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).
Home > Muscular System > Muscles of the Chest and Upper Back > Intercostal Muscles. The intercostal muscles are a group of 22 pairs of tiny muscles found between the ribs. These muscles play a vital role in the movement of the chest during breathing. They also help to solidify the thoracic region and protect the lungs.