This group of muscles can equally well be called the muscles of respiration, as they are the ones that raise the ribs or otherwise enlarge the cavity of the thorax, and make respiration possible.

Muscle.

Origin.

Insertion.

Nerve-supply.

Diaphragm

From the ventral surface of the ensiform cartilage; from the ventral surfaces of the cartilages of the lower six ribs interdigitating with trans-versalis; by two crura from the fronts of the bodies of the upper lumbar vertebrae-three on the right side, two on the left-which decussate in front of the aorta; and from the arcuate ligaments, which are thickenings in the fascia covering psoas and quadratus lumborum

It is inserted into a large trilobed central tendon, which is developed in the muscle itself, and has no bony attachment

Phrenic