Muscular Anatomy

1. Muscular Anatomy University of Washington PMT

2. Muscular Anatomy • Muscle Organization and Function • Muscle organization affects power, range and speed of muscle movement • Fascicles • Muscle cells (fibers) are organized into bundles • Classification of Skeletal Muscles • By the way fascicles are organized • By relationships of fascicles to tendons

3. Fascicle Arrangement • Organization of Skeletal Muscle Fibers • Four patterns of fascicle organization • Parallel • Convergent • Pennate • Circular

8. Levers • Levers • Mechanically, each bone is a lever (a rigid, moving structure) • And each joint a fulcrum (a fixed point) • Muscles provide applied force (AF) • Required to overcome resistance (R)

9. Levers • Function of a lever is to change • Direction of an AF • Distance and speed of movement produced by an AF • Effective strength of an AF • The Three Classes of Levers • Depend on the relationship between applied force, fulcrum, and resistance • First class, second class, and third class

10. First Class Lever

11. Second Class Lever

12. Third Class Lever

13. Types of Muscle--Actions • Prime mover (Agonist) – muscle with the major responsibility for a certain movement • Antagonist – muscle that opposes or reverses a prime mover • Synergist – muscle that aids a prime mover in a movement and helps prevent rotation • Fixator – stabilizes the origin of a prime mover

14. Direction of Muscle Fibers Location Action Skeletal Muscle Size Origin & Insertion Number Of Origins Shape Naming Skeletal Muscles

15. Direction of Muscle Fibers • Relative to the Midline • RECTUS = parallel to the midline • RectusAbdominus • TRANSVERSE = perpendicular to midline • TransverseAbdominus • OBLIQUE = diagonal to midline • External Oblique

16. Location • Structure near which muscle is found • FRONTALIS = near FRONTAL bone • OCCIPITALIS = near OCCIPITAL bone

17. Size • Relative Size of Muscle • MAXIMUS = largest • Gluteus Maximus • MEDIUS = middle • Gluteus Medius • MINIMUS = smallest • Gluteus Minimus • LONGUS = longest • Fibularis Longus • BREVIS = short • Fibularis Brevis • TERTIUS = shortest • Fibularis Tertius

18. Number of Origins • Number of tendons of origin • BICEPS = Two • Biceps Brachii • Biceps Femoris • TRICEPS = Three • Triceps Brachii • QUADRICEPS = Four • Quadriceps Femoris

19. Shape • Relative Shape of the Muscle • DELTOID = triangular shape Δ • TRAPEZIUS = trapezoid shape  SERRATUS = saw-toothed ♒ • RHOMBOIDEUS = rhomboid shape  • TERES = round ○

20. Origin & Insertion • Origin – attachment to an immoveable bone • Insertion – attachment to a movable bone • ILIOCOSTALIS= attaches to the ilium & ribs (costal = ribs)

21. Action

22. Head & Neck Muscles

23. Muscles of the Axial Skeleton

24. Intrinsic Muscles Erector Spinae: maintain posture of back/extension Spinalis Longissimus Iliocostalis Oblique Muscles: rotation of the vertebrae Semispinalis Multifidus Rotatores Muscles of Quiet Respiration Diaphragm External Intercostals Internal Intercostals—deep breaths Abdominal Muscles External Obliques Internal Obliques Transverse Abdominus Rectus Abdominus (flexes vertebral column) Quadratus Lumborum Muscles of the Axial Skeleton

25. Muscles of Scapular Stabilization • Trapezius: • Retraction • Elevation • Depression • Upward Rotation • Rhomboid—retraction • Levator Scapular—Elevation • Pectoralis Major—Protraction • Serratus Anterior—Protraction

26. Anterior Muscles of Shoulder • Deltoid • Whole muscle: Abduction @ shoulder • Anterior part: flexion / medial rotation • Posterior part: extension / lateral rotation • Pectoralis Major • Flexion • Adduction • Medial Rotation • Biceps Brachii—Flexion

27. Posterior Muscles of Shoulder • Teres Major • Adduction • Extension • Medial Rotation • Latissimus Dorsi • Adduction • Extension • Medial Rotation • Triceps Brachii • Extension

28. Muscles of the Elbow/Forearm • Triceps Brachii—Extension • Bicep Brachii— • Flexion • Supination • Brachialis—Flexion • Brachioradialis— • Flexion • Pronation • Pronator Teres • Pronator Quadratus • Supinator Longus

29. Muscles of the Wrist & Hand • Flexor Carpi Ulnaris • Flexor Carpi Radialis • Flexor Digitorum • Extensor Carpi Ulnaris • Extensor Carpi Radialis • Extensor Digitorum Anterior (Palmar) View Posterior (Dorsal) View

30. Muscles Of Hip:Anterior Muscles

31. Medial/Adductor Muscles: Adductor Magnus Adductor Longus Adductor Brevis Gracilis Anterior Muscles Iliopsoas—Flexion Pectineus— Flexion Sartorius— Flexion (knee) Lateral Rotation (hip) Muscles of Hip:Anterior Muscles

32. Muscles of Hip: Gluteal Muscles • Gluteus Maximus—Extension • Gluteus Medius—Abduction • Gluteus Minimus—Abduction • Tensor Fasciae Latae— • Flexion • Abduction ** Gluteus Minimus is under the Gluteus Medius

33. Muscles of Anterior Thigh • “Quadriceps” • Rectus Femoris— • Hip flexion • Knee extension • Vastus Lateralis—knee extension • Vastus Medialis—knee extension • Vastus Intermedius—knee extension • Sartorius— • Hip & Knee Flexion • Lateral Hip Rotation **Vastus Intermedius is beneath Rectus Femoris

34. Muscles of Posterior Thigh • “Hamstrings” • Responsible for Knee Flexion & Hip Extension • Semimembranosus • Semitendinosus • Biceps Femoris • Gastrocnemius • Knee Flexion

35. Muscles of the Lower Leg • Anterior Compartment • Tibialis Anterior—Dorsiflexion & inversion • Extensor Digitorum Longus • Fibularis Tertius—dorsiflexion & eversion • Posterior Compartment • Gastrocnemius—plantarflexion, knee flexion • Soleus—plantarflexion • Lateral Compartment • Fibularis Longus—plantarflexion & eversion • Fibularis Brevis—plantarflexion & eversion