1. Chapter 10
Muscular System

2. Terms Insertion – moveable attachment of the muscle
Origin – attachment of muscle that remains relatively fixed during muscular contractions
Innervations (innervate) – supply of nerves to body part (muscle)

3. Interactions of Skeletal Muscle
Skeletal muscles work together
Muscles only pull (never push)
Whatever a muscle (or group of muscles) “does”, another muscle (or group of muscles) “undoes”

4. Muscle Classification: Functional Groups
Prime Movers – provide the major force for producing significant movement
Antagonists – oppose or reverse a particular movement
Synergists – add force to a movement and reduce unnecessary movement
Fixators – synergists that immobilize a bone or muscle’s origin
Antagonist (an-tag-o-nist)
Synergists – (sin-er-jist)

5. Naming Skeletal Muscles
Location of the muscle – bone or body region associated with the muscle
Shape of muscle –
Relative size – maximus –largest, minimums-smallest
Directions of fibers
Rectus – fibers run straight
Transverse and oblique – fibers run at an angle to an imaginary axis

6. Naming of Skeletal Muscles Cont.
Number of origins
Bicep – 2 points or origin
Triceps – 3 points of origin
Location of attachments
Action
Flexor
Extensor

7. Arrangement of Fascicles

8. Major Skeletal Muscle: Anterior View
The 40 superficial muscles here are divided into 10 regional areas of the body

9. Posterior View
The 27 superficial muscles here are divided into seven regional areas of the body

10. Muscles of the Scalp
Epicranius (occipitofrontalis) – bipartite muscle consisting of the:
Frontalis
Occipitalis
Galea aponeurotica – cranial aponeurosis connecting above muscles
These two muscles have alternate actions of pulling the scalp forward and backward

11. Muscles of the face 11 muscles are used to
Lift eyebrows
Flare nostrils
Open and close mouth and eyes
Smiling
Usually insert in skin (rather than bone), and adjacent muscles often fuse

12. Muscles of the Face/Scalp

13. Figure it out There are 4 pairs of muscles involved in chewing
Can you identify which muscles are the
Prime movers
Grinding movements
Hint: Pretend chewing and Use your book if you don’t have the muscles of your face identified.

14. Muscles of mastication
Mastication – chewing
There are 4 pairs of muscles involved
Prime movers
Temporalis
Masseter
Grinding movements
Pterygoids
Buccinators
All are innervated by cranial nerve V (Trigeminal nerve)

15. Muscles of Mastication

16. Sticking out your tongue
Three major muscles that anchor and move the tongue
All are innervated by cranial nerve XII (hypoglossal nerve)

17. Muscles of the Abdominal wall
The abdominal wall is composed of four paired muscles (internal and external obliques, transversus abdominis, and rectus abdominis), their fasciae, and their aponeuroses
In addition to forming the abdominal wall, these muscles:
Are involved with lateral flexion and rotation of the trunk
Help promote urination, defecation, childbirth, vomiting, coughing, and screaming

18. Abdomen

19. Abdomen

20. Upper Limb Muscles

21. Shoulder Muscles Muscles of the thorax
Anterior: pectoralis major, pectoralis minor, serratus anterior, and subclavius
Posterior: latissimus dorsi, trapezius muscles, levator scapulae, and rhomboids
These muscles are involved with the movements of the scapula including elevation, depression, rotation, and lateral and medial movements
Prime movers of shoulder elevation are the trapezius and levator scapulae

22. Shoulder Muscles

23. Posterior View

24. Shoulder Joint
Nine muscles cross the shoulder joint and insert into the humerus
Prime movers include:
Pectoralis major – arm flexion
Latissimus dorsi and posterior fibers of the deltoid – arm extension
Middle fibers of the deltoid – arm abduction

25. Shoulder Muscles
Rotator cuff muscles – supraspinatus, infraspinatus, teres minor, and subscapularis
Function mainly to reinforce the capsule of the shoulder
The coracobrachialis and teres major:
Do not contribute to reinforcement of the shoulder joint

26. Anterior View Posterior View

28. Elbow Joint Forearm extension Forearm flexion
The triceps brachii is the prime mover of forearm extension
Forearm flexion
Brachialis and biceps brachii are the chief forearm flexors
The brachioradialis helps stabilize the elbow

29. Forearm Muscles
The two functional forearm muscle groups are: those that cause wrist movement, and those that move the fingers and the thumb
These muscles insert via strong ligaments called flexor and extensor retinacula
Most anterior muscles are flexors, and posterior muscles are extensors
The pronator teres and pronator quadratus are not flexors, but pronate the forearm
The supinator muscle is a synergist with the biceps brachii in supinating the forearm

31. Muscles of the forearm: Anterior
These muscles are primarily flexors of the wrist and fingers

32. Forearm Muscles – Posterior
These muscles are primarily extensors of the wrist and fingers

33. Lower Limb - Muscles

34. Anterior View

35. Posterior View

39. Foot/Hand Muscles

40. Hand

41. Foot

42. The Pelvic Diaphragm
The pelvic diaphragm is composed of two paired muscles – levator ani and coccygeus
These muscles:
Close the inferior outlet of the pelvis
Support the pelvic floor
Elevate the pelvic floor to help release feces
Resist increased intra-abdominal pressure

43. Pelvic Diaphragm