Anatomy Positions and Planes

Anatomical Position

• Body is standing upright
• Eyes are looking forward
• Arms are at the sides of the body, with palms facing forward
• Feet are together

Planes

• Vertical Planes
  • Sagittal plane: A vertical plane dividing the body into right and left halves.
    • Midsagittal plane: A sagittal plane running directly down the middle of the body.
    • Parasagittal plane: Any vertical plane parallel to the midsagittal plane, but not down the exact midline.
• Coronal plane: A vertical plane dividing the body into anterior (front) and posterior (back) portions.
• Transverse plane: A horizontal plane dividing the body into superior (upper) and inferior (lower) portions.

Terms of Direction

• Anterior (ventral): Toward the front of the body
• Posterior (dorsal): Toward the back of the body
• Superior (cranial, cephalic): Toward the top of the body
• Inferior (caudal): Toward the bottom of the body
• Medial: Toward the midline of the body
• Lateral: Away from the midline of the body
• Proximal: Closer to the origin of the body part or point of attachment
• Distal: Farther from the origin of the body part or point of attachment
• Superficial: Closer to the surface of the body
• Deep: Farther from the surface of the body
• Ipsilateral: On the same side of the body
• Contralateral: On the opposite side of the body
• Palmar/volar: Palm side of the hand/sole of the foot
• Dorsal: Back of the hand/top of the foot

Terms of Movement

• Flexion: Bending a joint
• Extension: Straightening a joint
• Abduction: Moving a limb away from the midline of the body
• Adduction: Moving a limb toward the midline of the body
• Rotation: Turning a bone around its long axis
  • Lateral rotation: Turning a bone outward
  • Medial rotation: Turning a bone inward
• Circumduction: Moving a limb in a circular motion
• Pronation: Turning the palm of the hand downward or posteriorly
• Supination: Turning the palm of the hand upward or anteriorly
• Eversion: Turning the sole of the foot outward
• Inversion: Turning the sole of the foot inward
• Protraction: Moving a body part forward
• Retraction: Moving a body part backward

Muscular System

• Muscles are composed of contractile cells
• They produce movement of the body and its internal organs
• Types of muscles:
  • Smooth muscles
  • Cardiac muscles
  • Skeletal muscles

Smooth Muscles

• Found in walls of visceral organs and blood vessels
• Controlled by involuntary parts of the nervous system
• Spindle-shaped cells with a central nucleus

Cardiac Muscles

• Forms the middle layer of the heart
• Has the property of spontaneous rhythmic contraction
• Controlled by involuntary parts of the nervous system
• Branching cells

Skeletal Muscles

• Account for 40% of total body mass
• Attached to bones by tendons
• Produce movement, maintain posture, and generate body heat
• Controlled by the voluntary part of the nervous system
• Types of skeletal muscle arrangements:
  • Parallel fibers
  • Oblique fibers (e.g., triangular, spiral)
  • Pennate fibers

Action of Skeletal Muscle

• Prime mover: Initiates a specific movement
• Antagonist: Opposes the action of the prime mover
• Synergist: Assists the prime mover
• Fixator: Stabilizes a joint

Skeletal System

• Composed of cartilage and bones
• Cartilage:
  • Softer than bone
  • Forms temporary skeleton of developing fetus
  • Found in external ear, costal cartilage, articular surfaces, and respiratory passages
• Bone:
  • Hard tissue
  • Consists of osteocytes, fibers, and matrix with calcification
• Bone Forms:
  • Compact bone: Outer layer of most bones
  • Spongy (cancellous) bone: Found inside compact bone, and in the ends of long bones
• Bone Development:
  • Membranous ossification: Forms flat bones
  • Cartilaginous ossification: Forms long bones
• Bone Shapes:
  • Long bones
  • Short bones
  • Flat bones
  • Irregular bones
  • Sesamoid bones
• Parts of the Skeleton:
  • Axial skeleton
  • Appendicular skeleton
• Function of Skeleton:
  • Supports body
  • Gives shape to body
  • Allows movement
  • Blood formation
  • Stores calcium and phosphorus
  • Protects vital organs (e.g., brain in cranium, spinal cord in vertebral column)

Bone Markings

• Elevations
• Depressions
• Perforations
• Heads

Joints

• Where two or more bones meet
• Fibrous Joints: Bones are joined tightly by fibrous tissue, allow little or no movement (e.g., sutures of the skull)
• Cartilaginous Joints: Bones are united by cartilage, allow some limited movement (e.g., pubic symphysis)
• Synovial Joints: Most movable joint type, with a cavity filled with synovial fluid (e.g., hinge joints like elbows, ball-and-socket joints like hips)

Classification of Synovial Joints

• Plane joint

• Hinge joint

• Pivot joint

• Condyloid (ellipsoid) joint

• Saddle joint

• Ball-and-socket joint

• Stability of the Joint: Depends on shape/size of articular surfaces, ligaments and surrounding muscles.

Explore the fundamental concepts of anatomical positions and planes in this quiz. Understand the differences between sagittal, coronal, and transverse planes, as well as directional terms used in anatomy. Perfect for medical and biology students seeking to enhance their knowledge of human anatomy.