1a. Anterior Deltoid
Action: moves arm forward
Innervation: the axillary nerve
1b. Posterior deltoid
Action: extend, rotate, and horizontally abduct the shoulders and arms
Innervation: axillary nerve
2a. Rectus femoris
Action: extend the knee and flex the hip
Innervation: femoral nerve
2b. Tibialis anterior muscle
Action: adduction of the foot, inversion of the foot
Innervation: deep fibular nerve
3a. Rectus femoris
Action: extend the knee and flex the hip
Innervation: femoral nerve
3b. Gluteus maximus
Action: powerful lower limb movements
Innervation: inferior gluteal nerve
4a. Diaphragm
Action: enlarges and shrinks the chest cavity
Innervation: phrenic nerve
4b. Rectus abdominis
Action: flexion of the trunk
Innervation: thoracoabdominal nerves