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

Turning a doorknob

1. Pronator quadratus

   1. Action : Pronates forearm on the proximal radioulnar joint 

   2. Innervation: Median nerve 

2. Pronator teres

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

   2. Innervation: Median nerve 

3. 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 and assists in adduction and medial rotation of the arm at the shoulder joint 

   2. Innervation: Lower subscapular nerve 

2. Subscapularis 

   1. Action: Medially rotates are at the shoulder joint

   2. Innervation: Upper and lower subscapular nerve 

3. Deltoid 

   1. Action: At the shoulder joints, posterior fibers cause the area to stretch and rotate laterally. The lateral fibers abduct the arm at the shoulder joint. Anterior fibers flex and medially rotate the arm at the shoulder joint. 

   2. Innervation: Axillary nerve 

Kicking a ball 

1. Rectus femoris 

   1. Action: extend leg at the knee joints and flexes thigh at the hip joints

   2. Innervation: Femoral nerve 

2. Vastus medialis 

   1. Action: Extend leg at the knee joint 

   2. Innervation: Femoral nerve 

3. Gluteus medius 

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

   2. Innervation: Superior gluteal nerve 

Doing sit-ups 

1. Rectus abdominis 

   1. Action: Flexes the vertebral column, especially the lumbar portion and comprise the abdomen to help in the defecation, urination, forced exhalation and childbirth. Flexes pelvis on the vertebral column. 

   2. Innervation: Thoracic spinal nerves 

2. iliopsoas 

   1. Action: Psoas major and iliacus muscle acting together flex thigh at the hip joint, rotate thigh laterally and flex trunk on the hip

   2. Innervation: Lumbar spinal nerves L2-L3 

3. External obliques 

   1. Action: Compresses the abdomen and flexes the vertebral column; acting unilaterally, laterally flex the vertebral column, especially lumbar portion and rotate the vertebral column

   2. Innervation: Thoracic spinal nerves T7-T12 and the iliohypogastric nerve 

Walking 

1. Tibialis anterior

   1. Action: Inverts and dorsiflexes the foot

   2. Innervation: Deep fibular (peroneal) nerve L4,L5

2. Soleus 

   1. Action: Plantar flexes foot at ankle joint 

   2. Innervation: Tibial nerve 

3. Gastrocnemius

   1. Action: Flexes the leg and plantar flexes the foot

   2. Innervation: Tibial nerve 

Breathing

1. Diaphragm

   1. Action: Contracting which increases vertical dimension of thoracic cavity (inhale) and relaxation which decreases vertical dimension of thoracic cavity (exhale) of diaphragm

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

2. External intercostal

   1. Action: Contraction which elevates ribs and increases anteroposterior and lateral dimensions of thoracic cavity (inhale) and relaxation which depresses ribs and decreases anteroposterior and lateral dimensions of thoracic cavity (exhale) 

   2. Innervation: Thoracic spinal nerve (T2-T12) 

3. Internal intercostal

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

   2. Innervation: Thoracic spinal nerves (T2-T12)