General Anatomy & Radiographic Positioning Terminology - Part 1

Vocabulary flashcards covering anatomy positioning terms, body planes, surface landmarks, habitus types, osteology, ossification, and joint classifications from the lecture.

Central Ray (CR)

The primary beam of radiation used in radiographic positioning to center a body part and ensure proper alignment with the image receptor.

Image Receptor (IR)

The device that receives the radiation exit beam and creates the image, requiring alignment with the central ray and body part.

Coronal Plane

A plane that passes through the body vertically from one side to the other, dividing it into anterior and posterior segments.

Midcoronal Plane (Midaxillary Plane)

A specific plane passing through the midline of the body, dividing it into equal anterior and posterior halves.

Sagittal Plane

A plane passing vertically through the body from front to back, dividing the body into right and left segments.

Midsagittal Plane (MSP)

A specific plane passing through the midline of the body, dividing it into equal right and left halves.

Transverse / Horizontal Plane

A plane passing crosswise through the body at right angles to the longitudinal axis, dividing the body into superior and inferior portions; also called an axial plane.

Oblique Plane

A plane passing through the body at any angle between the sagittal, coronal, and transverse planes.

Interiliac Plane

A special plane that transects the pelvis at the top of the iliac crests.

Occlusal Plane

A special plane formed by the biting surfaces of the upper and lower teeth that lines up with the mastoid tip.

Thoracic Cavity

One of the two great cavities of the torso, containing the pleural membranes, lungs, trachea, esophagus, pericardium, heart, and great vessels.

Abdominal Cavity

The upper portion of the abdominopelvic cavity containing the peritoneum, liver, gallbladder, pancreas, spleen, stomach, intestines, ureters, and major blood vessels.

Pelvic Cavity

The lower portion of the abdominopelvic cavity containing the rectum, urinary bladder, and parts of the reproductive system.

Mastoid Tip

An external surface landmark corresponding to the level of vertebra $C1$.

Gonion

An external surface landmark at the angle of the mandible corresponding to the level of vertebrae $C2$ and $C3$.

Hyoid Bone

An external surface landmark corresponding to the level of vertebrae $C3$ and $C4$.

Thyroid Cartilage

An external surface landmark corresponding to the level of vertebra $C5$.

Vertebra Prominens

An external surface landmark corresponding to the level of vertebrae $C7$ and $T1$.

Jugular Notch

An external surface landmark located at the level of vertebrae $T2$ and $T3$

Sternal Angle

An external surface landmark corresponding to the level of vertebrae $T4$ and $T5$.

Inferior Angle of Scapulae

An external surface landmark corresponding to the level of vertebra $T7$.

Xiphoid Process

An external surface landmark corresponding to the level of vertebrae $T9$ and $T10$.

Inferior Costal Margin

An external surface landmark corresponding to the level of vertebrae $L2$ and $L3$.

Superior Iliac Crest

An external surface landmark corresponding to the level of vertebrae $L4$ and $L5$.

Anterior Superior Iliac Spine (ASIS)

An external surface landmark corresponding to the level of vertebrae $S1$ and $S2$.

Coccyx

An external surface landmark corresponding to the level of the pubic symphysis and greater trochanters.

Body Habitus

Common variations in body shape that affect the positioning, centering, technical factors, and location of internal organs such as the heart, lungs, diaphragm, stomach, colon, and gallbladder.

Sthenic Body Habitus

A body habitus type representing 50% of the population that is near average in height, weight, and length.

Hyposthenic Body Habitus

A body habitus type representing 35% of the population that is generally tall and thin with a long torso.

Hypersthenic Body Habitus

A massive body habitus type representing 5% of the population, characterized by broad shoulders and hips, a short torso, shorter height, and a very high diaphragm.

Asthenic Body Habitus

A frail, tall, and thin body habitus type representing 10% of the population, where the stomach extends to its lowest location.

Osteology

The study of bones.

Axial Skeleton

The skeletal division that protects vital organs, supports the head, neck, and trunk, maintains upright posture, and provides muscle attachment.

Appendicular Skeleton

The skeletal division that allows a wide range of movement, supports body weight through the pelvis and lower limbs, and functions in locomotion and object manipulation.

Compact Bone (Cortex)

The strong, dense outer layer of bone that provides protection, strength, and support.

Spongy Bone

Internal bone tissue composed of trabeculae containing red marrow for red and white blood cell production and yellow marrow for storing fat cells.

Medullary Cavity

The central cavity inside long bones containing trabeculae and yellow marrow.

Periosteum

A tough, fibrous connective tissue membrane covering bones (except at articular cartilage) through which blood vessels and nerves enter and exit.

Endosteum

The tissue lining the medullary cavity inside bones.

Nutrient Foramen

An opening in the periosteum located near the center of all long bones through which blood vessels and nerves pass.

Intramembranous Ossification

A fast embryonic bone formation process where flat bones (cranium, clavicles, sternum, scapula, mandible) develop directly from fibrous membranes (mesenchyme).

Endochondral Ossification

A slower embryonic bone formation process where short, irregular, and long bones develop from hyaline cartilage.

Primary Ossification

Bone formation that begins before birth, forming all short bones, irregular bones, and the central shaft (diaphysis) of long bones.

Diaphysis

The long shaft of a long bone formed during primary ossification.

Secondary Ossification

Bone development occurring after birth where separate bone segments form at the ends of long bones.

Epiphysis

The end section of a long bone formed during secondary ossification.

Epiphyseal Plate

A plate of cartilage between the diaphysis and epiphysis during development that is a common fracture site in pediatric patients and unites into a line by age $21$.

Long Bones

Bones consisting of a body/shaft and two articular extremities, found exclusively in the extremities.

Short Bones

Bones consisting mainly of cancellous bone containing red marrow with a thin outer layer of compact bone, allowing minimal motion flexibility (e.g., carpals and tarsals).

Flat Bones

Bones made of two tables of compact bone separated by a narrow space containing cancellous bone and red marrow (diploe); examples include the cranium, sternum, and scapula.

Diploe

The inner layer of cancellous bone and red marrow situated between the two compact bone tables in flat bones.

Irregular Bones

Bones with peculiar shapes that do not fit other categories, consisting of an exterior compact bone layer and an interior cancellous bone with red marrow (e.g., vertebrae and pelvis).

Sesamoid Bones

Small, oval bones that develop in and beside tendons to decrease wear on tendons, the patella being the largest example.

Arthrology

The study of joints.

Synarthroses

A functional classification for immovable joints.

Amphiarthroses

A functional classification for slightly moveable joints.

Diarthroses

A functional classification for freely moveable joints.

Fibrous Joints

The strongest and virtually immovable structural joint type, lacking a joint cavity and united by connective tissue or ligaments (e.g., syndesmosis, suture, gomphosis).

Cartilaginous Joints

Barely moveable structural joints lacking a joint cavity that are united by hyaline cartilage or fibrocartilage (e.g., symphysis, synchondrosis).

Synovial Joints

Complex, freely moveable joints surrounded by an articular capsule composed of an outer fibrous capsule and an inner layer containing synovial fluid.

Gliding Joint

A uniaxial synovial joint with flat or slightly curved surfaces where bones slide past one another (e.g., intercarpal and intertarsal joints).

Hinge Joint

A uniaxial synovial joint allowing only flexion and extension movements (e.g., elbow, knee, and ankle joints).

Pivot Joint

A uniaxial synovial joint in which one bone rotates around another (e.g., atlas and axis joint).

Ellipsoid Joint

A biaxial synovial joint featuring an oval-shaped surface fitting into an oval depression, permitting movement in two directions (e.g., radiocarpal joint).

Saddle Joint

A biaxial synovial joint in which both articulating surfaces are saddle-shaped (e.g., carpometacarpal joint between trapezium and 1st metacarpal).

Ball and Socket Joint

A multiaxial synovial joint where a round head fits into a cup-like socket, permitting movement in many axes (e.g., hip and shoulder joints).

Tendon

A connective tissue structure that attaches muscle to bone and helps move the body.

Ligament

A connective tissue structure that connects bone to bone, holds joints together, and provides stability.