Anatomical Position and Body Regions Notes

Anatomical Position

  • Anatomical position is the standard reference point used to describe the location of body parts. When a body is in anatomical position it is:
    • Erect
    • Feet slightly apart
    • Palms face forward and thumbs point away from the body

Directional Terms

  • Directional terms are like a map for the human body, using the anatomical position as a reference point.

  • They allow us to explain where one structure is relative to another.

  • They are inseparable from anatomical position. Without one, the terms would be meaningless.

  • Superior (cranial): toward the head or above another structure.

    • Example: The head is superior to the abdomen.

  • Inferior (caudal): away from the head or below another structure.

    • Example: The navel is inferior to the chin.

  • Anterior (ventral): toward the front of the body.

    • Example: The breast bone is anterior to the heart.

  • Posterior (dorsal): toward the back of the body.

    • Example: The heart is posterior to the breast bone.

  • Medial: toward the midline of the body.

    • Example: The heart is medial to the lungs.

  • Lateral: away from the midline of the body.

    • Example: The lungs are lateral to the heart.

  • Intermediate: between a more medial and a more lateral structure.

    • Example: The collarbone is intermediate between the breastbone and shoulder.

  • Proximal: closer to the point of attachment to the trunk (think proximity).

    • Example: The elbow is proximal to the wrist. (the elbow is close to the shoulder where the arm attaches to the body)

  • Distal: farther from the point of attachment to the trunk.

    • Example: The wrist is distal to the elbow. (the wrist is farther away from the elbow)

  • Superficial (external): toward or on the surface of the body.

    • Example: The skin is superficial to the skeletal muscles.

  • Deep (internal): away from the body surface.

    • Example: The lungs are deep to the skin.

  • These are the basic directional terms used when describing the human body in its anatomical position.

Regional Terms

  • The body is divided into two fundamental divisions:

    • Axial division
    • Appendicular division

  • Axial division

    • The main, central axis of the body, the “core.”
    • Head: cranial (skull) and facial (face)
    • Neck: cervical
    • Trunk: thoracic (chest), abdominal (stomach area), pelvic (pelvis), dorsal (back)

  • Appendicular division

    • Includes the limbs (arms and legs) and the girdles that attach them to the axial skeleton.
    • Upper limbs: brachial (arm), antebrachial (forearm), carpal (wrist), manual (hand)
    • Lower limbs: femoral (thigh), crural (leg), tarsal (ankle), pedal (foot)
    • Girdles: pectoral (shoulder) and pelvic girdle

  • In short: Axial = head, neck and trunk; Appendicular = arms and legs

Axial Regions (Head, Neck, Trunk)

  • Head = Cephalic (entire head region)

    1. Skull = Cranial
    2. Face = Facial
    3. Forehead = Frontal
    4. Eye = Orbital / Ocular
    5. Ear = Otic
    6. Nose = Nasal
    7. Cheek = Buccal
    8. Mouth = Oral
    9. Chin = Mental
    10. Neck = Cervical
    11. Occipital = back of head

  • Trunk = Torso (entire torso region)

    • Anterior
    • Thoracic = Chest
      • Sternal = breastbone
      • Pectoral = chest muscle region
      • Mammary = breast
    • Abdominal = abdomen
    • Umbilical = navel
    • Pelvic = pelvic
    • Inguinal = groin
    • Pubic = genital
    • Posterior
    • Dorsal = back
      • Scapular = shoulder blade
      • Vertebral = spine
      • Lumbar = lower back
      • Sacral = between hips
      • Gluteal = buttocks
      • Perineal = region between anus and genitals

Appendicular Regions (Shoulder to Fingers)

  • Upper Limb

    • Acromial = point of shoulder
    • Axillary = armpit
    • Brachial = arm (upper arm)
    • Antecubital = front of elbow
    • Olecranal = back of elbow
    • Antebrachial = forearm
    • Carpal = wrist
    • Manual (Hand)
    • Palmar = palm
    • Digital/Phalangeal = finger

  • Lower Limb

    • Coxal = hip
    • Femoral = thighs
    • Patellar = front of knee
    • Popliteal = back of knee
    • Crural = leg (shin)
    • Sural = calf
    • Fibular (Peroneal) = lateral side of sural
    • Pedal (foot)
    • Tarsal = ankle
    • Calcaneal = heel
    • Metatarsal = midfoot
    • Plantar = sole of foot
    • Digital/Phalangeal = toes
    • Hallux = big toe

Body Planes and Sections

  • There are two main plane types used to section the body:

    • Frontal Plane (coronal plane): divides the body into anterior and posterior sections
    • Sagittal Plane: divides the body into left and right sections; the midsagittal plane runs down the midline
    • Transverse Plane: divides the body into superior and inferior sections
    • Note: transcript lists "Saittal Plane" (likely a misspelling of Sagittal Plane)

  • These planes help describe the location of structures in the body relative to each other.

Body Cavities and Serous Membranes

  • There are two main body cavities generally viewed from a lateral and anterior perspective:

  • Dorsal cavity (protects the nervous system)

    • Cranial cavity – holds the brain
    • Vertebral (spinal) cavity – holds the spinal cord

  • Ventral cavity (houses internal organs, viscera)

    • Thoracic cavity (chest)
    • Pleural cavities – each holds a lung
      • Visceral pleura – attached to the lung surface
      • Parietal pleura – lines the chest wall
    • Mediastinum – central region; contains esophagus, trachea, major vessels
    • Pericardial cavity – within mediastinum; surrounds the heart
      • Visceral pericardium (epicardium) – attached to the heart
      • Parietal pericardium – outer sac
    • Abdominopelvic cavity (below the diaphragm)
    • Abdominal cavity – contains stomach, intestines, liver, spleen, etc.
    • Pelvic cavity – contains bladder, reproductive organs, rectum

  • Serous membranes across cavities have two layers and a serous fluid between them:

    • Parietal serosa lines the cavity walls
    • Visceral serosa covers the organs
    • Serous fluid provides a slippery medium to reduce friction when organs move

  • Peritoneum in the abdominopelvic cavity:

    • Visceral peritoneum – covers abdominal organs
    • Parietal peritoneum – lines the abdominal wall

  • Specific naming hints:

    • Pleura = lungs
    • Pericardium = heart
    • Peritoneum = gut/belly

  • Quadrants of the Abdominopelvic cavity (4 quadrants):

    • Right Upper Quadrant (RUQ): liver, gallbladder, right kidney, part of stomach, small/large intestine
    • Left Upper Quadrant (LUQ): stomach, spleen, pancreas, left kidney, part of liver, small/large intestine
    • Right Lower Quadrant (RLQ): Appendix, Cecum, right ovary (females), right ureter, part of small/large intestine
    • Left Lower Quadrant (LLQ): Left ovary (females), left ureter, sigmoid colon, part of small/large intestine

Nine-Region Division of the Abdominopelvic Cavity

  • Top row (from patient’s right to left): Right hypochondriac, Epigastric, Left hypochondriac
    • Right hypochondriac: liver, gallbladder, right kidney
    • Epigastric: stomach, pancreas, part of liver
    • Left hypochondriac: spleen, part of stomach, left kidney
  • Middle row: Right lumbar, Umbilical, Left lumbar
    • Right lumbar: ascending colon, right kidney
    • Umbilical: small intestine, transverse colon
    • Left lumbar: descending colon, left kidney
  • Bottom row: Right iliac (inguinal), Hypogastric (pubic), Left iliac (inguinal)
    • Right iliac (inguinal): appendix, cecum
    • Hypogastric (pubic): bladder, reproductive organs, small intestine
    • Left iliac (inguinal): sigmoid colon

1.5 Recap and Review Topics

  • 1.5 recap soon.

  • Review topics (Noji reviews):

    • All of chapter one
    • Organ systems
    • Directional terms
    • Regional terms
    • Planes
    • Cavities
    • Serous membranes
    • Abdominal quadrants