Tires â Retreading is less expensive than new tires and is a large portion of this cost. Although mere pennies per mile, an average tire can cost over $250 and annual tire expenses can exceed $4,000 ($0.03 per mile), enough to purchase 16 new tires annually, but still not enough to replace every tire of an 18-wheeler.
With the head in a forward position, a passive tensile force is created in the hyoid muscles resulting in hyoid muscle tension, causing the mandible to be depressed and translated posteriorly. The patient is therefore forced to contract the temporalis and masseter muscles to keep the mouth closed.
According to researchers every inch the head moves forward of the shoulders, weight is elevated by 10 pounds. As a result, a 12 pound head held 3 inches forward, forces the cervical extensors (semispinalis, splenii, longissimus, upper traps, etc.) to isometrically hold up 42 pounds against the unrelenting force of gravity. And we are amazed that so many clients present with degenerative disc disease, head pain and TMJ.