General Anatomy and Radiographic Positioning Terminology

Vocabulary terms covering general anatomy, body planes, skeletal systems, join classifications, and radiographic positioning terminology based on the lecture notes.

ALARA

Acronym for "as low as reasonably achievable," a fundamental principle of radiation protection.

Anatomy

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

Physiology

The study of the function of the body organs.

Osteology

The detailed study of the body of knowledge related to the bones of the body.

Midsagittal plane

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

Midcoronal plane

A specific vertical plane that passes through the midline of the body, dividing it into equal anterior and posterior halves; also known as the midaxillary plane.

Horizontal plane

Passes crosswise through the body at right angles to the longitudinal axis, dividing the body into superior and inferior portions; also called an axial, transverse, or cross-sectional plane.

Oblique plane

A plane that can pass through a body part at any angle among the sagittal, coronal, and horizontal planes.

Interiliac plane

A special plane that transects the pelvis at the top of the iliac crests at the level of the fourth lumbar spinous process.

Occlusal plane

A special plane formed by the biting surfaces of the upper and lower teeth with the jaws closed.

Thoracic cavity

The superior great cavity of the torso, subdivided into a pericardial segment and two pleural portions, containing the lungs, heart, trachea, and esophagus.

Abdominal cavity

The inferior great cavity of the torso containing the liver, gallbladder, pancreas, spleen, stomach, intestines, kidneys, and ureters.

Quadrants

Four clinical divisions of the abdomen (RUQ, RLQ, LUQ, LLQ) created by the intersection of the midsagittal plane and a horizontal plane at the umbilicus.

Sthenic

The predominant body habitus type, representing $50\%$ of the population, characterized by a moderately heavy build and moderately high diaphragm.

Hyposthenic

The most difficult body habitus to classify, intermediate between sthenic and asthenic, representing $35\%$ of the population.

Asthenic

An extreme body habitus type ($10\%$ of the population) characterized by a frail build, long shallow thorax, and low stomach and gallbladder.

Hypersthenic

An extreme body habitus type ($5\%$ of the population) characterized by a massive build, short broad deep thorax, and high transverse stomach.

Axial skeleton

A group of $80$ bones that supports and protects the head and trunk.

Appendicular skeleton

A group of $126$ bones that allows the body to move in various positions and from place to place.

Trabeculae

A spiculated network of interconnecting spaces in spongy bone filled with red and yellow marrow.

Periosteum

A tough, fibrous connective tissue that covers all bony surfaces except the articular surfaces.

Endosteum

The tissue lining the medullary cavity of bones.

Ossification

The term for the development and formation of bones, which begins in the second month of embryonic life.

Diaphysis

The long central shaft of a long bone during development.

Epiphysis

A separate bone center that develops at both ends of each long bone after birth.

Epiphyseal plate

A plate of cartilage that develops between the diaphysis and epiphysis during growth, seen in long bone radiographs of pediatric patients.

Sesamoid bones

Small, oval bones that develop inside and beside tendons, such as the patella.

Arthrology

The study of the joints or articulations between bones.

Syndesmosis

A type of fibrous joint that is immovable or slightly movable and united by sheets of fibrous tissue, such as the inferior tibiofibular joint.

Symphysis

A slightly movable cartilaginous joint designed for strength and shock absorbency, such as the pubic symphysis.

Synchondrosis

An immovable cartilaginous joint containing rigid cartilage that unites two bones, such as an epiphyseal plate.

Synovial joints

The most complex joints in the body, which are all freely movable and characterized by an articular capsule and synovial fluid.

Bursae

Synovial fluid-filled sacs outside the main joint cavity that help to reduce friction between skin, tendons, muscles, and bones.

Saddle joint

A biaxial synovial joint where opposing bones fit like a rider in a saddle, such as the carpometacarpal joint of the thumb.

Condyle

A rounded process at an articular extremity.

Foramen

A hole in a bone for transmission of blood vessels and nerves.

Open fracture

A serious fracture in which the broken bone or bones project through the skin.

Anterior (ventral)

Refers to the forward or front part of the body or organ.

Caudad (caudal)

Refers to parts away from the head of the body.

Cephalad (cephalic)

Refers to parts toward the head of the body.

Contralateral

Refers to a part or parts on the opposite side of the body.

Ipsilateral

Refers to a part or parts on the same side of the body.

Distal

Refers to parts farthest from the point of attachment, origin, or center of the body.

Proximal

Refers to parts nearer the point of attachment, origin, or center of the body.

Palmar

Refers to the palm of the hand.

Plantar

Refers to the sole of the foot.

Projection

The path of the central ray as it exits the x-ray tube and goes through the patient to the image receptor (IR).

Position

Refers to the overall posture of the patient or the specific placement of the body part in relation to the table or IR.

Decubitus

A vertical body position indicates that the patient is lying down and that the central ray is horizontal (parallel with the floor).

Abduction

Movement of a part away from the central axis of the body or body part.

Adduction

Movement of a part toward the central axis of the body or body part.

Eversion

Outward turning of the foot at the ankle.

Inversion

Inward turning of the foot at the ankle.

Dorsiflexion

Flexion or bending of the foot toward the leg.

Plantar flexion

Flexion or bending of the foot downward toward the sole.