N3 Anatomy and Physiology (1st Sem AY 2022-2023)

1. Turning a door knob

   1. Supinator

      1. Action: Supinates forearm at radioulnar joints

      2. Innervation: Deep radial nerve

   2. Pronator quadratus

      1. Forearm pronation at radioulnar joints.

      2. Innervation: median nerve

   3. Pronator teres

      1. Action: Pronates forearm at radioulnar joints and weakly flexes forearm at elbow joint.

      2. Innervation: Median nerve.

2. Throwing a baseball overhead

   1. Deltoid

      1. 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.

      2. Innervation: Axillary nerve

   2. Latissimus Dorsi

      1. Action: Extends, adducts, and medially rotates arm at shoulder joint; draws arm inferiorly and posteriorly. RMA: Elevates vertebral column and torso.

      2. Innervation: Thoracodorsal nerve.

   3. Pectoralis Major

      1. Action: Adducts and medially rotates arm at shoulder joint; clavicular head flexes arm, and sternocostal head extends flexed arm to side of trunk.

      2. Innervation: Medial and lateral pectoral nerves.

3. Kicking a ball

   1. Psoas Major

      1. Action:  Flex thigh at hip joint, rotate thigh laterally, and flex trunk on hip as in sitting up from supine position.

      2. Innervation: Lumbar spinal nerves L2–L3.

   2. Quadratus Plantae

      1. Action: Assists flexor digitorum longus to only flex toes II–V at interphalangeal and metatarsophalangeal joints.

      2. Innervation: Lateral plantar nerve.

   3. Iliacus

      1. Action: Flex thigh at hip joint, rotate thigh laterally, and flex trunk on hip as in sitting up from supine position.

      2. Innervation: Femoral nerve

4. Doing sit-ups

   1. Rectus abdominis.

      1. 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.

      2. Innervation: Thoracic spinal nerves T7–T12.

   2. Internal obliques

      1. Action: Acting together, compress abdomen

      2. and flex vertebral column; acting singly, laterally flex vertebral column, especially lumbar portion, and rotate vertebral column.

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

   3. External obliques.

      1. Action: Acting together (bilaterally), compress

      2. abdomen and flex vertebral column; acting singly (unilaterally), laterally flex vertebral column, especially lumbar portion, and rotate vertebral column.

      3. Innervation: Thoracic spinal nerves T7–T12 and the iliohypogastric nerve.

   4. Transverse abdominis.

      1. Action: Compresses abdomen.

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

5. Walking

   1. Rectus femoris

      1. Action: Extend leg at knee joint; rectus femoris muscle acting alone also flexes thigh at hip joint.

      2. Innervation: Femoral Nerve

   2. Soleus

      1. Action: Plantar flexes foot at ankle joint.

      2. Innervation: Tibial nerve.

   3. Tibialis posterior

      1. Action: Plantar flexes foot at ankle joint and inverts (supinates) foot at intertarsal joints.

      2. Innervation: Tibial nerve.

6. Breathing

   1. Diaphragm:

      1. 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.

      2. Innervation: Phrenic nerve, which contains axons from cervical spinal nerves (C3–C5).

   2. Internal Intercostals

      1. Action: Contraction draws adjacent ribs together to further decrease anteroposterior and lateral dimensions of thoracic cavity during forced exhalation.

      2. Innervation: Thoracic spinal nerves T2–T12.

   3. External Intercostals

      1. 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.

      2. Innervation: Thoracic spinal nerves T2–T12.

Reference:

Principles of Anatomy & Physiology 14th Edition by Derrickson, B. and Tortora, G.