Turning a door knob
Muscle | Action | Innervation |
Supinator | Supinates forearm at radioulnar joints | Deep radial nerve |
Brachioradialis | Flexes forearm at elbow joint | Radial nerve |
Biceps Brachii | Flexes forearm at elbow joint; flexes arm at shoulder joint | Musculocutaneous nerve |
Triceps Brachii | Extends forearm at elbow joint; extends arm at shoulder joint | Radial nerve |
Throwing a baseball overhead
Muscle | Action | Innervation |
Teres Major | Extends arm at shoulder joint; assists in adduction and medial rotation of arm at shoulder joint | Lower subscapular nerve |
Subscapularis | Medially rotates arm at shoulder joint | Upper and lower subscapular nerve |
Deltoid | Lateral fibers abduct arm at shoulder joint; anterior fibers flex and medially rotate arm at shoulder joint | Axillary nerve |
Pectoralis Major | Adducts and medially rotates arm at shoulder joint | Medial and lateral pectoral nerves |
Kicking a ball
Muscle | Action | Innervation |
Iliopsoas | Flex thigh at hip joint, rotate thigh laterally, and flex trunk on hip | Lumbar spinal nerves L2–L3 |
Quadriceps femoris | Extend leg at knee joint | Femoral nerve |
Hamstrings | Flexes leg at knee joint and extends thigh at hip joint | Tibial nerve |
Doing sit-ups
Muscle | Action | Innervation |
Rectus Abdominis | Flexes vertebral column, and compresses abdomen to aid in defecation, urination, forced exhalation, and childbirth | Thoracic spinal nerves T7–T12 |
Internal Oblique | Acting together, compress abdomen and flex vertebral column | Acting together, compress abdomen and flex vertebral column |
Transverse Abdominis | Compresses abdomen | Thoracic spinal nerves T8–T12, iliohypogastric nerve, and ilioinguinal nerve |
Walking
Muscle | Action | Innervation |
Tibialis Posterior | Plantar flexes foot at ankle joint and inverts foot at intertarsal joints | Tibial nerve |
Gastrocnemius | Plantar flexes foot at ankle joint and inverts foot at intertarsal joints | Tibial nerve |
Quadriceps Femoris | Extend leg at knee joint | Femoral nerve |
Breathing
Muscle | Action | Innervation |
Diaphragm | 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 | Phrenic nerve, which contains axons from cervical spinal nerves (C3–C5) |
External Intercostals | 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 | Thoracic spinal nerves T2–T12 |
Internal Intercostals | Contraction draws adjacent ribs together to further decrease anteroposterior and lateral dimensions of thoracic cavity during forced exhalation | Thoracic spinal nerves T2–T12 |