Anatomical Planes

  • Transverse (or cross-sectional) plane:

    • Definition: A horizontal plane dividing the body into superior (top) and inferior (bottom) parts.

  • Midsagittal (or median) plane:

    • Definition: A vertical plane dividing the body into equal left and right halves.

  • Parasagittal plane:

    • Definition: A plane parallel to the midsagittal plane, located to the left or right of the midsagittal plane; it divides the structure into unequal portions.

  • Oblique plane:

    • Definition: A plane that passes through a structure at an angle.

Anatomic Directions

  • In the anatomical position, specific directional terms are employed to describe relative positions:
    • Anterior:
    • Also referred to as ventral; it indicates the front side of the body.
    • Posterior:
    • Also referred to as dorsal; it denotes the backside of the body.
    • Dorsal:
    • Another term for posterior; it signifies the back side.
    • Ventral:
    • Synonymous with anterior; it indicates the belly side.
    • Proximal:
    • Refers to being closer to the point of attachment or to the trunk of the body.
    • Distal:
    • Refers to being further away from the point of attachment or the trunk of the body.

Regional Anatomy

  • The human body is partitioned into two main regions:
    • Axial region:
    • Composed of the head, neck, and trunk.
    • Appendicular region:
    • Composed of the upper and lower limbs.

Regional Terms

  • Common regional terms to determine areas of the human body include:
    • Cephalic region: Refers to the head.
    • Cervical region: Refers to the neck.
    • Thoracic region: Refers to the chest area.
    • Abdominal region: Refers to the abdominal area.
    • Pelvic region: Refers to the area surrounding the pelvis.
    • Upper extremity: Refers to the upper limbs including arms and shoulders.
    • Lower extremity: Refers to the lower limbs including legs and feet.
    • Posterior cranial region: Refers to the back portion of the skull.

Body Cavities and Membranes

  • Internal organs are located within enclosed spaces known as body cavities. These body cavities are grouped into:
    • Axial aspect:
    • Definition: Completely encased in bone.
    • Cranial cavity:
      • Formation: Formed by the bones of the cranium.
      • Function: Houses the brain.
    • Vertebral canal:
      • Formation: Formed by the bones of the vertebral column.
      • Function: Houses the spinal cord.