IB 131 LEC 7

what is the prime mover?

muscle responsible for producing motion

what is the synergist?

facilities the prime mover

what is the antagonist?

muscle whose action opposes prime mover

when is maximum isometric force generated?

resting sarcomere length, optimal overlap

what do longer muscles do?

increase range of motion and distance is shortened

what does increased cross sectional area do?

increases force production capacity

what length change does an isometric contraction do?

no change

what length change does an isotonic concentric contraction do?

shortens

what length change does an isotonic eccentric contraction do?

lengthens

what is special about the force production of isometric muscle contractions?

force without joint movement

what happens during concentric prime mover activation?

opposing antagonist muscles undergo eccentric contraction

what is a motor unit?

single motor neuron and muscle fibers it innervates

what is recruitment mechanism?

additional motor units recruited for nervous system regulation

where does the trapezius originate?

vertebrae/base of skull

where is the trapezius inserted?

spine

acromion of scapula

what is the primary superior action of the trapezius?

elevation and extension

what is the primary inferior action of the trapezius?

depression

what is the primary middle action of the trapezius?

retraction

where does the rhomboids originate?

thoracic vertebral spine

where is the rhomboids inserted?

medial border of scapula

what is the primary action of the rhomboids?

retraction

downward rotation of scapula

where does the serratus anterior originate?

anterior/lateral libs

where is the serratus anterior inserted?

medial border of scapula

what is the primary action of the serratus anterior?

protraction and upward rotation

where does the levator scapulae originate?

cervical transverse processes

where is the levator scapulae inserted?

superior angle of scapula

what is the primary action of the levator scapulae?

elevation and downward rotation of scapula

where does the pectoralis minor originate?

anterior ribs 3-5

where is the pectoralis minor inserted?

coracoid process of scapula

what is the primary action of the pectoralis minor?

protraction and depression of scapula

what scapular muscles do protraction?

serratus anterior

pectoralis minor

what scapular muscles do retraction?

trapezius

rhomboids

what scapular muscles do upward rotation?

trapezius

serratus anterior

what scapular muscles do downward rotation?

rhomboids

levator scapulae

how do glenohumeral joint mechanics work? where do they originate/insert onto?

originate from axial skeleton/scapula

insert onto humerus

where is the origin of the latissimus dorsi muscle?

axial skeleton (lower back)

where is the insertion for the latissimus dorsi?

intertubercle sulcus

what is the primary action of the latissimus dorsi?

shoulder extension

adduction

medial rotation

where is the origin of the teres major muscle?

inferior lateral scapula

where is the insertion for the teres major?

intertubercular area (lesser tubercle)

what is the primary action of the teres major?

shoulder extension

adduction

medial rotation

where is the origin of the pectoralis major muscle?

axial skeleton (chest)

where is the insertion for the pectoralis major?

greater tubercle

what is the primary action of the pectoralis major?

shoulder flexion

adduction

medial rotation

where is the origin of the deltoid muscle?

clavicle

acromion

scapular spine

where is the insertion for the deltoid?

deltoid tuberosity of humerus

what is the primary action of the deltoid?

primary abductor of shoulder

where is the origin of the anterior deltoid muscle?

anterior clavicle

where is the insertion for the anterior deltoid?

deltoid tuberosity

what is the primary action of the anterior deltoid?

shoulder flexion

medial rotation

where is the origin of the posterior deltoid muscle?

spine of scapula

where is the insertion for the posterior deltoid?

deltoid tuberosity

what is the primary action of the posterior deltoid?

shoulder extension

lateral rotation

what is the primary functional role of rotator cuff muscles?

hold the head of humerus secure within glenoid cavity

where does the supraspinatus originate?

supraspinous fossa

where is the tubercle insertion for the supraspinatus?

greater tubercle

what does the supraspinatus do?

initiates shoulder abduction

where does the infraspinatus originate?

infraspinous fossa

where is the tubercle insertion for the infraspinatus?

greater tubercle

what does the infraspinatus do?

lateral rotation of shoulder

where does the teres minor originate?

lateral scapular border

where is the tubercle insertion for the teres minor?

greater tubercle

what does the teres minor do?

lateral rotation of shoulder

where does the subscapularis originate?

subscapular fossa

where is the tubercle insertion for the subscapularis?

lesser tubercle

what does the subscapularis do?

medial rotation of shoulder

all posterior rotator cuff muscles insert on the…?

greater tubercle