34 terms

Extremity imaging

The primary center of ossification in long bones is the
Long bones are composed of
a shaft, or diaphysis, and two extremities.
In the growing bone,
the cartilaginous epiphyseal plate (located at the extremities of long bones) is gradually replaced by bone. For this reason, the epiphyses are referred to as the secondary ossification centers.
The ossified growth area of long bones is the
vertebral joints formed by articulation of superjacent articular facets
synovial, joints, such as the knee and the TMJ, are freely movable. Most diarthrotic joints are associated with a joint capsule containing synovial fluid. Diarthrotic joints are the most numerous in the body and are subdivided according to type of movement
Amphiarthrotic joints
partially movable joints whose articular surfaces are connected by cartilage, such as intervertebral joints
Synarthrotic joints
such as the cranial sutures, are immovable.
types of bony articulations
diarthrotic (freely movable), fibrous (synarthrotic/immovable) and cartilaginous (amphiarthrotic/partially movable).
The peritoneal and pleural cavities are associated with
a lubricating serous fluid
In which type of fracture are the splintered ends of bone forced through the skin?
The type of fracture in which the splintered ends of bone are forced through the skin is
a compound fracture.
In a closed fracture
no bone protrudes through the skin
Compression fractures
are seen in stressed areas, such as the vertebrae
A depressed fracture
pushed in.
Examples of synovial pivot articulations include the
1. atlantoaxial joint.
2. radioulnar joint.
3. temporomandibular joint.
Synovial pivot joints are
diarthrotic, that is, freely movable. Pivot joints permit rotation motion. Examples include the proximal radioulnar joint that permits supination and pronation of the hand. The atlantoaxial joint is the articulation between C1 and C2 and permits rotation of the head. The temporomandibular joint is diarthrotic, having both hinge and planar movements.
Skeletal conditions characterized by faulty bone calcification include
1. osteomalacia.
2. rickets.
Rickets and osteomalacia
are skeletal disorders characterized by abnormal calcification processes.
In osteomalacia,
bones become soft and are easily misshapen.
Rickets affects
the growing bones of children and is also characterized by soft, misshapened bones—as a result of calcium salts not being deposited in bone matrix.
Osteoarthritis is
a degeneration of articular cartilage; when these surfaces then attempt to articulate and move, bone friction and pain occur
A frontal projection (AP or PA) demonstrates
the medial and lateral relationship of structures.
A lateral projection demonstrates
the anterior and posterior relationship of structures. Two views, at right angles to each other, are generally taken of most structures.
Radiographic measurement of long bones of an upper or lower extremity requires the following accessories:
Bell-Thompson scale
Radiographic measurement of long bone length
can be required on adults or children having extremity length (especially leg) discrepancies. This can be most easily performed with the use of the metallic Bell-Thompson scale secured to the x-ray tabletop adjacent to the limb being examined (or between both limbs for simultaneous bilateral examination. A 14 x 17 cassette is in the Bucky tray and 3 well-collimated exposures are made: at the hip joint, the knee joint, and the ankle joint.
The term proximal refers to
structures closer to the point of attachment. For example, the elbow is described as being proximal to the wrist; that is, the elbow is closer to the point of attachment (the shoulder) than the wrist is.
A spontaneous fracture most likely would be associated with
Spontaneous fractures
most often affect bone weakened by a pathologic condition, for example, metastatic bone disease. The spontaneous fracture occurs suddenly, without trauma.
Crepitus refers to
a crackling sound made by a body part—such as the sound of fractured ends of bones rubbing together.
Remember to always view a part in its
anatomic position
The tissue that occupies the central cavity within the shaft of a long bone in an adult is
yellow marrow
The central cavity of a long bone is
the medullary canal. It contains yellow bone marrow, the most abundant type of marrow in the body.
Red marrow is found
within the cancellous tissue forming the extremities of long bones.