Bone Anatomy (General Osteology) – classifications, Types, Shape

Bone Anatomy (General Osteology)

In Anatomy of Bone (General Osteology) – Bone (os) is an organ consisting of bone tissue, including cells and a solid intercellular substance, rich in collagen fibers and mineral compounds. Bone contains 50% water, organic compounds (ossein), and inorganic substances (compounds of calcium, phosphorus, magnesium, etc.).
Outside the Anatomy, the bone is covered with the periosteum – a thin connective tissue plate that firmly adheres to the bone. The periosteum contains many vessels, nerves, receptors. The outer layer of the periosteum is fibrous, and the inner layer is germ: young cells are formed in it – osteoblasts, due to which the bone grows in thickness. In the case of fractures, a callus is formed from them.
The outer layer of the bone is represented by a plate of compact substance, under which there is a porous spongy substance, built of bone trabeculae with cells between them. Inside the diaphysis of the tubular bones, there is a marrow cavity containing yellow ( fatty) bone marrow. The compact substance consists of lamellar bone tissue and is penetrated by longitudinal (central) and transverse (about the surface of the bone) thin nutrient tubules, through which vessels and nerves pass into the bone. The walls of the central canals are bone plates in the form of tubes inserted into one another. The central canal with a system of 5-20 concentric plates surrounding it is called an osteonOsteon is a structural unit of bone. The spaces between the osteons are made with insertion plates.
The epiphyses of tubular bones, cancellous bones that are loaded in many directions, consist of a cancellous substance and are covered with a thin layer of a compact substance. The cells of the cancellous substance in the epiphyses of tubular bones and cancellous bones are filled with red bone marrow, which performs hematopoietic functions.
Bone plates of cancellous substance are located at an angle to each other, under the lines of compression and extension, which ensures an even distribution of muscle traction and pressure acting on the bone. This arched and tubular structure provides significant strength and lightness to the bone structure.

The human skeleton consists of more than 200 bones, of which about 40 are unpaired, and the rest are paired. Bones makeup 1 / 5-1 / 7 of the body weight and are subdivided into the bones of the head – the skull, the bones of the trunk, and the bones of the upper and lower extremities.

Bone is an organ consisting of several tissues (bone, cartilage, and connective tissue) and has its own vessels and nerves. Each one has a specific structure, shape, position inherent only to it.


FROM mobility is a very important function of the human body. Due to the evolutionary process, the initial simplest forms of movement due to motor proteins in the composition of cilia and flagella in microorganisms have been developed to complex mechanisms that we can observe in higher animals. The locomotor system, or the musculoskeletal system, is represented by a passive component, bones, and an active component, muscles.

The skeleton system forms a skeleton that is held in a physiological position by ligaments and muscles. Internal organs are also attached to this frame. In a healthy person, the bones are located symmetrically relative to the central plane of the body.

The skeleton consists of more than 200 bones, only 170 of which are paired, which is about 15% of the body weight.

There are two sections of the skeleton:

  • Axial: vertebral column, skull, chest.
  • Additional: bones of the upper and lower extremities.


Bone classification – Bone Morphology (General Osteology)

The anatomy of bone, It’s having some classifications. In terms of shape, function, structure, and development, bones are divided into groups.

1. Long (tubular) bones are characterized in bone anatomy by the bones of the skeleton of the free part of the limbs. They are built from a compact material located at the periphery and internal spongy material. In tubular bones, the diaphysis is distinguished – the middle part containing the medullary cavity, the pineal glands – the ends, and the metaphysis – the area between the pineal gland and the diaphysis. Tubular bones, as their name implies, are an oblong body or diaphysis and two thickenings at the ends, epiphyses. Between the pineal gland and the diaphysis, there are metaphyses – bone growth zones in length. Metaphysis gradually ceases its activity and gradually ossify by the age of puberty, when the growth of the body in height stops. This period corresponds to approximately 18 years for girls and 25 years for boys. In the modern world, there is a concept of bone age, or true age, of the body, as opposed to the calendar age. It is determined based on the stage of ossification of the metaphyses.

2. Short (cancellous) bones are characterized in bone anatomy by bones of the wrist, tarsus. These bones are built of spongy material surrounded by a thin plate of compact material. The cancellous bones are located in places with a high axial load, for example, in the vertebral bodies. The cancellous body is covered with compact bone tissue on the outside.

3. Flat bones are characterized in bone anatomy by bones of the cranial vault, scapula, pelvic bone. In them, the layer of spongy substance is less developed than in cancellous bones. Flat bones perform mainly a protective function, for example, the scapula covers the back surface of the ribs and underlying organs, and the pelvic bones serve as reliable protection for the pelvic organs. Both the scapula and the pelvis are involved in the formation of the girdles of the limbs and their joints. The cerebral section of the skull also consists of flat bones that reliably protect the brain. The frontal bones are so strong that there are cases of bullet ricochet when hitting directly.

4. Irregular (mixed) bones are characterized in bone anatomy by built more complexly and combine the structural features of the previous groups. These include vertebrae, bones of the base of the skull. They are formed from several parts with different development and structure. In addition to these groups of bones, there are

5. Air bones, which contain cavities filled with air and lined with mucous membranes. These are the bones of the skull: the upper jaw, frontal, sphenoid, and ethmoid bones.

Also, the skeleton system includes special characterized in bone anatomy i.e.

6. Sesamoid bones (patella, pisiform bone), located in the thickness of the tendons and helping the muscles.

Bone relief is determined by roughness, grooves, holes, canals, tubercles, processes, dimples. Roughness

and the processes are the sites of attachment to the bones of muscles and ligaments. Tendons, vessels, and nerves are located in the channels and grooves. Pinholes on the surface of the bone are the places where the vessels supplying the bone pass.

Bone shape – Bone Anatomy (General Osteology)

· Tubular bones (long and short) – In bone anatomy, It has a body ( diaphysis ) and two thickened ends ( epiphyses ), which have articular surfaces. The site of the transition of the diaphysis to the pineal gland is called the metaphysis. Metaphyseal hyaline cartilage, due to which the bone grows in length, is characteristic of the growth period of the human body (up to 25-28 years). The tubular bones form the skeleton of the limbs and function as levers.
· Spongy bone – irregular shapes, they are located in those parts of the skeleton which require a combination of strength with mobility (carpal bones, tarsus) In bone anatomy.
· Flat bones characterized in bone anatomy by limit the body cavity, protect and support internal organs, muscles attached to them (the bones of the cranial vault, sternum, ribs, pelvis).
· Mixed bones are characterized in bone anatomy by consist of parts with different structures and shapes. For example, the structure of the vertebral body is spongy bone, and its processes and arch are flat.
· Pneumatic bone is characterized in bone anatomy by having a cavity lined with a mucous membrane and filled with air (frontal, sphenoid, ethmoid bone, the upper jaw).
In the medullary canals, which are present in most tubular and flat, as well as in tubular bones, there is the main organ of hematopoiesis – the bone marrow. In the red bone marrow, there is a gradual maturation of blood cells from precursors, the so-called stem cells. Yellow bone marrow is a gradual reverse development of red bone marrow to adipose tissue with rare islets still performing a function.

Types of bone connection In Anatomy, The structure and types of joints.

The branch of anatomy that studies bone connections is called syndesmology.

Types of bone connection:

1) synarthrosis (continuous joints) in bone anatomy is characterized by the bones are connected by a continuous connecting tissue; strong, resilient, their mobility is limited. Depending on the type of fabric, they are divided into 3 groups:
· Syndesmoses in bone anatomy is characterized by compound bone dense fibrous connective tissue (ligament, membrane, sutures; Welding of – compound tooth alveolus by a thin fibrous layer – periodontium );
· The articular capsule attaches to the articulating bones near the edges of the articular surfaces, forming a sealed articular cavity. The capsule has 2 layers:
– external ( fibrous membrane ), thick, strong, consists of dense fibrous connective tissue and forms ligaments that inhibit movement in the joint.
– inner ( synovial membrane ), thin. It is attached to the fibrous membrane from the inside and has outgrowths – villi, which increase the area of ​​the layer, are rich in blood vessels, and produce synovial fluid. This fluid moisturizes the articular surfaces, reducing friction.
· The articular cavity – the slit space between the articular surfaces, contains a little synovial fluid.

In addition to the main elements, auxiliary formations are found in the joints :

a) extracapsular ligaments,
b) intracapsular ligaments,
c) articular discs, articular menisci,
d) synovial folds.

Torso skeleton – The Bone Anatomy

in bone anatomy, The skeleton of the torso consists of

  • The vertebral column (column vertebral),
  • Sternum (sternum),
  • Ribs (costae).

The skeleton of the trunk serves as protection, support, and movement.

The vertebral column – The Bone Anatomy

The vertebral column includes 33-34 vertebrae in bone anatomy, has 5 sections:

  • Cervical – 7 vertebrae,
  • Thoracic – 12 vertebrae,
  • Lumbar – 5 vertebrae,
  • Sacral – 5 vertebrae,
  • Coccygeal – 4-5 vertebrae.

In bone anatomy, Each vertebra (vertebra) has a Body, The arc closing the spinal foramen. 7 processes depart from the arc: 2 upper and 2 lower articular, left and right transverse processes, and unpaired spinous.
There are top and bottom notches on the arc. The lower notch of the upper vertebra and the upper notch of the lower vertebra limit the intervertebral foramen. There are 31 pairs of such holes for the exit of the spinal nerves.

in bone anatomy, Cervical vertebrae (vertebrae cervicales) differ from others

  • The presence of holes in the transverse processes in which the vertebral artery passes.
  • I cervical vertebra – atlas, does not have a body but is formed by the anterior and posterior arches and two lateral masses, the spinous process is absent.
  • II cervical vertebra – axial, has a dentate process and a bifurcated spinous process on the body.
  • III, IV, V, VI cervical vertebrae have a bifurcated spinous process.
  • VII cervical vertebra – protruding, has an undivided long spinous process.

In bone anatomy, The thoracic vertebrae (vertebrae thoracic) are somewhat more massive than the cervical, on the lateral surfaces of the bodies and transverse processes, there are facets (articular costal fossae), which serve to form joints with the ribs. Most of the thoracic vertebrae have a long downward spinous process.
In bone anatomy, The lumbar vertebrae (vertebrae lumbales) differ Massive bean-shaped bodies, The location of the articular processes of the sagittal plane, Spinous processes are thickened and directed posteriorly almost horizontally.
In bone anatomy, The sacral vertebrae (vertebrae sacrales) in adults grow together into one bone – the sacrum (os sacrum), triangular in shape. Distinguish between the base of the sacrum, facing up, the top, directed down. The anterior surface is concave into the pelvic cavity, the posterior surface is convex. On the anterior pelvic surface, there are 4 paired pelvic openings connected by transverse lines – traces of fusion of the vertebral bodies. On the dorsal surface, there are 4 pairs of the dorsal sacral foramen5 sacral ridges – unpaired median, intermediate and lateral – traces of fusion of the processes of the vertebrae. On the lateral parts of the sacrum, ear-shaped surfaces are distinguished for articulation with the pelvic bone. The sacral canal runs inside the sacrum. The base of the sacrum connects to the V lumbar vertebra at an angle to form a promontory that juts out into the pelvic cavity.
In bone anatomy, The coccyx (os coccygis) is a rudiment of the coccygeal vertebrae that form one bone in an adult.

In an adult, the spine has 4 physiological curves: 2 directed bulge forward – lordosis (cervical and lumbar) and 2 are directed with a bulge posteriorly – kyphosis (thoracic and sacral). Curves soften shocks and shaking of the body when walking, running, jumping (shock absorption).

The sternum (sternum) – The Bone Anatomy

In bone anatomy, The sternum (sternum) is a flat spongy oblong bone, consisting of the Body, Handles, and the xiphoid process.
The sternum arm articulates with the clavicle of the sternoclavicular joint. On the upper edge of the handle, there is an unpaired jugular notch and a paired clavicular notch. On the lateral surfaces of the sternum, there are 7 coastal notches, and in the spongy substance of the sternum, there is red bone marrow.

The ribs (costae) – The Bone Anatomy

In bone anatomy, The ribs (costae) of 12 pairs, are long, flat, curved spongy bone. They consist of bone and cartilaginous parts. The costal cartilage is the anterior part of the rib. In the bony part of the rib, ahead, a neck, a tubercle with an articular surface for connection with the transverse process of the corresponding vertebra, and a body are distinguished. On the lower edge on the inner surface is the costal groove – the location of the intercostal vessels and nerves. The seven upper pairs of ribs are called true ribs and connect to the sternum, 8-9-10 pairs are connected to each other by cartilage and are called false, 11-12 pairs –oscillating, their front ends lie freely in soft tissues.
By connecting the ribs with the spine at the back and the sternum in front, the thorax (thorax) is formed. It contains vital organs (heart, lungs, trachea, esophagus, large vessels, and nerves). The rib cage has 2 apertures (holes): the upper one facing the head and the lower one toward the diaphragm. The shape of the chest is a truncated cone. The shape depends on gender (in women it is rounder and shorter), constitution, age, profession, lung diseases. The following compounds are distinguished in the chest:

  • 1 pair of ribs is connected to the sternum by synchondrosis,
  • 2-3-4-5-6-7 pairs of ribs form cost-sternum joints with the sternum,
  • 8-9-10 pairs of ribs form costal arches,

Each rib is connected to the thoracic vertebra by a combined joint :

  1. the head of the rib joins the facet on the vertebral body, forming the joint of the head of the rib;
  2. tubercle – to the facet on the transverse process, forming the costotransverse joint.