This document provides an overview of radiographic positioning terminology and concepts. It defines common anatomical terms used to describe body positions, planes, and radiographic views. It also covers bone development, classification, and features. Key points include: - Standard terminology is used to describe patient positioning for radiographs, including terms for anatomical positions, body planes, movements, and projections. - The human skeleton consists of 206 bones that are classified as long, short, flat, irregular, or sesamoid based on their shape. - Bones develop through two processes - intramembranous ossification forms flat bones, while endochondral ossification forms long, short, and irregular bones via primary and secondary centers of

1. RADIOGRAPHIC
POSITIONING
TERMINOLOGY
A. Harvin Nelson

2. Radiographic positioning
terminology
 Radiographic positioning terminology is used
routinely to describe the position of the patient for
taking various radiographs. Standard nomenclature
is employed with respect to the anatomic position.

3. Terminology
 Basic terms of relations
 anterior is towards the front of the body (Latin: before)
 posterior is towards the back of the body (Latin: after)
 superior is towards the top of the body (Latin: above)
 inferior is towards the bottom of the body (Latin:
below)
 medial is towards the midline (Latin: middle)
 compared with median which is in the midline rather than
towards the midline

4. Terminology
 lateral is away from the midline (Latin: side)
 proximal is towards the center of the body (Latin:
near)
 distal is away from the center of the body (Latin:
far)
 superficial is towards the surface of the body
 deep is away from the surface of the body
 ipsilateral is on the same side of the body
 contralateral is on the opposite side of the body

5. Body Planes
 The full dimension of the human body as viewed in
the anatomic position can be effectively subdivided
through the use of imaginary body planes. These
planes slice through the body at designated levels
from all directions.

6. Body Planes

7. Body Planes
• Sagittal
• Coronal
• Horizontal
• Oblique

8. Body Planes
 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 .
The midsagittal plane is a specific sagittal plane that passes through the
midline of the body and divides it into equal right and left halves .
 Coronal plane
 A coronal plane divides the entire body or a body part into anterior and
posterior segments. The plane passes through the body vertically from one
side to the other The midcoronal plane is a specific coronal plane that passes
through the midline of the body, dividing it into equal anterior and posterior
halves. This plane is sometimes referred to as the midaxillary plane.
 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.

9. Body Planes
 Oblique plane
 An oblique plane can pass through a body part at any
angle among the three previously described planes. 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.
The midsagittal plane may be centered and perpendicular
to the IR with the long axis of the IR parallel to the same
plane. Planes can also be used to guide projections of the
central ray. The central ray for an anteroposterior (AP)
projection passes through the body part parallel to the
sagittal plane and perpendicular to the coronal plane.
Quality imaging requires attention to all relationships
among body planes, the IR, and the central ray.

10. SPECIAL PLANES
 Two special planes are used in radiographic
positioning. These planes are localized to a specific
area of the body only.
 Interiliac 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.


11. SPECIAL PLANES

12. SPECIAL PLANES
 Occlusal plane
 The occlusal plane is formed by the biting surfaces
of the upper and lower teeth with the jaws closed. It
is used in positioning of the odontoid process and
some head projections.

13. Body positions
 erect: either standing or sitting
 decubitus: lying down
 supine: lying on back
 Trendelenburg position: the patient is supine (on an
inclined radiographic table) with the head lower than
the feet
 prone: lying face-down
 lateral decubitus: lying on one side
 right lateral: right side touches the cassette
 left lateral: left side touches the cassette

14. Movement
 flexion: decrease in the angle of the joint
 extension: increase in the angle of the joint
 abduction: movement of limb away from midline
 adduction: movement of limb towards the midline
 pronation: movement of hand and forearm to bring the
palm facing posterior
 supination: movement of hand and forearm to bring
the palm facing anterior
 circumduction: circular movement of a joint using a
combination of flexion, abduction, extension and
adduction such that the distal limb describes a circle

15. Movement
 opposition: thumb brought to oppose another digit
 reposition: thumb repositioned back to the anatomic position
 elevation: movement of the scapular superiorly
 depression: movement of the scapular inferiorly
 eversion: movement of the sole of the foot away from the
median plane
 inversion: movement of the sole of the foot towards from the
median plane
 protrusion: movement of the mandible, lips or tongue
anteriorly
 retraction: movement of the mandible, lips or tongue
posteriorly

16. Projections
 antero-posterior (AP): central ray passes, perpendicular to the
coronal plane, from anterior to posterior
 postero-anterior (PA): central ray passes, perpendicular to the
coronal plane, from posterior to anterior
 depending on the anatomic segment to radiograph, synonyms can be
used, for example: occipito-frontal (skull); dorso-ventral (thorax); dorso-
palmar (hand)
 lateral: central ray, perpendicular to the sagittal plane and parallel
to the coronal plane, passes from one side of body to the other
 oblique: central ray passes through the body/body part through a
plane which is at an angle to the transverse plane/coronal plane
 axial: central ray passes through (or parallel) to the long axis of the
body
 in some cases, however, the central ray runs through (or parallel) to the
long axis of the skeletal segment studied (for example, the axial view of
the calcaneus)

17. BODY CAVITIES
 The two great cavities of the torso are
the thoracic and abdominal cavities . The thoracic
cavity is subdivided into a pericardial segment and
two pleural portions. Although the abdominal cavity
has no intervening partition, the lower portion is
called the pelvic cavity. Some anatomists combine
the abdominal and pelvic cavities and refer to them
as the abdominopelvic cavity.

18. BODY CAVITIES

19. Thoracic cavity
 • Pleural membranes
 • Lungs
 • Trachea
 • Esophagus
 • Pericardium
 • Heart and great vessels

20. Abdominal cavity
 • Peritoneum
 • Liver
 • Gallbladder
 • Pancreas
 • Spleen
 • Stomach
 • Intestines
 Kidneys
 • Ureters
 • Major blood vessels

21. Abdominal cavity
 •• Pelvic portion—rectum, urinary bladder, and
parts of the reproductive system

22. BODY HABITUS
 Common variations in the shape of the human body
are termed the body habitus(constitution of human
body, especially physical build). 1 determined the
primary classifications of body habitus based on his
study of 1000 patients. The specific type of body
habitus is important in radiography because it
determines the size, shape, and position of the
organs of the thoracic and abdominal cavities.

23. Landmarks

24. BODY HABITUS
 Body habitus directly affects the location of the
following:
 • Heart
 • Lungs
 • Diaphragm
 • Stomach
 • Colon
 • Gallbladder

25. External Landmarks

26. BODY HABITUS
 An organ such as the gallbladder may vary in
position by 8 inches, depending on the body
habitus. The stomach may be positioned
horizontally, high, and in the center of the abdomen
for one type of habitus and positioned vertically,
low, and to the side of the midline in another type.

27. BODY HABITUS
 Body habitus and the placement of the thoracic and
abdominal organs are also important in the
determination of technical and exposure factors for the
appropriate radiographic density and contrast and the
radiation doses.
 Contrast medium in the gallbladder may affect the
automatic exposure control detector.
 For one type of habitus, the gallbladder may lie
directly over the detector (which is undesirable); for
another, it may not even be near the detector.


28. BODY HABITUS
 The selection of kilovolt (peak) and milliampere-
second exposure factors may also be affected by
the type of habitus because of wide variations in
physical tissue density. These technical
considerations are described in greater detail in
radiography physics and imaging texts.

29. Osteology
 The adult human skeleton is composed of 206
primary bones. Ligaments unite the bones of the
skeleton. Bones provide the following:
 • Attachment for muscles
 • Mechanical basis for movement
 • Protection of internal organs
 • A frame to support the body
 • Storage for calcium, phosphorus, and other salts
 • Production of red and white blood cells

30. Osteology
 The 206 bones of the body are divided into two
main groups:
 • Axial skeleton
 • Appendicular skeleton

31. Axial skeleton

32. Appendicular skeleton

33. Classification of Bones

34. Classification of Bones
Long Bones
 The bones of the body come in a variety of sizes
and shapes. The four principal types of bones are
long, short, flat and irregular. Bones that are longer
than they are wide are called long bones. They
consist of a long shaft with two bulky ends or
extremities. They are primarily compact bone but
may have a large amount of spongy bone at the
ends or extremities. Long bones include bones of the
thigh, leg, arm, and forearm.

35. Long Bones

36. Classification of Bones
Short Bones
 Short bones are roughly cube shaped with vertical
and horizontal dimensions approximately equal.
They consist primarily of spongy bone, which is
covered by a thin layer of compact bone. Short
bones include the bones of the wrist and ankle.

37. Short Bones

38. Classification of Bones
Flat Bones
 Flat bones are thin, flattened, and usually curved.
Most of the bones of the cranium are flat bones.

39. Flat Bones

40. Classification of Bones
Irregular Bones
 Bones that are not in any of the above three categories are
classified as irregular bones. They are primarily spongy
bone that is covered with a thin layer of compact bone. The
vertebrae and some of the bones in the skull are irregular
bones.
 All bones have surface markings and characteristics that
make a specific bone unique. There are holes, depressions,
smooth facets, lines, projections and other markings. These
usually represent passageways for vessels and nerves,
points of articulation with other bones or points of
attachment for tendons and ligaments.

41. Irregular Bones

42. Classification of Bones
 Sesamoid bones are small, flat bones and are
shaped similarly to a sesame seed. The patellae
are sesamoid bones. Sesamoid bones develop
inside tendons and may be found near joints at the
knees, hands, and feet

43. Sesamoid bones

44. GENERAL BONE FEATURES
 The general features of most bones are shown in Fig A. 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. Red marrow
produces red and white blood cells, and yellow marrow stores
adipose (fat) cells.
 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.

45. BONE VESSELS AND NERVES
 Bones are live organs and 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.
 Near the center of all long bones is an opening in the
periosteum called the nutrient foramen.
 The nutrient artery of the bone passes into this opening and
supplies the cancellous bone and marrow.
 The epiphyseal artery separately enters the ends of long
bones to supply the area, and periosteal arteries enter at
numerous points to supply the compact bone.
 Veins exiting the bones carry blood cells to the body .

46. BONE VESSELS AND NERVES

47. BONE DEVELOPMENT
 Ossification is the term given to the development and
formation of bones. Bones begin to develop in the 2nd
month of embryonic life. Ossification occurs separately
by two distinct processes: intermembranous
ossification and endochondral 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.

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

49. Primary ossification

50. Secondary ossification
 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 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
.

51. Secondary ossification

52. How Many Joints Are in the Human
Body?
 The definition of joints. Some define a joint as a point
where 2 bones connect. Others suggest it is a point where
bones connect for the purpose of moving body parts.
 The inclusion of sesamoids. Sesamoids are bones
imbedded in tendons, but not connected to other bones.
The patella (kneecap) is the largest sesamoid. These bones
vary in number from person to person.
 The age of the human. Babies start out with about 270
bones. Some of these bones fuse together during growth.
Adults have about 206 named bones, with 80 in the axial
skeleton and 126 in the appendicular skeleton.
 In short, there’s no definite answer to this question. The
estimated number is between 250 and 350.

53. Types of joints

54. How Many Joints Are in the Human
Body?
 The human body has three main types of joints. They’re
categorized by the movement they allow:
 Synarthroses (immovable). These are fixed or fibrous joints.
They’re defined as two or more bones in close contact that have
no movement. The bones of the skull are an example. The
immovable joints between the plates of the skull are known as
sutures.
 Amphiarthroses (slightly movable). Also known as
cartilaginous joints, these joints are defined as two or more
bones held so tightly together that only limited movement can
take place. The vertebrae of the spine are good examples.
 Diarthroses (freely movable). Also known as synovial joints,
these joints have synovial fluid enabling all parts of the joint to
smoothly move against each other. These are the most prevalent
joints in your body. Examples include joints like the knee and
shoulder.

55. Types of freely movable joints
 There are six types of freely movable diarthrosis
(synovial) joints:
 Ball and socket joint. Permitting movement in all
directions, the ball and socket joint features the rounded
head of one bone sitting in the cup of another bone.
Examples include your shoulder joint and your hip joint.
 Hinge joint. The hinge joint is like a door, opening and
closing in one direction, along one plane. Examples include
your elbow joint and your knee joint.
 Condyloid joint. The condyloid joint allows movement, but
no rotation. Examples include your finger joints and your
jaw.

56. Types of freely movable joints
 Pivot joint. The pivot joint, also called the rotary joint or
trochoid joint, is characterized by one bone that can swivel
in a ring formed from a second bone. Examples are the
joints between your ulna and radius bones that rotate your
forearm, and the joint between the first and second
vertebrae in your neck.
 Gliding joint. The gliding joint is also called the plane join.
Although it only permits limited movement, it’s characterized
by smooth surfaces that can slip over one another. An
example is the joint in your wrist.
 Saddle joint. Although the saddle joint does not allow
rotation, it does enable movement back and forth and side
to side. An example is the joint at the base of your thumb.