N3 Anatomy and Physiology AY 2023-2024

1. Throwing a baseball overhead

   1. Latissimus Dorsi

      1. Action

         1. Extends, adducts, and rotated the arm medially at the shoulder joint

         2. Overall, it draws the arms inferiorly and posteriorly

      2. Innervation 

         1. Thoracodorsal nerve

   2. Deltoid

      1. Action

         1. Its lateral fibers abduct the arms at the shoulder joint

         2. Next, the anterior fibers of the deltoid flex and rotate the arm medially at the shoulder joint

         3. Lastly, the posterior fibers extend and rotate the arms laterally at the shoulder joint

      2. Innervation 

         1. Axillary nerve

2. Kicking a ball

   1. Quadriceps Femoris

      1. Action 

         1. Extends the leg at the knee joint.

         2. Notably, the rectus femoris muscle of the quadriceps also flexes the thigh at the hip joint

      2. Innervation 

         1. Femoral nerve

   2. Gastrocnemius

      1. Action

         1. Plantar flexes (downward motion) the foot at the ankle joint

         2. It also flexes the leg at the knee joint

      2. Innervation 

         1. Tibial nerve

3. Doing sit-ups

   1. Rectus Abdominis

      1. Action

         1. These are the muscles referred to in “six-pack abs.” These are involved in the flexion of the trunk, especially the vertebral column (notably the lumbar vertebrae). Rectus abdominis muscles also compress the abdomen to aid in certain activities such as urination, childbirth, defecation, and forced exhalation.

      2. Innervation 

         1. Thoracic spinal nerves (T7-T12)

   2. Transversus Abdominis

      1. Action

         1. Similar with the Rectus abdominis, the Traversus abdominis primarily compresses the abdomen and flexes the trunk

      2. Innervation 

         1. Thoracic spinal nerves (T8-T12)

         2. Iliohypogastric nerve

         3. Ilioinguinal nerve 

4. Breathing

   1. Diaphragm

      1. Action

         1. Contraction causes the diaphragm to flatten, thus increasing the surface area and vertical dimension of the thoracic cavity, which in turn aids and results in inhalation

      2. Innervation 

         1. Phrenic nerve (C3-C5)

   2. External Intercostals

      1. Action

         1. Contraction causes the ribs to elevate, thus increasing the anteroposterior and lateral dimensions of the thoracic cavity. This, in turn, aids and results in inhalation

      2. Innervation 

         1. Thoracic spinal nerves (T2-T12)

References:

Dauzvardis, M. F., PhD. (1996). Master Muscle List. Loyola University Medical Center -  Stritch School of Medicine. https://www.meddean.luc.edu/lumen/meded/grossanatomy/dissector/mml/ 

Tortora, G. J., & Derrickson, B. (2017). Principles of Anatomy & Physiology. http://ndl.ethernet.edu.et/bitstream/123456789/1717/1/36%2c2012.pdf.pdf