ACTIVITY 2

Balasta, Shiela Maye M.

Balasta, Shiela Maye M.

by Shiela Maye Balasta -
Number of replies: 0

1. Throwing a baseball overhead

  • Subscapularis

    • Action: Medially rotates arm at shoulder joint.

    • Innervation: Upper and lower subscapular nerve.

  • Latissimus 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

  • Quadriceps

    • Action: All four heads extend leg at knee joint; rectus femoris muscle acting alone also flexes thigh at hip joint.

    • Innervation: Femoral nerve.

  •  Iliopsoas

    • Action: Psoas major and iliacus muscles acting together flex thigh at hip joint, rotate thigh laterally, and flex trunk on hip as in sitting up from supine position.

    • Innervation: Lumbar spinal nerves L2–L3.

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.

  • Transverus abdominis

    • Action: Compresses abdomen.

    • Innervation: Thoracic spinal nerves T8–T12, iliohypogastric nerve, and ilioinguinal nerve.

4. Breathing

  • Diaphragm 

    • Action: Contraction of diaphragm causes 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).

  • Exterior intercostals

    • Action: Contraction elevates ribs and increases anteroposterior and lateral dimensions of thoracic cavity, resulting in inhalation; relaxation depresses ribs and decreases anteroposterior and lateral dimensions of thoracic cavity, resulting in exhalation.

    • Innervation: Thoracic spinal nerves T2–T12.

Reference

Tortora, G. J., & Derrickson, B. (2017). Principles of anatomy & physiology. Fifteenth edition; Wiley Loose-Leaf Print Companion. Hoboken, New Jersey, John Wiley & Sons, Inc.