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Anatomy Essentials: Planes, Positions, Movements, Cavities

Anatomy Essentials (Planes, Positions, Movements, Cavities)

Anatomy Basics

  • Anatomy: descriptive study of body parts; derives from Greek terms for dissecting (ana = part, tom = cut).
  • Subdivisions:
    • Gross (Macroscopic) Anatomy
    • Microscopic Anatomy (Histology)
    • Applied/Clinical Anatomy
    • Radiological Anatomy
    • Developmental Anatomy (Embryology)
    • Surface Anatomy
    • Endoscopic Anatomy
    • Functional Anatomy
  • Importance: clear knowledge of basic anatomical terms is essential for medical professionals.

Methods of Studying Anatomy

  • Dissection
  • Surface Anatomy
  • Microscopic Anatomy
  • Embryology (Developmental)
  • Endoscopic Anatomy
  • Gross (Macroscopic) Anatomy
  • Functional Anatomy
  • Radiological Anatomy

Anatomical Position

  • Person stands upright with
    • Head, eyes, and toes directed anteriorly
    • Arms at sides with palms facing anteriorly
    • Lower limbs close together with feet parallel

Other Body Positions

  • Supine: lying on back, face upwards
  • Prone: lying on abdomen, face down
  • Lithotomy: supine with hips/knees semiflexed, thighs abducted, feet strapped
  • Other positions used for pelvic exams or childbirth

Anatomical Planes

  • Sagittal Plane: vertical plane; divides body into left and right
  • Midsagittal (Median) Plane: vertical; divides body into equal left and right halves
  • Parasagittal Plane: parallel to the midline, offset to one side
  • Coronal (Frontal) Plane: vertical; divides body into anterior and posterior
  • Transverse (Horizontal) Plane: horizontal; divides body into superior and inferior

Planes in Practice

  • Planes are imaginary lines used to section the body for orientation and imaging
  • Coronal planes are perpendicular to the midsagittal plane
  • Transverse planes are perpendicular to both sagittal and coronal planes

Directional Terms (Standard Right/Left)

  • Anterior (ventral): toward the front
  • Posterior (dorsal): toward the back
  • Superior (cranial): toward the head
  • Inferior (caudal): toward the feet
  • Medial: toward the midline
  • Lateral: away from the midline
  • Intermediate: between medial and lateral
  • Proximal: nearer to trunk/origin
  • Distal: farther from trunk/origin
  • Ipsilateral: same side
  • Contralateral: opposite sides
  • Superficial: toward the surface
  • Deep: toward the interior
  • Dorsal surface: posterior surface of hands/feet
  • Palmar surface: anterior (ventral) surface of the palm
  • Plantar surface: anterior (ventral) surface of the sole

Anatomical Terms Related to Movements

  • Flexion: angle between parts decreases
  • Extension: angle increases (straightening)
  • Abduction: limb moves away from midline
  • Adduction: limb moves toward midline
  • Medial rotation: anterior surface faces toward midline
  • Lateral rotation: anterior surface faces away from midline
  • Circumduction: circular combination of flexion, abduction, extension, and adduction (at the shoulder)
  • Elevation: raise body part toward the head
  • Depression: lower body part toward the feet
  • Protrusion: forward movement of a part
  • Retraction: backward movement of a part
  • Protraction: anterior movement of a part (e.g., scapula)
  • Dorsiflexion: foot/ankle movement so toes move upward
  • Plantar flexion: foot movement so toes point downward
  • Inversion: sole faces medially
  • Eversion: sole faces laterally
  • Pronation: forearm rotates so palm faces backward
  • Supination: forearm rotates so palm faces forward
  • Opposition: thumb and little finger move toward each other
  • Reposition: return to neutral position between thumb and finger

Body Cavities

  • Dorsal (posterior) cavity: includes
    • Cranial cavity
    • Vertebral (spinal) cavity
  • Ventral (anterior) cavity: includes
    • Thoracic cavity (contains mediastinum, pleural cavities, pericardial cavity within the mediastinum)
    • Abdominopelvic cavity (abdominal + pelvic cavities)
  • Diaphragm separates thoracic from abdominal cavities
  • Cavities are spaces that house internal organs

Quick References

  • Planes: sagittal, midsagittal, parasagittal, coronal, transverse
  • Positions: anatomical position, supine, prone, lithotomy
  • Movements: flexion/extension, abduction/adduction, rotation, circumduction, special movements (elevation/depression, protraction/retraction, dorsal/plantar flexion, inversion/eversion, pronation/supination, opposition/reposition)
  • Cavities: dorsal vs ventral; key subdivisions within each