You can elect to use a 52-53-week tax year if you keep your books and records and report your income and expenses on that basis. If you make this election, your 52-53-week tax year must always end on the same day of the week.
Forced Inhalation. Involved in the mechanics of breathing; The muscles involved in this type of breathing are the diaphragm, the external intercostal muscles, and the accessory respiratory muscles (activated when respiration increases significantly).
During times of stress, injury or just difficulty breathing, other muscles will kick in to help out. These muscles are called accessory muscles and are not used during normal breathing. These muscles are the front of the neck (sternocleidomastoid), the chest pectorals muscles and the abdomen.