Muscles
- Classification of Muscles
Muscles are classified into three main types:
- Smooth muscles (visceral muscles)
- Skeletal muscles
- Cardiac muscles
Skeletal muscles are further classified into voluntary muscles.
- Classification of Skeletal Muscles
Skeletal muscles are classified based on their fascicular architecture and their blood and nerve supply.
- Circumferential muscles: Fibres run around the organ or bone.
- Circular muscles: Fibres are arranged in a circular manner.
- Longitudinal muscles: Fibres run along the length of the organ or bone.
- Oblique muscles: Fibres run at an angle to the longitudinal axis.
Skeletal muscles can be classified based on their nerve supply:
- Innervated muscles: Nerve supply is provided by a motor nerve.
- Innervated muscles with dual supply: Nerve supply is provided by two motor nerves.
Skeletal muscles can be classified based on their blood supply:
- Arterially supplied muscles: Blood supply is provided by an artery.
- Veinously supplied muscles: Blood supply is provided by a vein.
- Actions of Skeletal Muscles
Skeletal muscles can be classified based on their actions:
- Flexors: Bending movement of a joint.
- Extensors: Straightening movement of a joint.
- Abductors: Movement of a limb away from the midline of the body.
- Adductors: Movement of a limb towards the midline of the body.
- Rotators: Rotating movement of a limb.
Skeletal muscles can also be classified based on their action:
- Prime movers: Main muscle responsible for a movement.
- Fixators: Muscle that stabilizes the bone.
- Assistants: Muscle that assists the prime mover.
- Synergists: Muscle that works with the prime mover.
Muscle Action Sequence
1 → Prime mover contracts 2 → Joint movement occurs 3 → Other muscle actions occur (assistance, fixation, synergy)
Muscle Action Diagram
Prime Mover | | Contract v Joint Movement | | Assisted by v Other Muscle Actions
Muscle Action Flowchart
Prime Mover → Contract → Joint Movement → Assisted by → Other Muscle Actions