Majmaah University
College of Applied Medical Science
Department of Radiological Science and Medical Imaging
General Anatomy, Terminology
and Positioning
Dr. Yousif Mohamed Y. Abdallah
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 Anatomy is the science of the structure of the human
body, whereas physiology deals with functions of the
body, or how the body parts work. In the living subject, it
is almost impossible to study.
 Anatomy without also studying some physiology.
 Radiographic study of the human body, however, is
primarily a study of the anatomy of the various systems
with lesser emphasis on the physiology.
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Review of Structural
Organization
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Atoms
Molecules
Cell
Tissue
Organ
System
organism
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Body Systems-10
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Skeletal
Circulatory
Digestive
Respiratory
Urinary
Reproductive
Nervous
Muscular
Endocrine
Integumentary
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Skeletal
• Much general diagnostic radiography
involves exams of the bones and joints
(osteology and arthrology)
• 206 separate bones
• Divided into axial and appendicular
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Axial Skelton- 80 bones
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Cranium-8
Facial-14
Hyoid-1
Auditory ossicles-6
Cervical vert.-7
Thoracic vert.-12
Lumbar vert.-5
Sacrum-1
Coccyx-1
Sternum-1
Ribs-24
Total-80
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Appendicular Skeleton- 126
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Clavicles-2
Scapulae-2
Humeri-2
Ulnae-2
Radii-2
Carpals-16
Metacarpals-10
Phalanges-28
Hip bones-2
Femora-2
Tibias-2
Fibulas-2
Patellae-2
Tarsals-14
Metatarsals-10
Phalanges-28
total: 126
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Sesamoid Bones
• Special, oval-shaped bones found in tendons
mostly near joints
• Not present in developing fetus
• The only sesamoids that are included in the total
body bone count are the patellae
• Commonly found on the palmar surface of hand
and sometimes in tendons of other upper of
lower limb joints
• Any sesamoid can be fractured and may need to
be demonstrated radiographically
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Bone Classification
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Long
Flat
Short
Irregular
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Long Bones
• Body
• 2 ends or extremities
• Composed of compact bone or cortex,
body, spongy bone (red marrow),
medullary cavity, periosteum, hyaline
cartilage, articular cartilage and the
periosteum
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Short Bones
• Carpals and tarsals
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Flat Bones
• Consist of 2 plates of compact bone with
cancellous bone and marrow between
them
• Examples- calvarium, sternum, ribs and
scapulae
• Diploe: space between the inner and
outer table of flat bones in the cranium
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Irregular Bones
• Bones with peculiar shapes- vertebrae,
facial bones, bones of the cranial base
and bones of the pelvis
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Blood Cell Production
• RBCs (red blood cells) are produced in the
red bone marrow of certain flat and
irregular bones
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Bone Development
• Ossification begins in the sixth embryonic
week and continues until adulthood
• 2 kinds of bone formation
– Intramembranous: occurs rapidly in bones
necessary for protection (i.e. sutures of the
skull)
– Endochondral: much slower than
intramembranous; occurs in most parts of the
skeleton
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Centers of Endochondral
Ossification
• Primary center- midbody or diaphysis
• Secondary center- ends or extremities of
the long bones or epiphysis
– Epiphyseal plates: found between the
diaphysis and the epiphysis until skeletal
growth is complete
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Arthrology: study of joints
• Functional classification– Synarthrosis- immovable
– Amphiarthrosis- limited movement
– Diarthrosis- freely moveable
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Structural Classification
• #1 Fibrous: held together by fibrous
connective tissue
– Syndesmosis: only one in the body- distal
tibiofibular joint- amphiarthrodial
– Sutures: between the bones of the skullsynarthrodial
– Gomphoses: roots of the teeth- very limited
movement
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• #2 Cartilaginous: held tightly together by
cartilage
– Symphyses:example is intervertebral disksamphiarthrodial
– Synchondroses: these are temporary growth
joints; example is the acetabulum- they are
synarthrodial
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• #3 Synovial: fibrous capsule containing
synovial fluid- they are diarthodial and
some examples are the knee, elbow.
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Movement Types of Synovial
Joints
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plane or gliding
ginglymus or hinge
trochoid or pivot
ellipsoid or condyloid
sellar or saddle
spheroid or ball and socket
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General Terms
 Radiograph (ra'de-o-grof) A radiograph is a film or other base
material containing a processed image of an anatomic part of a
patient as produced by action of x-rays on an IR.
 Radiography (ra"de-og'rah-fe): The production of radiographs
and/or other forms of radiographic images.
 Radiograph vs. x-ray film: In practice, the terms radiograph and xray film (or just film) are often used interchangeably.
 The x-ray film specifically refers to the physical piece of material on
which a radiographic image is exposed.
 The term radiograph includes the film and the image.
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Radiographic examination or procedure
 A radiographer is shown positioning the patient for a
routine chest , exam or procedure (Fig. 1-33).
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5 Functions of a Radiographic
Procedure
• Positioning of the body and CR alignment
• Selection of the radiation protection
measures
• Selection of exposure factors on the
control panel
• Patient instructions relating to breathing
• Processing of the IR (image receptorcould be film or a digital plate)
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Anatomic Position
• Upright, arms adducted,
palms forward, head and
feet directed straight
ahead
• Viewing Radiographs:
Display x-rays so that the
patient is facing the
viewer in anatomic
position
R
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Body Planes, Sections and Lines
• Sagittal- any longitudinal plane dividing
the body into right and left parts
• Mid-sagittal or median plane- divides the
body into equal right and left halves
• Coronal- longitudinal plane dividing the
body into anterior and posterior parts
• Mid-coronal- divides the body into equal
anterior and posterior parts
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• Horizontal or axial plane- transverse
plane passing through the body at right
angles to the longitudinal plane; divides
into superior and inferior portions
• Oblique plane- longitudinal or transverse
that is on an angle or slant to the sagittal,
coronal or horizontal planes.
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Understanding CT and MRI
Images
• Longitudinal sections can be taken in
sagittal, coronal or oblique planes
• Transverse (axial) or cross sections
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Planes of the Skull
• Base plane
• Occlusal plane
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Base plane of skull
This precise transverse plane is formed by connecting the lines from
the infraorbital margins (inferior edge of bony orbits) to the superior
margins of the external auditory meatus (EAM, the external opening
of the ear). This is also sometimes called the anthropologic plane or
the Frankfort horizontal plane as used in orthodontics and cranial
topography to measure and locate specific cranial points or
structures.
Occlusal plane
This horizontal plane is formed by the biting surfaces of the upper and
lower teeth with jaws closed (used as a reference plane of the head
for dental and skull radiography).
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Body Surfaces and Parts
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Posterior or dorsal
Anterior or ventral
Plantar- sole of foot
Dorsal- top of anterior surface of foot, back
or posterior aspect of hand
• Palmar- palm of hand or the
anterior/ventral surface
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Radiographic Projections
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Posteroanterior or PA
Anteroposterior or AP
AP oblique (LPO and RPO)
PA oblique (LAO and RAO)
Mediolateral or Lateromedial
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Posteroanterior
(pos'tet-o-an-te're-cr)
(PA) projection
A projection of the CR from posterior to
anterior
It combines these two terms, posterior and
anterior, into one word,
abbreviated as PA.
The CR enters at the posterior surface and
exits at the anterior surface (PA projection).
It assumes a true PA without intentional
rotation, which requires the CR to be
perpendicular to the coronal body plane
and parallel to the sagittal plane, unless
some qualifying oblique or rotational
term is used to indicate otherwise
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Anteroposterior (on"ter-o-pos-te're-or) (AP) projection
 A projection of CR from anterior to posterior, the opposite of PA
 It combines these two terms, anterior and posterior, into one
word
 It describes the direction of travel of the CR, which enters at an
anterior surface and exits at a posterior surface (AP projection)
 It assumes a true AP without rotation unless a qualifier term is
also used, indicating it to be an oblique projection
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 An AP or a PA projection of the upper or lower limbs that is
obliqued or rotated and not a true AP or PA.
 Therefore it must also include a qualifying term indicating
which way it is rotated, such as medial or lateral rotation
(from AP or PA as based on the anatomic position)
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 A lateral projection described by the path of the CR.
 Two examples are the mediolateral projection of the ankle
(Fig. 1-47) and the lateromedial projection of the wrist (Fig.
1-48).
 It is determining the medial and lateral sides is again based
on the patient in the anatomic position.
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Body Positions and special
projections
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Supine
Prone
Erect
Recumbent
Trendelenburg
Fowler’s
Sim’s
Lithotomy
Decubitus
Axial
Inferosuperior or superioinferior
Tangenital
AP axial or lordotic
Transthoracic
Dorsoplantar or plantodorsal
Parietoacanthial or acanthioparietal
Submentovertex or verticosubmental (SMV and VSM)
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Supine (soo'pin)
 Lying on back, facing upward
Prone (pron)
Lying on abdomen, facing downward (head may be turned to
one side)
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Erect (i'reckt') (upright)
An upright position, to stand or sit erect
Recumbent (re-kum'bent) (reclining)
Lying down in any position (prone, supine, on side, and so on)
 Dorsal Recumbent: Lying on back (supine)
 Ventral Recumbent: Lying face down (prone)
 Lateral Recumbent: Lying on side (right or left lateral)
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Trendelenburg* (tren-del'en-berg)
A recumbent position with the whole body tilted so that the head is
lower than the feet
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Sim's position (semiprone position)
 A recumbent oblique position with the patient lying on the left
anterior side with the left leg extended and the right knee and
thigh partially flexed
 A modified Sim's position is used for insertion of the rectal tube
for barium enemas
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Fowler'st (faw'lerz) position
 A recumbent position with the body tilted so that the head is
higher than the feet
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Lithotomy (li-thoto-me) position
A recumbent (supine) position with knees and hip flexed and thighs
abducted and rotated externally, supported by ankle supports
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Lateral (later-d) position
 It refers to the side of, or a side view Specific lateral positions
described by the part closest to the IR, or that body part from
which the CR exits (Figs. 1-55 and 1-56).
 A true lateral position will always be 90° or perpendicular or at
a right angle to a true AP or PA projection.
 If it is not a true lateral, it is an oblique position.
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Oblique (ob-/~k: or ob-lik)* position
 An angled position in which neither the sagittal nor the coronal
body plane is perpendicular or at a right angle to the IR Oblique
body positions of the thorax, abdomen, or pelvis are described by
the part closest to the IR, or that body part from which the CR
exits.
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Decubitus (de-kubi-tus) (decub) position
 The word decubitus literally means to "lie down," or the position
assumed in "lying down:"
 This body position, meaning to lie on a horizontal surface, is
designated according to that surface on which the body is
resting.
 This therefore refers to the patient lying down on one of the
following body surfaces: back (dorsal), front (ventral), or side
(right or left lateral).
 In radiographic positioning, decubitus is always used with a
horizontal x-ray beam.
 Decubitus positions are essential to detect air-fluid levels or free
air in a body cavity such as in the chest or abdomen where the
air rises to the uppermost part of the body cavity.
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Right or left lateral decubitus position (AP or PA projection)
 In this position the patient lies on the side and the x-ray beam is
directed horizontally from anterior to posterior (AP) (Fig.1-61) or
posterior to anterior (PA) (Fig. 1-62)
 The AP or PA in parenthesis is important as a qualifying term to
denote the direction of the CR.
 This position is either a left lateral decub (Fig. 1-61) or right
lateral decub (Fig. 1-62).
 It is named according to the dependent side (side down).
Note: This is similar to a recumbent lateral body position except that
the x-ray beam is directed horizontally, making this a lateral
decubitus position (AP or PA projection).
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Dorsal decubitus position (left or right lateral)
 In this position the patient is lying on the dorsal (posterior)
surface with the x-ray beam directed horizontally, exiting from the
side closest to the IR (Fig. 1-63).
 The position is named according to the surface on which the
patient is lying (dorsal or ventral) and by the side dosest to the IR
(right or left).
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Ventral decubitus position (right or left lateral)
In this position the patient is lying on the ventral (anterior) surface with the xray beam directed horizontally, exiting from the side dosest to the IR (Fig. 164).
The position is named according to the surface on which the patient is lying
(ventral or dorsal) and by the side dosest to the IR (right or left).
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 Axial refers to the long axis of a structure or part (around which a
rotating body turns or is arranged).
 The term superoinferior or cephalocaudad describes a true axial
projection where the CR is directed along the long axis or center line of
the human body from the head (superior or cephalad) to the feet
(inferior or caudad) (Fig. 1-65).
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 Special application-AP or PA axial: In radiographic positioning, the term axial has
been used to describe any angle of the CR more than 10 degrees along the long
axis of the body.
 It should be noted, however, in a true sense an axial projection would be directed
along, or parallel too the long axis of the body or part.
 The term semiaxiol, or "partly" axial more accurately describes any angle along
the axis that is not truly along or parallel to the long axis.
 However, for the sake of consistency with other references, the term axial
projection will be used throughout this text to describe both axial and semiaxial
projections as defined above and as illustrated in Figs. 1-65 through 1-67.
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Inferosuperior and superoinferior axial projections
Inferosuperior projections are frequently performed for the shoulder and hip where
the CR enters below or inferiorly and exits above or superiorly (Fig. 1-67).
The opposite of this is the superoinferior projection, such as a special nasal bones
projection (Fig. 1-65).
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Tangential (tan'j'en'shaO projection
Means touching a curve or surface at only one point
A special use of the term projection to describe a projection that merely skims
a body part to project that part into profile and away from other body structures
Examples: Following are three examples or applications of the term tangential
projection as defined above: Zygomatic arch projection (Fig. 1-68).
Trauma skull projection for demonstrating depressed skull fracture (Fig. 1-69).
Special projection of patella (Fig. 1-70).
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AP axial projection-lordotic position
This is a specific AP chest projection for demonstrating the apices of the lungs. It
is also sometimes called the apical lordotic projection.
In this case the long axis of the body is angled rather than the CR.
The term lordotic comes from lordosis, a term denoting curvature of the cervical
and lumbar spine. (See Figs. 1-84 and 1-85.)
As the patient assumes this position (Fig. 1-71)/ the lumbar lordotic curvature is
exaggerated, making this a descriptive term for this special chest projection.
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Transthoracic lateral projection (right lateral position)
A lateral projection through the thorax
It requires a qualifying positioning term (right or left lateral position) to indicate
which shoulder
Note: This is a special adaptation of the projection term, meaning the CR passes
through the thorax even though it does not include an entrance or exit site. In
practice this is a common lateral shoulder projection and is referred to as a right or
left transthoracic lateral shoulder.
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Relationship Terms
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Medial v. lateral
Proximal v. distal
Cephalad v. caudad
Interior v. exterior
Superficial v. deep
Ipsilateral v. contralateral
Lordosis v. kyphosis
Scoliosis
Flexion v. extension
Ulnar deviation v. radial deviation
Dorsiflexion v. plantar flexion
Eversion v. inversion
Valgus v. varus
Medial rotation v. lateral rotation
Abduction v. adduction
Supination v. pronation
Protraction v. retraction
Elevation v. depression
Circumduction
Rotation v. tilt
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Dorsoplantar and plantodorsal projections:
 These are secondary terms for AP or PA projections of the
foot.
 Dorsoplantar (OP) describes the path of the CR from the
dorsal (anterior) surface to the plantar (posterior) surface of
the foot (Fig. 1-73).
 A special plantodorsal projection of the heel bone (calcaneus)
is called an axial plantodorsal projection (PO) because the
angled CR enters the plantar surface of the foot and exits the
dorsum surface
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Parietoacanthial and acanthioparietal projections
 The CR enters at the cranial parietal bone and exits at the
acanthion (junction of nose and upper lip) for the parietoacanthial
projection (Fig. 1-75).
 The opposite CR direction would describe the acanthioparietal
projection (Fig. 1-76).
These are also known as PA Waters and AP Reverse Waters
projections of the facial bones.
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Submentovertex (SMV) and verticosubmental (VSM) projections:
 These projections are for the skull and mandible.
 CR enters below the chin or mentum and exits at the vertex or
top of the skull for the submentovertex (SMV) projection
(Fig. 1-77).
 The less common opposite projection of this would be the
verticosubmental (VSM) projection, entering at top of skull and
exiting below mandible (not shown).
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Stay Well
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