Journal of Ultrasound

, Volume 21, Issue 4, pp 287–291 | Cite as

Ultrasound morphology of cecal appendix in pet rabbits

  • Annalisa NicolettiEmail author
  • Nicola Di Girolamo
  • Ulrich Zeyen
  • Paolo Selleri
  • Marco Masi
  • Paolo Fonti
Original Article



Cecal appendix is the terminal part of cecum and is characteristic of rabbit, among domestic animals. The purpose of this work is to evaluate its morphology upon ultrasound.


A prospective study was planned for the duration of approximately 1 year. Rabbits presented in the study period for abdominal ultrasound with no clinically evident alterations of the gastrointestinal tract were eligible for inclusion in the study. Abdominal ultrasound was performed under manual restrain with a high frequency linear probe (8–18 MHz).


Cecal appendix was visualized in 40/42 rabbits (95.2%) with median or left paramedian views. The wall appeared multilayered in accordance with normal bowel anatomy, and the luminal content showed in all cases an alimentary pattern. Measurement of appendix wall thickness (AWT) was possible in all 40 rabbits in which the appendix was visualized while measurement of the appendix diameter (AD) was possible in 39 rabbits. Reference intervals for AWT were 1.1–2.1 mm, and for AD were 3.9–8.8 mm. There was a negative correlation between age and AWT (r = − 0.35, P = 0.027) and a moderate positive correlation between AWT and AD (r = 0.71, P < 0.001).


Cecal appendix is recognizable via ultrasound in the vast majority of rabbits. We describe the normal morphological aspect of the appendix and we provide reference intervals for wall thickness and diameter of the appendix, in order to aid in the diagnosis of disorders of the appendix. The negative correlation between age and AWT indicates lower values of AWT associated with increasing age that could represent the physiological decrease in the immunitary function of the appendix in aged rabbits.


Appendix Rabbit, ultrasound Appendicitis Gastrointestinal stasis 



L’appendice cecale rappresenta la parte terminale del cieco e tra gli animali domestici è caratteristica del coniglio. Lo scopo di questo lavoro è di valutare la sua morfologia in ecografia.


È stato pianificato uno studio prospettico della durata di circa 1 anno. I conigli presentati per ecografia addominale nel periodo dello studio e senza alterazioni cliniche evidenti dell’apparato gastro-enterico sono stati inclusi. L’ecografia addominale è stata effettuata tramite contenimento manuale utilizzando una sonda lineare ad elevata frequenza (8-18 MHz).


L’appendice cecale è stata visualizzata in 40/42 (95,2%) animali utilizzando scansioni mediane e paramediane sinistre. La parete appare pluristratificata in accordo con la normale anatomia intestinale ed il contenuto luminale è rappresentato in tutti i casi da pattern alimentare. La misurazione dell’AWT è stata possibile in tutti i 40 conigli in cui l’appendice è stata visualizzata mentre la misurazione dell’AD è stata possibile in 39 conigli. Gli intervalli di riferimento per AWT sono stati di 1,1-2,1 mm e per l’AD di 3,9-8,8 mm. È stata evidenziata una correlazione negativa tra l’età e AWT (r = -0,35, P = 0,027) ed una moderata correlazione positiva tra AWT e AD (r = 0,71, P < 0,001).


L’appendice cecale è un organo riconoscibile attraverso l’ecografia nella maggior parte dei conigli. Descriviamo l’aspetto morfologico dell’appendice e forniamo parametri di riferimento per lo spessore parietale e il diametro dell’appendice, con lo scopo di facilitare la diagnosi delle patologie dell’appendice. La correlazione negativa tra l’età e AWT indica valori più bassi di AWT associati all’aumento dell’età, che potrebbe rappresentare la diminuzione della funzione immunitaria dell’appendice nei conigli adulti.


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted. This article does not contain any studies with human participants performed by any of the authors.

Human and animal rights statement

All the described animal-related procedures were conducted according to the Directive 2010/63/EU of the European Parliament and of the Council of September 22nd 2010 on the protection of animals used for scientific purposes (Art.1, Par.1, letter “b”), which does not require any approval by the competent Authorities.

Informed consent

Informed consent was obtained from all individual participants included in the study.


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Copyright information

© Società Italiana di Ultrasonologia in Medicina e Biologia (SIUMB) 2018

Authors and Affiliations

  1. 1.Diagnostica per immagini, Centro Veterinario SpecialisticoRomeItaly
  2. 2.Tai Wai Small Animal and Exotic HospitalSha TinHong Kong
  3. 3.Clinica per animali Esotici, Centro Veterinario SpecialisticoRomeItaly

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