Chapter 1: General Anatomy,

Terminology and Positioning

Dr Mohamed El Safwany, MD.

Intended learning outcome

• The student should learn at the end of this lecture general Radiological Anatomy , terminology and positioning procedures.

Review of Structural Organization

• Atoms

• Molecules

• Cell

• Tissue

• Organ

• System

• organism

Body Systems-10• Skeletal• Circulatory• Digestive• Respiratory• Urinary• Reproductive• Nervous• Muscular• Endocrine• Integumentary

Skeletal

• Much general diagnostic radiography involves exams of the bones and joints (osteology and arthrology)

• 206 separate bones

• Divided into axial and appendicular

Axial Skelton- 80 bones

• 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

Appendicular Skeleton- 126• 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

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

Bone Classification

• Long

• Flat

• Short

• Irregular

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

Short Bones

• Carpals and tarsals

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

Irregular Bones

• Bones with peculiar shapes- vertebrae, facial bones, bones of the cranial base and bones of the pelvis

Blood Cell Production

• RBCs (red blood cells) are produced in the red bone marrow of certain flat and irregular bones

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

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

Arthrology: study of joints

• Functional classification-– Synarthrosis- immovable– Amphiarthrosis- limited movement– Diarthrosis- freely moveable

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 skull-

synarthrodial– Gomphoses: roots of the teeth- very limited

movement

• #2 Cartilaginous: held tightly together by cartilage– Symphyses:example is intervertebral disks-

amphiarthrodial– Synchondroses: these are temporary growth

joints; example is the acetabulum- they are synarthrodial

• #3 Synovial: fibrous capsule containing synovial fluid- they are diarthodial and some examples are the knee, elbow.

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 receptor- could be film or a digital plate)

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

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

• 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.

Understanding CT and MRI Images

• Longitudinal sections can be taken in sagittal, coronal or oblique planes

• Transverse (axial) or cross sections

Planes of the Skull

• Base plane

• Occlusal plane

Body Surfaces and Parts

• 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

Radiographic Projections

• Posteroanterior or PA

• Anteroposterior or AP

• AP oblique (LPO and RPO)

• PA oblique (LAO and RAO)

• Mediolateral or Lateromedial

Clarification on Positioning Terms

• Position: use this when indicating the patient’s general physical position such as supine, prone, etc. It is also used to describe specific body positions such as obliques and laterals. Restrict the use of this word to the patient’s physical position.

• Projection: describes the path or direction of the central ray; restrict the use of this word to the CR

• View: not a correct positioning term in the US; restrict the use of the word view to describing the image from the vantage of the image receptor

Radiographic Criteria

• The goal of every technologist should be not just a passable radiograph, but rather an optimal one that can be evaluated by a definable standard as described under radiographic criteria– Structures shown– Position– Collimation and CR– Exposure criteria– Image markers

Image Markers and Patient ID

• All films should have two markers:– Patient ID and date– Anatomic side markers

Principle for Determining Positioning Routines

• A minimum of two projections (90 degrees from each other) is required for most procedures. Why? Because:– Certain conditions may not be visualized on one projection only– Sometimes foreign bodies are embedded and two projections

are needed to determine exact location– All fractures require two projections at 90 degree angles to

determine alignment of the fracture parts

• A minimum of three projections when joints are in interest area. Why? Because more information is needed than can be provided by two projections. See list in book on page 37 to determine which procedures require two projections and which require three.

IR (Film) Sizes

• Must be familiar with metric and traditional units or be able to convert– 20 x 25 cm or 8 x 10 in– 25.4 x 30.5 cm or 10 x 12 in– 30 x 35 cm or 11 x 14 in– 35 x 43 cm or 14 x 17 in

Body Habitus

• Hypersthenic

• Sthenic

• Hyposthenic

• Asthenic

Text Book

• David Sutton’s Radiology

• Clark’s Radiographic positioning and techniques

Assignment

• Two students will be selected for assignment.

Question

• Define 5 Functions of a Radiographic Procedures?

Thank You

38