1. Muscles of the Body

2. http://www. rad. washington
"Copyright University of Washington. All rights reserved including all photographs and images. No re-use, re-distribution or commercial use without prior written permission of the authors and the University of Washington." "Musculoskeletal Images are from the University of Washington "Musculoskeletal Atlas: A Musculoskeletal Atlas of the Human Body" by Carol Teitz, M.D. and Dan Graney, Ph.D."
Other copies materials from Marieb, 5th ed., Martini, 6th ed. or online with reference

3. Fascicles
Bundles of fibers *

4. Skeletal muscle Epimysium: surrounds whole muscle
Endomysium is around each muscle fiber
Perimysium is around fascicle

5. Different arrangements of fascicles

6. Arrangement of fascicles influences movement and power
Skeletal muscles can shorten by about 1/3 of their resting length
The more nearly parallel to the axis, the more they can shorten
This results in a larger distance of movement
The power depends on the total number of fibers
Stocky muscles (like bipennate vs parallel) have more fibers, therefore more powerful even though shorten very little

7. Interactions of Skeletal Muscles
Muscles can only pull, they can’t push
Actions must be “undone” by a different muscle
Muscles that produce opposite movements usually lie on opposite sides of a given joint

8. Interactions, continued
Agonist: prime mover, major responsibility for producing a specific movement
Antagonist: oppose or reverse a particular movement
Usually contract a little to prevent overshooting the mark or slow the agonist’s action near the end
Are being stretched or can remain relaxed when agonist works
Antagonists for one movement can be agonists for another

9. Synergists help prime movers
Add a little extra force to the same movement
Or reduce undesirable extra movements (e.g. making a fist without flexing at wrist)
Fixators: hold a bone firmly so agonist has a stable base on which to move a body part (e.g. fixing scapula when arm moves)

10. Compartments
Contain muscles of similar developmental origin and function
Dense fibrous connective tissue separates
Upper limb: 2 compartments
Lower limb: 3 compartments

11. Naming skeletal muscles (examples)
Location: brachialis is in arm (brachium = arm)
Shape: deltoid is triangular (delta = triangle)
Size: minimus (smallest), longus (long), brevis (short)
Direction of fascicles and fibers: rectus (straight); transversus (right angle) and oblique (oblique) to midline
Number of origins: biceps (“two heads”), triceps (“three heads”), quadriceps (“four heads”)
Action: “flexor,” “extensor,” “adductor” or “abductor” appear in the name
Combinations of the above, e.g. extensor carpi radialis longus

12. Axial muscles
Lie anterior and posterior to body axis (vertebral column)
Move trunk; maintain posture
Skeletal muscles of thorax, abdomen, and pelvis
Many muscles of neck
A few muscles in head

13. Limb muscles Arise from ventral region as limb buds
Muscles develop from lateral parts of myotomes
In general: dorsal (posterior) muscles become extensors and ventral (anterior) become flexors
Lower limb rotates during embryonic development:
Extensors on anterior (ventral) side: extend leg at knee, dorsiflex foot at ankle and extend toes
Flexors on posterior (dorsal) side: flex leg at knee, plantarflex foot at ankle, flex toes

14. to use for studying...
anterior
Text
Text

15. posterior

16. 16

17. 17

18. 18

19. 19

20. 20

21. 21

22. Muscles of the Head and Neck
Scalp Muscle: epicranius
frontal belly
occipital belly
gala aponeurotica
Muscles of Facial Expression: insert on skin or another muscle
Muscles of Mastication (chewing): all have insertions on the mandible
Anterior Neck Muscles
Posterior Neck Muscles

23. 23

24. 24

26. Extrinsic tongue muscles Pharyngeal constrictors
Mastication:
Jaw closure: masseter
and temporalis
Side to side grinding:
pterygoids
Buccinator: compresses cheek
“glossus” = tongue
Deep chewing muscles
Extrinsic tongue muscles
Pharyngeal constrictors
Tongue itself (instrinsic muscles): digestive tract section

27. Muscles of the Anterior Neck
Above hyoid (suprahyoid): form floor of oral cavity, anchor tongue, elevate hyoid, move larynx superiorly during swallowing
Below hyoid (infrahyoid): depress hyoid and larynx during swallowing and speaking
Right side (of slide) is deeper than left
Sternocleodomastoid

28. Neck Posterior neck Anterolateral neck
Splenius’ (capitis and cervicis) extend head
Anterolateral neck
Scalenes elevate first 2 ribs

29. Deep muscles of back Quadratus lumborum Erector spinae
Right side: deeper
Quadratus lumborum
(lateral flexion)
Erector spinae
(extend back):
Iliocostalis
Longissimus
Spinalis
Labeled cervicis,
thoracics, lumborum depending on where they are

30. Per Marieb… (worthwhile to know)
“During full flexion (i.e. when touching fingertips to floor), erector spinae are relaxed and strain is borne entirely by ligaments of back; on reversal of the movement, these muscles are initially inactive, and extension is initiated by hamstring muscles of thighs and gluteus maximus muscles of buttocks. As a result of this peculiarity, lifting a load or moving suddenly from a bent over position is potentially injurious to muscles and ligaments of back and intervertebral discs; erector spinae muscles readily go into painful spasms following injury to back structures.”

31. Deep muscles of the thorax: breathing
Lift rib cage: inspiratory
Intercostals
Short: rib to rib
Diaphragm
prime mover
of inspiration
Depress rib cage: in forced expiration
Floor of thoracic cavity: when flattens, air moves in

32. Anterior Chest Muscles
Superficial:
sternocleidomastoid
pectoralis major
Deeper:
pectoralis minor
serratus anterior
subclavius

33. Muscles of the abdominal wall
From more superficial to deep:
External oblique
Internal oblique
Transversus abdominis
Nearer midline:
Rectus abdominis
Note inguinal ligament- from anterior superior iliac spine to pubic symphysis: lower border of external oblique rolls up on itself to form it * *
The rectus abdominis is the medial pair of muscles; it is ensheathed by the aponeurosis of the lateral muscles, which don’t come to the midline

34. Muscles of the abdominal wall from the side

35. Muscles moving the scapula
trapezius
levator scapulae
rhomboids
posterior

36. 9 Muscles crossing shoulder joint: movement of arm (humerus)
Three most powerful of the nine and prime movers:
pectoralis major
latissimus dorsi
deltoid

37. Rotator cuff supraspinatus, infraspinatus, subscapularis, teres minor
remaining 2muscles : teres major and coracobrachialis

38. Forearm extensors (posterior)
Triceps brachii
Anconeus helps

39. Forearm flexors (anterior)
Brachioradialis
Brachialis
Biceps brachii
3 muscle on right from this site:

40. Retinaculae (retinaculum, singular)
“retainers,” “wrist bands”, “ankle bracelets”
Bands of fascia holding tendons of wrist and ankle in place (prevent “bow-stringing”)
Tendons covered by slippery tendon sheets

41. Forearm muscles: movement of wrist, hand and fingers
Many arise from distal humerus
Cross elbow, wrist and finger joints
Minimal action at elbow
At wrist joint: flexion, extension, abduction and adduction of the hand
At finger joints: mostly just flex and extend (other movements- by small muscles in the hand itself)

42. Forearm muscles, continued
Two compartments (each with superficial and deep muscle layers)
Anterior = flexor compartment ( except includes 2 pronators)
Most originate from a common tendon on the medial epicondyle of humerus
Posterior = extensor compartment (except includes supinator and brachioradialis)
Many arise from a common tendon from lateral epicondyle of humerus
Most muscles that move the palm and fingers are located in the forearm, not the hand itself
They operate by tendons like strings with puppets
There are some small muscles in the hand itself

43. Anterior wrist pronator and flexors
Origin on medial epicondle of humerus: pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris, flexor digitorum superficialis
Pronator teres
Palmaris longus

44. Deep anterior hand muscles (some)
Flexor pollicis longus
Flexor digitorum profundus (only muscle that flexes DIPs)

45. Individually Flexor digitorum superficialis
(this is right arm, anterior)
Flexor digitorum profundus
Flexor pollicis longus
Pronator quadratus

46. Extensor carpi radialis (longus & brevis)
origin on lateral
epicondyl of humerus
Extensor carpi radialis (longus & brevis)
Extensor digitorum
Extensor carpi ulnaris
See individually in next slide

47. Superficial extensors
Extensor carpi radialis longus
Extensor digitorum
Extensor carpi ulnaris
Extensor carpi radialis brevis

48. Deep posterior muscles
Extensor pollicis longus & brevis
Abductor pollicis longus
Supinator
Extensor indicis

49. Hand Te
Thenar
Hypothenar
Midpalmar
Lumbricals
Interossei

50. Thenar and hypothenar muscles

52. Right forearm, anterior view, from superficial to deep

54. Right forearm, posterior, from superficial to deep

58. Muscles crossing the hip and knee joints
Three groups separated by fascia; all three enclosed by deep fascia of thigh (fascia lata)
1. Anterior
Flex femur at hip; extend leg at knee (e.g. foreswing phase of walking)
2. Posterior
Mostly extend thigh and flex leg (backswing phase of walking)
3. Adductor (medial)
Move thigh only, not leg

59. Muscles that flex thigh at hip
Originate from vertebral column and pelvis and pass anterior to hip joint
Sartorius
Iliopsoas
Tensor fasciae lata
Rectus femoris (only quad with origin on pelvis)
Pectineus (medial compartment)

60. Muscles that flex thigh at hip: individually (go between last slide and this one)
Iliopsoas
Pectineus
Tensor fascia lata
Sartorius
Rectus femoris
Inserts on tibial tuberosity via patellar tendon

61. Thigh extensors (posterior)
Arise posterior to hip joint
Gluteus maximus
Hamstrings (cross hip and knee joints: extend thigh & flex knee)
Biceps femoris
Semitendinosus
Semimembranosus
(antagonists of quads)
_______

62. Hamstrings cross hip and knee joints: extend thigh and flex knee
Biceps femoris long head
Biceps femoris short head
Semitendinosus
Semimembranosus

63. Abductors of thigh Buttocks muscles that lie lateral to hip joint
Gluteus medius
Gluteus minimus (under medius)
Tensor fascia lata

64. Thigh abductors Buttocks muscles that lie lateral to the hip joint
Gluteus medius
Gluteus minimus

65. Lateral rotators Piriformis
Piriformis laterally rotates hip; also helps abduct hip if it is flexed
Piriformis
Also shown are other rotators and the gluteus muscles

66. Adduction of thigh Muscles originate medial to hip joint Gracilis
Adductor magnus
Adductor longus
Adductor brevis
Pectineus

67. Thigh adductors (originate medial to hip joint)
Adductor magnus
Pectineus
Adductor brevis
Gracilis
Adductor longus

68. Knee extensors
Quadraceps femoris – the only extensors of the leg (lower leg) at the knee
Rectus femoris (only quad with origin on pelvis)
Vastus lateralis
Vastus intermedius
Vastus medialis
Antagonized by hamstrings
Rectus femoris

69. Quadriceps Vastus lateralis, intermedius, and medialis
Rectus femoris
(only quad with origin on the pelvis)
Quadriceps
Vastus lateralis, intermedius, and medialis
Note “o” and “i”
_________
Insert: tibial tuberosity via patellar ligament

70. Leg (lower leg) 3 compartments Movements at joints: Anterior Posterior
Lateral
Movements at joints:
Ankle
Dorsiflex
Plantarflex
Intertarsal
Inversion of foot
Eversion of foot
Toes
Flex (point)
Extend

71. Posterior compartment of leg
Superficial: these plantarflex foot
Gastrocnemius
Soleus
Plantaris

72. Posterior leg Plantaris Soleus Gastrocnemius

73. Posterior leg continued
Deep
Popliteus
Flexor digitorum longus
Flexor hallucis longus
Tibilialis posterior

74. Deep posterior leg Popliteus Flexor digitorum longus
Flexor hallucis longus
Tibialis posterior

75. Anterior leg extensors
Mainly extend toes and dorsiflex foot
Tibialis anterior
Extensor digitorum longus
Extensor hallucis longus

77. More pics Extensor hallucis longus Tibialis anterior
Extensor digitorum longus

78. Lateral compartment of leg
Fibularis (peroneus) longus:
to first metatarsal and cuneiform
Fibularis (peroneus) brevis:
to fifth metatarsal

84. Sole – third (deepest) layer

85. Addendum: some rotator cuff tests (FYI)
FIGURE 3. Supraspinatus examination ("empty can" test). The patient attempts to elevate the arms against resistance while the elbows are extended, the arms are abducted and the thumbs are pointing downward.
FIGURE 2. Apley scratch test. The patient attempts to touch the opposite scapula to test range of motion of the shoulder. (Left) Testing abduction and external rotation. (Right) Testing adduction and internal rotation.

86. FIGURE 4. Infraspinatus/teres minor examination
FIGURE 4. Infraspinatus/teres minor examination. The patient attempts to externally rotate the arms against resistance while the arms are at the sides and the elbows are flexed to 90 degrees.
FIGURE 5. Neer's test for impingement of the rotator cuff tendons under the coracoacromial arch. The arm is fully pronated and placed in forced flexion.
FIGURE 6. Hawkins' test for subacromial impingement or rotator cuff tendonitis. The arm is forward elevated to 90 degrees, then forcibly internally rotated.