Overview
This lecture introduces the foundational concepts of anatomy, including anatomical position, common directional terms, and the main anatomical planes and sections used to describe locations and relationships in the human body.
Anatomical Position
- Anatomical position is the standard reference: standing, facing forward, arms at sides, palms forward, thumbs pointing outward.
- All anatomical descriptions and directional terms refer to this position, regardless of the subject's actual posture.
Directional Terms in Anatomy
- Anterior (ventral) means toward the front; e.g., the sternum is anterior to the vertebral column.
- Posterior (dorsal) means toward the back; e.g., the vertebral column is posterior to the sternum.
- Superior means toward the top; e.g., the nose is superior to the mouth.
- Inferior means toward the bottom; e.g., the mouth is inferior to the nose.
- Cranial (cephalic) means toward the head, used mainly for the skull/vertebral column.
- Caudal means toward the tail or bottom, for brain/spinal cord references.
- Medial means toward the midline; e.g., the nose is medial to the ears.
- Lateral means toward the side; e.g., ears are lateral to the nose.
- Superficial (external) means toward or on the surface; e.g., skin is superficial to bone.
- Deep (internal) means away from the surface; e.g., bones are deep to the skin.
- Proximal means closer to the origin (shoulder or hip); e.g., elbow is proximal to the wrist.
- Distal means farther from the origin; e.g., wrist is distal to the elbow.
Practice Examples
- The nose is inferior and medial to the eyes.
- The ears are lateral and posterior to the nose.
- Hair is superficial/external to the skull.
- The biceps brachii muscle originates proximally (or superiorly) on the scapula and inserts distally (or inferiorly) on the radius.
Anatomical Planes and Sections
- Sagittal plane divides the body into left and right parts; midsagittal is equal halves, parasagittal is unequal.
- Coronal (frontal) plane divides into anterior (front) and posterior (back) parts.
- Axial (transverse, horizontal, cross) plane divides into superior (top) and inferior (bottom) parts.
- In radiology, axial images are viewed from foot to head (opposite to classical anatomy view).
Orientation in Imaging
- In axial CT, anterior is at the top of the image, posterior at the bottom; right and left correspond to the patient's sides as if facing their feet.
- Practice in identifying planes: A = axial, B = sagittal, C = coronal.
- Posterior left of trunk = left and back on the imaging view.
Key Terms & Definitions
- Anatomical Position — Standard body stance for reference.
- Anterior/Posterior — Front/back direction.
- Superior/Inferior — Top/bottom direction.
- Medial/Lateral — Toward midline/side.
- Superficial/Deep — Surface/inside relation.
- Proximal/Distal — Closer/further from origin.
- Sagittal/Coronal/Axial Planes — Main sections to view/describe internal anatomy.
Action Items / Next Steps
- Review and memorize key directional terms.
- Practice labeling anatomical planes and body parts using the correct terms.
- Prepare for quizzes on anatomical positions, directional terms, and planes.