Chapter 1 - Introduction


Surface Anatomy
     Anatomical description requires universally accepted standards of reference and language for describing the relative position of structures and organs. These standards include the anatomical position.
  Anatomical position
     In the anatomical position the person stands with the legs together and the feet flat on the floor, the hands are at the sides, and the palms face forward.
     Anatomical directions are used to describe the relative positions of various organs. These directions come in opposing pairs and include:
  Anterior (ventral) vs. Posterior (dorsal) - anterior or ventral refers to the front of the body; posterior or dorsal refers to the back of the body.
  Cranial (cephalic) vs. Caudal - cranial or cephalic is toward the head; caudal is toward the tailbone (coccyx).
  Superior vs. Inferior - superior is toward the head; inferior is toward the feet.
  Medial vs. Lateral - medial is toward the midline of the body; lateral is away from the midline of the body.
  Proximal vs. Distal - proximal is toward the attached base; distal is away from the detached base.
  Superficial vs. Deep - superficial is toward the body surface; deep is toward the interior of the body.
Sectional Anatomy
     Sectional anatomy divides the three dimensional structure or body into cut sections that reveal the internal positions of structures and organs. There are three planes by which sections are revealed:
  Frontal or Coronal Plane is parallel to the longitudinal axis of the body and divides the body into anterior and posterior sections.
  Sagittal Plane is also parallel  to the longitudinal axis of the body that divides the body into right and left sections. Subcategories of this plane are:
  midsagittal plane that divides the body along the midline into equal right and left parts; and
  parasagittal plane that divides the body parallel to the midsagittal plane but in unequal right and left sections.
  Transverse Plane is at a right angle to the long axis of the body and divides the body into superior and inferior sections. The sections are called transverse sections or cross sections.
Ventral Body Cavity
     Many vital organs are suspended in the ventral body cavity or coelom. This cavity contains the organs of the respiratory, cardiovascular, digestive, urinary and reproductive systems. The ventral body cavity is divided by a muscular sheet called the diaphragm into a superior thoracic cavity and an inferior abdominopelvic cavity. The organs that project into these cavities are called viscera (sing. viscus (organ in Latin)).
Thoracic Cavity
     The thoracic cavity is divided into left and right pleural cavities by the mediastinum.
  Pleural cavity contains the lungs and is lined by serous membranes called pleurae (sing. pleura (rib in Greek)).
  Mediastinum (middle wall in Latin) consists of all the organs between the pleural cavities including the lower parts of the esophagus and trachea, thymus, the major blood vessels leaving the heart and the pericardial cavity.
  Pericardial cavity contains the heart and is lined by a serous membrane called the pericardium.
Abdominopelvic Cavity
     The abdominopelvic cavity contains a peritoneal cavity that is lined by a serous membrane called the peritoneum. The abdominopelvic cavity can be divided into a superior abdominal cavity and an inferior pelvic cavity.