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).
More about the breathing muscles. The left side of figure 1 shows the muscles involved with taking a breath in (inspiration). As previously mentioned, the diaphragm is the main muscle responsible for this.There are also muscles of the neck, which are supplied by the cervical nerves, which assist breathing in. The rib muscles or intercostals also work in co-operation with the diaphragm.n general breathing out is passive and requires no muscle effort, but occasionally we need to exhale forcefully, for example when coughing, throat clearing, shouting or blowing our nose. It is during these times of forceful breathing out that the stomach and rib (intercostal) muscles are used.