Each cerebral hemisphere is divided into four lobes; the frontal, parietal, temporal, and the occipital. The Frontal Lobe is the most anterior lobe of the brain.Its posterior boundary is the fissure of Rolando, or central sulcus, which separates it from the parietal lobe.Inferiorly, it is divided from the temporal lobe by the fissure of Sylvius which is also called the lateral fissure.he Frontal Lobe is the most anterior lobe of the brain. Its posterior boundary is the fissure of Rolando, or central sulcus, which separates it from the parietal lobe. Inferiorly, it is divided from the temporal lobe by the fissure of Sylvius which is also called the lateral fissure.
Main article: Thoracic diaphragm. The diaphragm is the major muscle responsible for breathing. It is a thin, dome-shaped muscle that separates the abdominal cavity from the thoracic cavity. During inhalation, the diaphragm contracts, so that its centre moves caudally (downward) and its edges move rostrally (upward).
Accessory muscles refers to muscles that assist, but do not play a primary role, in breathing. There is some controversy concerning which muscles may be considered accessory muscles of inhalation.