The human skeleton is the set of bones that give the body its structure. It is made up of a total of 206 bone pieces and occupies 15% of the total mass of an adult individual. In other words, a person weighing 75 kilograms will have approximately 9 kilograms of bone stored in their bone structure.
The skeleton has various functions: it acts as a mechanical support and allows postural maintenance in a three-dimensional space, it enables movement (along with muscles and tendons), it protects our organs against mechanical forces, it is a metabolic storehouse of minerals (such as calcium and phosphate) and allows the formation of blood cells. Within some bones is bone marrow, a tissue that contains pluripotent hematopoietic stem cells. From here all the formed elements of blood arise, from red blood cells to lymphocytes.
Bones are essential to understanding the life of vertebrates. Beyond its structural function, all blood cells and many minerals are stored and synthesized here. Here we tell you everything about flat bones but not before reviewing the general bone physiology of human beings.
According to the Oxford Languages dictionary, a bone can be defined as a hard and resistant piece of the skeleton of vertebrate animals, yellowish white in color. The bone is formed by organic substance and mineral salts, and surrounded by a fibrous membrane.
Simply put, bone structures are composed of a protein framework of collagen (30%), together with a mineral known as calcium phosphate (hydroxyapatite, 70% of the matrix), which gives hardness and resistance to said framework. Bone tissue is very atypical, since 98% of it corresponds to extracellular matrix substances and only 2% is represented by cells (osteocytes, osteoblasts and osteoclasts).
We can categorize bones according to multiple parameters, but the simplest organization is based on their dimensions. Based on them, we find the different types of bone tissue:
As indicated by the United States National Library of Medicine, flat bones are those that are composed of a layer of spongy bone between two thin layers of compact bone They have a flat and non-rounded shape, hence their name, and they have marrow, but they do not have a bone marrow cavity per se. In them, length and width dominate over thickness.
Thus, we can imagine flat bones as a “sandwich” of different tissues. Spongy bone tissue is made up of a mesh-like framework made up of small pieces of bone, called bone trabeculae. On the other hand, Compact bone is the hardest and most external part of the bone, the whitish and resistant part that is already part of the collective imagination It has an ivory appearance and is extremely resistant.
The places where most flat bones are located are the skull, pelvis and thorax. Below we show you some examples within this category. Don’t miss them.
1. Scapula
The scapula or scapula is the flat bone par excellence, since every human being knows it and it is easily identifiable by touch above the skin. It is a very flat, triangular bone, with a costal or anterior face and a dorsal or posterior face
It is located in the back of the thorax, at the level of the first 7 ribs, and helps connect the humerus with the clavicle, giving shape to the structure known as the shoulder girdle. The scapula has a total of 18 muscles that originate or insert into it so it is a highly mobile structure subject to various dysfunctions due to mechanical stress.
2. Frontal bone
A bone of the skull, which in humans is odd-shaped, central (in the forehead), symmetrical and flat It has an endocranial face and another exocranial face, but the important thing about it is to know that it is one of the central elements of the human face, since it is also widely related to other bone structures, such as the sphenoid, the ethmoid, part of the maxilla. superior, the zygomatic, the parietal and the bones found internally in the nose.
This bone has enormous physiological importance, because in addition to acting as mechanical protection of the brain, serves as the insertion point of the occipitofrontal muscle, essential for gestural language and body communication in the human being.
3. Sternum
A flat, central, elongated bone finished in a point. It is located in the front part of the thorax, where the upper ribs and collarbones meet In humans, this vitally important bone is made up of 3 different parts: the handle or manubrium, the body and the xiphoid process or process.
Sometimes, the sternum is synonymous with the chest bone, due to the place it occupies and its physiological importance. Its main function is to protect the heart and lungs from possible mechanical damage, since thanks to him the rib cage exists. Injuries to the clavicle, hernias, fractures, gastric reflux, muscle strains and many more events can cause sternal and substernal pain.
4. Ribs
We cannot leave aside the ribs, the flat bones that give our trunk its appearance and allow the formation of the rib cage, along with the sternum and other associated structures. The ribs are flat, curved bones of different sizes that surround the chest of vertebrates, allowing the lungs to expand during the respiratory process.
Human beings generally have about 12 pairs of ribs. 7 of them are true or sternal, 3 are false or asternal and 2 are considered floating. Each of them has 2 faces, 2 edges and 2 ends. They serve to protect the internal organs of the thorax, although in other species they provide support and protection to practically their entire body segment.
As you may have seen at this point, The typical functionality of flat bones is protection, beyond the production of movement They keep soft structures safe, such as the brain (cranial bones), heart, aorta and lungs (bones of the rib cage), and even the reproductive organs, both male and female.
Flat bones are not specifically vulnerable, but due to their damage-absorbing function, they may be the first to be affected during serious blows or trauma. Fractures in flat bones can be costly in the long term, as the underlying structures they protect are extremely fragile and their damage is sometimes irreparable. Therefore, in the event of any trauma, no matter how small, it is always advisable to go to a medical specialist.
Summary
Usually, when we think of a bone, the femur, tibia or fibula comes to mind. It is normal, since these bone structures are the longest and most striking in the body, at least from an anatomical point of view. In any case, as you may have seen, there are many other types of bones: from those that accompany tendons to flat bones, each and every one of our bone structures fulfills an essential and irreplaceable function.
Flat bones do their part by forming a physical armor that protects the weakest organs in the body, such as the heart, lungs or brain. They ensure that a strong blow does not always end in disaster and, as a first barrier, they are prone to suffering fractures and breaks during serious accidents.
