Introduction to Anatomical Terminology

Introduction to Anatomical Terminology

• Anatomical position is the standard reference point for describing body structures
• Body is upright, feet slightly apart, palms forward, thumbs outward
• Directional terms describe the position of one body part relative to another
  • Superior (cranial): toward the head or upper part
  • Inferior (caudal): away from the head or toward the lower part
  • Anterior (ventral): toward or at the front
  • Posterior (dorsal): toward or at the back
  • Medial: toward or at the midline
  • Lateral: away from the midline
  • Proximal: closer to the origin or point of attachment
  • Distal: farther from the origin or point of attachment
  • Superficial: toward or at the body surface
  • Deep: away from the body surface

Body Planes and Sections

• Sagittal plane divides the body into right and left parts
  • Midsagittal (median) plane divides into equal halves
  • Parasagittal plane divides into unequal halves
• Frontal (coronal) plane divides into anterior and posterior parts
• Transverse (horizontal) plane divides into superior and inferior parts
• Oblique section is a diagonal cut between horizontal and vertical planes

Body Cavities

• Dorsal body cavity protects the nervous system
  • Cranial cavity encases the brain
  • Vertebral canal encases the spinal cord
• Ventral body cavity houses internal organs (viscera)
  • Thoracic cavity (superior)
    • Pleural cavities (2) surround the lungs
    • Mediastinum is the central region between lungs, containing heart, esophagus, trachea, and major blood vessels
    • Pericardial cavity encloses the heart
  • Abdominopelvic cavity (inferior)
    • Abdominal cavity contains stomach, intestines, spleen, liver, and other organs
    • Pelvic cavity contains urinary bladder, reproductive organs, and rectum

Body Regions

• Abdominal regions divided into nine regions
• Quadrants: four main regions (right upper, right lower, left upper, left lower)
• Other body regions, including head, neck, limbs, etc.

Body Systems

• Integumentary system: skin, hair, and nails
• Skeletal system: bones, cartilages, and ligaments
• Muscular system: skeletal muscles
• Nervous system: brain, spinal cord, and nerves
• Endocrine system: glands and hormones
• Cardiovascular system: heart and blood vessels
• Lymphatic system: lymphatic vessels, lymph nodes, and lymphoid organs
• Respiratory system: lungs and airways
• Digestive system: mouth, esophagus, stomach, intestines, and accessory organs
• Urinary system: kidneys, ureters, bladder, and urethra
• Reproductive system: gonads and associated structures

Basic Organizational Structure

• Cells: basic structural and functional units
• Tissues: groups of similar cells with a specific function
• Organs: structures of two or more tissue types working together
• Organ systems: groups of organs performing a broad function
• Body organization: cells to tissues, organs, organ systems, to the entire organism

Anatomical Variation

• Individuals exhibit significant anatomical variations (size, shape of organs, presence/absence of structures)
• Variations are important for understanding health and treatment
• Variations must be considered in medical procedures

Embryology

• Early development of body structures from fertilization to birth
• Prenatal development reveals potential issues
• Embryological knowledge helps understand congenital defects and potential treatments

Other Important Concepts

• Homeostasis: maintaining a stable internal environment
• Feedback mechanisms for homeostasis
  • Negative feedback opposes change from a set point
  • Positive feedback amplifies change from a set point
• Anatomical imaging techniques (X-rays, CT scans, MRIs, ultrasounds) for visualizing internal structures with differing specifics and applications
• Varying terminology based on the medical discipline