sternum or breastbone is a flat bone located in the center of the chest. It connects to the ribs through the cartilage and forms the front of the rib, thus helping to protect the heart, lungs, and major blood vessels from injury. Roughly shaped like a tie, it is one of the largest and longest flat bones of the body. Its three areas are the manubrium, body, and process of xifoideus. The word "sternum" comes from the Greek word ???????, meaning "chest".
Video Sternum
Structure
Chest bone is a long, flat bone, forming the center of the front of the chest. The top of the sternum supports the clavicle (collarbone) and the ends join the costal cartilage of the first seven ribs. The inner surface of the sternum is also a sternopericardial ligament attachment. The upper part is also connected to the sternocleidomastoid muscle. Sternum consists of three main sections, listed from above:
- Manubrium
- Contents
- Xiphoid Process
In its natural position, the sternum tilts downward, downward and forward. It's slightly convex in front and sunken in the back; The area above, shaped like a "T", becomes narrowed at the point where the manubrium joins the body, then again extends slightly down the center of the body, and then narrows to the lower limb. In adults, the breastbone averages about 17 cm, longer in men than in women.
Manubrium
Manubrium (Latin: handle ) is the top of the broad sternum. It has a rectangular shape, narrowed from the top, which gives it four bounds. The suprasternal position (jugular notch) is located in the center of the uppermost part of the manubrium. This notch can be felt between two clavicles. On both sides this notch is a right and left clavicle notch.
Manubrium joins the sternum, clavicle and cartilage bodies of the first pair of ribs. The inferior, oval and rough border, covered with a thin layer of cartilage for articulation with the body. Each lateral border is marked above by depression for the first cost cartilage, and below by a small side, which, in the same aspect at the upper corners of the body, forms a notch for the acceptance of the second ribcell cartilage of the ribs. Between depression for the first cost cartilages and the sake-facet for the latter is a narrow, curved edge, which tilts from top to bottom toward the middle. Also, the superior sternopericardial ligament attaches the pericardium to the posterior side of the manubrium.
Body
The body, or gladiolus, is the longest part. It is flat and is considered to have only front and rear surfaces. It is flat in front, directed upward and forward, and is marked by three transverse protrusions that cross the opposite bone of the third, fourth, and fifth articular depressions. The main pector attached to it on both sides. At the intersection of the third and fourth body parts are sometimes seen orifisium, foramen sternum, with different sizes and shapes. The posterior surface, slightly concave, is also characterized by three transverse lines, less distinct, but from the front; from the bottom, on both sides, the transversus thoracis takes its origin.
The sternal angle lies at the point where the body joins the manubrium. The sternal angle can be felt at the point where the sternum project is furthest forward. However, in some people the sternal angle is concave or round. During physical examination, the angle of the sternum is a useful landmark because the second rib is attached here.
Each outer border, at the angle of its superior, has a small side, which with a similar side to the manubrium, forms a cavity for the second rib; below are the four corners of the depression that receive the cartilage of the third, fourth, fifth, and sixth ribs. The inferior angle has a small side, which, with one corresponding to the xifoid process, forms a grooves for the seventh rib cartilage. This articular depression is separated by a series of curved interarticular intervals, which decrease in length from top to bottom, and corresponds to the intercostal space. Most of the cartilage, including the right rib, articulates with the sternum at the junction line of its primitive component segment. This is evident in some other vertebrates, where the parts of the bone stay apart for longer.
The upper border is oval and articulated with manubrium, at the sternal angle. Narrow bottom border, and articulate with xifoid process.
Xiphoid Process
Located at the inferior end of the sternum is a tapered xiphoid process. Improper compression of the chest during cardiopulmonary resuscitation can cause the xifoid process to stop, pushing it to the liver which can cause fatal bleeding.
The sternum consists of a very vascular tissue, covered by a thick layer of the thickest compact bone in the manubrium between the articular side for the clavicle. The inferior sternopericardial ligament attaches the pericardium to the posterior xiphoid process.
Superficial effect
The inner triangle, the surface pendant of the xhipoid process, of the pectoralis major, the rectus abdominis and the sternum, forms the sternum fossa, calix , and in the rectum fossae of the tendon knot sequence.
Joints
Cartilage of the upper seven ribs joins the sternum in the sternocostal joint. Right and left clavicle needles articulate with right and left clavicle, respectively. The rib cartilages of the second ribs articulate with the sternum at the angle of the sternum making it easy to find.
The transverse thoracic muscle is innervated by one of the intercostal nerves and attached to the posterior surface of the lower sternum. The inferior attachment is the internal surface of the two to six rib cartilages and serves to suppress the ribs.
Development
The sternum develops from two cartilage stems one on the left and one on the right, connected to the ribs of the ribs on each side. These two bars are fused together along the center to form a cartilage cartilage of six centers: one for manubrium, four for the body, and one for the xifoid process.
The ossification center appears within the interval between articular depression for the costal cartilage, in the following order: in the manubrium and first part of the body, during the sixth month of fetal life; in the second and third parts of the body, during the seventh month of fetal life; in the fourth part, during the first year after birth; and in the xifoid process, between the fifth and eighteenth years.
Centers make their appearance at the top of the segment, and proceed gradually down. For this it can be added to the occasional existence of two small central episodes, which make their appearance one on either side of the jugular notch; they may be the remains of episternal bones of monotremes and lizards.
Sometimes some segments are formed from more than one center, the number and position varies [Fig. 6]. Thus, the first work may have two, three, or even six centers.
When two are present, they are generally located above the other, the upper one is the greater; the second piece rarely has more than one; the third, fourth, and fifth chunks are often formed from two laterally laid centers, irregular unity which explain the rarer occurrence of the sternal foramen [Fig. 7], or vertical fissures that sometimes bypass the bone part which is a malformation known as the fissura sterni; This condition is further described in the way in which cartilage cartilage is formed.
More rarely the upper end of the sternum can be divided by a gap. The unity of various centers of the body begins about puberty, and continues from the bottom up [Fig. 5]; at the age of twenty-five they all united.
The xifoid process can become joined to the body before the age of thirty, but this happens more often after forty; on the other hand, sometimes remain united in old age. In later life the manubrium sometimes joins the body by the bone. When this happens, however, bone tissue is generally only superficial, the central part of the remaining cartilage intervention is not absorbed.
At the beginning of life, the sternum's body is divided into four segments, not three, called sternebrae (single: sternebra ).
Maps Sternum
Clinical interests
Bone marrow biopsy
Because the sternum contains bone marrow, it is sometimes used as a place for bone marrow biopsy. In particular, patients with high BMI (obese or overweight) may present with excess tissue that makes access to traditional marrow biopsy sites such as pelvis difficult.
Stern Opening
A rare congenital disorder of the sternum sometimes referred to as anatomic variation is the sternal foramen, a single round hole in the sternum that is present at birth and is usually not centered to the right or left, usually formed on the 2nd, 3rd, and 4th segments of the breastbone. The congenital sternum foramen can often be misconstrued as a bullet hole. They are usually asymptomatic but can be problematic if acupuncture in the area is intended.
Fracture
Sternal fractures are somewhat rare. They may result from trauma, such as when the driver's chest is forced into the car's steering column in a car accident. A sternal fracture is usually a comminuted fracture. The most common place of sternal fractures is at the angle of the sternum. Several studies have revealed that repeated blows or continuous blows, sometimes called "bone stroke", to the sternal region also cause a cracked sternum. They are known to have occurred in contact sports such as rugby and football. Sternal fractures are often associated with underlying injuries such as pulmonary contusions, or bruised lung tissue.
Dislocation
Manubriosual dislocation is rare and is usually caused by severe trauma. This may also be the result of minor trauma in which there are arthritis prerequisites.
Sternotomi
The breastbone is sometimes cut open (the median sternotomi) to gain access to the thoracic contents when performing cardiothoracic surgery.
Resection
The abdomen can be completely removed (resected) as part of a radical operation, usually for surgical treat malignancy, either with or without mediastinal lymphadenectomy (Current Prosedural Terminology codes # 21632 and # 21630, respectively).
Bifid sternum or sternal gap
Bifid sternum is a very rare congenital aberration caused by failure of sternum fusion. This condition produces a sternal cleft that can be observed at birth without any symptoms.
Other animals
The sternum, in the vertebrate anatomy, is a flat bone located at the front of the middle of the rib cage. It comes from the endokhondral. This may first evolve in early tetrapods as an extension of the bodice of the chest; it is not found in fish. In amphibians and reptiles are usually shaped, often consisting of cartilage. Not in turtles and snakes. In birds it is a relatively large bone and usually holds an enormous stomach forward in which the flight muscles are attached. Only in mammals, the sternum has an elongated and segmented form seen in humans.
Arthropoda
In arachnids, the sternum is the ventral (bottom) portion of the cephalothorax. It consists of a single sclerite located between the coxa, opposite to the carapace.
Etymology
English sternum is a translation of the Ancient Greek ??????? , sternon . The Greek author Homer used the term ??????? to refer to men's chest . Glossary ?????? , stithos is used by Homer to refer to both sex chests . Greek doctor Hippocrates used ??????? to refer to chest , and ?????? to breastbone . Greek physician, Galen is the first to use ??????? in the current sense of breastbone .
Sternum as part of the solid bone of the chest can be attributed to the Ancient Greek ???????????? , (stere? s/sterr? s) , which means firmly or solid . The term English breast is actually more similar to Latin os pectoris , derived from classical Latin os , bones and pectus , chest or breast. Confusing, pectus is also used in classical Latin as breastbone .
Additional Images
See also
- Pectus carinatum
- Pectus excavatum
References
Source of the article : Wikipedia
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