Skeleton: Classification and Structure of Bones and Cartilages

Flashcards covering the classification of the skeleton, types of cartilage, categories of bone shapes, bone markings, gross anatomy of long bones, and microscopic bone structure based on the lecture notes.

Axial skeleton

The division of the skeleton consisting of bones that lie around the body’s center of gravity.

Appendicular skeleton

The division of the skeleton consisting of the bones of the limbs, or appendages.

Perichondrium

A covering of dense irregular connective tissue that surrounds cartilage and acts to resist distortion.

Hyaline cartilage

The most common type of cartilage in the body; includes articular, costal, respiratory, and nasal cartilages.

Elastic cartilage

A flexible type of cartilage found in the external ear and the epiglottis.

Fibrocartilage

Cartilage that provides strength and shock absorption, found in intervertebral discs, the menisci of the knee, and the pubic symphysis.

Compact bone

Dense osseous tissue made up of organizational units called osteons.

Spongy (cancellous) bone

Osseous tissue composed of small trabeculae (columns) of bone and lots of open space.

Long bones

Bones that are much longer than they are wide, consisting of a shaft with heads at either end, such as the femur and phalanges.

Short bones

Cube-shaped bones containing more spongy bone than compact bone, such as the tarsals and carpals.

Flat bones

Thin bones consisting of two waferlike layers of compact bone sandwiching a thicker layer of spongy bone, such as the bones of the cranium.

Irregular bones

Bones that do not fall into categories based on standard shapes, such as the vertebrae.

Sesamoid bones

Special types of short bones formed within tendons, such as the patellas.

Sutural bones

Tiny bones located between cranial bones.

Tuberosity

A large rounded projection that may be roughened.

Crest

A narrow ridge of bone that is usually prominent.

Trochanter

A very large, blunt, irregularly shaped process, with the only examples found on the femur.

Line

A narrow ridge of bone that is less prominent than a crest.

Tubercle

A small rounded projection or process.

Epicondyle

A raised area on or above a condyle.

Spine

A sharp, slender, often pointed projection.

Process

Any bony prominence.

Head

A bony expansion carried on a narrow neck.

Facet

A smooth, nearly flat articular surface.

Condyle

A rounded articular projection.

Ramus

An armlike bar of bone.

Fissure

A narrow, slitlike opening.

Foramen

A round or oval opening through a bone.

Notch

An indentation at the edge of a structure.

Meatus

A canal-like passageway.

Sinus

A bone cavity filled with air and lined with mucous membrane.

Fossa

A shallow, basinlike depression in a bone, often serving as an articular surface.

Diaphysis

The shaft of a long bone.

Periosteum

A fibrous membrane covering made of dense irregular connective tissue.

Perforating fibers

Collagen fibers of the periosteum that penetrate into the bone.

Epiphysis

The end of a long bone, composed of a thin layer of compact bone enclosing spongy bone.

Articular cartilage

Glassy hyaline cartilage covering the epiphysis to minimize friction at joints.

Epiphyseal plate

A thin area of hyaline cartilage that allows for longitudinal growth of a long bone during youth.

Epiphyseal line

A thin, barely discernible remnant of the epiphyseal plate once long bone growth has stopped.

Medullary cavity

The central cavity of the shaft, serving as a storage region for adipose (yellow bone marrow) in adults.

Yellow bone marrow

Adipose tissue stored in the medullary cavity of adult long bones.

Red bone marrow

Tissue involved in blood cell formation, found in marrow cavities of infants and the interior of epiphyses in adults.

Endosteum

A delicate lining of the shaft that also covers trabeculae and lines central and perforating canals.

Osteon (Haversian system)

The structural unit of compact bone, consisting of a central canal and its surrounding concentric lamellae.

Central canal (Haversian canal)

A canal running parallel to the long axis of the bone carrying blood vessels, nerves, and lymphatic vessels.

Osteocytes

Mature bone cells found in chambers called lacunae.

Lacunae

Chambers in the bony matrix where osteocytes reside.

Concentric lamellae

Concentric circles of bony matrix arranged around a central canal.

Canaliculi

Tiny canals radiating from the central canal to lacunae, forming a transportation network for living bone cells.

Perforating (Volkmann's) canals

Canals that run at right angles to the shaft, connecting blood and nerve supplies of the medullary cavity to the central canals.

Endochondral ossification

The process by which all bones inferior to the skull (except collarbones) form using hyaline cartilage as a model.

Osteoblasts

Bone-forming cells located in the inner layer of the periosteum and endosteum.

Osteoclasts

Cells that remove spongy bone to produce the medullary cavity during ossification.