Anatomy & Physiology Ch 10 – Muscular System

1. Anatomy & Physiology Ch 10 – Muscular System

2. Interactions of Skeletal Muscles in the Body • Muscles only pull; they’re not capable of pushing. • The prime mover or agonist provides major force for specific mvmt. • Muscles that oppose or reverse specific mvmt are called antagonists. • Synergists help prime movers by adding extra force to a mvmt or reduce undesirable mvmts.

3. II. Naming Skeletal Muscles • Named for body region where located. • Shape • Size (maximus, minimus, longus, brevis) • Direction of fibers to body (like midline) • Number of origins (biceps, triceps, quadriceps) • Location of origin & insertion • Action (flexor or extensor)

4. Muscle Mechanics • Operation of skeletal muscles involves leverage & lever systems, partnerships between muscular & skeletal systems) • Lever is bar that moves on fixed point, or fulcrum, when force is applied. • Applied force, or effort, is used to move a resistance or load. • Joints act as fulcrums, bones as levers, & muscle contraction as effort. • 3 types of levers: 1st class, 2nd class, & 3rd class

5. Major Skeletal Muscles • Head: Facial Expression • 1. Scalp – frontalis & occipitalis • 2. Face – zygomaticus, mentalis, buccinator • Head: Tongue Movement • 1. Mastication – masseter, temporalis, buccinator • 2. Tongue mvmt – genioglossus, hypoglossus, styloglossus

6. Neck & Vertebral Column: Head & trunk mvmts • 1. Neck Muscles: Sternocleidomastoid, scalenes • 2. Back: erector spinae, longissimus, spinalis • Thorax: Respiration • External & internal intercostals & diaphragm

7. Abdominal Wall: trunk mvmts • Rectus abdominis, external & internal oblique, & transverse abdominis • Pelvic: support abdominopelvic organs • 1. Pelvic diapragm – levator ani & coccygeus • 2. Urogenital diaphragm – deep transverse perineus & sphincter urethrae

8. Anterior & posterior Thorax: Mvmts of Scapula • 1. Anterior – pectoralis minor, serratus anterior, & subclavius • 2. Posterior – trapezius, lavator scapulae, & rhomboids (major & minor) • Muscles Crossing Shoulders: mvmt of arm • Pectoralis major, latissimus dorsi, deltoid, subscapularis, terres major & minor

9. Muscles Crossing Elbow Joint: Flexion & extension of forearm • 1. Posterior – triceps brachii, brachialis, & brachioradialis • 2. Anterior – biceps brachii, brachialis, & brachioradialis • Muscles of Forearm: mvmt of wrist, hand, fingers • 1. Anterior superficial – flexor carpi radialis, palmaris longus, flexor cari ulnaris • 2. Ant. Deep – flexor digitorum profundus

10. Muscles Crossing Hip & Knee Joints: thigh & leg mvmts • 1. Adductor group of thigh – adductor longus, adductor magnus, adductor brevis • 2. Quadriceps femoris group – rectus femoris, vastus lateralis, vastus medialis • 3. Posterior – gluteal muscles are gluteus maximus, gluteus medius, gluteus maximus • 4. Posterior of thigh – hamstring group is biceps femoris, semitendinosus, & semimembranosus

11. Muscles of Leg: mvmts of ankle & toes • 1. Fibularis longus, fibularis brevis, plantaris, tibialis posterior • 2. Sole - plantar