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Muscles of the Body. 2 c-sections/msk/muscle-atlas "Copyright 2003-2004 University of Washington. All.

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Presentation on theme: "Muscles of the Body. 2 c-sections/msk/muscle-atlas "Copyright 2003-2004 University of Washington. All."— Presentation transcript:

1 Muscles of the Body

2 2 c-sections/msk/muscle-atlas "Copyright 2003-2004 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, 5 th ed., Martini, 6 th ed. or online with reference

3 Fascicles  Bundles of fibers *

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

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 anterior Text to use for studying...

15 posterior

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22 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

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

27 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 28 Neck Anterolateral neck Scalenes elevate first 2 ribs Posterior neck Splenius’ (capitis and cervicis) extend head

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

30 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 31 Deep muscles of the thorax: breathing  Intercostals Short: rib to rib  Diaphragm prime mover of inspiration Lift rib cage: inspiratory Depress rib cage: in forced expiration Floor of thoracic cavity: when flattens, air moves in

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

33 Muscles of the abdominal wall  Note inguinal ligament- from anterior superior iliac spine to pubic symphysis: lower border of external oblique rolls up on itself to form it From more superficial to deep: External oblique Internal oblique Transversus abdominis Nearer midline: Rectus abdominis 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 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 37 Rotator cuff supraspinatus, infraspinatus, subscapularis, teres minor remaining 2muscles : teres major and coracobrachialis

38 38 Forearm extensors (posterior)  Triceps brachii  Anconeus helps

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

40 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 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 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 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 44 Deep anterior hand muscles (some)  Flexor pollicis longus  Flexor digitorum profundus (only muscle that flexes DIPs)

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

46 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 brevis Extensor carpi radialis longus Extensor digitorum Extensor carpi ulnaris

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

49 Hand  Thenar  Hypothenar  Midpalmar  Lumbricals  Interossei Te

50 Thenar and hypothenar muscles academic-sections/msk/muscle-atlas

51 51

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

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54 54 Right forearm, posterior, from superficial to deep

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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  Sartorius  Iliopsoas  Tensor fasciae lata  Rectus femoris (only quad with origin on pelvis)  Pectineus (medial compartment) Originate from vertebral column and pelvis and pass anterior to hip joint

60 Muscles that flex thigh at hip: individually (go between last slide and this one) Tensor fascia lata Iliopsoas Sartorius Rectus femoris Pectineus 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 Biceps femoris long head Biceps femoris short head Semitendinosus Semimembranosus cross hip and knee joints: extend thigh and flex knee

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

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

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

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 Adductor longus Pectineus Adductor brevis Gracilis

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

70 Leg (lower leg)  3 compartments  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 Soleus Gastrocnemius Plantaris

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

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

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


77 More pics Tibialis anterior Extensor digitorum longus Extensor hallucis longus

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


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84 Sole – third (deepest) layer

85 Addendum: some rotator cuff tests (FYI) 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. 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.

86 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 6. Hawkins' test for subacromial impingement or rotator cuff tendonitis. The arm is forward elevated to 90 degrees, then forcibly internally rotated. 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.

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