Muscle SystemMuscle System

Ch. 10Ch. 10

Four functional groups of muscle:Four functional groups of muscle:1- prime movers (agonists): Muscle 1- prime movers (agonists): Muscle

that bears the prime responsibility that bears the prime responsibility for effecting a movementfor effecting a movement

2- antagonist: Muscle that opposes the 2- antagonist: Muscle that opposes the action of another muscle.action of another muscle.

3- synergists: these muscles act as 3- synergists: these muscles act as stabilizers to the prime movers. They stabilizers to the prime movers. They may also contribute extra force to may also contribute extra force to the prime mover as well.the prime mover as well.

4- fixator: muscle that immobilizes one 4- fixator: muscle that immobilizes one or more bones (scapula)or more bones (scapula)

Muscle are classified according to their Muscle are classified according to their fascicular arrangement or attachment. fascicular arrangement or attachment.

ParallelParallel - long axis of fascicle runs with - long axis of fascicle runs with longitudinal axis of muscle: sartorius muscle longitudinal axis of muscle: sartorius muscle

PennatePennate - fascicle branch form central - fascicle branch form central tendon diagonally tendon diagonally UnipennateUnipennate - extensor muscles - extensor muscles BipennateBipennate - rectus femoris - rectus femoris MultipennateMultipennate - deltoid - deltoid

Convergent Convergent - fascicle converge toward a - fascicle converge toward a single tendon: pectoralis major single tendon: pectoralis major

Circular Circular - fascicle are arranged in concentric - fascicle are arranged in concentric ringsrings

Orbicularis oris and oculiOrbicularis oris and oculi

Types of muscle attachments: direct Types of muscle attachments: direct and indirect and indirect

Direct (Direct (tendontendon) - epimysium of muscle ) - epimysium of muscle fused to periosteum of bone or fused to periosteum of bone or perichondrium of cartilage. perichondrium of cartilage.

Indirect (Indirect (aponeurosisaponeurosis) - muscle fascia ) - muscle fascia extends beyond the muscle to bone extends beyond the muscle to bone or another muscle. Latissimus dorsi or another muscle. Latissimus dorsi or galea aponeuroticaor galea aponeurotica

Muscle have points of attachment on Muscle have points of attachment on the skeleton via tendons or the skeleton via tendons or aponeurosisaponeurosis

Origin and insertionOrigin and insertion

OriginOrigin: end of the muscle attaches to : end of the muscle attaches to the stationary bone (non-moveable)the stationary bone (non-moveable)

Insertion:Insertion: end of muscle attaches to end of muscle attaches to the moving bonethe moving bone

Biceps (two heads) have two origins Biceps (two heads) have two origins on the scapulaon the scapula

Biceps inserts on the radius (crosses Biceps inserts on the radius (crosses elbow joint)elbow joint)

Muscle listMuscle list1- 1- Frontalis:Frontalis:O: galea aponeuroticaO: galea aponeuroticaI: skin of eyebrowsI: skin of eyebrowsN: Facial nerve (CN VII)N: Facial nerve (CN VII)A: raises eyebrowsA: raises eyebrows

2- 2- Orbicularis oculi:Orbicularis oculi:O: frontal boneO: frontal boneI: tissues of eyelidI: tissues of eyelidN: Facial nerveN: Facial nerveA: closes eyesA: closes eyes

3- 3- Temporalis:Temporalis:O: temporal fossaO: temporal fossaI: coronoid process of mandibleI: coronoid process of mandibleN: Trigeminal nerve (CN V)N: Trigeminal nerve (CN V)A: closes jaw (muscle of mastication)A: closes jaw (muscle of mastication) 4- 4- Orbicularis orisOrbicularis oris O: indirectly from maxilla and O: indirectly from maxilla and

mandiblemandibleI: encircles mouthI: encircles mouthN: Facial nerveN: Facial nerveA: puckers lips (kissing and whistling)A: puckers lips (kissing and whistling)

5- 5- Platysma: Platysma:

O: subcutaneous skin over delto-O: subcutaneous skin over delto-pectoral region pectoral region

I: skin widely over the mandible I: skin widely over the mandible A: depress mandible and lower lip A: depress mandible and lower lip

tenses the skin over the lower necktenses the skin over the lower neck

N: facial nerveN: facial nerve6- 6- ScalenesScalenes: located deep in the neck: located deep in the neck

anterioranteriormiddlemiddleposteriorposterior

7- 7- Sternohyoid:Sternohyoid: O: manubriumO: manubriumI: hyoid boneI: hyoid boneA: depresses hyoid and larynxA: depresses hyoid and larynx8- 8- Digastric:Digastric: consists of two bellies that are consists of two bellies that are

connected by an intermediate connected by an intermediate tendon tendon

9- 9- Sternocleidomastoid:Sternocleidomastoid:O: manubrium and medial portion of clavicleO: manubrium and medial portion of clavicleI: mastoid processI: mastoid processA: together they flex head forward;A: together they flex head forward;

separately they rotate head opposite to separately they rotate head opposite to muscle contracting muscle contracting

N: Spinal accessory (CN XI)N: Spinal accessory (CN XI)

10- 10- Deltoid:Deltoid:O: lateral 1/3 of clavicle, acromion and O: lateral 1/3 of clavicle, acromion and

spine of scapulaspine of scapulaI: deltoid tuberosityI: deltoid tuberosityA: arm abductionA: arm abductionN: axillary nerve N: axillary nerve 11: 11: Pectoralis minorPectoralis minor: Thin muscle : Thin muscle

located underneath pectoralis majorlocated underneath pectoralis majorO: ribs 3-5O: ribs 3-5I: coracoid processI: coracoid process

12- 12- Pectoralis majorPectoralis majorO: medial 1/3 of clavicleO: medial 1/3 of clavicleI: lateral lip of bicipital groove to the crest of I: lateral lip of bicipital groove to the crest of

the greater tubercle the greater tubercle A: arm flexion, rotates arm mediallyA: arm flexion, rotates arm mediallyN: lateral and median pectoral nervesN: lateral and median pectoral nerves13- 13- Serratus anteriorSerratus anterior O: ribs 1-8O: ribs 1-8I: vertebral border of scapulaI: vertebral border of scapulaA: protract and hold scapulaA: protract and hold scapulaN: long thoracic nerveN: long thoracic nerve14- 14- IntercostalsIntercostals: accessory muscle to : accessory muscle to

respiration respiration

15- 15- Rectus abdominisRectus abdominis::

O: pubic symphysisO: pubic symphysis

I: xiphoid process and costal cartilageI: xiphoid process and costal cartilage

A: flex lumbar spineA: flex lumbar spine

N: intercostal nervesN: intercostal nerves

16- 16- Diaphragm:Diaphragm:

O: inferior surface of rib cageO: inferior surface of rib cage

I: central tendonI: central tendon

A: primary muscle of respirationA: primary muscle of respiration

N: phrenic nerve (C3,4,5)N: phrenic nerve (C3,4,5)

17- 17- Triceps brachiiTriceps brachii::O: long head: infraglenoid tubercle of O: long head: infraglenoid tubercle of

scapulascapulamedial head: posterior humeral shaftmedial head: posterior humeral shaftlateral head: posterior humeral shaftlateral head: posterior humeral shaft

I: olecranon process of ulnaI: olecranon process of ulnaA: forearm extensionA: forearm extensionN: radial nerve N: radial nerve 18- 18- Biceps brachiiBiceps brachii : :O: short head: coracoid processO: short head: coracoid process

long head: supraglenoid tuberclelong head: supraglenoid tubercleI: radial tuberosityI: radial tuberosityA: forearm flexorA: forearm flexorN: musculocutaneous nerveN: musculocutaneous nerve

19-19- Brachialis Brachialis::

Forearm flexor (lifts ulna) Forearm flexor (lifts ulna)

20-20- Brachioradialis Brachioradialis: “drinking muscle”: “drinking muscle”

O: distal end of humerusO: distal end of humerus

I: styloid process of radiusI: styloid process of radius

A: forearm flexorA: forearm flexor

N: radial nerveN: radial nerve

21- 21- Flexor carpi radialisFlexor carpi radialis: :

A: wrist flexorA: wrist flexor

N: median nerveN: median nerve

22- 22- Palmaris longusPalmaris longus::

O: medial epicondyle of humerusO: medial epicondyle of humerus

I: palmar aponeurosisI: palmar aponeurosis

A: weak wrist flexorA: weak wrist flexor

N: median nerveN: median nerve

Absent in 15% of the population (More Absent in 15% of the population (More females than males)females than males)

23-23- Lumbricals Lumbricals: 4 worm shaped : 4 worm shaped musclesmuscles

A: flex fingers at MCP joint A: flex fingers at MCP joint

24- 24- Iliopsoas:Iliopsoas: combination iliacus and combination iliacus and psoas musclepsoas muscle

A: primary hip and trunk flexorA: primary hip and trunk flexor25- 25- PectineusPectineus::Short flat muscle that adducts thighShort flat muscle that adducts thighO: pubisO: pubisI: lesser trochanter I: lesser trochanter 26- 26- Tensor fasciae latae:Tensor fasciae latae:O: ASISO: ASISI: Iliotibial tract (Gerdy’s tubercle)I: Iliotibial tract (Gerdy’s tubercle)A: thigh abduction A: thigh abduction

27- 27- SartoriusSartorius: “tailor’s muscle”: “tailor’s muscle”O: anterior superior iliac spine (ASIS) O: anterior superior iliac spine (ASIS) I: upper medial surface of body of tibia I: upper medial surface of body of tibia A: Flexes, abducts and laterally rotates thighA: Flexes, abducts and laterally rotates thighN: Obturator nerve N: Obturator nerve

28: 28: Adductor longus Adductor longus Common thigh adductorCommon thigh adductor

29: 29: GracilisGracilis::O: pubisO: pubisI: tibiaI: tibiaA: adducts thighA: adducts thigh

Quadriceps:Quadriceps: 30: 30: Rectus femorisRectus femoris O: ASISO: ASIS I: patella by way of quadriceps tendon I: patella by way of quadriceps tendon

and tibial tuberosity by way of patellar and tibial tuberosity by way of patellar ligamentligament

A: hip flexor and knee extensionA: hip flexor and knee extension N: femoral nerveN: femoral nerve

31: Vastus lateralis31: Vastus lateralis

medius knee medius knee extensionextension

intermedius intermedius

32: 32: Tibialis anteriorTibialis anterior::

O: lateral condyle of tibiaO: lateral condyle of tibia

I: medial cuneiform and 1I: medial cuneiform and 1stst MTP. MTP.

A: dorsiflexion of footA: dorsiflexion of foot

N: deep fibular nerveN: deep fibular nerve

33: 33: Flexor hallucis longusFlexor hallucis longus: flexes great : flexes great toetoe

““push off” while taking a steppush off” while taking a step

PosteriorPosterior1- 1- Occipitalis:Occipitalis:O: occipital boneO: occipital boneI: galea aponeuroticaI: galea aponeuroticaA: pulls scalp posteriorlyA: pulls scalp posteriorlyI: facial nerve I: facial nerve

2- 2- TrapeziusTrapezius O: Occipital bone, vertebra of cervical and O: Occipital bone, vertebra of cervical and

thoracic spinous processesthoracic spinous processesI: acromion, spine of scapula and lateral 1/3 I: acromion, spine of scapula and lateral 1/3

of clavicleof clavicleA: extends head and raises scapula. A: extends head and raises scapula.

“shrugging shoulders”“shrugging shoulders”N: Spinal Accessory nerve (CNXI)N: Spinal Accessory nerve (CNXI)

Rotator cuff of shoulderRotator cuff of shoulder: Holds humerus : Holds humerus tight to glenoid fossa (S.I.T.S.)tight to glenoid fossa (S.I.T.S.)

3- 3- Supraspinatus:Supraspinatus:O: supraspinous fossa of scapulaO: supraspinous fossa of scapulaI: greater tubercle of humerusI: greater tubercle of humerusA: assists in abductionA: assists in abduction

4- 4- InfraspinatusInfraspinatusO: infraspinous fossa of scapulaO: infraspinous fossa of scapulaI: greater tubercle of humerusI: greater tubercle of humerusA: rotates humerus laterally A: rotates humerus laterally

5- 5- SubscapularisSubscapularis

O: subscapular fossaO: subscapular fossa

I: lesser tubercle of humerusI: lesser tubercle of humerus

A: medial rotation of humerusA: medial rotation of humerus

6- 6- Teres minorTeres minor::

A: Arm adductorA: Arm adductor

7- 7- Teres major:Teres major:

A: posteromedial extension of humerusA: posteromedial extension of humerus

8- 8- Rhomboid major and minorRhomboid major and minor

O: spinous processes of C7-T1 (minor)O: spinous processes of C7-T1 (minor)

I: medial border of scapulaI: medial border of scapula

A: retract scapula “standing up A: retract scapula “standing up straight”straight”

N: dorsal scapular nerveN: dorsal scapular nerve

9- 9- Erector SpinaeErector Spinae::IliocostalisIliocostalisLongissimusLongissimusSpinalisSpinalisA: prime muscles for back extensionA: prime muscles for back extension

10- 10- Latissimus dorsiLatissimus dorsiO: Thoracolumbar fascia (aponeurosis)O: Thoracolumbar fascia (aponeurosis)

- T6-T12 and L1-L5 and iliac - T6-T12 and L1-L5 and iliac crestcrest

I: intertubercular groove of humerusI: intertubercular groove of humerusA: arm extension and adductorA: arm extension and adductorN: thoracodorsal nerveN: thoracodorsal nerve

11- 11- Extensor carpi ulnaris:Extensor carpi ulnaris:Extension of the wristExtension of the wrist

12- 12- Extensor carpi radialisExtensor carpi radialis Extends and abducts wristExtends and abducts wrist

13- 13- Flexor carpi ulnarisFlexor carpi ulnaris Powerful wrist flexorPowerful wrist flexorN: ulnar nerveN: ulnar nerve

14- 14- Extensor digitorum Extensor digitorum Prime mover of finger extensionPrime mover of finger extension

15- 15- Gluteus mediusGluteus medius

A: abducts and medial rotates thighA: abducts and medial rotates thigh

N: superior gluteal nerveN: superior gluteal nerve

16- 16- Gluteus maximusGluteus maximus

O: dorsal ilium, sacrum and coccyxO: dorsal ilium, sacrum and coccyx

I: gluteal tuberosity of femurI: gluteal tuberosity of femur

A: powerful thigh extenderA: powerful thigh extender

N: inferior gluteal nerveN: inferior gluteal nerve

Hamstrings Hamstrings (crosses knee joint- popliteal)(crosses knee joint- popliteal)17- 17- Biceps femorisBiceps femoris::O: ischial tuberosityO: ischial tuberosityI: head of fibula and lateral condyle of tibiaI: head of fibula and lateral condyle of tibiaA: thigh extension and knee flexionA: thigh extension and knee flexionN: Sciatic nerve N: Sciatic nerve

18- 18- Semitendinosus:Semitendinosus:A: extends thigh and knee flexionA: extends thigh and knee flexion

19- 19- SemimembranosusSemimembranosusA: extends thigh and flexes kneeA: extends thigh and flexes knee

20- 20- GastrocnemiusGastrocnemius

O: medial and lateral condyles of femurO: medial and lateral condyles of femur

I: posterior calcaneus (achilles tendon)I: posterior calcaneus (achilles tendon)

A: plantar flexes foot (raise up on toes)A: plantar flexes foot (raise up on toes)

N: Tibial nerveN: Tibial nerve

21- 21- Soleus Soleus

A: plantar flexes foot and raise up on A: plantar flexes foot and raise up on toes while seatedtoes while seated

N: Tibial nerveN: Tibial nerve