Anatomy of the Skeletomuscular System

The Skeletomuscular System

• The skeletomuscular system provides movement, stability, shape, and support to the human body.
• It is divided into two broad systems: the skeletal system and the muscular system.

Skeletal System

• The skeletal system is composed of 206 bones and their associated cartilages.
• Bones are rigid organs that form part of the endoskeleton of vertebrates.
• Functions of bones:
  • Provide framework to support the body.
  • Provide points of attachment for skeletal muscles.
  • Protect organs within body cavities.
  • Store inorganic salts such as calcium and phosphate.
  • Contain and protect red bone marrow.

Axial Skeleton

• Includes bones along the longitudinal axis of the body.
• Comprises the vertebral column, cranial and facial bones, and bones of the thoracic cage.

Appendicular Skeleton

• Includes bones of the upper and lower extremities.
• Comprises bones of the shoulder and pelvic girdles, bones of the upper and lower limbs.

Types of Bones

• Long bone: length is more than its width (e.g., humerus, ulna, tibia, clavicle, phalanges).
• Short bone: cuboid or round shape (e.g., tarsal and carpal bones).
• Flat bone: thin, flattened (e.g., most skull bones, scapula, sternum).
• Sesamoid bone: small, rounded, embedded in muscle (e.g., patella of knee).
• Irregular bone: irregular and complex shape (e.g., vertebrae, hip bone).

Joints

• Joints are classified into three types depending on the tissue that holds the neighboring bones together.
• Types of joints:
  • Synovial joint: movable, bones joined together by synovial fluid (e.g., shoulder, elbow, hip, knee, wrist joints).
  • Fibrous joint: immovable, bones joined together by dense fibrous connective tissue (e.g., cranial sutures, distal tibiofibular).
  • Cartilaginous joint: limited movement, bones joined together by cartilage (e.g., joints between vertebral bodies, joint between first rib and sternum).

Muscular System

• The muscular system includes all types of muscles in the body.
• Skeletal muscles act on the body joints to produce movements.
• The muscular system also contains tendons that attach muscles to bones.

Types of Muscle Tissue

• Cardiac muscle: forms the muscular layer of the heart (myocardium).
• Smooth muscle: found in the walls of blood vessels and hollow organs.
• Skeletal muscle: attaches to bones and provides voluntary movement.

Functions of Skeletal Muscles

• Production of movement.
• Maintenance of posture and muscle tone.
• Heat production.
• Stabilization of joints and protection of bones and internal organs.

Organization of Skeletal Muscles

• Muscles are organized into four groups for every region of the body:
  • Muscles of the head and neck.
  • Muscles of the trunk.
  • Muscles of the upper limbs.
  • Muscles of the lower limbs.