Jaw series- causes of a tight Jaw
The Digastric Muscle
Have you ever experienced discomfort when swallowing or a sensation of a “lump in the throat”? Do you experience jaw pain? Does your jaw pull to one side on opening? Do you have a tight jaw and tongue that impedes freedom of your voice throughout your range? You may have tight digastric muscles.
The digastric muscle is one of 4 suprahyoid muscles (along with the stylohyoid, geniohyoid and mylohyoid muscles) that elevate the hyoid bone (the horseshoe-shaped bone you can see in this image). They are important for control of the oesophagus and pharynx during speaking, singing and swallowing. The hyoid bone elevates to help place the epiglottis over our windpipe when we swallow so that food or liquid does not enter our lungs.
The digastric muscle has two sections or “bellies”. The back section attaches from the mastoid process (just under your ear lobe) to the hyoid bone and lifts the larynx and hyoid when swallowing. The front portion extends from under the chin to the hyoid and along with the Lateral Pterygoid muscle helps to drop the jaw quickly. Unfortunately if you have tight jaw muscles the front portion of the digastric muscles cannot depress the jaw and instead changes its action to elevate the larynx.
For singers this means the optimal high soft palate and neutral or slightly depressed larynx used in classical singing is unachievable. It also can restrict access to the top of their range.
Tight digastric muscles can cause or contribute to:
• A sensation of a lump in the throat when swallowing
• A chronically protracted jaw (a jaw that is pulled back) and impeded
• A forward head posture
• A narrowing of the airways when sleeping contributing to sleep apnoea
• TMJ pain, jaw tracking incorrectly and ‘clicking’ of the jaw
The digastric can become overly tight when you have a tight Masseter muscle (possibly from grinding your teeth when asleep); or you constantly breathe through your mouth due to sinus issues or a deviated septum.
Treatment for tight digastric muscles:
Massage, trigger point work, and myofascial release can be particularly effective to help release the digastric muscles. Other muscles such as the masticators- the masseter and temporalis need to be released also. I also look at surrounding muscles such as the pterygoids, infra and suprahyoids. This is to ensure the whole area is functioning well.
Singing exercises that train the muscles that raise the larynx to relax during phonation will also help alleviate the problem. Best results are achieved when releasing the muscles prior to retaining singing technique.