Shoulder and Back Muscles

Question 1

what is an active open chain?

Answer 1

movement of distal segment of bone about a fixed proximal segment (movement of insertion)

Question 2

what type of muscle contraction occurs in an active open chain?

Answer 2

concentric

Question 3

what is an active closed chain?

Answer 3

movement of the proximal segment of bone about a fixed distal segment (movement of origin)

Question 4

what does the shoulder girdle contain?

Answer 4

20 muscles
3 bony articulations
3 soft tissue surfaces (fx joints)

Question 5

what is the shoulder girdle used for?

Answer 5

stabilization for hand use
lifting, pushing
elevation of the body
forced inspiration & expiration
weight bearing

Question 6

what does the shoulder use for stability?

Answer 6

soft tissue

Question 7

what are the bones of the shoulder complex?

Answer 7

sternum
clavicle
scapula
humerus

Question 8

what are the articulations of the shoulder?

Answer 8

sternoclavicular
acromioclavicular
glenohumeral

Question 9

what are the false (fx) joints of the shoulder?

Answer 9

scapulothoracic
super humeral
bicipital groove

Question 10

What are the scapular movements?

Answer 10

1. elevation
2. depression
   distal end of clavicle & acromion move up and down
3. protraction
4. retraction
   clavicle & scapula move anterior and posterior
5. upward & downward rotation

Question 11

how does scapular upward rotation occur?

Answer 11

ocurring at scapula during flexion or abduction of humerus
glenoid fossa moves superiorly
inferior angle moves laterally, anteriorly, up

Question 12

how does scapular downward rotation occur?

Answer 12

occurring at scapula when hand goes to small of back

glenoid fossa moves inferiorly and medially

Question 13

what are the muscle groups of the shoulder complex?

Answer 13

group 1: muscles connecting shoulder to trunk, neck, skull
group 2: muscles connecting scapula to humerus
group 3: muscles connecting humerus to trunk

Question 14

what is the significance of the serratus anterior?

Answer 14

most important muscle for shoulder stability

Question 15

what the the origin, insertion and fx of the serratus anterior?

Answer 15

origin: 1st-9th rib
insertion: medial border of scapula
fx: scapular protraction, upward rotation

Question 16

what is the origin, insertion, nerve and fx of the upper traps?

Answer 16

origin: occipital bone
insertion: lateral 1/3 of calvicle
nerve: spinal accessory
fx: raise shoulder

Question 17

what is the origin, insertion, nerve, fx of the middle traps?

Answer 17

origin: spinous process C7-T5
insertion: medial margin, acromion
nerve: spinal accessory C2-C4
fx: scapular adduction, move shoulder posteriorly

Question 18

what is the origin, insertion, nerve, fx of the lower traps?

Answer 18

origin: thoracic vertebrae
insertion: medial portion, spine of scapula
nerve: spinal accessory
fx: pull scapula inferior & medially (addiction, depression)

Question 19

what is a dyscfx of the scapula?

Answer 19

winged scapula

Question 20

what is a dysfx of the lower traps?

Answer 20

shoulder slops forward from the weight of the arm

Question 21

what is the origin, insertion, nerve, fx of the rhomboids?

Answer 21

origin: C6-T5
insertion: medial border of scapula
nerve: dorsal scapular
fx: retraction/adduction, downward rotation

Question 22

what is the origin, insertion, nerve, fx of the pec minor?

Answer 22

origin: 2-5th ribs
insertion: coracoid process
nerve: anterior thoracic
fx: depresses shoulder girdle to face glenoid inferiorly

Question 23

what is the origin, insertion, nerve, fx of the levator scapula?

Answer 23

origin: C1-C4
insertion: superior angle of scapula
nerve: dorsal scapular
fx: elevates scapula with U. traps + rhoms

Question 24

what is a dysfx of the levator scapula?

Answer 24

sagging shoulder girdle

Question 25

what is the origin, insertion, nerve, fx of the latissimus dorsi?

Answer 25

origin: T6-crest of ilium insertion: bottom of bicipital groove nerve: medial & lateral anterior thoracic fx: adduct (powerful)

Question 26

what is the origin, insertion, nerve, fx of the pec major?

Answer 26

origin: clavicle, sternum, 2-7th ribs insertion: greater tuberosity of humerus nerve: anterior thoracic fx: adduction of humerus

Question 27

how do fore couples work?

Answer 27

since translatory forces (linear motion) cancel each other out force couple produces torque only. magnitude of force couple = sum of the products of each force + moment arm

Question 28

what force couple create upward rotation of arm?

Answer 28

serratus ant upper trap lower trap

Question 29

what force couple creates downward rotation of arm?

Answer 29

lat dorsi levator scap rhoms serratus ant

Question 30

what type of movement does the glenohumeral joint cause?

Answer 30

in-congruent movement

Question 31

what is the glanohumeral joint accompanied by?

Answer 31

movement at scapulothoracic joint

Question 32

what types of movement does the glenohumeral joint do?

Answer 32

``` flexion extension abduction adduction internal & external rotation ```

Question 33

what make up the SITS muscles?

Answer 33

supraspinatus infraspinatus teres minor subscapularis

Question 34

what is the origin, insertion, nerve, fx of the supraspinatus?

Answer 34

origin: supraspinatus fossa insertion: greater tuberosity nerve: subscapular fx: abduction, external rotation (most active SITS)

Question 35

what is the origin, insertion, nerve, fx of the infraspinatus?

Answer 35

origin: infraspinatus fossa insertion: greater tuberosity of humerus nerve: suprascapular fx: external rotation, horizontal abduction (helps)

Question 36

what is the origin, insertion, nerve, fx of the teres minor?

Answer 36

origin: axillary border of scapula insertion: greater tuberosity of humerus nerve: axillary fx: external rotation, horizontal abduction

Question 37

what is the origin, insertion, nerve, fx of the subscapularis?

Answer 37

origin: anterior surface of scapula insertion: lesser tuberosity of humerus nerve: subscapular fx: internal rotation

Question 38

what is the rotator cuff fx of the supraspinatus?

Answer 38

snugs head of humerus to glenoid via horizontal pull | stabilizer

Question 39

what is the rotator cuff fx of the infraspinatus?

Answer 39

depresses humeral head (pulls humerus down in2 glen fossa to prevent injuring acromion) prevents posterior dislocation

Question 40

what is the rotator cuff fx of the teres minor?

Answer 40

depresses humeral head | prevents anterior dislocation

Question 41

what is the rotator cuff fx of the subscapularis?

Answer 41

depresses humeral head | prevents anterior dislocation

Question 42

what is the origin, nerve, fx of the anterior deltoid muscle?

Answer 42

origin: lateral 3rd of clavicle nerve: axillary fx: flexion of humerus

Question 43

what is the origin, nerve, fx of the middle deltoid?

Answer 43

origin: acromion nerve: axillary fx: flexion, extension, abduction of arm

Question 44

what is the origin, nerve, fx of the posterior deltoid?

Answer 44

origin: spine of scapula nerve: axillary fx: extension, abduction

Question 45

what are the proximal stabilizers?

Answer 45

muscles originating on spine, ribs, cranium & insert on scapula and clavicle i.e. serr ant, traps

Question 46

what are the distal stabilizers?

Answer 46

muscles originating on scapula & clavicle and insert on humerus & forearm