How Do Dogs’ Noses Work?

April 30, 2014
dog nose

Photo: Mark Watson

Dog noses have been in the news lately. Not just because dogs can sniff out a cracker crumb between the sofa cushions or because dogs smell the new bag of bacon strips through the closed pantry door, but because dog noses are being put to work in a very serious way.

For hundreds of years, dogs, like the Bloodhound, have been employed as search and rescue workers to find missing people after being given a whiff of the missing person’s clothing. Now medical sniffer dogs are being trained to diagnose cancer, detect low blood sugar and predict an epileptic seizure. Several features of dogs’ noses make their sense of smell better than our own.

Bigger is Better
CT scan of a dog's noseCompared to the size of their face, dogs have big noses – well most of them do. And, a bigger nose means they have more area for smell receptors. Inside the nasal passages, the dog has ruffles of tissue called turbinates which increase the surface area that accommodates their smell receptors. Compared to our 5 million, dogs have 300 million receptors on their nasal turbinates. The CT scan on the right shows the ruffles of tissue inside a dog’s nasal passages, and if you watch our video, you can see what turbinates actually look like when a rhinoscopy (nasal endoscopy) is performed.

Bidirectional Smelling
Take a look at your dog’s nose. Notice the nostrils have slits on the sides and the openings are a bit more to the side than directly out front. These features give your dog’s sense of smell directionality. New smells come in from the front and old smells go out through the side slits with exhalation, allowing new smells to constantly bathe the smell receptors.

More Brain Power
Because dogs’ sense of smell is their most highly developed sense, they devote an enormous amount of brain power to the act of smelling. Compared to our rudimentary sense of smell, there is 40 times more canine brain power dedicated to smelling, which allows dogs to differentiate 30,000 to 100,000 different smells. Our repertoire of smells is only 4,000 to 10,000 different smells.

For more about these scent-sitive dogs, watch my interview on Fox5 News with Liz Dahlem.

Blueberry: An AMC Living Legend

April 12, 2012

Blueberry in a stabilizing neck wrap. Photo: Dr. Joshua Gehrke

Blueberry, a 2 year old fawn and white Chihuahua, was rushed to The Animal Medical Center one night after having what his family thought might be a seizure. When he arrived at The AMC and was under observation by the ER staff, Blueberry had another terrible episode of pain which appeared to be originating from his neck. The astute observation of excruciating neck pain coupled with weakness in all four legs helped the ER staff to formulate a short list of possible diagnoses for further investigation.

Drs. John McCue and Joshua Gehrke and The AMC’s Neurology Service consulted on Blueberry’s case and confirmed the list of possible diagnoses: a disk extrusion in the neck pressing on the spinal cord, cranial occipital malformation syndrome or an atlantoaxial luxation. Later that same day, under general anesthesia, an MRI was performed to determine the diagnosis.

Using The AMC’s 1.5 Tesla MRI, the strongest magnet in use for veterinary patients in the New York Metropolitan area, The AMC’s radiologist confirmed one of the potential diagnoses, atlantoaxial luxation, a common condition of toy breed dogs. In addition, The AMC radiologist also noted that Blueberry’s spinal cord had kinked, resulting in a hemorrhage in the spinal cord.

Immediately, Blueberry was wrapped in a stabilizing neck splint and prescribed cage rest until surgery could be performed. The AMC neurology service was unsatisfied with the standard techniques often used to repair the alignment of the first and second neck bones. Current techniques were fraught with potential complications and Blueberry’s small size made many of these risky. A dorsal (top) stabilization was considered the best approach. Stabilizing the bones from the top requires a wire be passed over the spinal cord and anchored into the spinous process of the second cervical bone; sounds tricky and it is.

Radiograph taken after placement of Kishigami device (fishhook-like image). Blueberry's head is on left, neck to right.

For Blueberry, the Neurology Service recommended a state of the art repair technique using the Kishigami atlantoaxial tension band. The technique was developed 25 years ago by a Japanese veterinarian, but the procedure was not widely utilized. In 2010, a group of French veterinarians published the results of using the Kishigami technique in eight toy breed dogs and The AMC Neurology team was anxious to use this improved procedure in a dog with an atlantoaxial luxation. To repair Blueberry’s neck, the special device had to be purchased and shipped from Spain since a Spanish company currently is the only manufacturer of this device. Due to difficulties in purchase and transport of the Kishigami device, Blueberry waited one month after his diagnosis for surgery wrapped in a neck stabilizing bandage resembling a cocoon to prevent further damage to his brain stem.

At his three month post-operative check, Blueberry was given a clean bill of health by Dr. McCue. “Blueberry is completely back to normal.” Dr. McCue told me. “Even better, the Kishigami device holds Blueberry’s first and second cervical vertebra in perfect stable alignment and he should continue to do well on a long term basis.” Based on the success Blueberry enjoys with his Kishigami device, a box of the devices are sterilized and ready to go so no dog will have to wait for this repair again.

Blueberry will be honored as an AMC Living Legend at the Fourth Annual Living Legends Luncheon on May 9th. Blueberry’s is being recognized for his patience during a month long hospitalization and for his pioneering spirit in being the first AMC patient treated with the Kishigami technique.

Could My Pet Die from Epilepsy?

March 31, 2011

Learning a Lesson from Knut the Polar Bear

I have loved zoos since I was a child when my mother used to take me to the Como Park Zoo in St. Paul, Minnesota to see the Sammy the Seal show. I am a regular at the Central Park Zoo polar bear enclosure here in Manhattan.

Knut the polar bear

The death last week of 4 year old Knut, the celebrity polar bear, at the Berlin Zoo was exceptionally sad. On Monday, a Reuters news feed reported the cause of death as epilepsy.

Epilepsy is a caused by abnormal function of the brain. In its worst form, epilepsy causes loss of consciousness, recumbancy and generalized, uncontrolled movement of the body. Epilepsy is not the only cause of seizures, which can result from trauma, infection or tumor in the brain, or a low blood sugar depriving the brain of glucose for energy.

Several features of Knut’s case are apropos to our dog and cat companions who suffer from epilepsy. The Reuters article says Knut inherited epilepsy from his father, Lars. Epilepsy also runs in some dog breeds: border collies, Dalmatians, Siberian Huskies, German shepherds, golden retrievers and St. Bernards, who tend to have high frequency seizures. Some breeds seem to be less likely to have epilepsy such as the Doberman pinscher, Rottweiler and Newfoundland. Epilepsy is generally an uncommon diagnosis in cats.

A prolonged seizure, also called status epilepticus, demands a trip to the emergency room. Seizures occurring in rapid succession, also called cluster seizures, require an emergency room visit. There, testing will begin to determine if epilepsy is the cause of the seizure. If the seizures are recurrent or persistent, antiseizure medication will likely be administered. Like in the case of Knut, a severe or prolonged seizure can sometimes result in death if treatment is not immediately administered.

A word to the wise pet owner: know where your closest animal ER is and don’t hesitate to go — it just might save your pet’s life.


This may also be found in the “Tales from the Pet Clinic” blog on

For over a century, The Animal Medical Center has been a national leader in animal health care, known for its expertise, innovation and success in providing routine, specialty and emergency medical care for companion animals. Thanks in part to the enduring generosity of donors, The AMC is also known for its outstanding teaching, research and compassionate community funds. Please help us to continue these efforts. Send your contribution to: The Animal Medical Center, 510 East 62nd Street, New York, NY 10065. For more information, visit To make an appointment, please call 212.838.7053.


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