1. THE MUSCULAR SYSTEM

2. INTERACTIONS OF SKELETAL MUSCLES IN THE BODY
Muscles only pull; they are not capable of pushing
The muscle that provides the major force for the specific movement is called the prime mover or the agonist
Muscles that oppose or reverse a particular movement are called the antagonists
Synergists help the prime movers by adding extra force to the same movement, or by reducing undesirable or unnecessary movement

3. NAMING SKELETAL MUSCLES
Some muscle names indicate the bone or body region with which the muscle is associated
Some muscles are named for their shape
Terms such as maximus, minimus, longus, and brevis are often used in muscle names to indicate relative size of the muscle
The names of some muscles indicate the direction in which their fibers run in relation to an imaginary line of the body, such as the midline
The number of origins a muscle has may be indicated by the word biceps, triceps, or quadriceps
Some muscles are named according to the location of their origin and insertion
A muscle may be named for its action by using a word such as flexor or extensor in its name

4. MUSCLE MECHANICS: IMPORTANCE OF FASCICLE ARRANGEMENT AND LEVERAGE
In skeletal muscles the common arrangement of the fascicles varies, resulting in muscles with different shapes and functional capabilities
The fascicular pattern is circular when the fascicles are arranged in concentric rings
A convergent muscle has a broad origin and its fascicles converge toward a single tendon of insertion
In parallel arrangement, the long axis of the fascicles runs parallel to the long axis of the muscle
A spindle-shaped parallel arrangement of fascicles is sometimes classified as a fusiform muscle
In a pennate pattern of arrangement the fascicles are short and attach obliquely to a central tendon that runs the length of the muscle

5. FASCICLE ARRANGEMENT TO MUSCLE STRUCTURE

6. MUSCLE MECHANICS: IMPORTANCE OF FASCICLE ARRANGEMENT AND LEVERAGE
The operation of most skeletal muscles involves the use of leverage and lever systems, partnerships between the muscular and skeletal systems
A lever is a rigid bar that moves on a fixed point, or a fulcrum, when a force is applied to it
The applied force, or effort is used move a resistance or load
In your body, your joints act as the fulcrums, the bones as the levers, and the muscle contraction as the effort
There are three types of levers:
First-class
Second-class
Third-class

7. MUSCLE LEVERAGE

8. MUSCLE LEVERAGE

9. ANTERIOR SUPERFICIAL MUSCLES

10. DIAGRAMMATIC VIEW OF ANTERIOR MUSCLES

11. POSTERIOR VIEW OF SUPERFICIAL MUSCLES

12. DIAGRAMMATIC VIEW OF POSTERIOR MUSCLES

13. MAJOR SKELETAL MUSCLES OF THE BODY
Muscles of the Head: Facial Expression
Muscles of the scalp include the epicranius consisting of the frontalis and the occipitalis
Muscles of the face include corrugator supercilii, orbicularis oculi, zygomaticus, risorius, levator labii superioris, depressor labii inferioris, depressor anguli oris, orbicularis oris, mentalis, buccinator, and platysma

14. HEAD MUSCLES

15. MAJOR SKELETAL MUSCLES OF THE BODY
Muscles of the Head: Mastication and Tongue Movement
Muscles of mastication include the masseter, temporalis, medial pterygoid, lateral pterygoid, and the buccinator
Muscles promoting tongue movement are the genioglossus, hypoglossus, and the styloglossus

16. TONGUE MUSCLES

17. TONGUE MUSCLES

18. TONGUE MUSCLES

19. MAJOR SKELETAL MUSCLES OF THE BODY
Muscles of the Anterior Neck and Throat: Swallowing
Suprahyoid muscles include digastric, stylohyoid, mylohyoid, and geniohyoid
Infrahyoid muscles include sternohyoid, sternothyroid, omohyoid, thyrohyoid, and the pharyngeal constrictor muscles (superior, middle, and inferior)

20. NECK MUSCLES

21. NECK MUSCLES

22. MAJOR SKELETAL MUSCLES OF THE BODY
Muscles of the Neck and Vertebral Column: Head and Trunk Movement
Anterolateral neck muscles include the sternocleidomastoid, and scalenes (anterior, middle, and posterior)
Intrinsic muscles of the back include splenius capitis, erector spinae or sacrospinalis, iliocostals, longissimus, spinalis, semispinalis, and the quadratus lumborum

23. NECK AND VERTEBRAL COLUMN MUSCLES

24. NECK AND VERTEBRAL COLUMN MUSCLES

25. NECK AND VERTEBRAL COLUMN MUSCLES

26. NECK AND VERTEBRAL COLUMN MUSCLES

27. MAJOR SKELETAL MUSCLES OF THE BODY
Muscles of the Thorax: Breathing
Muscles of the thorax include the external intercostals, internal intercostals, and the diaphragm
Muscles of the Abdominal Wall: Trunk Movement and Compression of Abdominal Viscera
Muscles of the anterolateral abdominal wall include the rectus abdominis, external oblique, and the transversus abdominis

28. RESPIRATORY MUSCLES

29. RESPIRATORY MUSCLES

30. ABDOMINAL MUSCLES

31. ABDOMINAL MUSCLES

32. MAJOR SKELETAL MUSCLES OF THE BODY
Muscles of the Pelvic Floor and Perineum: Support of Abdominopelvic Organs
Muscles of the pelvic diaphragm include the levator ani and the coccygeus
Muscles of the urogenital diaphragm include the deep transverse perineus and the sphincter urethrae
Muscles of the superficial space include the ischiocavernosus, bulbospongiosus, and the superficial transverse perineus

33. PELVIC FLOOR AND PERINEUM MUSCLES

34. PELVIC FLOOR AND PERINEUM MUSCLES

35. MAJOR SKELETAL MUSCLES OF THE BODY
Superficial Muscles of the Anterior and Posterior Thorax: Movements of the Scapula
Muscles of the anterior thorax include the pectoralis minor, serratus anterior, and the subclavius
Muscles of the posterior thorax include the trapezius, levator scapulae, and the rhomboids (major and minor)

36. THORAX MUSCLES

37. MAJOR SKELETAL MUSCLES OF THE BODY
Muscles Crossing the Shoulder Joint: Movement of the Arm
Muscles moving the arm include the pectoralis major, latissimus dorsi, deltoid, subscapularis, supraspinatous, infraspinatous, teres minor, teres major, and the coracobrachialis

38. SHOULDER MUSCLES

39. SHOULDER MUSCLES

40. MAJOR SKELETAL MUSCLES OF THE BODY
Muscles crossing the Elbow Joint: Flexion and Extension of the Forearm
Posterior muscles include the triceps brachii, and the anconeus
Anterior muscles include the biceps brachii, brachialis, and the brachioradialis

41. ANTERIOR ARM MUSCLES

42. POSTERIOR ARM MUSCLES

43. ARM MUSCLES

44. MAJOR SKELETAL MUSCLES OF THE BODY
Muscles of the Forearm: Movements of the Wrist, Hand, and Fingers
Anterior superficial muscles include the pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris, and the flexor digitorum superficialis
Anterior deep muscles include the flexor pollicis longus, flexor digitorum profundus, and the pronator quadratus
Posterior superficial muscles include the brachioradialis, extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, and the extensor carpi ulnaris
Posterior deep muscles include the supinator, abductor pollicis longus, extensor pollicis longus, and the extensor pollicis brevis

45. MAJOR SKELETAL MUSCLES OF THE BODY
Summary of Actions of Muscles Acting on the Arm, Forehead, and Hand

46. ARM MUSCLE ACTIONS

47. ARM MUSCLE ACTIONS

48. MAJOR SKELETAL MUSCLES OF THE BODY
Intrinsic muscles of the Hand: Fine Movements of the Fingers
Thenar muscles in ball of thumb include the abductor pollicis brevis, flexor pollicis brevis, opponnens pollicis, and the adductor pollicis
Hypothenar muscles in ball of little finger include the abductor digiti minimi, flexor digiti minimi brevis, and the opponens digiti minimi
Midpalmar muscles include the lumbricals, palmar interossei, and the dorsal interossei

49. HAND MUSCLES

50. HAND MUSCLES

51. MAJOR SKELETAL MUSCLES OF THE BODY
Muscles Crossing the Hip and Knee Joints: Movements of the Thigh and Leg
Anteromedial muscles include the iliopsoas, which is composed of the iliacus, the psoas major, and the sartorius
Muscles of the medial compartment of the thigh include the adductor group, which is made up of the adductor magnus, adductor longus and the adductor brevis, the pectineus, and the gracilis
Muscles of the anterior compartment of the thigh include the quadriceps femoris group, which is made up of the rectus femoris, vastus lateralis, vastus medialis and vastus intermedius, and the tensor fasciae latae
Posterior Muscles: gluteal muscles (origin on pelvis) include the gluteus maximus, gluteus medius, and the gluteus minimus
Lateral rotators include the piriformis, obturator externus, obturator internus, gemellus, and the quadratus femoris
Muscles of the posterior compartment of the thigh include the hamstring group, which consist of the biceps femoris, semitendinosus, and the semimembranosus

52. ANTERIOR THIGH MUSCLES

53. ANTERIOR THIGH MUSCLES

54. POSTERIOR THIGH MUSCLES

55. POSTERIOR THIGH MUSCLES

56. MAJOR SKELETAL MUSCLES OF THE BODY
Muscles of the Leg: Movements of the Ankle and Toes
Muscles of the anterior compartment include the tibialis anterior, extensor digitorum longus, fibularis (peroneus) tertius, and the extensor hallucis longus
Muscles of the lateral compartment include the fibularis (peroneus) longus and the fibularis (peroneus) brevis
Superficial muscles of the posterior compartment include the triceps surae, which is composed of the gastrocnemius and the soleus, and the plantaris
Deep muscles of the posterior compartment include the popliteus, flexor digitorum longus, flexor hallucis longus, and the tibialis posterior

57. ANTERIOR LEG MUSCLES

58. ANTERIOR LEG MUSCLES

59. LATERAL LEG MUSCLES

60. LATERAL LEG MUSCLES

61. POSTERIOR LEG MUSCLES

62. POSTERIOR LEG MUSCLES

63. POSTERIOR LEG MUSCLES

64. POSTERIOR LEG MUSCLES

65. MAJOR SKELETAL MUSCLES OF THE BODY
Summary of Actions of Muscles Acting on the Thigh, Leg, and Foot

66. LEG MUSCLE ACTIONS

67. LEG MUSCLE ACTIONS

68. MAJOR SKELETAL MUSCLES OF THE BODY
Intrinsic Muscles of the Foot: Toe Movement and Arch Support
The muscle found on the dorsum of the foot is the extensor digitorum brevis
Muscles on the sole of the foot found in the first layer are the flexor digitorum brevis, abductor hallucis, and the abductor digiti minimi
Muscles on the sole of the foot found in the second layer are the flexor accessorius (quadratus plantae) and the lumbricals
Muscles of the sole of the foot found in the third layer include the flexor hallicis brevis, adductor hallucis, and the flexor digiti minimi brevis
Muscles of the sole of the foot found in the fourth layer include the plantar and the dorsal interossei

69. FOOT MUSCLES

70. FOOT MUSCLES

71. FOOT MUSCLES