What are flat bones?

Bones are a form of extremely specialized connective tissue, consisting of a mix of a dense organic matrix and inorganic mineral component. They are characterized by their hardness and mechanical resistance. Bones are segments of varying shape, size and density, all of which constitute to form the skeletal system.

The surface of the bone is covered by the periosteum, a membrane connecting the processes responsible for bone growth and callus formation in fractures. The compact bone (or cortical), which is a layer of dense bone, is located below the periosteum; and underneath the compact bone, is the location of the spongy bone (also called trabecular or cancellous bone), which contains bone marrow responsible for the production of blood cells.

Depending on their shape formations, bones can be divided into long bones, flat bones, short bones and irregular bones.  Long bones develop mainly in length (such as the femur, tibia, fibula, radius, ulna, humerus); flat bones are characterized by having higher length and width than thickness (such as bones of the skull, shoulder blades, sternum); short bones are developed in a similar way in all three dimensions (such as the carpus and tarsus); and irregular bones are characterized by not having any dominant morphological element (such as in the case of the vertebrae). Under normal circumstances, bones stop growing when an individual has reached late teens or early twenties.

Flat bones are formed by a thin layer of spongy bone tissue inside of which is located bone marrow. This spongy layer is then wrapped by two sheets (one for each side) of cortical or compact bone tissue. Examples of flat bones include the shoulder blades, sternum and bones of the skull and pelvis.

Conditions associated with flat bones include flat feet and tarsal coalition. Flat feel occur when the middle of the feet, which is normally arched, appear drawn in. This condition may be caused due to unusual flexibility or stiffening of the foot joints. In regards to stiffing of the foot joints, tarsal coalition occurs when the bones of the feet fail to separate during fetal development.  This condition may be a birth defect or the result of conditions such as flat feet, injuries, or prolonged swelling. In any case, seeking proper medical assistance is essential for determining the most appropriate form of treatment and preventing further complications, such as pain and muscle spasms, from arising  

Calcium is an extremely important feature in an individual’s diet. Calcium intake is stored in the bones as a sort of mineral deposit, which in turn helps build stronger and healthier bones.


What function do flat bones serve?

Flat bones perform different functions in the human body:

  • They provide strength, structure and mobility to the areas of the body from which they are composed of.
  • They have important extensive protection features (such as the skull protecting the brain and protection of other internal organs in the body).
  • The bone marrow in them is capable of producing blood cells (white blood cells, red blood cells, platelets).
  • They act as a broad surface for large muscle groups to attach to.
  • Like all the other bones, they are spares and storage of minerals such as calcium, phosphorus, sodium and magnesium, essential for regulating many physiological mechanisms.