N3 Anatomy and Physiology AY 2023-2024

1. Throwing a baseball overhead

   • Deltoid

     • Action: Lateral fibers abduct arm at shoulder joint; anterior fibers flex and medially rotate arm at shoulder joint; posterior fibers extend and laterally rotate arm at shoulder joint

     • Innervation: Axillary nerve

2. • Lumbricals

   1. • Action: Flex each finger at metacarpophalangeal joints and extend each finger at interphalangeal joints

      • Innervation: Median and ulnar nerves

2. Kicking a ball

   • Gastrocnemius 

• Action: Plantar flexes foot at ankle joint and flexes leg at knee joint

• Innervation: Tibial nerve

2. • Plantaris

   1. • Action: Plantar flexes foot at ankle joint and flexes leg at knee joint

      • Innervation: Tibial 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

• •  Iliopsoas

  1. • 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

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)

2. • External 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
     

References:

Tortora, G. & Derrickson, B. (2017). Principles of Anatomy and Physiology (15th ed.). Retrieved from https://handoutset.com/wp-content/uploads/2022/05/Principles-of-anatomy-and-physiology-Wiley-2017-Derrickson-Bryan-H._-Tortora-Gerard-J..pdf