1. a) Latissimus dorsi
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- Action: Extends, adducts, and rotates arm medially; draws arm downward and backward
- Innervation: Thoracodorsal nerve
b) Subscapularis
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- Action: Rotate arm medially
- Innervation: Upper and lower subscapular nerves
2. a) Inferior Gemellus
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- Action: Rotates thigh laterally and abducts it
- Innervation: Nerve to quadratus femoris
b) Biceps Femoris
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- Action: Flexes leg and extends thigh
- Innervation: Tibial and common peroneal nerves from sciatic nerve
3. a) Rectus Abdominis
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- Action: Compresses abdomen to aid in defecation, urination, forced expiration, and childbirth and flexes vertebral column
- Innervation: Branch of thoracic nerves T7-T12
b) Transversus Abdominis
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- Action: Compresses abdomen
- Innervation: Branches of thoracic nerves T8-T12, iliohypogastric, and ilioinguinal nerves
4. a) Diaphragm
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- Action: Forms floor of thoracic cavity; pulls central tendon downward during inspiration and as dome of diaphragm flattens increases vertical length of thorax
- Innervation: Phrenic nerve
b) Internal Intercostals
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- Action: May draw adjacent ribs together during forced expiration and thus decrease lateral and anteroposterior dimensions of thorax
- Innervation: Intercostal nerves
Reference: Tortora, G. J., & Grabowski, S. R. (1993). Principles of Anatomy and Physiology (7th ed.). HarperCollins College.