Human Skeletal System Overview

A bone located in the middle ear. It is the largest of the three ossicles and connects to the malleus.

A bone located in the middle ear. It is the smallest of the three ossicles and connects to the stapes.

A bone located in the middle ear. It connects the malleus to the stapes.

Ribs that attach directly to the sternum via costal cartilage.

Ribs that do not attach directly to the sternum, but connect via cartilage to the 7th rib.

Ribs that have no attachment to the sternum.

The anterior portion of the chest wall. It consists of three segments: manubrium, body, and xiphoid process.

The bone that runs from the shoulder to the elbow. It is the longest bone in the upper arm.

Red bone marrow is found in the ends of long bones (epiphyses) and is responsible for producing red blood cells (RBCs), white blood cells (WBCs), and platelets.

Yellow bone marrow is found in the shafts of long bones and is mostly composed of fat. It can produce blood cells in emergencies, like during anemia.

Joints are connections between two or more bones, allowing for movement. They are the structural arrangements that enable us to move.

Fibrous joints are fixed joints, also called immovable joints, where bones are fused together. They are found in areas where stability and strength are more important than flexibility.

Cartilaginous joints are slightly movable joints, where bones are connected by cartilage. They provide a cushion and allow for limited movement.

A strong, flexible framework made up of bones, cartilages, and sometimes ligaments.

Protects vital organs, provides a framework for movement, stores minerals, and produces blood cells.

Rigid, strong, and not flexible. Made up of osteoblasts, osteoclasts, and osteocytes. Contains a rich blood supply and grows bidirectionally.

Flexible and elastic. Made up of chondrocytes and chondrin protein. Lacks a rich blood supply and grows unidirectionally.

Consists of bones located around the central axis of the body, protecting vital organs like the brain, heart, and lungs.

Includes bones of the upper and lower limbs, enabling body movement. Contains 126 bones in total.

The skull is part of the axial skeleton and consists of 29 bones including the cranium, face, ear ossicles, and hyoid bone.

A type of joint where a pad of fibrocartilage sits between the bone ends, allowing very slight movement due to the compression of cartilage. Examples: pubic symphysis and intervertebral discs.

The upper limb (hand) and lower limb (leg) each contain 30 bones. The pelvic bone, clavicle, and scapula connect the axial and appendicular skeletons.

The most common type of joint, known for its flexibility and wide range of motion. Examples: shoulder, neck, knee, wrist.

The membrane in synovial joints that secretes synovial fluid.

The thick, sticky fluid secreted by the synovial membrane. It lubricates joints, provides nutrients, and helps maintain joint stability.

The smooth cartilage that covers the ends of bones in synovial joints.

Strong bands of fibrous tissue that connect bones and provide stability in synovial joints.

Strong, fibrous cords that connect muscles to bones in synovial joints.

Small, fluid-filled sacs found in some joints to provide cushioning.

A tough sheath that surrounds the bone, composed of two layers: the fibrous layer and the osteogenic layer.

A thin layer of fibrous connective tissue and a layer of osteoblasts.

The matrix is the substance that makes up the bone and is composed of a protein called Ossein.

The plates formed within the matrix of the bone.

The type of lamellae that is present around the Haversian canals.

The thin layer of fibrous connective tissue and a layer of osteoblasts that are found lining the inner surface of the bone marrow cavity.

A soft, semi-solid tissue found within the bone marrow cavity, composed of fat, nerve tissue, and blood vessels.

A cavity within long bones like the humerus and femur, filled with bone marrow.

Allows movement primarily in one plane. A spool (reel) like surface of one bone fits into the concave surface of another bone. The elbow, knee, ankle, and interphalangeal joints are examples.

Allows movement in one plane. A rounded or pointed bone fits into a shallow depression in another bone. The joints between atlas and axis and between the radius and ulna (radioulnar joint) are examples. The primary movement is rotation.

Allows movement in two planes, back and forth and side-to-side. An oval shaped condyle of one bone fits into an elliptical cavity in another bone. The joints between the metacarpals and phalanges (metacarpo-phalangeal joint) of the fingers are examples.

Allows the same movements as an ellipsoid joint, but the movements are free. The projection of one bone fits in a saddle-shaped depression in another bone. The joint between the carpal and metacarpal of thumb (carpometacarpal joint of thumb) is an example.

The most freely movable joint. A ball-like structure of one bone fits into a socket-like structure in another bone. Shoulder and hip joints are examples.