Bone - Types


There are five types of bones in the human body: long, short, flat, irregular, and sesamoid.

  • Long bones are characterized by a shaft, the diaphysis, that is much longer than it is wide. They are made up mostly of compact bone, with lesser amounts of marrow, located within the medullary cavity, and spongy bone. Most bones of the limbs, including those of the fingers and toes, are long bones. The exceptions are those of the wrist, ankle and kneecap.
  • Short bones are roughly cube-shaped, and have only a thin layer of compact bone surrounding a spongy interior. The bones of the wrist and ankle are short bones, as are the sesamoid bones.
  • Flat bones are thin and generally curved, with two parallel layers of compact bones sandwiching a layer of spongy bone. Most of the bones of the skull are flat bones, as is the sternum.
  • Sesamoid bones are bones embedded in tendons. Since they act to hold the tendon further away from the joint, the angle of the tendon is increased and thus the leverage of the muscle is increased. Examples of sesamoid bones are the patella and the pisiform.
  • Irregular bones do not fit into the above categories. They consist of thin layers of compact bone surrounding a spongy interior. As implied by the name, their shapes are irregular and complicated. Often this irregular shape is due to their many centers of ossification or because they contain bony sinuses. The bones of the spine, hips, and some bones of the skull are irregular bones. Examples include the ethmoid and sphenoid bones.

Read more about this topic:  Bone

Other articles related to "types, type":

General Aviation
... General aviation involves a wide range of aircraft types such as Business jets, trainers, homebuilt, aerobatic types, racers, gliders, warbirds, firefighters and medical transports ... The vast majority of aircraft today are general aviation types ...
Netwar - Network Structures
... Arquilla and Ronfeldt point to three basic types of networks that may be used by netwar actors Chain network – typified by smuggling networks, where end-to-end ... actors may also take on hybrid forms as well, blending different types of networks and hierarchies ... the same group may be networked to each other through different types of network structures ...
Prolog - Extensions - Types
... Attempts to introduce types date back to the 1980s, and as of 2008 there are still attempts to extend Prolog with types ... Type information is useful not only for type safety but also for reasoning about Prolog programs ...
Types of Graphemes
... The principal types of graphemes are logograms, which represent words or morphemes (for example, Chinese characters, or the ampersand representing ... For a full discussion of the different types, see Writing system Functional classification of writing systems ...
Small Boat Anchors - Bruce or Claw Anchor
... Claw-types set quickly in most seabeds and although not an articulated design, they have the reputation of not breaking out with tide or wind changes, instead slowly ... Claw types have difficulty penetrating weedy bottoms and grass ... have to be oversized to compete with other types ...

Famous quotes containing the word types:

    The rank and file have let their servants become their masters and dictators.... Provision should be made in all union constitutions for the recall of leaders. Big salaries should not be paid. Career hunters should be driven out, as well as leaders who use labor for political ends. These types are menaces to the advancement of labor.
    Mother Jones (1830–1930)

    If there is nothing new on the earth, still the traveler always has a resource in the skies. They are constantly turning a new page to view. The wind sets the types on this blue ground, and the inquiring may always read a new truth there.
    Henry David Thoreau (1817–1862)

    The wider the range of possibilities we offer children, the more intense will be their motivations and the richer their experiences. We must widen the range of topics and goals, the types of situations we offer and their degree of structure, the kinds and combinations of resources and materials, and the possible interactions with things, peers, and adults.
    Loris Malaguzzi (1920–1994)