Osteology: what is it and what is this branch of the study of anatomy

Anatomy is a science that studies the structure of the different living things that inhabit planet Earth. A specialist in anatomical studies studies the topography, shape, location, arrangement and relationship between the organs and systems that make up a living being.

If anatomy is based on an objective description of the analyzed structures, each of them must also be contrasted with its function, so it is closely related to the physiological study of systems.

There are many types of anatomy: Descriptive, comparative, topographical, surgical, clinical, radiological, pathological terms and many others. Some branches of anatomy focus on the clinical peculiarities of human organs, while other aspects study the tissues and systems of plants, for example. From plant to mammal, thousands of years ago, but anatomists, specialists in their field, describe the structures of each in the same detail.

Because the human body is so complex, it is not enough to specialize in “human anatomy” to describe each of its peculiarities. Based on this premise, osteology was born, Or what is the same, the study of bones. We tell you all about this exciting discipline.

    What is osteology?

    As we have indicated in the previous lines, osteology can be defined as a branch of descriptive anatomy responsible for studying the shape, structure and arrangement of bones. It is a variant of systematic or descriptive anatomyAs he studies one of the many subsystems into which the body is divided and is responsible for its study exclusively.

    Related to the section of chordates (Chordata), the human species Homo sapiens sapiens is characterized to present an osteocartilaginous skeleton, comprising in order all the bones and joints which constitute the skeletal system. All this bone conglomerate makes up about 12% of the human body: if an adult weighs 75 kilograms, 9 of them will be pure bone tissue.

    Below, we present a series of peculiarities about the human skeleton and the composition and function of bone tissue. Knowledge of all these data is possible thanks to the work of anatomists specializing in osteology.As we recall that this branch of descriptive anatomy has historically focused on the study of the human skeletal system.

    The peculiarities of the human skeleton

    As we said, about 12% of our weight is made up of pure bone. From an anatomical point of view (or now that we have learned the term osteological), our skeleton is divided into 2 large sections: axial and appendicular.

    The axial skeleton is made up of 80 bones that define the central axis of the human being, that is to say, it includes the bony structures that form the skull, the auditory bones, the hyoid, the rib cage , the breastbone and the spine. The main function of the axial skeleton is to shape us, to allow us to connect in a three-dimensional environment on the right and, above all, to serve as protection for vital organs (brain, heart and lungs, among others).

    On another side, the appendicular skeleton consists of the 126 bones that make up the lower and upper limbs (arms and legs), as well as bone size.. Some of them will ring you: the femur, humerus, radius, ulna, phalanges of the fingers, and many more. The main function of the appendicular skeleton is movement, which is why there is also a great diversity of muscles and tendons.

    Human skeleton (206 bones): axial skeleton (80 bones) + appendicular skeleton (126 bones)


    Bones are defined as hard, sturdy pieces of white / yellowish vertebrate skeletons that they consist of organic substances, mineral salts and a fibrous shell. Bone tissue is distinguished above all by its hardness, since 98% of it is composed of mineralized extracellular material, while only 2% are living cells per se.

    The extracellular matrix of bones (what we think of as the hard white material) is made up of 70% hydroxyapatite, an extremely tough substance rich in calcium and phosphorus. Without going any further, our body stores 1 to 1.2 kilograms of pure calcium, which forms the structure of bones at 99%. The remaining 1% of calcium performs its relevant tasks in the bloodstream and target tissues. Returning to the “do not live” structure of bone, the remaining 30% of the bone matrix is ​​organic matter, mainly collagen fibers.

    Bone tissue is distinguished by its poor representation of cell bodies. Either way, here’s a quick list of the major cells found in bones:

    • Osteogenic cells: Unspecialized stem cells derived from mesenchyme that specialize and give rise to other types of cells.
    • Osteoblasts: synthesize the bone matrix, they are therefore responsible for bone hardness, normal development and growth throughout an individual’s life.
    • Osteocytes: derived from osteoblasts. They make up 95% of bone cells and are responsible for secretion or reabsorption of the surrounding matrix.
    • Osteoclasts: its function is bone resorption, that is, the digestion and dissolution of the hard matrix of bones.

    Thanks to this cellular diversity, the bone tissue is not waterproof and unchanged over time.. Bone is constantly being formed and destroyed, and generally the two processes are balanced throughout an individual’s life. Osteoblasts and osteoclasts are regulated by the hormonal action of calcitonin, estrogen, vitamin D, cytokines and many other substances.

    Peak bone mass in both men and women is at age 30. Once this peak is reached, bone mass remains stable for 10 years, to begin to lose bone through resorption processes of the order of 0.3 to 0.5% per year. After menopause, this loss accelerates in women by 3 to 5%, making them much more prone to osteoporosis.

      The functionality of the skeleton

      How to imagine, the main function of the skeleton is to provide vertebrates with support and protection. The human bone system is a kind of “carcass” which holds all the soft tissues of the body and protects vital organisms from shock and mechanical stress. However, this is not its only task from an anatomical and physiological point of view.

      For example, bones are the places where hematopoiesis occurs, which is the formation of all the cell bodies that circulate in the blood (white blood cells, red blood cells and others). Some types of bone contain a substance called bone marrow, which harbors multipotent hematopoietic stem cells, which in turn differentiate into different circulating elements. Hematopoiesis occurs primarily in the skull, pelvis, ribs, breastbone, and ends of the femur and humerus.

      To finish, bones are also a great place to book. In addition to harboring large amounts of calcium and phosphate with structural function, bone tissue can be reabsorbed depending on the physiological needs of the individual. For example, in the presence of prolonged hypocalcemia, some of the bone material is digested to release calcium circulating in the bloodstream. As you can imagine, this is counterproductive in the long run, but it can take the body away from more than a one-time commitment.


      Osteology is a branch of descriptive anatomy that has allowed us, as a society, to know all the data that we have presented here. Anyway, you don’t have to see this scientific discipline as an isolation from the rest: Osteology must be based on physiology, cell biology, histology and many other aspects to fully understand the human skeleton and its relationship to other systems.

      Nothing in the human being is waterproof. After all, we are nothing more than a network of connected systems complex: if a piece falls, the domino effect may be more or less, but nothing acts by itself. The relationship between the bone system and other organs and physiological processes is clear evidence of this.

      Bibliographical references:

      • Blazquez, C. Skeletal System: Functions. Bones: structure and classification. Histology of bone tissue: cells, compact bone tissue, and spongy bone tissue. Bone formation and growth. Divisions of the skeletal system. Main bones of different regions of the skeleton. Mexico: University of Veracruz; 2012.[Acceso el 19 de mayo del 2017].
      • Estrada, C., Pau, AC and López, LI (2006). Bone tissue engineering: basic considerations. EIA Journal, (5), 93-100.
      • Osteology, University of the Andes. Collected February 24 from https://www.uandes.cl/macroscopico/osteologia/
      • Osteology and arthrology: functional anatomy. Collected February 24 at https://www.berri.es/pdf/ANATOMIA%20FUNCIONAL%E2%80%9A%20Estructura%E2%80%9A%20funci%C3%B3n%20y%20palpaci%C3%B3n% 20del % 20aparato% 20locomotor% 20para% 20terapeutas% 20manuales / 9789500602815

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