Skeletal Muscles Muscle Man Muscles are arranged as

Skeletal Muscles “Muscle Man”

Muscles are arranged as levers to make work easier.

• Each muscle has an origin (immovable end) and an insertion (movable end). • The muscle can only contract.

• Muscles are arranged in pairs antagonistic muscle pairs to allow continuous movement. ex: biceps brachii flexes forearm triceps brachii extends forearm

• The muscle with the main responsibility for movement of a body part is the prime mover or agonist • The opposing muscle is the antagonist • Other muscles that aid in movement are synergists • Synergists that immobilize a bone or joint are fixators

Muscle names derive from: 1. Location frontalis

Muscle names derive from: 2. Shape deltoid

Muscle names derive from: 3. Size gluteus maximus

Muscle names derive from: 4. direction of fibers external oblique

Muscle names derive from: 5. number of origins biceps brachii

Muscle names derive from: 6. location of origin and/or insertion sternocleidomastoid

Muscle names derive from: 7. action of muscle flexor digitorum

Sometimes several of these are combined. ex: extensor carpi radialis longus

Muscles to learn name (correct spelling), general location, and action. Muscle Name 1. orbicularis oris 2. orbicularis oculi 3. frontalis 4. masseter 5. sternocleidomastoid 6. deltoid 7. pectoralis major Action of Muscle pucker mouth squint eye raises eyebrows closes jaw head flexion abduct / rotates arm adduct arm; flexes arm

Muscles to learn name (correct spelling), general location, and action. Muscle Name 8. external oblique 9. rectus abdominis 10. trapezius 11. latissimus dorsi 12. biceps brachii 13. triceps brachii 14. flexor digitorum 15. extensor digitorum Action of Muscle trunk flexion / rotates flex / rotates lumbar raises / rotates scapula extend / adduct arm flexes forearm extends forearm flexes wrist and fingers extends wrist and fingers

Muscles to learn name (correct spelling), general location, and action. Muscle Name 16. rectus femoris 17. sartorius 18. gracilis 19. gluteus maximus 20. hamstrings 21. gastrocnemius 22. diaphragm Action of Muscle knee extensor flexes / laterally rotates thigh flexes / medially rotates thigh extensor thigh extension; knee flexion flex foot inspiration