A tip for newer groomers:
If you're combing or brushing on a dog's hair and you're pulling at it when you hit a snarl or matting, etc., aside from the damage you're likely doing to the hair, you're also possibly damaging every layer of the skin and also the connective tissue over the muscle which lies beneath the skin.
If you feel a "pop" or a "crack" come from the skin while you're tugging, you're pulling *way* too hard.
I saw on a message board someone mentioned this and I know they just didn't realize what they were doing, but this can be very serious and such an injury is easily avoidable.
Underneath the final layer of muscle there is an layer of tissue called the epimysium and then a thin layer of "fat", nerves and fine capillaries,etc.
Beneath that there is a very thin fascial membrane layer. Beneath that there is bone. If you're a meat eater then you know what the fascia looks like already. It lays in between each bundle of muscle and is translucent and color often giving off a prism effect when viewed under direct light. You will also see multiple layers of this type of tissue occurring around joints, ligaments and tendons in weight-bearing areas, and working as connective tissue.
When groomers tug too hard on matted ears and cause swelling of the ears, edema, or bleeding around the edges of the ears, that's exactly the same thing that happens.
In the photo below you can see just how many veins and capillaries run through that the ear leather of the dog. It's easy to see why extremities such as this bleed so badly when they are cut.
A hematoma and petechial hemorrhaging is what usually develops in the case of hearing that "pop' or 'crack" sound when you're pulling too hard with your tools. It's basically a forceful separation between the fascia and the cartilage layers of the ear which fills with fluid and blood. This is similar to a blood blister. This can happen from pulling on an ear too hard and causing breakage of the cartilage or can happen when the pet shakes its head excessively as well.
The matting around the edges of an ear will slowly pull the skin beneath it tight to where it's not receiving normal blood circulation and even nerve damage can happen.
When you cut back the matted hair, there is a sudden resurgence of blood circulation to the fine capillaries. This causes a tingling, itching or burning, which in turn will often cause the dog to shake its head.
This is when the fascia damage occurs, and when that separation between the layers of tissue is made, it fills with fluid. These hematomas or fluid filled sacks rarely will go down on their own if large enough; they usually have to have a needle aspiration done in order to remove the fluid and sometimes that has to be done repeatedly.
To help lessen the chance of developing a hematoma on a matted ear:
Warn the owner ahead of time that you have found the mats and they must be removed carefully in order to not damage the ear. Let them know that brushing them out if they're too tight is not an option. I have found with some owners if I part the hair and show them the mat, and even actually have them feel it, their buy-in comes quite easily. You may also at this time want them to sign a matted pet release form.
I recommend removing the matting of the ears first, so that you have as much time as possible with the dog in the salon to see what their response will be.
Carefully lay the ear flat in your hand and clip with a shorter blade outward towards the edge of the year in a fanning pattern so that you're working from the center of the ear outward towards the edge and never along it.
You can choose as needed to completely clip down the ear into a lamb style, or you can lift up the matted hair away from the edges of the ear and just shave around the perimeter & the underside of the ear as shown below. This will leave you with a fall of ear tassel hair that will still look pretty nice although it will be thin.
Remember to tell the owners in the case where you leave shorter hair on the ears with longer hair over the top that they must be diligent with brushing as the short hair beneath grows out in length. Shorter hair beneath longer hair in any terms of dematting will usually end up matted again as the shorter hair brushes against the longer strands and catches in it. As well, if you damage the ends of the short hair which is left behind, the damaged ends will be fragmented and very easily grab onto the hair around it; knotting it up. In most cases it is just best to get all the hair off the same length at one time.
~In other cases there can be a solid mat with free flowing hair all around it. In that case I will go to my thinner shear and take a couple of strokes through the mat at the perimeter of the ear as also shown below, and then carefully brush the rest of the ear out~
Once you've carefully clipped off the hair from the topside and the underside of the ear leather, I recommend elevating the ears up and over the back of the head and holding them there with a Happy Hoodie or something of the like that will hold them in place but not squeeze them too hard.
Elevating the ears above the level of the heart, and up over the top of the head will bring them to the highest point. This will help to slow the resurgence of blood flow and hopefully lessen the tingling.
You can also use vet wrap or other rolled guaze to achieve the same type of wrap, but with a bit more steps as shown below.
photo courtesy: https://basc.org.uk/gundogs/gundog-advice/bandaging-part-1/
Leave the ears up over the top of the head while you do whatever remaining pre-bath grooming which needs to be done. In the bath carefully remove the Happy Hoodie or wrap and be sure that you're using cool to tepid water to wash the years and do not scrub them too deeply. Remember the idea here is that you're working with irritated tissue and you don't want to exacerbate the problem.
Monitor the dog during the duration of its stay, and be sure to go over the issue with the owner when they return. I recommend showing them what you've done,explaining the precautions, and letting them know to keep an eye out at home for headshaking and scratching. I also recommend if they do find the dog scratching at their ears, that they let me know right away.
Just some insight into what happens on the skin in these situations and why it's so important not to pull too hard just in order to leave a little longer hair. Never cause harm or pain in order to save hair. :)