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System

Muscular system

Not medically reviewed · Content last updated · 1 min read ·

This is the date the draft was written, not a medical review date.

The muscular system consists of skeletal muscles and their tendons, which produce voluntary movement, maintain posture and generate heat. Cardiac and smooth muscle are described with the heart and the viscera.

Terminologia Anatomica (Latin): Systema musculare

Components

Each skeletal muscle has a fleshy belly and tendinous or aponeurotic attachments (origin and insertion), enclosed by epimysium and organised into fascicles by perimysium. Muscles are grouped as head and neck, trunk (back, thoracic and abdominal wall) and limb muscles, and may be fusiform, pennate, flat or circular.

Function

Skeletal muscle contracts under somatic motor control to move the skeleton at joints, stabilise joints and sustain posture. Its metabolism also generates heat and contributes to glucose and protein homeostasis.

Clinical correlations

Muscle strains, tendon rupture, compartment syndrome, myopathies and neuromuscular junction disorders such as myasthenia gravis are examples of muscle-related disease. Weakness is classified as upper or lower motor neuron, neuromuscular junction or myopathic in origin.

Common exam points

  • Define origin, insertion, action, nerve supply and blood supply for each muscle.
  • Agonist, antagonist, synergist and fixator roles in a movement.
  • Muscle fibre types I and II and the sliding-filament basis of contraction.
  • Know the muscles of the rotator cuff, the abdominal wall and the back by group.
  • Compartment syndrome arises when raised fascial compartment pressure compromises perfusion.

References

  1. Drake RL, Vogl AW, Mitchell AWM. Gray's Anatomy for Students. Elsevier — Tier 3 (textbook)
  2. Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy. Wolters Kluwer, 8th edition (2018) — Tier 3 (textbook)
  3. Hall JE, Hall ME. Guyton and Hall Textbook of Medical Physiology. Elsevier, 14th edition (2020) — Tier 3 (textbook)

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