Anatomy Chapter 1 Study Notes: Orientation, Directional Terms, Planes, Quadrants, and Body Cavities
Surface Anatomy: Regional Terms
Cephalic (cephalon): Referencing the head as a whole.
Cranial (cranium): Pertaining specifically to the skull.
Facial (facies): Pertaining to the face.
Frontal (frons): Pertaining to the forehead.
Ocular or Orbital (oculus): Pertaining to the eye.
Otic (auris): Pertaining to the ear.
Nasal (nasus): Pertaining to the nose.
Buccal (bucca): Pertaining to the cheek.
Oral (oris): Pertaining to the mouth.
Mental (mentis): Pertaining to the chin.
Cervical (cervicis): Pertaining to the neck.
Thoracic (thoracis): Pertaining to the chest.
Mammary (mamma): Pertaining to the breast.
Axillary (axilla): Pertaining to the armpit.
Acromial: Pertaining to the shoulder.
Dorsal (dorsum): Pertaining to the back.
Lumbar (lumbus): Pertaining to the lower back, or loin.
Abdominal (abdomen): Pertaining to the region of the abdomen.
Umbilical (umbilicus): Pertaining to the navel.
Pelvic (pelvis): Pertaining to the pelvis in general.
Pubic (pubis): Pertaining to the anterior pelvis.
Inguinal (inguen): Pertaining to the groin; defined specifically as the crease where the thigh meets the trunk.
Gluteal (gluteus): Pertaining to the buttock.
Brachial (brachium): Pertaining to the arm; specifically defined as the segment of the upper limb closest to the trunk.
Antecubital (antecubitis): Pertaining to the front of the elbow.
Olecranal (olecranon): Pertaining to the back of the elbow.
Antebrachial (antebrachium): Pertaining to the forearm.
Carpal (carpus): Pertaining to the wrist.
Manual (manus): Pertaining to the hand.
Palmar (palma): Pertaining to the palm of the hand.
Digital (digits): Pertaining to the fingers or toes.
Pollex: Referencing the thumb.
Femoral (femur): Pertaining to the thigh.
Patellar (patella): Pertaining to the kneecap.
Popliteal (popliteus): Pertaining to the back of the knee.
Crural (crus): Pertaining to the leg, specifically measured from the knee down to the ankle.
Sural (sura): Pertaining to the calf.
Tarsal (tarsus): Pertaining to the ankle.
Calcaneal (calcaneus): Pertaining to the heel of the foot.
Pedal (pes): Pertaining to the foot.
Plantar (planta): Pertaining to the sole of the foot.
Hallux: Referencing the great toe.
Directional Terminology
Anatomical Position: Standard physical alignment where the body is standing erect, feet flat and facing forward, and arms resting at the sides with palms turned forward. All positional directional terms strictly assume the body is in this state.
Superior: Located above; positionally directed toward the head.
Inferior: Located below; positionally directed toward the feet.
Cranial or Cephalic: Positionally directed toward the head.
Caudal: Positionally directed toward the tail, which specifically refers to the coccyx in humans.
Anterior or Ventral: Positionally directed toward the front of the body.
Posterior or Dorsal: Positionally directed toward the back of the body.
Medial: Positionally directed toward the anatomical midline of the body.
Lateral: Positionally directed away from the anatomical midline of the body.
Proximal: Positionally directed toward an attached base, such as the point where a limb joins the main trunk of the body.
Distal: Positionally directed away from an attached base.
Superficial: Situated at or near the outer body surface.
Deep: Positionally directed toward the interior of the body; situated farther inward from the surface.
Right and Left Orientation: All directional descriptions of right and left always refer strictly to the patient's right and left, never the perspective of the observer.
Sectional Planes
Frontal or Coronal Plane: A sectioning plane oriented parallel to the long axis that divides the body into anterior and posterior portions.
Sagittal Plane: A sectioning plane oriented parallel to the long axis that divides the body into right and left portions.
Midsagittal Plane: A specific sagittal section passing directly through the midline, splitting the body into equal right and left halves.
Parasagittal Plane: A specific sagittal section that misses the midline, producing unequal right and left portions.
Transverse, Horizontal, or Cross-Sectional Plane: A sectioning plane oriented perpendicular to the long axis, setting it at exact right angles to both the frontal and sagittal planes; divides the body into superior and inferior portions.
Abdominopelvic Quadrants
Right Upper Quadrant (RUQ): Contains the right lobe of the liver, gallbladder, right kidney, and portions of the stomach, small intestine, and large intestine.
Left Upper Quadrant (LUQ): Contains the left lobe of the liver, stomach, pancreas, left kidney, spleen, and portions of the large intestine.
Right Lower Quadrant (RLQ): Contains the cecum, appendix, right ureter, portions of the small intestine and large intestine, and the right reproductive organs.
Left Lower Quadrant (LLQ): Contains most of the small intestine, portions of the large intestine, left ureter, and left reproductive organs.
Body Cavities and Serous Membranes
Function of Body Cavities: Internal spaces that serve three distinct structural roles:
Protect internal organs from physical shocks and impacts.
Allow internal organs to dynamically change size and shape during functional movement.
Are lined by specialized membranes that prevent friction against surrounding tissues.
Diaphragm: The muscular sheet separating the superior thoracic cavity from the inferior abdominopelvic cavity.
Thoracic Cavity: The cavity enclosed by the chest wall and diaphragm; divided into distinct sub-compartments:
Pleural Cavities: Two separate fluid-filled spaces within the thorax, each surrounding one individual lung.
Mediastinum: The central connective tissue region situated between the two pleural cavities; houses the trachea, esophagus, major blood vessels, and the pericardial cavity.
Pericardial Cavity: The specific cavity located within the mediastinum that surrounds the heart.
Abdominopelvic Cavity: The large continuous cavity located inferior to the diaphragm; contains the peritoneal cavity and is divided into two continuous regions:
Abdominal Cavity: The superior portion of the abdominopelvic cavity; contains many digestive organs and glands.
Pelvic Cavity: The inferior portion of the abdominopelvic cavity; contains the urinary bladder, reproductive organs, and the terminal portion of the digestive tract.
Serous Membrane Layers:
Visceral Layer: The inner membrane layer directly attached to and covering the organ itself.
Parietal Layer: The outer membrane layer lining the inner surface of the cavity wall.
Heart-in-Balloon Analogy: Conceptual visual model illustrating serous membrane organization. The physical projection of the heart into the pericardial cavity operates identically to pushing a fist into a fluid-filled balloon, where the inner balloon wall contacting the fist represents the visceral serous layer, and the outer balloon wall facing the room represents the parietal serous layer.