Muscle and Bone Healing Processes

Both muscle and bone healing share similar phases: inflammation, regeneration, and remodeling.
Recognizing parallels between muscle and bone healing processes facilitates better understanding and retention of the material.
Key differences exist in the types of cells involved: bone healing involves osteoblasts and osteoclasts, while muscle healing prominently features satellite cells.

A muscle strain, also known as a torn muscle or pulled muscle, occurs when muscle demands exceed its material properties, leading to myofibril rupture.
Sudden acceleration or deceleration often triggers muscle tears, categorized as small, medium, or large.
Various classification systems exist for muscle tears, such as the Barcelona (grade 1-3) based on MRI appearance and the British Athletic system, which classifies tears as small, moderate, extensive, or complete based on symptoms.

Initial muscle injury results in inflammation, with neutrophils being the first responders that release free radicals and enzymes.
This inflammatory response can worsen muscle damage post-injury, leading to further complications in the hours and days following the tear.

Satellite cells are crucial for muscle repair, remaining inactive until muscle injury occurs.
These cells are located adjacent to myofibrils and covered by sarcolemma, which envelops each myofibril.
Upon muscle injury, satellite cells activate and release mitogenic factors that stimulate mitosis, leading to the regeneration of muscle fibers.
Satellite cells undergo cell division to replace damaged myofibrils, contributing significantly to muscle healing.