Bone Growth and Fractures

Bone Growth and Remodeling

• Long bones grow in length due to cartilage growth at the epiphyseal plate
• Cartilage is replaced by bone at the epiphyseal plate
• Articular cartilage remains at the ends of the bones and doesn't get replaced by bone
• Growth in bone width is achieved by bone forming on the outside of bone (periosteum)
• Bone remodeling occurs throughout life and involves bone resorption and deposition
• Bone remodeling is influenced by hormones, physical activity, and diet
• During bone repair, a hematoma forms at the fracture site
• Fibrocartilage callus forms after the hematoma
• Bony callus forms replacing the fibrocartilage callus
• Bone remodeling occurs to remodel the bony callus into mature bone

Bone Fractures

• Bone fractures are breaks in the bone
• Common types of fractures include simple, compound, comminuted, and greenstick fractures

Axial Skeleton

• The axial skeleton forms the longitudinal axis of the body
• The axial skeleton is divided into the skull, vertebral column, and bony thorax

Vertebral Column (Spine)

• There are 33 vertebrae in the vertebral column, including 24 presacral and 9 sacral vertebrae
• The primary spinal curvatures are in the thoracic and sacral regions
• Primary spinal curvatures are present at birth
• Secondary spinal curvatures are in the cervical and lumbar regions
• Secondary spinal curvatures develop after birth
• Each vertebra consists of a body, vertebral arch, vertebral foramen, transverse processes, spinous process, and superior and inferior articular processes

Bones of the Lower Limbs

• The lower leg has two bones: the tibia (shinbone) and fibula
• The tibia is larger and medially oriented
• The fibula is thin and sticklike and lateral to the tibia
• The distal end of the tibia forms the medial malleolus, which forms the inner part of the ankle
• The distal end of the fibula forms the lateral malleolus, which forms the outer part of the ankle

Joints

• Synovial joints are freely movable joints
• Synovial joints are characterized by the presence of a joint cavity, articular cartilage, synovial membrane, and articular capsule
• The joint cavity is filled with synovial fluid, which lubricates the joint and reduces friction
• Bursae are flattened fibrous sacs that are lined with synovial membranes and filled with synovial fluid
• Tendon sheaths are elongated bursae that wrap around tendons
• Types of synovial joints are classified based on shape: plane, hinge, pivot, condylar, saddle, and ball-and-socket
• Plane joints allow for gliding movement
• Hinge joints allow for uniaxial movement, such as flexion and extension
• Pivot joints allow for uniaxial rotation
• Condylar joints allow for biaxial movement, such as flexion, extension, adduction, abduction
• Saddle joints allow for biaxial movement, such as flexion, extension, adduction, abduction, and circumduction
• Ball-and-socket joints allow for multiaxial movement, such as flexion, extension, adduction, abduction, rotation, and circumduction

Explore the processes of bone growth, remodeling, and the various types of fractures in this informative quiz. Learn about the anatomy of the axial skeleton and the role of cartilage and hormones in these critical functions. Test your knowledge on how bones adapt and repair throughout life.