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

Activities

Muscles

Action

Innervation

1. Turning a door knob

Flexor carpi ulnaris

Flexion and adduction at the wrist

Ulnar nerve

Palmaris longus

Flexion at the wrist

Median nerve

Flexor carpi radialis

Flexion and abduction of the wrist

Median nerve

Pronator teres

Pronation of the forearm

Median nerve

2. Throwing a baseball overhead

Biceps brachii

Flexion and supination of forearm; flexion of arm at the shoulder joint

Musculocutaneous nerve

Coracobrachialis

Adduction of arm; weak flexion of arm at the shoulder joint

Musculocutaneous nerve

Brachialis

Flexion of the forearm at the elbow joint

Musculocutaneous nerve; components of radial nerves

Triceps brachii

Extension of forearm at the elbow joint; extension and adduction of the arm at the shoulder joint

Radial nerve

3. Kicking a ball

Tibialis anterior

Dorsiflexion of the foot at the talocrural joint; inversion of the foot at the subtalar joint

Deep fibular branch of the common fibular nerve

Gastrocnemius

Plantar flexor of the foot at the ankle joint; flexion of the knee

Tibial nerve

Fibularis longus

Eversion of the foot at the subtalar joint; plantar flexion of the foot at the ankle joint

Superficial fibular nerve

Popliteus

Initiation of flexion of the fully extended knee

Tibial nerve

4. Doing sit-ups

Rectus abdominis

Trunk flexion; compresses abdominal viscera; involved in exhalation

Intercostal nerves; subcostal nerve

Pyramidalis

Tension of linea alba

Subcostal nerve

Transversus abdominis

Compression of abdominal organs; involved in exhalation; causes ipsilateral trunk rotation

Intercostal nerves; subcostal nerve; iliohypogastric nerve; ilioinguinal nerve

Quadratus lumborum

Extension of trunk; flexion of trunk laterally to the ipsilateral side

Subcostal nerve; spinal nerves

5. Walking

Soleus

Plantar flexion of the foot; postural control by balancing the leg during walking

Tibial nerve

Extensor digitorum longus

Extension of the 2^nd to 5^th toes; dorsiflexion of the foot

Deep fibular nerve

Fibularis tertius

Dorsiflexion of the foot at the ankle, subsequently complementing the actions of the tibialis anterior and extensor digitorum longus

Deep fibular nerve

Extensor hallucis longus

Extension of the big toe or hallux at the metatarsophalangeal joints; acts on the ankle joint; assists other muscles of the anterior group to produce dorsiflexion of the foot

Deep fibular nerve

6. Breathing

Diaphragm

Active in inhalation; expansion of the thoracic cavity

Phrenic nerves; intercostal nerves

Scalenus medius

Produces strong ipsilateral flexion of the neck; helps stabilize the 1^st rib during respiration

Anterior rami of cercical spinal nerves

Sternocleidomastoid

Accessory muscles in pulmonary ventilation; when head is fixed, elevates sternum and clavicle, subsequently expanding thoracic cavity

Accessory nerve; branches of cervical plexus

Serratus anterior

Draws scapula anterolaterally; suspends scapula on thoracic wall; rotates scapula; active in labored breathing

Long thoracic nerve