Skeletal System

Overview of Bone Structure

The skeletal system provides the framework for the body, supports movement, and protects vital organs. Bones are classified by their structure and function, and their development is essential for growth and health.

• Gross Anatomy of Bones: Includes compact and spongy bone, which differ in density and function.

• Microscopic Anatomy: Examines the cellular composition of bone tissue, including osteocytes, osteoblasts, and osteoclasts.

• Bone Composition: Bones are composed of organic (collagen, cells) and inorganic (hydroxyapatite) components.

• Bone Development: Involves endochondral and membranous ossification processes.

• Bone Growth: Occurs at the epiphyseal plate and is regulated by hormones such as growth hormone and sex steroids.

• Bone Remodeling: Involves bone resorption and formation, maintaining bone strength and calcium homeostasis.

• Bone Fractures: Healing involves inflammation, repair, and remodeling phases.

Additional info: Students are instructed not to study developmental aspects of bones or drug-related osteoporosis topics.

The Skeleton

The skeleton is divided into axial and appendicular components, each with specific bones and functions.

• Axial Skeleton: Includes the skull, vertebral column, and thoracic cage.

• Appendicular Skeleton: Includes the pectoral girdle, pelvic girdle, and limbs.

• Skull: Composed of cranial and facial bones. Do not study the orbits.

• Vertebral Column: Consists of cervical, thoracic, lumbar, sacral, and coccygeal vertebrae. Includes normal and abnormal spinal curvatures (e.g., scoliosis, kyphosis, lordosis).

• Thoracic Cage: Includes the sternum and ribs.

• Pelvic Girdle: Composed of the hip bones (os coxae), sacrum, and coccyx. Differences exist between male and female pelvises.

• Upper Limb: Includes the clavicle, scapula, humerus, radius, ulna, and bones of the hand.

• Lower Limb: Includes the femur, tibia, fibula, and bones of the foot.

Additional info: Students should focus on bone names, markings, and related questions. Do not study details of the foot or hand bones.

Joints (Articulations)

Classification and Structure of Joints

Joints, or articulations, are points where two bones meet. They are classified by their structure and function, which determines their range of movement.

• Structural Classification: Includes fibrous, cartilaginous, and synovial joints.

• Functional Classification: Includes synarthroses (immovable), amphiarthroses (slightly movable), and diarthroses (freely movable).

• Synovial Joints: Characterized by a joint cavity filled with synovial fluid, articular cartilage, and a fibrous capsule.

Major Synovial Joints and Movements

Synovial joints allow for a wide range of movements and are classified by the shapes of their articulating surfaces.

• Types of Synovial Joints: Plane, hinge, pivot, condyloid, saddle, and ball-and-socket.

• Major Joints Studied: Shoulder, knee, hip, elbow, jaw (temporomandibular joint excluded).

• Movements: Flexion, extension, abduction, adduction, circumduction, rotation, and others.

Examples of Joint Movements

• Shoulder Joint: Ball-and-socket; allows multiaxial movement.

• Elbow Joint: Hinge; allows flexion and extension.

• Knee Joint: Modified hinge; allows flexion, extension, and slight rotation.

• Hip Joint: Ball-and-socket; allows multiaxial movement.

Ligaments and Supporting Structures

Ligaments connect bones and stabilize joints. Each major joint has specific ligaments that contribute to its stability and function.

• Shoulder: Glenohumeral, coracoacromial, and coracoclavicular ligaments.

• Knee: Patellar, collateral, cruciate, and meniscal ligaments.

• Elbow: Annular, ulnar collateral, and radial collateral ligaments.

• Hip: Iliofemoral, pubofemoral, and ischiofemoral ligaments.

Inflammatory and Degenerative Joint Conditions

Joints are susceptible to various conditions that affect their function and cause pain or disability.

• Bursitis: Inflammation of the bursae.

• Tendinitis: Inflammation of tendons.

• Arthritis: Includes osteoarthritis (degenerative) and rheumatoid arthritis (autoimmune).

• Gout: Metabolic disorder causing joint inflammation due to uric acid crystals.

Summary Table: Major Synovial Joints and Their Features

Additional info: Temporomandibular joint (TMJ) is excluded from study. Students should focus on joint classification, structure, and major movements, as well as common joint pathologies.