Rad 101 Ch 3 in Merrills-General Anatomy & Radiographic Positioning & Terminology

tangential relationship

Occasionally the central ray is directed toward the outer margin of a curved body surface to profile a body part just under the surface and project it free of superimposition. This is called a tangential projection because of the tangential relationship formed between the central ray and the entire body or body part.

ASIS (anterior superior iliac spine)

S1-2;

method

Some radiographic projections and procedures are named after individuals (e.g., Waters, Towne) in recognition of their development of a method to show a specific anatomic part. Method, which was first described in the fifth edition of this atlas, describes the specific radiographic projection that the individual developed. Most methods are named after an individual; however, a few are named for unique projections. The method specifies the x-ray projection and body position, and it may include specific items such as IR, CR, or other unique aspects. In this atlas, standard projection terminology is used first, and a named method is listed secondarily (e.g., PA axial projection; Towne method).

2'' above the jugular notch

T1; top of the sternum, below the adam's apple

jugular notch

T2-3; top of sternum 'U'

sternal angle

T4-5; 2-3 fingers below notch

inferior angles of the scapula

T7; lower angle of the scapula

xiphoid process

T9-10; between the breasts

interilliac plane

The interiliac plane transects the pelvis at the top of the iliac crests at the level of the fourth lumbar spinous process. It is used in positioning the lumbar spine, sacrum, and coccyx.

view

The term is used to describe the body part as seen by the IR. Use of this term is restricted to the general discussion of a finished radiograph or image. View and projection are exact opposites. For many years, view and projection were often used interchangeably, which led to confusion. In the United States, projection has replaced view as the preferred terminology for describing radiographic images. In Canada, view remains an acceptable positioning term. For consistency, this atlas refers to all views as images or radiographs.

endosteum

The tissue lining the medullary cavity of bones

lordotic position

This position is achieved by having the patient lean backward while in the upright body position so that only the shoulders are in contact with the IR

fracture

a break in the bone; classified according to the nature of the break • Compression • Open or compound • Simple • Greenstick • Transverse • Spiral or oblique • Comminuted • Impacted

long bones have

a central cavity called the medullary cavity, which contains trabeculae filled with yellow marrow. In long bones, the red marrow is concentrated at the ends of the bone and not in the medullary cavity.

lateral projection

a perpendicular central ray enters one side of the body or body part, passes transversely along the coronal plane, and exits on the opposite side. Lateral projections can enter from either side of the body or body part as needed for the examination. This can be determined by the patient's condition or ordered by the physician. When a lateral projection is used for head, chest, or abdominal radiography, the direction of the central ray is described with reference to the associated radiographic position. A left lateral position or right lateral position specifies the side of the body closest to the IR and corresponds with the side exited by the central ray

anteroposterior projection

a perpendicular central ray enters the anterior body surface and exits the posterior body surface. This is an AP projection. The patient is shown in the supine or dorsal recumbent body position. AP projections can also be achieved with upright, seated, or lateral decubitus positions.

posteroanterior projection

a perpendicular central ray is shown entering the posterior body surface and exiting the anterior body surface. This illustrates a posteroanterior (PA) projection with the patient in the upright body position. PA projections can also be achieved with seated, prone (ventral recumbent), and lateral decubitus positions.

all bones are composed of...

a strong, dense outer layer called the compact bone and an inner portion of less dense spongy bone. The hard outer compact bone protects the bone and gives it strength for supporting the body. The softer spongy bone contains a spiculated network of interconnecting spaces called the trabeculae. The trabeculae are filled with red and yellow marrow.

flexion

act of bending a joint; opposite of extension

ellipsoid joint

allows flexion, extension, abduction, adduction and circumduction examples: radio carpal (wrist) joint

saddle joint

allows movement similar to ellipsoid; difference is in the shapes of the articular surfaces examples: carpometacarpal joint between the trapezium and first metacarpal

pivot joint

allows rotation around a single axis examples: atlantoaxial joint (C1-C2)

midcoronal plane (MCP)

also called midaxillary plane; the specific plane that passes through the midline and divides it into equal anterior and posterior parts

AP projection

anterior-posterior; CR enters the anterior surface and exits the posterior

long bones

are found only in the limbs. They consist primarily of a long cylindric shaft called the body and two enlarged, rounded ends that contain a smooth, slippery articular surface. A layer of articular cartilage covers this surface. The ends of these bones all articulate with other long bones. The femur and the humerus are typical long bones. The phalanges of the fingers and toes are also considered long bones. A primary function of long bones is to provide support.

depressions

are hollow or depressed areas sinus recess, groove, cavity, or hollow space, such as (1) recess or groove in bone, as used to designate a channel for venous blood on inner surface of cranium; (2) air cavity in bone or hollow space

sesamoid bones

are small and oval. They develop inside and beside tendons. Their precise role is not understood. Experts believe that they alter the direction of muscle pull and decrease friction. protects the tendon from excessive wear The largest sesamoid bone is the patella, or the kneecap. Other sesamoids are located beneath the first metatarsophalangeal articulation of the foot and on the palmar aspect of the thumb at the metacarpophalangeal joint of the hand. Two small but prominent sesamoids are located beneath the base of the large toe. Similar to all other bones, they can be fractured.

symphysis pubis

at the same level as the greater trochanter of femur

bone functions

attachment for muscles mechanical basis for movement protection of internal organs support frame for body storage for calcium, phosphorus, and other salts production of red and white blood cells

coracoid or coronoid

beaklike or crownlike process

primary ossification

begins before birth and forms long central shaft in long bones (diaphysis)

Primary Ossification

begins before birth and forms the entire bulk of the short and irregular bones. This process forms the long central shaft in long bones. During development only, the long shaft of the bone is called the diaphysis

Common variations in the shape and size of the human body are termed..

body habitus

left anterior oblique (LAO)

body is rotated so that the left anterior side of the patient is closer to the table or I angle of rotation us specific for anatomy of interest

left posterior oblique (LPO)

body is rotated so that the left posterior side of the patient is closest to the table or IR

right anterior obliques (RAO)

body is rotated so that the right anterior side of the patient is closest to the table or IR

right posterior oblique (RPO)

body is rotated so that the right posterior side of the patient is closest to the table or IR

medullary cavity

central cavity of long bones contains trabeculae filled with yellow marrow red marrow found in end of long bones

circumduction

circular movement of a limb

fissure

cleft or deep groove

malleolus

club-shaped process

flat bones

consist largely of two tables of compact bone. The narrow space between the inner and outer tables contains cancellous bone and red marrow, or diploë, as it is called in flat bones. The bones of the cranium, sternum, and scapula are examples of flat bones. The flat surfaces of these bones provide protection, and their broad surfaces allow muscle attachment.

short bones

consist mainly of cancellous bone containing red marrow and have a thin outer layer of compact bone. The carpal bones of the wrist and the tarsal bones of the ankles are the only short bones. They are varied in shape and allow minimum flexibility of motion in a short distance.

fibrous joints

do not have any joint cavity

trochanter

either of two large, rounded, and elevated processes (greater or major and lesser or minor) located at junction of neck and shaft of femur

upright

erect or marked by a vertical position

head

expanded end of a long bone

processes or projections

extend beyond or project out from the main body of a bone

plantar flexion

flexion or bending of the foot downward torward the sole

dorsiflexion

flexion or bending of the foot toward the leg

hyperextension

forced or excessive extension (straightening) of a limb or joints

hyperflexion

forced overflexion (bending) of a limb or joint

nondisplaced

fracture in which bone retains its normal alignment

closed

fracture that does not break through the skin

Diarthroses

freely movable

sulcus

furrow, trench or fissure like depression

recumbent

general term for lying down in any position

organ affected by body habitus

heart, lungs, diaphragm, stomach, colon, gallbladder

foramen

hole in a bone for transmission of blood vessels and nerves

depression

hollow or depressed area

hamulus

hook-shaped process

horn

hornlike process on a bone

intramembranous ossification

how flat bones are formed

Synarthroses

immovable joints

notch

indentation into border of a bone

spongy bone

inner, less dense layer contains a spiculated network called trabeculae

invert/inversion

inward turning of the foot at the ankle

midsagittal plane

is a specific sagittal plane that passes through the midline of the body and divides it into equal right and left halves

projection

is defined as the path of the central ray as it exits the x-ray tube and goes through the patient to the IR. Most projections are defined by entrance and exit points in the body and are based on the anatomic position. When the central ray enters anywhere in the front (anterior) surface of the body and exits the back (posterior), an anteroposterior (AP) projection is obtained. Regardless of which body position the patient is in (e.g., supine, prone, upright), if the central ray enters the anterior body surface and exits the posterior body surface, the projection is termed an AP projection

sthenic

is the most common. average persons habitus

ossification

is the term that applies to the development and formation of bones begins in the second month of embryonic life

position

is used in two ways in radiology. One way identifies the overall posture of the patient or the general body position. The patient may be described as upright, seated, or supine. The second use of position refers to the specific placement of the body part in relation to the radiographic table or IR during imaging. This is the radiographic position and may be a right lateral, left anterior oblique, or other position depending on the examination and anatomy of interest.

hypersthenic

large frame, broad, husky. least common

tuberosity

large, rounded, and elevated process

Three primary decubitus positions are named according to the body surface on which the patient is lying:

lateral decubitus (left or right), dorsal decubitus, and ventral decubitus. Of these, the lateral decubitus position is used most often to show the presence of air-fluid levels or free air in the chest and abdomen.

left lateral decubitus position

left lateral recumbent position with a horizontal CR (AP projection)

line

less prominent ridge than a crest; a linear elevation

styloid

long, pointed process

prone

lying face down

supine

lying on the back

adbuct or abduction

movement of a part away from the central axis of the body or body part

adduct or adduction

movement of a part toward the central axis of the body or the body part

Secondary ossification

occurs after birth when a separate bone begins to develop at both ends of each long bone. Each end is called the epiphysis. At first, the diaphysis and the epiphysis are distinctly separate. As growth occurs, a plate of cartilage called the epiphyseal plate develops between the two areas. This plate is seen on long bone radiographs of all pediatric patients. The epiphyseal plate is important radiographically because it is a common site of fractures in pediatric patients. Near age 21 years, full ossification occurs, and the two areas become completely joined; only a moderately visible epiphyseal line appears on the bone.

secondary ossification

occurs after birth when separate bones begin to develop at both ends (epiphysis) of long bones

evert/eversion

outward turning of the foot at the ankle

surface landmarks

palpable landmarks to determine location of body parts

coronal plane

passes through the body vertically from side to side. dividing the body into anterior and posterior (front and back)

anatomic position

patient is standing erect with palms facing forward, standing on their toes

synovial joints

permit a wide range of motion, and they all are freely movable. These joints are the most complex joints in the body.

hinge joint

permits flexion and extension only examples: elbow and knee

ball and socket joint

permits widest range of motion examples: hip and shoulder

asthenic

petite, frail, very thin

fossa

pit, fovea, or hollow space

lateral position

positions are always named according to the side of the patient that is placed closest to the IR

PA projection

posterior-anterior; CR enter the posterior surface and exits the positir

red marrow

produces red and white blood cells

protuberance

projecting part or prominence

epicondyle

projection above a condyle

The abdomen is often divided into four clinical divisions called

quadrants; The midsagittal plane and a horizontal plane intersect at the umbilicus and create the boundaries. The quadrants are named as follows: • Right upper quadrant (RUQ) • Right lower quadrant (RLQ) • Left upper quadrant (LUQ) • Left lower quadrant (LLQ)

sinus

recess, groove, cavity, or hollow space such as: -recess of groove in bone, as used to designate a channel for venous blood or inner surface of cranium -air cavity in bone or hollow space in other tissue (used to designate a hollow space within a bone, as in paranasal sinuses) - fistula or suppurating channel in soft tissues

sims position

recumbent position with the patient lying on the left anterior side (semiprone) with left leg extended and right knee and thigh partially flexed

posterior (dorsal)

refers to back part of body or organ (note, however, that the superior surface of the foot is referred to as the dorsal surface)

anterior (ventral)

refers to forward or front part of body or forward part of an organ

central

refers to middle area or main part of an organ

inferior

refers to nearer the feet or situated below

superior

refers to nearer the head or situated above

contralateral

refers to part or parts on opposite side of body

ipsilateral

refers to part or parts on same side of body

peripheral

refers to parts at or near the surface, edge, or outside of another body part

lateral

refers to parts away from median plane of body or away from the middle of another body part to the right or left

caudad

refers to parts away from the head of the body, toward the feet

deep

refers to parts far from the surface

distal

refers to parts farthest from point of attachment, point of reference, origin, or beginning; away from center of body

superficial

refers to parts near skin or surface

proximal

refers to parts nearer point of attachment, point of reference, origin, or beginning; toward center of body external refers to parts outside an organ or on outside of body

medial

refers to parts toward median plane of body or toward the middle of another body part

cephalad

refers to parts toward the head of the body

internal

refers to parts within or on the inside of an organ

visceral

refers to the covering of an organ

palmar

refers to the palm of the hand

planter

refers to the sole of the foot

dorsum

refers to the top or anterior surface of the foot or to the back or posterior surface of the hand

parietal

refers to the wall or lining of a body cavity

crest

ridgelike process

right lateral decubitus position

right lateral recumbent positon with a horizontal CR (AP projection)

supinate/supination

rotation of forearm so that the palm is up

pronate/pronation

rotation of the forearm so that the palm is face down

condyle

rounded process at an articular extremity

4 fundamental body planes

sagittal, coronal, horizontal and oblique

displaced

serious fracture in which bones are not in anatomic alignment

open

serious fracture in which broke bone or bones project through the skin

groove

shallow linear channel

spine

sharp process

endochondral ossification

short, irregular, and long bones are created by this ossification occurs from 2 distinct centers of development: primary and secondary

gliding joint

simplest synovial joint examples: intercarpal and intertarsal joints

appendicular

skeleton; 126 bones; yellow, provides means for movement

Amphiarthroses

slightly movable

tubercle

small, rounded, and elevated process

facet

small, smooth-surfaced process for articulation with another structure

yellow marrow

stores adipose (fat) cells

extension

straightening of a joint; when both elements of the joint are in the anatomic position; normal position of a joint

compact bone

strong, dense outer layer

Some anatomists divide the abdomen into nine regions by using four planes

superior, middle and inferior

trendelenburg

supine position with head tilted downward, feet above the head

lithotomy position

supine position with knees and hip flexed and thighs abducted and rotated externally, supported by ankle or knee supports

fowler position

supine position with the head higher than the feet

left dorsal decubitis position

supine recumbent position with a horizontal CR (lateral projection)

right dorsal decubitus position

supine recumbent position with a horizontal CR (lateral projection)

oblique projection

the central ray enters the body or body part from a side angle following an oblique plane. these projections may enter from either side of the body and from anterior or posterior surfaces. If the central ray enters the anterior surface and exits the opposite posterior surface, it is an AP oblique projection; if it enters the posterior surface and exits anteriorly, it is a PA oblique projection

osteology

the detailed study of the body of knowledge relating to the bones of the body

physiology

the study of the function of the body organs

anatomy

the term applied to the science of the structure of the body

axial projection

there is longitudinal angulation of the central ray with the long axis of the body or a specific body part. This angulation is based on the anatomic position and is most often produced by angling the central ray cephalad or caudad. The longitudinal angulation in some examinations is achieved by angling the entire body or body part while maintaining the central ray perpendicular to the IR.

irregular bones

these bones are so termed because their peculiar shapes and variety of forms do not place them in any other category. The vertebrae and the bones in the pelvis and face fall into this category. Similar to other bones, they have compact bone on the exterior and cancellous bone containing red marrow in the interior. Their shape serves many functions, including attachment for muscles, tendons, and ligaments, or they attach to other bones to create joints.

hyposthenic

thinner and taller than average

oblique position

this position is achieved when the entire body or body part is rotated so that the coronal plane is not parallel with the radiographic table or IR. The angle of oblique rotation varies with the examination and structures to be shown. In this atlas, an angle is specified for each oblique position (e.g., rotated 45 degrees from the prone position). Oblique positions, similar to lateral positions, are always named according to the side of the patient that is placed closest to the IR

decubitis position

this term indicates that the patient is lying down and that the central ray is horizontal and parallel with the floor.

two cavities of the torso are

thoracic and abdominal cavities

tilt

tipping or slanting a body part slightly; tilt is in relation to the long axis of the body

periosteum

tough, fibrous connective tissue that covers bone, except at articular ends

meatus

tubelike passageway running with a bone

deviation

turning away from the regular standard or course

rotate/rotation

turning or rotating of the body or a body part around its axis rotation of a limb either medial (toward midline) or lateral (away from midline)

seated

upright position in which the patient is sitting on a chair or stool

Bones contain various knoblike projections called tubercles and tuberosities,

which are covered by the periosteum. Muscles, tendons, and ligaments attach to the periosteum at these projections. Blood vessels and nerves enter and exit the bone through the periosteum.

classification of bones

• Long • Short • Flat • Irregular • Sesamoid

axial skeleton

80 bones; blue, supports and protects the head and trunk

horizontal plane

A horizontal plane passes crosswise through the body or a body part at right angles to the longitudinal axis. It is positioned at a right angle to the sagittal and coronal planes. This plane divides the body into superior and inferior portions. Often it is referred to as a transverse, axial, or cross-sectional plane

sagittal plane

A sagittal plane divides the entire body or a body part into right and left segments. The plane passes vertically through the body from front to back.

symphysis

A slightly movable joint. The bones in this joint are separated by a pad of fibrocartilage. The ends of the bones contain hyaline cartilage. A symphysis joint is designed for strength and shock absorbency. The joint between the two pubic bones (pubic symphysis) is an example of a symphysis joint. Another example of a symphysis joint is the joint between each vertebral body. These joints all contain a fibrocartilaginous pad or disk.

the periosteum

A tough, fibrous connective tissue; covers all bony surfaces except the articular surfaces, which are covered by the articular cartilage.

gomphosis

An immovable joint occurring only in the roots of the teeth. The roots of the teeth that lie in the alveolar sockets are held in place by fibrous periodontal ligaments

suture

An immovable joint occurring only in the skull. In this joint, the interlocking bones are held tightly together by strong connective tissues. The sutures of the skull are an example

syndesmosis

An immovable joint or slightly movable joint united by sheets of fibrous tissue. The inferior tibiofibular joint is an example

oblique plane

An this plane can pass through a body part at any angle. Planes are used in radiographic positioning to center a body part to the image receptor (IR) or central ray and to ensure that the body part is properly oriented and aligned with the IR.

foramina

Bones are live organs that must receive a blood supply for nourishment or they die. Bones also contain a supply of nerves. Blood vessels and nerves enter and exit the bone at the same point, through openings called the foramina

Endochondral Ossification

Bones created by endochondral ossification develop from hyaline cartilage in the embryo and produce short, irregular, and long bones. Endochondral ossification occurs from two distinct centers of development called primary and secondary centers of ossification.

Intermembranous Ossification

Bones that develop from fibrous membranes in the embryo produce the flat bones—bones of the skull, clavicles, mandible, and sternum. Before birth, these bones are not joined. As flat bones grow after birth, they join and form sutures. Other bones in this category merge and create the various joints of the skeleton.

mastoid tip

C1; behind the ear

gonion

C2-3; angle of the mandible

hyoid bone

C3-4; neck, surrounded by muscle

thyroid cartilage

C5; adam's apple

vertebrea prominens

C7-T1; bump on back of neck

During radiography, general body positions are combined with radiographic positions to produce the appropriate image

For clarification of positioning for an examination, it is often necessary to include references to both because a particular radiographic position, such as right lateral, can be achieved in several general body positions (e.g., upright, supine, lateral recumbent) with differing image outcomes. Specific descriptions of general body positions and radiographic positions follow.

inferior costal margin

L2-3; lower angle of the ribs

iliac crest

L4-5; different for men and women

abdominal cavity

• Peritoneum • Liver • Gallbladder • Pancreas • Spleen • Stomach • Intestines • Kidneys • Ureters • Major blood vessels • Pelvic portion—rectum, urinary bladder, and parts of the reproductive system

thoracic cavity

• Pleural membranes • Lungs • Trachea • Esophagus • Pericardium • Heart and great vessels

superior region

• Right hypochondrium • Epigastrium • Left hypochondrium

inferior region

• Right inguinal • Hypogastrium • Left inguinal

middle region

• Right lateral • Umbilical • Left lateral