many of those legends have been passed down without rigorous verification criteria, and bizarre as it might seem, there exist records of sword blade tests made on human bodies. Continuing our anatomical reasoning, passing the skull we reach the sternum. In the past they used to say that the sternum would retain the sword if the cut was wrongly made, so, in order to simulate this technique, the Kiriotoshi was trained in a species of bamboo called " Moso ", which would respond the beginning of the exercise. As soon as the student could traverse the entire bamboo tip, he should get into a more advanced test on the sternum of an ox. But this hasn ' t been not fully confirmed.
Returning to the sternum, at this time the hara is lightly tensed and it will fully contract after the cut passes through the sternum bone, to relax only at the end of the movement.
The thorax is formed by bones which together constitute the ribcage. The ribcage is formed by the collaboration of the dorsal or thoracic vertebrae on the back; one odd bone, the sternum, in the front; and finally the ribs, that lie between the sternum and the vertebrae.
The sternum is a median flat bone that resembles a Roman dagger, and is composed of three well-defined elements: an upper part called manubrium; an intermediate zone, called the body; and a lower, smaller part called xiphoid process or xiphoid appendix. The manubrium forms with the rest of the bone an angle known as Angle of Luys, which is very sharp and evident when the chest is poorly developed, or in the case of people with delicate constitution. At the edges of the manubrium and the body are inserted the collarbone and the first seven ribs. The upper edge presents a small pit, very evident in thin individuals: the jugular notch.
In order to cut through the sternum, the right hand which is placed before the sword must form an angle for all the weight to be centrated in the part ahead the Tsuka- the handle. Thus, the Ki will flow directly to the Kisaki- the tip of the sword.
In regard to the blade being trapped by the bone, it becomes necessary to further explain the anatomy of the area. Humans have 24 ribs( 12 pairs) that bind the sternum to the spine, where the dorsal vertebrae( twelve in number) are inserted; ribs are long curved bones, bow-shaped, and its position is not horizontal; starting from the thoracic vertebrae, the ribs become progressively oblique downwards.
Their forelimb( sternal) is lower than the rear part( vertebral). Ribs articulate with the thoracic vertebrae in two ways: there is a joint with the body and another one with the transverse process. The rib forelimbs are grafted to the sternum with the interposition of a cartilaginous segment or costal cartilage. The first seven pairs of ribs are called true ribs; in these, the rib cartilage directly inserts in the sternum. By contrast, the eighth, ninth and tenth ribs do not end in the sternum, but in the lower edge of the rib which is located above. The eleventh and the twelfth ribs are not linked to the sternum, but are free and are therefore called floating ribs.
Along the bottom edge of the ribs lie the intercostal vessels and nerves. Between one rib and another, that is, in the intercostal spaces, there are muscles.
The first rib presents a particular shape; while other ribs have a outer face and an inner face, the first rib is flattened from top to bottom and therefore has an upper face and a lower face. On the upper face there is a small projection, the Tubercle of Lisfranc, important because close to it lies the subclavian artery. The tubercule is thus an orientation point for finding the subclavian, and is useful when you need to tie or suture this artery.
Thus we have the elements that combine to form the rib cage. Let ' s observe now the rib cage as a whole. I has the shape of the trunk of a cone, with the smaller base upwards. The outer surface of the rib cage presents subsequently a projection that runs from top to bottom and is due to the series of vertebral spinous processes. Running alongside there are two vertebral chain of muscles that serve to move the spine.
The rib cage is open in the upper part, towards the neck, to give way to the esophagus, the trachea and the large blood vessels; on the contrary, the lower part is shut by a dome-shaped muscle: the diaphragm. The interior of the rib cage forms the thoracic cavity, laterally occupied by the lungs, and in the center part by the heart and the aorta, the largest artery in the human body, which, after describing an arch descends toward the abdomen through the diaphragm. The thoracic cavity is previously crossed by the trachea, which is divided into two bronchi, which are directed to the respective lungs. Subsequently, the cavity is traversed by the esophagus, which also penetrates into the abdomen after passing through the diaphragm.
The thoracic cavity contains, in part, the two vena cava and the thoracic duct. The shape of the chest changes with the age and the physiological conditions of the individual and differs depending on the sex. In men chest has a conical form, whilst in women reminds the rounded shape of a barrel. This counts on the different type of breathing: women usually breathe with the thorax, while men ' s breathing is abdominal. That diversity has also its own purpose and utility: in women, abdominal breathing would be highly affected during pregnancies.
The movements of the rib cage during breathing are: in inspiration, when chest expands, the ribs lift up and lengthen( more in women than in men). In the espiration, when the chest restricts, the ribs descend and come together. Thus, the three diameters of the rib cage increased and decreased alternately so that the lungs, that passively follow the movements of the rib cage, first dilate filling up with air, but thereupon contract, releasing part of the air locked.
To avoid the sword from being locked, the movement of the left hand should be ascending so that, in the case that the sword gets trapped, it might offer the space conditions for the blade to be rotated and removed.
And finally, an anatomical analysis of the cut: cutting the ilium is something surrealistic. It happens that at that time the movement itself of the Kenshi ' s body provides a " ma-ai ", so that when kneeling, he moves slightly away cutting scarcely the gut and bladder. It is believed to be a natural and consequent movement according to the technique form presented. At this time the hara should be totally relaxed, along with the arms, that prepare for the new contraction required by the next move, in case the Kiriotoshi doesn ' t succeed. The energy of the body should be deposited in the legs that rest on the ground, supporting on one knee. Otherwise, the hara will become the balance point extinguishing the remaining energy.
In this way we understand that many of the legends attributed to this movement correspond, in short, to a strategical way of offering the body weight to a long and deep cutting technique.
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