Activity 2
Name at least two muscles that actively contracts during the following activities and name its action and innervation:
- Throwing a baseball overhead
- Subscapularis -
Action: Medially rotates arm at shoulder.
Innervations: upper and lower sub scapular nerve.
- Latissimuss dorsi
Action: extends, adducts, and medially rotates arm at shoulder joint; draws arm inferiorly and posteriorly. RMA elevates vertebral column and torso.
Innervation: Thoracodorsal nerve
2. Kicking a ball
- Vastus Lateralis
Action: all four heads extend leg at knee joint; rectus femoris muscle acting alone also flexes thigh at hip joint.
Innervations: femoral nerve
- Biceps Femoris
Action: Flexes legs at knee joint and extends thigh at hip joint.
Innervations: Tibial and Fibular nerves from sciatic nerve.
3. Doing sit-ups
- Rectus Abdominis.
Action: Flexes vertebral column, especially lumbar portion, and compresses abdomen to aid in defecation, urination, forced exhalation, and childbirth. RMA: Flexes pelvis on the vertebral column.
Innervation: Thoracic spinal nerves. T7-T12
- Transversus Abdominis
Action: Compresses abdomen.
Innervation: Thoracic spinal nerves T8-t12, Iliohypogastric nerve, and Ilionguinal nerve.
4. Breathing
- Pectoralis Minor
Action: Abducts scapula and rotates it downward. RMA: elevates ribs 3-5 during forced inhalation when scapula is fixed.
Innervation: Medial pectoral nerve.
- Diaphragm
Action: Contraction of diaphragm cause it to flatten and increases vertical dimension of thoracic cavity, resulting in inhalation; relaxation of diaphragm causes it to move superiorly and decreases vertical dimension of thoracic cavity, resulting in exhalation.
Innervation: Phrenic nerve, which contains axons from cervical spinal nerves (C3-C5).
Reference:
Tortora, G. J., & Derrickson, B. (2017). Principles of Anatomy & Physiology. http://ndl.ethernet.edu.et/bitstream/123456789/1717/1/36%2c2012.pdf.pdf