1. Muscle System
Ch. 10

2. Four functional groups of muscle:
1- prime movers (agonists): Muscle that bears the prime responsibility for effecting a movement
2- antagonist: Muscle that opposes the action of another muscle.
3- synergists: these muscles act as stabilizers to the prime movers. They may also contribute extra force to the prime mover as well.
4- fixator: muscle that immobilizes one or more bones (scapula)

3. Pennate - fascicle branch form central tendon diagonally
Muscle are classified according to their fascicular arrangement or attachment.
Parallel - long axis of fascicle runs with longitudinal axis of muscle: sartorius muscle
Pennate - fascicle branch form central tendon diagonally
Unipennate - extensor muscles
Bipennate - rectus femoris
Multipennate - deltoid
Convergent - fascicle converge toward a single tendon: pectoralis major
Circular - fascicle are arranged in concentric rings
Orbicularis oris and oculi

5. Types of muscle attachments: direct and indirect
Direct (tendon) - epimysium of muscle fused to periosteum of bone or perichondrium of cartilage.
Indirect (aponeurosis) - muscle fascia extends beyond the muscle to bone or another muscle. Latissimus dorsi or galea aponeurotica

6. Muscle have points of attachment on the skeleton via tendons or aponeurosis
Origin and insertion
Origin: end of the muscle attaches to the stationary bone (non-moveable)
Insertion: end of muscle attaches to the moving bone
Biceps (two heads) have two origins on the scapula
Biceps inserts on the radius (crosses elbow joint)

10. Muscle list
1- Frontalis:
O: galea aponeurotica
I: skin of eyebrows
N: Facial nerve (CN VII)
A: raises eyebrows
2- Orbicularis oculi:
O: frontal bone
I: tissues of eyelid
N: Facial nerve
A: closes eyes

11. 3- Temporalis:
O: temporal fossa
I: coronoid process of mandible
N: Trigeminal nerve (CN V)
A: closes jaw (muscle of mastication)
4- Orbicularis oris
O: indirectly from maxilla and mandible
I: encircles mouth
N: Facial nerve
A: puckers lips (kissing and whistling)

13. O: subcutaneous skin over delto-pectoral region
5- Platysma:
O: subcutaneous skin over delto-pectoral region
I: skin widely over the mandible
A: depress mandible and lower lip
tenses the skin over the lower neck
N: facial nerve
6- Scalenes: located deep in the neck
anterior
middle
posterior

16. 7- Sternohyoid:
O: manubrium
I: hyoid bone
A: depresses hyoid and larynx
8- Digastric: consists of two bellies that are connected by an intermediate tendon
9- Sternocleidomastoid:
O: manubrium and medial portion of clavicle
I: mastoid process
A: together they flex head forward;
separately they rotate head opposite to muscle contracting
N: Spinal accessory (CN XI)

17. 10- Deltoid:
O: lateral 1/3 of clavicle, acromion and spine of scapula
I: deltoid tuberosity
A: arm abduction
N: axillary nerve
11: Pectoralis minor: Thin muscle located underneath pectoralis major
O: ribs 3-5
I: coracoid process

19. 12- Pectoralis major
O: medial 1/3 of clavicle
I: lateral lip of bicipital groove to the crest of the greater tubercle
A: arm flexion, rotates arm medially
N: lateral and median pectoral nerves
13- Serratus anterior
O: ribs 1-8
I: vertebral border of scapula
A: protract and hold scapula
N: long thoracic nerve
14- Intercostals: accessory muscle to respiration

21. 15- Rectus abdominis:
O: pubic symphysis
I: xiphoid process and costal cartilage
A: flex lumbar spine
N: intercostal nerves
16- Diaphragm:
O: inferior surface of rib cage
I: central tendon
A: primary muscle of respiration
N: phrenic nerve (C3,4,5)

25. 17- Triceps brachii:
O: long head: infraglenoid tubercle of scapula
medial head: posterior humeral shaft
lateral head: posterior humeral shaft
I: olecranon process of ulna
A: forearm extension
N: radial nerve
18- Biceps brachii :
O: short head: coracoid process
long head: supraglenoid tubercle
I: radial tuberosity
A: forearm flexor
N: musculocutaneous nerve

28. 19- Brachialis:
Forearm flexor (lifts ulna)
20- Brachioradialis: “drinking muscle”
O: distal end of humerus
I: styloid process of radius
A: forearm flexor
N: radial nerve
21- Flexor carpi radialis:
A: wrist flexor
N: median nerve

30. 22- Palmaris longus:
O: medial epicondyle of humerus
I: palmar aponeurosis
A: weak wrist flexor
N: median nerve
Absent in 15% of the population (More females than males)
23- Lumbricals: 4 worm shaped muscles
A: flex fingers at MCP joint

31. 24- Iliopsoas: combination iliacus and psoas muscle
A: primary hip and trunk flexor
25- Pectineus:
Short flat muscle that adducts thigh
O: pubis
I: lesser trochanter
26- Tensor fasciae latae:
O: ASIS
I: Iliotibial tract (Gerdy’s tubercle)
A: thigh abduction

32. 27- Sartorius: “tailor’s muscle”
O: anterior superior iliac spine (ASIS)
I: upper medial surface of body of tibia
A: Flexes, abducts and laterally rotates thigh
N: Obturator nerve
28: Adductor longus
Common thigh adductor
29: Gracilis:
O: pubis
I: tibia
A: adducts thigh

34. Quadriceps:
30: Rectus femoris
O: ASIS
I: patella by way of quadriceps tendon and tibial tuberosity by way of patellar ligament
A: hip flexor and knee extension
N: femoral nerve
31: Vastus lateralis
medius knee extension
intermedius

36. 32: Tibialis anterior:
O: lateral condyle of tibia
I: medial cuneiform and 1st MTP.
A: dorsiflexion of foot
N: deep fibular nerve
33: Flexor hallucis longus: flexes great toe
“push off” while taking a step

39. Posterior
1- Occipitalis:
O: occipital bone
I: galea aponeurotica
A: pulls scalp posteriorly
I: facial nerve
2- Trapezius
O: Occipital bone, vertebra of cervical and thoracic spinous processes
I: acromion, spine of scapula and lateral 1/3 of clavicle
A: extends head and raises scapula. “shrugging shoulders”
N: Spinal Accessory nerve (CNXI)

41. Rotator cuff of shoulder: Holds humerus tight to glenoid fossa (S.I.T.S.)
3- Supraspinatus:
O: supraspinous fossa of scapula
I: greater tubercle of humerus
A: assists in abduction
4- Infraspinatus
O: infraspinous fossa of scapula
A: rotates humerus laterally

42. 5- Subscapularis
O: subscapular fossa
I: lesser tubercle of humerus
A: medial rotation of humerus
6- Teres minor:
A: Arm adductor

43. 7- Teres major:
A: posteromedial extension of humerus
8- Rhomboid major and minor
O: spinous processes of C7-T1 (minor)
I: medial border of scapula
A: retract scapula “standing up straight”
N: dorsal scapular nerve

46. 9- Erector Spinae:
Iliocostalis
Longissimus
Spinalis
A: prime muscles for back extension
10- Latissimus dorsi
O: Thoracolumbar fascia (aponeurosis)
- T6-T12 and L1-L5 and iliac crest
I: intertubercular groove of humerus
A: arm extension and adductor
N: thoracodorsal nerve

48. 11- Extensor carpi ulnaris:
Extension of the wrist
12- Extensor carpi radialis
Extends and abducts wrist
13- Flexor carpi ulnaris
Powerful wrist flexor
N: ulnar nerve
14- Extensor digitorum
Prime mover of finger extension

50. 15- Gluteus medius
A: abducts and medial rotates thigh
N: superior gluteal nerve
16- Gluteus maximus
O: dorsal ilium, sacrum and coccyx
I: gluteal tuberosity of femur
A: powerful thigh extender
N: inferior gluteal nerve

52. Hamstrings (crosses knee joint- popliteal)
17- Biceps femoris:
O: ischial tuberosity
I: head of fibula and lateral condyle of tibia
A: thigh extension and knee flexion
N: Sciatic nerve
18- Semitendinosus:
A: extends thigh and knee flexion
19- Semimembranosus
A: extends thigh and flexes knee

55. 20- Gastrocnemius
O: medial and lateral condyles of femur
I: posterior calcaneus (achilles tendon)
A: plantar flexes foot (raise up on toes)
N: Tibial nerve
21- Soleus
A: plantar flexes foot and raise up on toes while seated