|
Activity |
Muscle |
Action |
Innervation |
|
Throwing a baseball overhead |
Subscapularis |
Medially rotates arm and shoulder joint. |
Upper and lower suprascapular nerve |
|
Deltoid |
Lateral fibers abduct arm at shoulder; anterior fibers flex and medially rotate arm at shoulder joint; posterior fibers extend and laterally rotate arm at shoulder joint. |
Axillary nerve |
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Triceps brachii |
Extends forearm at elbow joint and extends arm at shoulder joint. |
Radial nerve |
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|
Kicking a ball |
Rectus femoris |
All four heads extend leg at knee joint; rectus femoris muscle acting alone also flexes thigh at hip joint. |
Femoral nerve |
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Vastus medialis |
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Vastus lateralis |
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Doing sit-ups |
Rectus abdominis |
Flexes vertebral column, especially lumbar portion, and compresses abdomen. |
Thoracic spinal nerve T7 – T12 |
|
Transversus abdominis |
Compresses abdomen. |
Thoracic spinal nerve T8 – T12, iliohypogastric nerve, and ilioinguinal nerve |
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|
External oblique |
Acting together, compress abdomen and flex vertebral column; acting singly, laterally flex vertebral column, especially lumbar portion, and rotate vertebral column. |
Thoracic spinal nerves T7- T12 and the iliohypogastric nerve. |
|
|
Walking |
Gluteus maximus |
Extends thig at hip joint and laterally rotates thing; helps lock knee in extension. |
Inferior gluteal nerve |
|
Gluteus medius |
Abducts thigh at hip joint and medially rotates thighs. |
Superior gluteal nerve |
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Vastus medialis |
All four heads extend leg at knee joint. |
Femoral nerve |
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|
Breathing |
Internal intercostals |
Contractions draws adjacent ribs together to further decrease anteroposterior and lateral dimension of thoracic cavity during forced exhalation. |
Thoracic spinal nerves T2 – T12 |
|
External intercostals |
Contraction elevates ribs and increases anteroposterior and lateral dimensions of thoracic cavity (inhalation), while relaxation depresses ribs and decreases anteroposterior and lateral dimension of thoracic cavity (exhalation). |
Thoracic spinal nerves T2-T12 |
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|
Diaphragm |
During contraction it flattens and increases the vertical dimension of thoracic cavity (inhalation); while during relaxation it moves superiorly and decreases vertical dimension of thoracic cavity (exhalation). |
Phrenic nerve containing axons from cervical spinal nerve (C3-C5) |