Diaphragm: Anatomy, Function, and Attachments
The diaphragm forms the floor of the rib cage. It is a very wide, flat muscle that separates the chest wall from the abdomen. It is shaped like a dome, whose base corresponds to the lower chest girth and is wider transversely than anteroposteriorly. The convexity is related to the thoracic viscera and the concavity with the abdominal viscera.
Besides the lower attachment, the plan will lower the chest up and down, tilt the steering wheel, and move front to back.
The diaphragmatic dome rises a bit more in the right hemithorax than on the left. In normal breathing, during inspiration, it stands at the 6th rib on the right and the 5th rib on the left. In a forced inspiration, it is at the level of the 5th rib on the right and the 4th on the left.
Attachments
In its central part, the diaphragm consists of a broad aponeurosis on the periphery of which the beams forming the fleshy muscle itself will leave. It is divided into two parts:
Aponeurotic Central Portion
This is called the phrenic center.
Phrenic Center
This is a tendon or fibrous sheet that is very strong, with a pearly appearance and a clover shape, with a central sheet and two side sheets. The previous page will be the middle portion of the phrenic center.
Fleshy Portion or Peripheral Muscle
The muscle bundles originate from the phrenic center and insert into the chest wall. These beams are divided into three groups:
Sternal Bundles
These start from the front of the middle layer, moving forward until reaching the base of the xiphoid process.
Lateral Bundles
These originate at the side of the core sheet and are longer in the side blades. They have a downward concave curved arrangement, ending at the inner side of the last six ribs.
Posterior Lumbar Bundles
These start from the back side of the phrenic center and have different insertions depending on the lumbar region of the psoas muscle box or spine. Ahead of the psoas, the fibers end in a fibrous arch. As for insertion into the spine, muscle fibers are grouped into two thick bundles that have been called pillars of the diaphragm on both sides of the midline.
The prop is the most voluminous and heads down to finish on the body of L2 or L 3. Next to this pillar is a smaller beam, which is a pillar attachment that ends in L 2. Between the prop and the accessory is a small vertical slit through which pass the higher and lower splenic nerves from the thoracic cavity to the abdomen.
As the prop is shorter and is down in front of the spine and ends in L 2, at its side, there is a fixture pillar surrounding a recess for the passage of nerves.
These two pillars, which are independent in their upper portion, descend and form two beams that intersect at the midline, causing two holes: one superior and anterior to the esophagus and the other bottom or back to the aorta.
Diaphragmatic Openings
The diaphragm has a series of holes that lead to anatomical structures of the chest to the abdominal cavity. The esophageal opening, at the top of the pillars, gives way to the esophagus and vagus nerve. The aortic orifice, located under and behind the esophagus, between the pillars, leads to the aorta and thoracic duct. Splenic holes are left and right between the pillar and the main accessory. The opening of the inferior vena cava is at the level of the phrenic center at the junction of the middle and right leaf, more or less quadrilateral, giving way to the inferior vena cava.
Innervation is by phrenic nerves, branches of the cervical plexus, and nerve bundles deep within the last six intercostal nerves.
The diaphragm is a muscle of inspiration. The top of the center is attached to the pericardium, and the phrenic is considered immobile. Each bundle of muscle has an arched shape with downward concavity. The ends of other beams, on the one hand, are joined in the periphery in the phrenic center, which is stationary, and on the other hand, are inserted into different parts of the chest wall. We will find a first curvature that tends to straighten. This produces an enlarged vertical diameter of the chest. Then the sacks act on the ribs by pulling them upward, increasing the transverse diameter of the chest about 3 times the diameter of the chest.