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

Turning a door knob

1. Supinator

   1. Action: Supinates forearm at radioulnar joints

   2. Innervation: Deep radial nerve

 Throwing a baseball overhead

1. Teres Major

   1. Action: Extends arm at the shoulder joint and assists in adduction and medial rotation of the arm at the shoulder joint

   2. Innervation: Lower subscapular nerve

2. Pectoralis Major

   1. Action: As a whole, adducts and medially rotates arm at shoulder joint; clavicular head flexes arm, and sternocostal head extends flexed arm to the side of the trunk

   2. Innervation: Medial and lateral pectoral nerves

3. Latissimus Dorsi

   1. Action: Extends, adducts, and medially rotates arm at shoulder joint; draw arm inferiorly and posteriorly. 

   2. Innervation: Thoracodorsal nerve

 Kicking a ball

1. Iliopsoas

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

   2. Innervation: Lumbar spinal nerves

2. Rectus Femoris

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

   2. Innervation: Femoral nerve

3. Gluteus Maximus

   1. Action: Extends thigh at the hip joint and laterally rotates thigh; helps lock the knee in extension.

   2. Innervation: Inferior gluteal nerve

 Doing sit-ups

1. Transverse Abdominis

   1. Action: Compresses abdomen

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

2. Rectus Abdominis

   1. Action: Flexes vertebral column, especially the lumbar portion, and compresses abdomen to aid in defecation, urination, forced exhalation, and childbirth. 

   2. Innervation: Thoracic spinal nerves

3. Rectus Femoris

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

   2. Innervation: Femoral nerve

 Walking

1. Rectus Femoris

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

   2. Innervation: Femoral nerve

2. Tibialis Anterior

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

   2. Innervation: Deep fibular nerve

3. Gluteus Medius

   1. Action:  Abducts thigh at the hip joint and medially rotates thigh

   2. Innervation: Superior gluteal nerve

Breathing

1. Diaphragm

   1. Action: Contraction of the diaphragm causes it to flatten and increases the vertical dimension of the thoracic cavity, resulting in inhalation; relaxation of the diaphragm causes it to move superiorly and decreases the vertical dimension of the thoracic cavity, resulting in exhalation

   2. Innervation: Phrenic nerve, which contains axons from cervical spinal nerves

2. External Intercostals

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

   2. Innervation: Thoracic spinal nerves

3. Internal Intercostals

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

   2. Innervation: Thoracic spinal nerves