# Ultrasound Animal Challenge 5 – Answer

## Metadata
- Content type: Blog
- Canonical URL: https://123sonography.com/blog/cases/ultrasound-animal-challenge-5-answer
- Published: October 12, 2022
- Last updated: April 3, 2026

## Overview
The answer to our question "Which pathology would you suspect if you see the bunny sign?".

## Snapshot
- Category: Cases

## Authors
- [Univ. Prof. Dr. Thomas Binder](/speaker/146) - Medical University of Vienna and founder/CMO 123Sonography, Webinar Moderation
- [Ulrike Handler, MD](/speaker/33) - Herz Jesu Hospital, Vienna, Austria

## Tags
- Abdomen

## Related Courses
- [Abdominal Ultrasound MasterClass](/course/abdominalusmasterclass)
- [Abdominal Ultrasound BachelorClass](/course/abdominalusbachelorclass)

## Content
The answer to the question "[Which pathology would you suspect if you see the bunny sign?](https://123sonography.com/blog/ultrasound-animal-challenge-5-bunny-sign)" is:

## D) Congestive heart failure

![Ultrasound image of pathology that shows bunny as label.](https://123sonography.com/sites/default/files/styles/article_image/public/image/images/us-animal-challenge-bunny-label.png?itok=v4K_vNU5)

The bunny (Playboy bunny) sign describes the confluence of the dilated hepatic veins and inferior vena cava, which are commonly seen in congestive heart failure due to right heart failure.\* The very dilated vena cava represents the head of the bunny. This term is commonly used in emergency ultrasound.

[![](https://123sonography.com/sites/default/files/styles/video_thumbnail/public/video/images/us-animal-challenge-bunny-mark.jpeg?itok=YPKLpmOR)](https://vimeo.com/759446217&title=0&byline=0&portrait=0)

\*The bunny sign was previously applied for the normal anatomy of the hepatic vein / IVC confluence. This sign is also called the Mumoli´s sign. Since the dilated veins resemble the shape of a bunny more closely it is more widely used to denote cardiac congestion.

**Yours,**
**Ulrike Handler, Thomas Binder and the 123sonography team**

PS: If you missed the previous Animal Challenge posts you can always visit our “zoo”:

- [Tiger-stripe Sign](https://123sonography.com/blog/ultrasound-animal-challenge-1-%E2%80%93-what-tiger-stripe-sign)
- [Snake Sign](https://123sonography.com/blog/ultrasound-animal-challenge-2-snake-sign)
- [Tail of a whale](https://123sonography.com/blog/ultrasound-animal-challenge-3-tail-of-whale)
- [Butterfly Sign](https://123sonography.com/blog/ultrasound-animal-challenge-4-butterfly-sign)