The Skeletal System

Vocabulary flashcards covering skeletal system anatomy, bone structure, axial and appendicular skeleton, joint movements, pathology, surgical procedures, and medical combining forms.

Ossification

The process by which cartilage is gradually replaced by bone tissue as the skeleton develops.

Osteoblasts

Immature bone cells that build bone.

Osteocytes

Mature bone cells.

Osteoclasts

Cells that break down or crush bone.

Resorption

The process of destroying bone for absorption into circulation.

Compact bone

Dense, hard, strong bone forming the protective outer layers of bone.

Spongy bone

Porous, thin bone located within the epiphysis that contains red bone marrow.

Periosteum

Tough, fibrous tissue forming the outermost covering of bone.

Medullary cavity

Center region of long bones that serves as the storage site for yellow bone marrow.

Endosteum

Tissue layer that lines the medullary cavity.

Red bone marrow

Hemopoietic tissue located within spongy bone that produces red blood cells, hemoglobin, white blood cells, and thrombocytes (platelets).

Yellow bone marrow

Fat storage tissue located in the medullary cavity of long bones.

Diaphysis

The shaft of long bones.

Epiphysis

The wider ends of long bones, categorized as proximal epiphysis (nearest midline) and distal epiphysis (farthest from midline).

Metaphysis

Region between diaphysis and epiphysis containing the epiphyseal plate (growth region) allowing bone to grow lengthwise.

Sulcus

A groove or depression in a bone, such as a fissure.

Sinus

An opening or hollow space in a bone.

Fossa

A hollow or shallow concave depression in a bone.

Foramen

An opening in a bone through which blood vessels or nerves pass.

Process

A projection on a bone allowing for the attachment of muscles or tendons.

Foramen magnum

An opening on the underside of the skull through which the spinal cord passes to connect to the brain via the medulla oblongata.

Fibrous joints

Immoveable joints of connective tissue, such as sutures connecting facial and skull bones.

Cartilaginous joints

Slightly moveable joints consisting of bones connected by cartilage, such as a symphysis.

Synovial joints

Freely moveable joints described by motion type, such as ball-and-socket or hinge joints.

Ligaments

Connective structures that attach one bone to another bone, functioning to stabilize and strengthen synovial joints.

Tendons

Structures that attach muscles to bone.

Bursae

Fibrous sacs acting as cushions to ease movement in areas subject to friction.

Axial skeleton

Division of the skeleton that protects major organs of the nervous, respiratory, and circulatory systems; includes skull/facial bones, rib cage, and vertebral column.

Appendicular skeleton

Division of the skeleton that protects organs of digestion, excretion, and reproduction; includes upper and lower extremities.

Frontal bone

Anterior portion of the cranium forming the forehead.

Parietal bones

Paired cranial bones forming most of the roof and upper sides of the cranium.

Occipital bone

Cranial bone forming the back part of the skull and base of the cranium.

Temporal bones

Paired cranial bones forming the sides and base of the cranium, housing the external auditory meatus.

Sphenoid bone

Wedge-shaped bone at the base of the skull that makes contact with all other cranial bones.

Ethmoid bone

Spongy bone located at the roof and sides of the nose that separates the nasal cavity from the brain and forms part of each orbit.

Mandible

The lower jaw, which is the only movable bone of the skull.

True ribs

The first 7 pairs of ribs that attach anteriorly directly to the sternum.

False ribs

The 3 pairs of ribs following true ribs that attach anteriorly to cartilage connected to the sternum.

Floating ribs

The last 2 pairs of ribs that attach only posteriorly to vertebrae and are not attached anteriorly.

Manubrium

Bone structure forming the upper portion of the sternum.

Xiphoid process

Cartilaginous structure forming the lower portion of the sternum.

Vertebral foramen

Opening in the middle of a vertebra allowing passage for the spinal cord.

Cervical vertebrae

Set of seven vertebrae (C1–C7) forming the neck.

Thoracic vertebrae

Set of 12 vertebrae (T1–T12) with a pair of ribs attached to each.

Lumbar vertebrae

Set of 5 vertebrae (L1–L5) that are the largest and strongest, bearing most of the body's weight.

Sacrum

Lower back structure formed by 5 separate bones present at birth that fuse into a single bone.

Coccyx

The tailbone forming the end of the spine, made of 4 fused small bones.

Acromion

Extension of the scapula that forms the high point of the shoulder.

Olecranon process

Large projection on the upper end of the ulna forming the prominent bone of the elbow.

Acetabulum

Large circular cavity in each side of the pelvis that articulates with the head of the femur to form the hip joint.

Pubic symphysis

Cartilaginous joint uniting the left and right pubic bones.

Calcaneus

The heel bone, which is the largest of the tarsal bones.

Abduction

Joint movement that moves a limb away from the midline.

Adduction

Joint movement that moves a limb toward the midline.

Extension

Motion that increases the angle of a joint.

Flexion

Motion that decreases the angle of a joint.

Dorsiflexion

Movement of bending the foot upward.

Plantar flexion

Movement of bending the foot downward.

Pronation

Turning downward of the palm or sole.

Supination

Turning upward of the palm or sole.

Circumduction

Movement of a limb in a circular manner.

Osteomyelitis

Inflammation of bone caused by pus-forming bacteria.

Pott disease

Tuberculosis that has spread to the spine.

Arthrosclerosis

Stiffness of joints.

Chondromalacia

Abnormal softening of cartilage.

Costochondritis

Inflammation of the cartilage that connects a rib to the sternum.

Hallux valgus

Abnormal enlargement of the joint at the base of the great toe.

Hemarthrosis

Presence of blood within a joint.

Osteoarthritis

Degenerative joint disease associated with aging, characterized by wearing away of articular cartilage and formation of osteophytes.

Rheumatoid arthritis

Chronic autoimmune disorder attacking joints and other organs, causing joints to become inflamed, thickened, swollen, painful, and immobile.

Gout

Type of arthritis characterized by deposits of uric acid crystals in joints, causing warmth, redness, and extreme sensitivity.

Ankylosing spondylitis

Disease of the spine mainly in males where joint cartilage is destroyed, intervertebral disks calcify, and bones fuse ('bamboo spine').

Herniated disk

Condition where the central mass of an intervertebral disk protrudes into the spinal column, compressing spinal nerves.

Kyphosis

An exaggerated outward curve in the thoracic spine causing a hunchback posture.

Lordosis

An exaggerated inward (forward) curve in the lumbar spine causing a swayback posture.

Scoliosis

An abnormal lateral curvature of the spine in any region.

Osteoporosis

Metabolic bone disease marked by loss of bone mass/density and increased bone porosity, leading to weakened bones.

Osteomalacia

Softening of bone tissue in adults, caused by vitamin D deficiency, renal disorders, liver disease, or intestinal disorders.

Rickets

Defective bone growth in children due to a lack of vitamin D.

Paget's disease

Disorder of aging characterized by excessive bone destruction followed by unorganized bone formation by osteoblasts, leading to thick and weak bones.

Crepitation

Grating sound produced when the ends of broken bone move together.

Callus

Bulging deposit around the area of a bone break that eventually turns into bone tissue.

Closed reduction

Procedure to manipulate and realign a fractured bone or joint dislocation without surgery.

Open reduction

Surgical procedure to realign fractured bones when closed reduction is not practical.

Arthrodesis

Surgical fusion of 2 bones.

Chondroplasty

Surgical repair of damaged cartilage.

Laminectomy

Surgical removal of the posterior portion of a vertebra.

Craniectomy

Surgical removal of a portion of the skull.

Craniotomy

Surgical incision or opening into the skull.

Cranioplasty

Surgical repair of the skull.

myel/o

Combining form meaning bone marrow or spinal cord.

chondr/o

Combining form meaning cartilage.

arthr/o

Combining form meaning joint.

spondyl/o

Combining form meaning vertebra.

rachi/o

Combining form meaning spine.

cost/o

Combining form meaning rib.