¶ … Skeletal Muscle
Academic Institution
The most important skeletal muscle in the human body is the diaphragm. The diaphragm is the large dome shaped muscle that functions as the main muscle involved in respiration (Drake, Vogl, & Mitchell, 2009; Moore, 2014). Of course the reason that this muscle is the most important skeletal muscle is that it is involved in breathing and without oxygen the organism would perish in only a few moments. Thus, before any other muscle or organ can perform for any length of time they need to receive oxygen.
The lungs are surrounded by the rib cage with the diaphragm forming the floor of the thoracic cavity. The entire diaphragm separates the chest cavity (thoracic cavity) from the abdominal cavity. There are openings in the diaphragm that allow the descending aorta, inferior vena cava, the esophagus, and the phrenic and vagus nerves to pass between the thoracic cavity and the abdominal cavity (Drake et al., 2009). Anatomists generally divide the diaphragm into two parts: (1) the peripheral muscle, and (2) the central tendon (Drake et al., 2009).
The peripheral muscle of the diaphragm is composed of a large number of radial muscle fibers that originate...
The costal region of the peripheral muscle is composed of several segments of muscle that originate on the internal surface of the inferior six ribs and the costal cartilages. The sternal area of the peripheral muscle is composed of two muscular portions that attach to the posterior portion of the xiphoid process. The lumbar region begins on the lumbar vertebrae with two tendinous pillars known as the musculotendinous crura (Moore, 2014). These wrap around the aorta as it passes through the diaphragm and form the aortic hiatus (Drake et al., 2009). The flat aponeurosis central tendon is composed of dense collagen fibers and is anterior to the vault formed by the muscle (Drake et al., 2009).
When the muscles of the diaphragm contract they pull the central tendon into the abdominal cavity while at the same time the external intercostals muscles located between the ribs elevate the anterior portion of the ribcage enlarging the thorax and allowing air to inflate the lungs (Moore, 2014). When the person exhales the rib cage returns to its resting position, the diaphragm relaxes, and air in the lungs is…
