Head halters are often used as a method of assisting with dog walking and controlling a dog while walking.  But if we simply read the name – it is a head halter or the halter for the head.  When the dog pulls ahead during a walk, the HEAD is turned back toward the person walking the dog, preventing them from getting further ahead.  It is designed to be a training tool, but not a permanent fixture on the dog.  I have often seen these devices as a permanent structure, and I am often alarmed at a permanent loss of hair on the nose where the halter sits.  This is certainly an indication the tool has been overused.

When we look at the biomechanics of the cervical spine and the dogs’ head, we can see there are potential forces on the upper and lower cervical spine or the neck.

Head halters
Image of C1 or the Wings of the Atlas
Image of the relationship of the head to the upper cervical spine. My thumb is on C2 and my index finger is supporting C1.

The dog’s neck is comprised of seven vertebrae or segments.  The upper cervical spine, C1 and C2, and the lower cervical spine, C6 and C7, are the most mobile. The head sits on the atlas or the first cervical vertebrae. The next vertebrae, C2, assists with rotation of the neck.  This is the area often stressed and injured with head halters.  The area is simply not able to withstand the constant stress and pressure of a head halter.

When the dog pulls on the harness, or the harness is pulled on, it forces the neck to tuck in.  This creates a sheering force on the cervical spine – specifically where the upper cervical spine is.  This is often the headache zone in people. Repetitive stress on this area may cause pain similar to a headache in people, eye squinting, aggression related to pain, and compensations in the rest of the body.

The head halter will cause the dog to stop pulling, but there will be repeated stress on the upper cervical region.

The below images demonstrate where the gentle leader falls on the head.  The yellow tape on the back of the head illustrates where the majority of the forces are placed.  The yellow area falls on the upper cervical spine.

While the head halter may be used as a temporary training tool to discourage pulling, the chances of injuring the dog should be realized.  Utilizing this tool for a prolonged period of time, or over a few days, most likely will have negative implications on the cervical spine.  The goal of the tool is to teach the dog not to pull, and then carry over with other training methods.  Prolonged use may be connected with behavioral issues related to pain such as aggression, cervical pain, and alterations in movement.