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.
When all the erector spinae muscles contract together, they extend or hyperextend the vertebral column. When only one side contracts, the trunk, neck or head move laterally toward the contracting side. The movement is accomplished because the articular facets of the vertebrae glide on each other.hen all the erector spinae muscles contract together, they extend or hyperextend the vertebral column. When only one side contracts, the trunk, neck or head move laterally toward the contracting side. The movement is accomplished because the articular facets of the vertebrae glide on each other.