muscular part of diaphragm

Structure: the muscular part is situated peripherally with fibers that converge radially on the central tendon. -> forms a continuous sheet; however for descriptive purposes divided into 3 parts: 1) Sternal part: -> consists of 2 muscular slips that attach to the posterior aspect of the xiphoid process: this part is not always present. 2) Costal part: -> consists of wide muscular slips that attach to the internal surfaces of the inferior 6 costal cartilages & their adjoining ribs on each side; the costal part forms the right & left domes. 3) Lumbar part: -> arise from 2 aponeurtic arches - the medial arcuate ligament, the lateral arcuate ligament & the 3 superior lumbar vertebrae -> forms right & left muscular crura of diaphragm that ascends to the central tendon

References

Clinically Oriented Anatomy, 4th edition, KL Moore & AF Dalley (eds), Lippincott Williams & Wilkins, Philadelphia, PA 1999.