skeleton
from the Greek word meaning "dried-up body"; system consists of bones, joints, cartilages, and ligaments.
axial skeleton
the bones that form the longitudinal axis of the body.
appendicular skeleton
the bones of the limbs and girdles.
compact bone
dense and looks smooth and homogeneous.
spongy bone
composed of small needlelike pieces of bone and lots of open space.
hematopoiesis
formation of blood cells
long bones
typically longer than they are wide; have a shaft with heads at both ends; mostly compact bone; all bones of the limbs except wrist and ankle bones.
short bones
generally cube-shaped and contain mostly spongy bone; bones of wrist and ankle, patella (sesamoid)
flat bones
thin, flattened, usually curved; two thin layers of compact bone sandwiching a layer of spongy bone between them; skull, ribs, sternum.
irregular bones
Do not fit into any of the other bone categories, made up of both spongy and compact bone; vertebrae and hip bones.
diaphysis
shaft of a long bone, makes up most of its length.
periosteum
covers and protects diaphysis, fibrous connective tissue membrane.
Sharpey's fibers
secure the periosteum to the underlying bone
epiphysis
end of a long bone; thin layer of compact bone enclosing an area filled with spongy bone.
articular cartilage
covers external surfaces of epiphyses; glassy hyaline cartilage that provides smooth, slippery surface to decrease friction at joint surfaces.
epiphyseal line
remnant of epiphyseal (growth) plate
epiphyseal plate
growth plate; flat plate of hyaline cartilage seen in young, growing bones. lengthwise growth of a long bone, replaced by bone by end of puberty.
medullary cavity (yellow marrow)
cavity inside the shaft where adipose tissue is stored in adults; forms blood cells in infants
red marrow
confined to the cavities of spongy bone of flat bones and the epiphyses of some long bones
osteocyte
mature bone cells
lacunae
small cavities in bone that contain osteocytes
lamellae
concentric circles of lacunae
Haversian canal
one of a network of tubes running through compact bone that contains blood vessels and nerves
osteon
central canal and matrix rings consisting of Haversian canals (Haversian system)
canaliculi
tiny canals, radiate outward from the central canals to all lacunae; form a transport system that connects all the bone cells to the nutrient supply through the hard bone matrix.
Volkmann's canals
run into the compact bone at right angles to the shaft.
tuberosity
large, rounded projection; may be roughened
crest
Narrow ridge of bone; usually prominent
trochanter
very large, blunt, irregularly shaped process. (The only examples are on the femur)
line
Narrow ridge of bone; less prominent than a crest
tubercle
small, rounded projection or process.
epicondyle
Raised area on or above a condyle
spine (of bone)
sharp, slender, often pointed projection
process
any bony prominence
head (of bone)
bony expansion carried on a narrow neck
facet
smooth, nearly flat articular surface
condyle
rounded articular projection
ramus
armlike bar of bone
meatus
canal-like passageway
sinus
Cavity within a bone, filled with air and lined with mucous membrane
fossa
Shallow, basinlike depression in a bone, often serving as an articular surface
groove
furrow
fissure
narrow, slitlike opening
foramen
round or oval opening through a bone
ossification
process of bone formation
osteoblasts
bone-forming cells
articular cartilages
cover the bone ends at movable joints
appositional growth
Growth by forming new layers on the surface of pre-existing layers; process of increasing in thickness rather than length.
comminuted fracture
bone breaks into many fragments; particularly common in the aged, whose bones are more brittle
compression fracture
bone is crushed; common in porous bones (i.e., osteoporotic bones)
depressed fracture
broken bone portion is pressed inward; typical of skill fracture
impacted fracture
broken bone ends are forced into each other; commonly occurs when one attempts to break a fall with outstretched arms.
spiral fracture
ragged break occurs when excessive twisting forces are applied to a bone; common sports fracture.
greenstick fracture
bone breaks incompletely, much in the way a green twig breaks; common in children, whose bones are more flexible than those of adults.
osteoclasts
giant bone-destroying cells
hypercalcemia
excessive calcium in the blood
hematoma
(bruise) mass of clotted blood showing through skin
fibrocartilage
cartilage that contains fibrous bundles of collagen, such as that of the intervertebral disks in the spinal cord.
bony callus
this forms during fracture repair when the fibrocartilage is converted to spongy bone; lasts 3-4 months
primary curvatures of spine
spinal curvatures in the thoracic and sacral regions; present when we are born.
secondary curvatures of spine
develop after birth, cervical curvature and lumbar curvature
joints
Areas where two or more bones join together
ligaments
a cord of fibrous tissue that connects bones
synarthroesis/fibrous
an immovable joint
amphiarthroses/cartilaginous
a slightly movable joint
diarthrosis/synovial
a freely movable joint
syndesmoses
The connecting fibers are longer than those of sutures; thus the joint has more "give"; joint connecting distal ends of tibia and fibula
bursae
flattened fibrous sacs lined with synovial membrane and containing a thin film of synovial fluid; bags of lubricant that act like ball bearings to reduce friction between adjacent structures during joint activity; common where ligaments, muscles, skin, te
plane joint
the articular surfaces are essentially flat, and only short slipping or gliding movements are allowed; nonaxial movements; intercarpal joints of the wrist
hinge joint
the cylindrical end of one bone fits into a trough-shaped surface on another bone; uniaxial; elbow joint, ankle joint, joints b/w phalanges of fingers
condyloid joint
Knuckle-like"; The egg-shaped articular surface of one bone fits into an oval concavity in another; allow the bone to move from side to side and back and forth; biaxial; knuckle joints
saddle joint
each articular surface has both convex and concave areas; biaxial; carpometacarpal joints in thumb
ball-&-socket joint
head fits into socket; movement in all axes; shoulder, hip
arthritis
inflammation of the joints
osteoarthritis
the most common form of arthritis; chronic degenerative condition that typically affects the aged. affects articular cartilages
rheumatoid arthritis
chronic inflammatory disorder; onset is insidious and usually occurs b/w age 40 and 50; autoimmune disease
gout
a disease in which uric acid (a normal waste product of nucleic acid metabolism) accumulates in the blood and may be deposited as needle-shaped crystals in the soft tissues of joints.
osteoporosis
an increased softening of the bone resulting from a gradual decrease in rate of bone formation; a common condition in older people.