1. Chapter 11 Muscles
Exam 1 will cover sections

2. Section 1 Fascicle Arrangement
Fascicles: bundles of muscle fibers in skeletal muscle
fibers in each fascicle are parallel, but fascicle arrangement can vary
parallel muscles- fascicles are parallel to long axis of muscle (biceps brachii), when muscle fibers contract, muscle shortens by 30 %
convergent muscles- fascicles extend over a broad area & meet (converge) at the attachment site, (pectoralis muscles)

3. Pennate muscles- (feather) fascicles form a shared angle w/ tendon
contracted muscle doesn’t move tendon as far as parallel muscles-fibers angle
contain more muscle fibers than parallel muscle, so they produce more tension
Circular muscles- (sphincter) arranged around openings
when contracted, diameter decreases

5. 11.2 Classes of Levers
Nature and site of muscle connection determine force, speed, and range of motion
lever (bone) moves when the applied force (AF) is great enough to overcome the load (L) or resistance (R) that would prevent the movement
in the body, each joint acts as a fulcrum, and muscles provide the applied force
the load can vary (weight of limb, object held, or entire body)

6. Classes of levers levers can change
direction of applied force
distance & speed of movement
effective strength of applied force
Classes of levers
first class: fulcrum in the middle (teeter totter)
second class: load in the middle (wheel barrow), small force can move a larger weight, at the expense of speed and distance

7. third class: most common in body, force is between the load and the fulcrum, speed and distance traveled are increased at the expense of effective force (muscles must generate 6X the tension to support the load)

8. 11.3 Muscle Origins & Insertions
Ends of skeletal muscle are attached to structures that limit their motion (bone, cartilage, connective tissue)
origin-the place where fixed end of muscle attaches
insertion-the site where the moveable end attaches to another structure
action- movement produced when muscle contracts

9. Actions by bone or region affected (flexion of forearm)
Actions are described
by bone or region affected (flexion of forearm)
by joint involved (flexion of elbow)
based on functions
agonist (prime mover)- contraction responsible for producing specific movement, ex: biceps brachii muscle produces flexion of elbow
antagonist- muscle whose action opposes the action of an agonist, ex: triceps brachii extends the elbow, going against the biceps brachii

10. synergist- helps a larger agonist work efficiently, may provide pull near insertion or may stabilize near origin; useful in start of motion
fixator- a synergist that stabilizes origin of agonist by preventing movement at another joint

11. 11.4 Descriptive terms Locational terms Origin and Insertion
regional terms are common; abdominis- abdomen, capitis- head, femoris- femur, etc (PG 342)
Origin and Insertion
first part of name indicates the origin, second part, the insertion ex: sternocleidomastoid originates at sternum, inserts at the clavicle (cleido)

12. Fascicle organization
Rectus: straight, parallel muscles that run along long axis of body (rectus abdominis)
transverse/oblique: muscles have fibers that run at an angle to long axis of body (external obliques)
Position
externus/superficialis: visible at the body surface
internus/profundus:deeper muscles
Intrinsic: located within an organ

13. Structural Characteristics
number of tendons (biceps brachii, triceps brachii)
shape- muscles named after their shape: trapezius, deltoid(triangle), rhomboid
length and size:
longus (long), longissimus (longest)
teres (long & round), brevis (short)
magnus (large), major (bigger), or maximus (biggest)
minor (small), or minimus (smallest)

14. Stop! Test 1 will cover

15. 11.5 Muscles of facial expression
Orbicularis oculi
Sphincter muscle of eyelid
O: frontal & maxillary bones
I: tissue of eyelid
Action: closes eye
Nerve: facial / CN VII
(11.6)

16. Muscles of facial expression
Zygomaticus
O: zygomatic bone
I: corners of mouth
Action: smiling
Nerve: facial / CN VII
Major and Minor
(11.6)

17. Muscles of mastication
Masseter
O: zygomatic arch
I: angle & ramus of mandible
Action: elevate mandible
Nerve: trigeminal nerve / CN V (foramen ovale)
Masseter
(11.7a)

18. Muscles of mastication
Temporalis
O: temporal fossa
I: coronoid process of mandible
Action: elevate and retract mandible
Nerve: trigeminal n. / CN V
(11.7a)

19. Extrinsic tongue muscles
Styloglossus
O: styloid process of temporal bone
I: tongue
Action: retract & elevate tongue
Nerve: hypoglossal n. / CN XII
Styloglossus
(11.7c)

20. Extrinsic tongue muscles
Hyoglossus
O: hyoid bone
I: tongue
Action: depresses tongue
Nerve: hypoglossal n. / CN XII
Hyoid bone
(11.7c)

21. Muscles of neck & throat
Digastric
two muscle bellies with an intermediate tendon attached to the hyoid bone
O: inferior margin of mandible (anterior belly); mastoid process of temporal bone (posterior belly)
I: hyoid bone
Action: elevate hyoid, stabilize hyoid, depress mandible
Nerve: trigeminal n. / CN V (anterior belly), facial n. / CN VII (posterior belly)
Posterior belly
Anterior belly
(11.8a)

22. Muscles of neck & throat
Stylohyoid
O: styloid process of temporal bone
I: hyoid bone
Action: elevate & retract hyoid, swallow
Nerve: facial n. / CN VII
Stylohyoid
(11.7c)

23. Muscles of neck & throat
Sternohyoid
O: manubrium & medial end of clavicle
I: hyoid bone
Action: depress hyoid
Sternohyoid
(11.8a)

24. Muscles of neck & throat
Pharyngeal constrictors
O: mandible, pterygoid process, hyoid, laryngeal cartilages
I: posterior medial raphe of pharynx
Action: peristaltic contraction / swallow
Superior
Middle
Inferior
(11.8b)

25. Muscles of neck & throat
Sternocleidomastoid
O: manubrium & medial clavicle
I: mastoid process of temporal bone
Action: head & neck flexion, rotate head contralaterally
Nerve: accessory n. / CN XI
(11.8a)

26. Muscles of neck & throat
Sternocleidomastoid

27. Back muscles
Spinalis
O: spines of upper lumbar and lower thoracic vertebrae
I: spines of upper thoracic and cervical vertebrae
Action: extends vertebral column
(11.9d)

29. Deep thorax muscles External & internal intercostals
O&I: inferior & superior border of ribs
Action: inspiration and expiration
Internal
(11.10a)

30. Deep thorax muscles Diaphragm
Xiphoid process
Diaphragm
O: inferior internal surface of rib cage & sternum, inferior costal cartilages, lumbar vertebrae
I: central tendon
Action: flattens on contraction (inspiration)
Nerve: phrenic nerves
(11.10b)

32. Abdominal wall muscles
Rectus abdominis
O: pubic crest & symphysis
I: xiphoid process and costal cartilages of ribs 5-7
Action: flex & rotate lumbar vertebrae, fix & depress ribs, stabilize pelvis during walking, increase intraabdominal pressure
Note: 3 tendinous insertions, aponeurosis & linea alba
(11.11ab)

34. Section 11.6 Appendicular Muscles
Position & stabilize pectoral & pelvic girdles
Move upper & lower limbs
Split into 2 major groups:
Muscles of shoulder & upper limb
Muscles of pelvis & lower limb

35. Differences in function:
Pectoral girdle has muscular connections with axial skeleton, acts as a shock absorber
Example: can use hands when you run
Pelvic girdle transfers weight from axial muscles to appendicular skeleton, needs more bony support

36. I. Shoulder & Upper Limb Muscles that position the pectoral girdle
1.Trapezius- covers back & parts of the neck
*reaches the base of the skull
*inserts on the clavicles and spines of the scapulae
*regions can contract independently so the action varies
*superficial

37. Superificial thorax muscles
Trapezius
I: spine of scapula, clavicle
Action: stabilize, elevate, adduct, depress scapula, extend head
(11.13b)

38. B. Rhomobid. adducts (retracts) scapula
B. Rhomobid *adducts (retracts) scapula * attaches to cervical and thoracic vertebrae *inserts at the scapula *deep C. Levator scapulae *elevates scapula * deep

40. Superficial thorax muscles

41. D. Serratus anterior- on the chest. fan shaped
D. Serratus anterior- on the chest *fan shaped *originates on chest side of ribs *inserts on the scapula *protracts scapula, swings shoulder forward (pushing) *superficial

42. E. Subclavius. deep chest muscle. originates on rib 1
E. Subclavius *deep chest muscle * originates on rib 1 *inserts on inferior border of clavicle * depresses & protracts clavicle & shoulder F. Pectoralis Minor * originates on ribs 3-5 *inserts on coracoid process of scapulae *complements contraction of subclavius, downward rotation of shoulder

43. Superficial thorax muscles
Pectoralis minor
O: anterior surface of ribs 3-5
I: coracoid process of scapula
Action: pulls scapula anterior & inferior
(11.13a)

44. Shoulder muscles Pectoralis major
O: medial clavicle, sternum, cartilage of ribs 1-6, aponeurosis of external oblique
I: greater tubercle of humerus
Action: arm-flexion, medial rotation, adduction, elevation of rib cage
(11.13a)
Nerve: Medial and lateral
pectoral nerves (C6-C8)

45. Shoulder muscles Deltoid (11.13ab)
O: lateral clavicle, acromion & spine of scapula (compare to insertion of trapezius)
I: deltoid tuberosity of humerus
Action: arm-abduction, flexion, extension, medial & lateral rotation
Nerve: Axillary nerve(C5- C-6)
(11.13ab)

46. Shoulder muscles Subscapularis O: subscapular fossa
I: lesser tubercle of humerus
Action: medial rotate arm, stabilize shoulder joint
Nerve: Subscapular nerves (C5-C7)
(11.14d)

47. Shoulder muscles Infraspinatus O: infraspinous fossa
I: greater tubercle of humerus
Action: lateral rotate humerus, stabilized shoulder joint
Nerve: Suprascapular nerve
(11.14b)

48. Rotator cuff muscles
Act to stabilize head of humerus in glenoid cavity and prevent dislocation
Supraspinatous (Suprascapular nerve)
Infraspinatus (Suprascapular nerve)
Subscapularis (Subscapular nerve)
Teres minor (Axillary nerve)

49. Elbow muscles Triceps brachii
O: long head- infraglenoid tubercle, lat. & med. heads-posterior shaft of humerus
I: olecranon process of ulna
Action: extend forearm, assist adduction of arm
Nerve: Radial nerve
(11.14b)

50. Elbow muscles Biceps brachii (11.14c)
O: short head-coracoid process, long head-tubercle above glenoid cavity and lip of glenoid cavity (intertubercular groove)
I: radial tuberosity
Action: flex elbow, supinate forearm, weak arm flexor
Nerve: Musculocutaneous nerve (C5 & C6)
(11.14c)

52. Forearm muscles Flexor carpi (radialis & ulnaris)
O: medial epicondyle of humerus, ulna
I: metacarpals and carpals
Action: wrist flexion, abduct & adduct hand
Carpal tunnel (Median nerve) syndrome p. 184
radialis
ulnaris
(11.15a)
Anterior view

54. Forearm muscles Extensor carpi O: lateral epicondyle of humerus
I: base of metacarpals
Action: extend, abduct, and adducts wrist
Palpate forearm muscles

56. Hip & knee muscles Quadriceps femoris
O: anterior inferior iliac spine, superior margin of acetabulum, greater trochanter, shaft of femur
I: patella and tibial tuberosity via patellar tendon
Action: extend knee, flex thigh

57. Hip & knee muscles Gluteus muscles O: ilium, sacrum, coccyx
I: shaft & greater trochanter of femur
Action: extend thigh (climb stairs, running), lateral & medial rotate thigh, abduct thigh, steadies pelvis

58. Hip & knee muscles Hamstrings O: ischial tuberosity, shaft of femur
I: lateral & medial condyles and shaft of tibia, head of fibula, lateral condyle femur
Action: extend thigh, flex knee
Makes touching toes hard

59. Leg muscles Tibialis anterior O: lateral condyle and shaft of tibia
I: tarsal and first metatarsal bones
Action: dorsiflexion

60. Leg muscles Gastrocnemius O: medial & lateral condyles of femur
I: calcaneus via Achilles tendon
Action: plantar flexion, flex knee