A 55 y.o. woman who has had sinus surgery comes in for epistaxis. When you scope her you see what is pictured below.

 what is it?

what is it?

This is a remnant of our reptilian  ancestry called the vomeronasal organ(VNO)  or Jacobson’s organ. It is auxillary olfactory sense organ useful for detecting pheromones.  It was discovered in 1732 by Frederick Ruysch and later rediscovered by Ludwig Jacobson in 1813. In humans the organ, which is found along the nasal septum,  regresses during fetal development but can be seen in about 25% of adults.  Image below is from Chapter 41. Physiology of olfaction. DA Leopold and EH Holbrook. Cummings Otolaryngology. 5th edition.  

 close up of the Vomeronasal organ on the septum

close up of the Vomeronasal organ on the septum

The organ has been widely studied in animals. The vomeronasal organ connects to the olfactory bulb and eventually to the amygdala and hypothalamus. This is extremely important  in reproduction and social behavior in animals since it triggers release of hormones needed for mating. The organ can detect both odorants and nonvolatile proteins such as urinary tract proteins. This explains why your dog is constantly sniffing urine from other dogs.

VNO snake.JPG

Snakes use this organ to sense prey, sticking out their tongue to gather scents and then touching it to the VNO. Elephants transfer scents from the tip of their trunks to the VNO connection which is located in the roof of their mouths. Cattle and pigs also have a  connection to the VNO  in the roof of their mouths behind their teeth and they often exhibit the Flehmen response in response to an odor.  They lift their heads , wrinkle their noses and cease to breathe momentarily allowing the odor to go through the mouth into the VNO.

 tiger catching a scent

tiger catching a scent

Our patient was being scoped  for possible bleeding after sinus surgery.  Her vomeronasal organ is just a vestigial remnant  of evolution. It does not function in humans.  Our patient had no nasal bleeding and was found to have an ulcer.

Jacobson L Anatomisk Beskrivelse over et nyt Organ I huusdyrenes naese veternaer-selskapets skrifter 1813. 2, 209-246.

Stoyanov G, Moneva K, sapundzhiev N, Tonchev AB. The vomeronasal organ incidence in a bulgarian population. 2016. The Journal of Laryngology & Otology. 130:1-4.

Trotier D. Vomeronasal organ and human pheromones. Annales francaises et de Pathologie Cervico-faciales. 2010. Vol 128 (4)222-28