38 terms

ACE Chapter 1 Skeletal System

important functions of the skeletal system
support, movement, protection, storage, and hemopoieses
formation of blood cells
two essential minerals stored in the skeleton
calcium and phosphorous
cortical bone
the dense outer layer of bones
trabecular bone
the honeycomb-like inner structure of bone
a disorder in which bone density decreases
the shaft of a long bone
proximal epiphysis
the end of the bone nearest to the midline of the body
distal epiphysis
the end of the bone farthest from the midline of the body
medullary cavity
the hollow space inside the diaphysys; yellow bone marrow cavity
a thin connective tissue layer lining the medullary cavity
epiphyseal cartilage
cartilaginous layer between the head and shaft of a long bone where bone growth occurs; growth plate
a dense connective-tissue layer, well supplied with blood vessels and nerves, surrounding the outer surface of the diaphyisis of a long bone
continuous reshaping and rebuilding of the skeleton; repairs damage to the skeleton, prevents the accumulation of too much old bone, and plays an important role in the removal of calcium and phosphorous from the bones when these minerals are deficient in the diet
Wolff's law
a principle stating that bone is capable of increasing its strength in response to stress by laying down more bone
axial skeleton
consists of 74 bones, including the skull, vertebral column, sternum, and ribs; provides the main axial support for the body and protects the CNS and the organs of the thorax
vertebral column
33 vertebrae: upper region contains seven cervical vertebrae, mid-region contains 12 thoracic vertebrae (each attached to a rib), lower region contains 5 lumbar vertebrae, the sacrum (5 fused vertebrae), and the coccyx (4 fused vertebrae)
appendicular skeleton
consists of 126 bones, including the bones of the upper and lower limbs and the pectoral and pelvic girldes
3 main types of joints
fibrous, cartilaginous, and synovial
fibrous joints
held tightly together by fibrous connective tissue and allow little or no movement
cartilaginous joints
bones are connected by cartilage and little or no movement is allowed
synovial joint
most common type of joint in the body, which is freely moveable
4 characteristics of synovial joints
an articular cartilage, an articular capsule, a synovial membrane, and synovial fluid
a strong, fibrous tissue that connects one bone to another
axis of rotation
the imaginary line of point about which an object, such as a joint, rotates
uniplanar or uniaxial joints
joints that move in one plane only and have one axis of rotation (ankles and elbows)
biplanar or biaxial joints
joints that allow movement in two planes that are perpendicular to each other (foot, knee, hand and wrist)
multiplanar or triaxial joints
joints that permit movement in three axes of rotation (hip, thumb and shoulder)
4 general groups of movements that occur in synovial joints
gliding, angular, circumduction and rotation
4 angular movements defined for synovial joints
flexion, extension, abduction and adduction
movement in which the bones comprising a joint move toward each other in the sagittal plane, decreasing the joint angle between them
the opposite of flexion and causes the angle between two adjoining bones to increase in the sagittal plane
occurs when a part of the body is moved away from the midline of the body
the opposite of abduction and refers to a movement of a body part toward the midline of the body
motion of a bone around a central (longitudinal) axis
rotating the forearm outward so the palm faces anteriorly
rotating the forearm inward so the palm faces posteriorly