Anatomy: Directional Terms and Body Planes

Introduction to Human Anatomy and Physiology

• Directional terms describe one body structure in relation to another, enabling clinicians to communicate effectively.
• Anatomical planes are hypothetical planes that transect the body, allowing the viewing of bodily structures from different perspectives.
• The anatomical position is a standardized reference point to avoid confusion.
• A person in anatomical position stands facing forward with arms at their sides, palms facing forward, and feet pointing forward.

Directional Terminology

• Anterior (ventral) indicates towards the front.
• Posterior (dorsal) indicates towards the back.
• Medial indicates towards the midline.
• Lateral indicates away from the midline.
• Superior (cranial) indicates towards the head.
• Inferior (caudal) indicates towards the tail.
• Proximal indicates towards the origin or torso.
• Distal indicates away from the origin or torso.
• Superficial indicates toward the body's surface (external).
• Deep indicates away from the body's surface (internal).
• Supine indicates laying face up.
• Prone indicates laying face down.

Anatomical Planes

• Frontal (or coronal) plane divides the body into anterior and posterior portions.
• Sagittal plane divides the body into left and right portions.
• Transverse plane divides the body into superior and inferior portions.
• Movements occur within each anatomical plane around an axis of motion.
• The axis of motion is perpendicular to the anatomical plane.
• Frontal plane movements occur around the sagittal axis.
• Sagittal plane movements occur around the frontal axis.
• Transverse plane movements occur around the longitudinal axis.

Organization of the Body

• The body is organized into levels, starting with chemical, then cellular, tissue, organ, organ system, and the organism as a whole.
• Chemical level includes atoms and molecules.
• Cellular level involves collections of molecules to forms cells.
• Tissue level consists of collections of similar cells performing specific functions.
• Organ level comprises discrete structures made of multiple tissue types.
• Organ system level includes groups of organs contributing to a mutual function.
• Organismal level represents the whole person with multiple organ systems working together.
• The body's systems include integumentary, lymphatic, skeletal, muscular, nervous, cardiovascular, respiratory, endocrine, digestive, urinary, and reproductive systems.

Body Regions and Cavities

• Major body regions include the head and neck, trunk, and upper and lower extremities.
• Ventral cavities: thoracic, abdominal, and pelvic.
• Dorsal cavities: cranial and vertebral.
• Membranes can be cutaneous (exterior), mucous (in between), or serous (interior).

Tissue Level

• Epithelial tissue protects, secretes, absorbs, and filters.
• Connective tissue protects, supports, and binds.
• Muscular tissue facilitates movement.
• Nervous tissue generates impulses for internal communication.

Angular Movement

• Angular movements increase or decrease the angle between bones and occur across multiple body regions.
• Special movements are specific to one or two body regions.

Movements in the Coronal (Frontal) Plane

• Adduction moves a limb toward the midline.
• Abduction moves a limb away from the midline.
• Lateral flexion bends sideways.

Movements in the Sagittal Plane

• Flexion decreases the angle between two bones.
• Extension increases the angle between two bones.

Movements in the Transverse Plane

• Rotation turns a bone around its longitudinal axis.
• Internal rotation turns a bone towards the midline.
• External rotation turns a bone away from the midline.

Special Movements

• Elevation/depression glides a body part superiorly or inferiorly.
• Radial/ulnar deviation moves the wrist towards the radius or ulna.
• Inversion/eversion tilts the sole of the foot medially or laterally.
• Dorsiflexion/plantarflexion moves the ankle upwards or downwards.
• Protraction/retraction glides a body part anteriorly or posteriorly.
• Horizontal flexion/extension moves a limb toward or away from the midline in the transverse plane.
• Supination/pronation rotates the forearm so the palms are up or down.
• Opposition touches the tip of the thumb to the tip of another finger.

Terminology

• A prefix is a word or letter placed before another.
• A root word is the core word.
• A suffix is a word or letter placed after another.

Imaging Techniques

• Radiography uses X-rays to form 2-dimensional images, where dense objects appear bright.
• CT scans use X-rays to form 3-dimensional images, where dense objects appear bright.
• MRI uses magnetic materials to form 3-dimensional images; T1-weighted images show fat as bright, and T2-weighted images show water as bright.
• Ultrasound uses ultrasound waves to form 2D or 3D images, where dense objects appear bright. The anterior-posterior (AP) view is a type of standard view in medical radiography.

Radiography Overview

• Radiography uses X-rays to view internal human anatomy with dense structures appearing bright.
• It is used for bones, organs, and dense structures and is quick, requires low expertise, and is inexpensive.
• Radiography provides a 2D image with low resolution and involves radiation exposure.

Computed Tomography (CT) Overview

• CT uses X-rays for viewing internal anatomy, highlighting dense structures.
• It is used on bones, organs, and dense structures.
• CT provides a 3D image with a deep view and high resolution, is relatively quick and cheap.
• CT involves very high radiation exposure and can be reasonably expensive, requiring high expertise.

Magnetic Resonance Imaging (MRI) Overview

• MRI uses magnetic materials to view internal human anatomy.
• It's used for tissues containing fluid.
• MRI provides a 3D image with deep view and high resolution without radiation exposure.
• MRI is inaccessible, slow, expensive, requires high expertise, and is not suitable for claustrophobic people.

Ultrasound (US) Overview

• Ultrasound uses ultrasound waves to view internal human anatomy, emphasizing dense structures.
• It's used for soft tissues, organs, and superficial structures.
• Ultrasound provides "real time" imaging, is dynamic, inexpensive, and involves no radiation exposure.
• US has low resolution, allows superficial viewing only, and requires high expertise.

Imaging Checklist

• Written information on the image should include patient information, date of image, referrer information, and provisional diagnosis.
• Orientation notes should include type of scan, view or position, and region or side.
• Assessment of the image should include quality.
• The report should include the patient's presenting signs, symptoms, your clinical findings then the radiology report.