouch of Douglas: fluid assessment
   → Adnexa: tubes, masses
─────────────────────────────────────────
Total scan time: ~8-15 minutes

What NOT to Miss in Real Time