General Anatomy Overview

General Anatomy

• Anatomy is the study of the structure of the human body.
• Anatomical terms often come from Latin or Greek.
• Anatomical position is a standard reference point for describing body parts. The body is standing upright, facing forward, with arms hanging down at the sides, and palms facing forward. Feet are pointed forward.
• Anatomical planes are imaginary lines used to describe the location of body parts relative to each other.
  • Sagittal plane: divides the body into right and left halves.
    • Median plane: a specific sagittal plane that divides the body into equal right and left halves.
    • Parasagittal planes: other sagittal planes that divide the body into unequal right and left parts.
  • Coronal plane (frontal plane): divides the body into front (anterior) and back (posterior) portions.
  • Horizontal plane (transverse plane): divides the body into upper (superior) and lower (inferior) portions.
• Terms are used to describe the location of one structure in relation to others.

Skin

• The skin has two layers: epidermis and dermis.
• The epidermis is the outermost layer, consisting of stratified epithelium.
• The dermis is made of connective tissue, with collagen fibers arranged in lines (Langer's lines.)
  • Surgical incisions should ideally follow the lines of cleavage for better healing.

Fascia

• Fascia is a connective tissue layer located deep to the skin.
• It is divided into superficial and deep layers.
• Superficial fascia is a mixture of loose and adipose tissue, connecting the skin to deeper structures.
• Deep fascia is a membranous layer of connective tissue and encloses muscles. Fibrous septa created between muscle groups, form compartments.
• Fascia plays a role in surgeries and repair of wounds.

Musculoskeletal System

• The musculoskeletal system involves the bones, joints, and muscles.

  • Bones provide a framework and protect organs.
  • Joints connect bones and facilitate movement
  • Muscles enable movement and provide support.
  • Axial skeleton: forms the central axis of the body (skull, vertebral column, hyoid bone, ribs, and sternum.)
    • Skull has two parts: cranium and mandible.
    • The vertebral column is a series of bones (vertebrae). It is curved and flexible, with 5 sections (cervical, thoracic, lumbar, sacral, and coccygeal.) Each section contains a specific number of vertebrae. Specific ribs connect to the thoracic vertebrae and sternum
  • Appendicular skeleton: includes bones of the limbs (upper and lower).
  • The bones are categorized by type based on shape (long bones, short bones, flat bones, irregular bones, and pneumatic bones.)

• Bone Development

• Bones develop from mesenchymal proliferations, either as membrane bones or cartilage bones

• Bone structure- Compact and Spongy bone in long bones

• Parts of a long bone:

  • Diaphysis
  • Epiphysis
  • Articular cartilage
  • Periosteum
  • Medullary cavity.
  • Metaphysis

• Different types of cartilage in the body include: hyaline, elastic, and fibrocartilage.

• Skeletal muscles can be categorized based on their shape (parallel, triangular, fusiform/spindle-shaped, circular, pennate) and based on their action (prime mover, antagonist, fixator, synergist.)

Joints

• Joints connect bones, facilitating movement.
• Fibrous joints: offer very little movement.
  • Sutures (skull)
  • Syndesmoses (between radius and ulna)
  • Gomphoses (teeth in sockets.)
• Cartilaginous joints: have some flexibility.
  • Primary cartilaginous joints allow little movement
  • Secondary cartilaginous joints have slightly more flexibility,
• Synovial joints: provide significant movement.
  • Various types distinguished by their shape and the movement they allow.

Cardiovascular System

• The cardiovascular system circulates blood throughout the body.
  • Heart.
    • Located in the thoracic cavity. Has a specific position relative to rib cage, lungs and the diaphragm.
  • Blood vessels.
    • Arteries carry blood away from the heart.
    • Veins carry blood toward the heart.
    • Capillaries connect arteries and veins, enabling the exchange of substances between the blood and tissues.

Lymphatic System

• The lymphatic system is a network of vessels and nodes, contributing to fluid balance and immunity.
• Lymph, the fluid circulating in these vessels, helps with infection control.
• Lymphatic vessels collect lymph from tissue spaces and drain into the venous system.
• Lymph nodes filter the lymph and contain lymphocytes.

Nervous System

• The nervous system is a complex network that controls body functions. Divided into:
  • Central Nervous system (CNS)
    • Brain and spinal cord
  • Peripheral Nervous system (PNS)
    • Cranial nerves (emerge from the brain)
    • Spinal nerves (emerge from spinal cord)
    • Ganglia (clusters of nerve cells)
• Spinal nerves have anterior and posterior roots. Both are important for nerve function.