Cartilage
Type of connective tissue consisting largely of water, minerals, and the proteins collagen and elastin.
Hyaline Cartilage
Covers the surface of joints and allows bones to move easily against one another.
Elastic Cartilage
Provides structure for body parts that need to be pliable, such as ears and nose.
Fibrocartilage
Provides solidity in the spine's intervertebral disks or the knee's menisci.
Cartilaginous Joint
Held together by flexible cartilage that allows for limited movement, are found in between the vertebrae in the spine.
Cortical Bone
Dense, strong outer layer surrounding a bone's relatively light honeycomb-like inner structure. Also known as compact bone, it is called cortical bone because it forms the cortex (outer coating) of the bone. Cortical bone makes up 80 percent of the weight of the human skeleton.
Femur
Also known as the thighbone, bone that reaches from the hip joint to the knee joint; typically 19 inches in length and capable of supporting up to 30 times a person's weight, the femur is the longest and strongest in the body.
Fibrous Joint
Found only in the skull, a type of joint that connects bones with fibrous tissue and allows for no movement.
Flat Bone
Bone that takes the form of a wide plate to provide protection for a body organ or a surface for the attachment of muscles; examples include the sternum (breastbone) and scapula (shoulder blade).
Humerus
Long bone that connects the scapula (shoulder blade) to the radius and ulna of the forearm.
Irregular Bone
Bone with unusual form that cannot be classified within the categories of long, short, flat, and sesamoid bones. Examples include the vertebrae, which protect the spinal cord.
Ligament
Type of connective tissue that connects bones to one another and limits movement between them.
Limb
Appendage on the side of the body. Humans have four limbs - two upper (arms) and two lower (legs). E ach has four sections: shoulder, arm, forearm, and hand in the upper limb; buttock, thigh, leg, and foot in the lower limb.
Long Bone
Elongated bone, one longer than it is wide. Examples include the humerus and radius in the arm, and the femur and tibia in the leg. Small bones, such as the phalanges (in the fingers and toes), are classified as long bones because of their elongated shape.
Sesamoid Bone
Rounded piece of bone, usually set within tendon, often less than 1/4 inch in length. A larger example of a sesamoid bone is the kneecap (patella), which is embedded in the tendon of the thigh's extensor muscle and serves to protect the knee joint.
Short Bone
Bone as wide as it is long; examples include the carpals and tarsals in the wrist and foot.
Synovial Joint
Type of joint which is designed to facilitate movement; it is filled with a lubricating fluid.
Pivot Joint
Allow rotation, as, for example, in the neck.
Hinge Joint
Allow for a body part to be straightened or retracted, as in the elbow.
Ball-and-Socket Joint
Allow for radial movement, for example in the hip.
Saddle Joint
Found in the thumb, permit up-and-down and forward-and-backward movement, but not rotation.
Plane Joint
Between the intertarsal bones of the feet, allow for gliding of bones.
Ellipsoid Joint
In the wrist, allow for the same movement as ball-and-socket joint, but to a lesser extent.
Tendon
Band of connective tissue that attaches a muscle to a bone.
Trabecular Bone
Lighter inner part of bone, also called cancellous bone, which is protected by a stronger outer layer
(cortical bone); trabecular bone often contains red bone marrow, in which red blood cells are protected.
Vertebrae
One of the interconnecting bones that form the spinal column. Children have 33 vertebrae, but in adults 5 unite to make the sacrum and 4 combine to form the coccyx, reducing the number of bones to 26.