Shoulder joint- muscles and movements

Question 1

planes of scapula

Answer 1

scapula doesn’t sit on anterior coronal plane; it is anteriorly facing- glenoid faces laterally and anteriorly. plane is 45° between frontal and sagittal planes- where normal physiological movement occurs at shoulder joint

Question 2

flexion at shoulder joint

Answer 2

110° (anything beyond this is elevation- upto 180°)

deltoid (anterior fibres), pectoralis major (clavicular head)

Question 3

extension at shoulder joint

Answer 3

50-70°- deltoid (posterior fibres), teres minor, latissimus dorsi, pectoralis major (sternocostal head)- from flexion to neutral

Question 4

abduction at shoulder joint

Answer 4

100-120°- anything more than this is elevation (up to 180°)

deltoid (middle fibres), supraspinatus (initiates)

Question 5

adduction at shoulder joint

Answer 5

30-40°- has to be slight glenohumeral joint flexion, against resistance (physical or gravity) by pectoralis major, latissimus dorsi, teres minor, coracobrachialis

Question 6

medial rotation at shoulder joint

Answer 6

+-90°- subscapularis, pectoralis major, latissimus dorsi, anterior fibres of deltoid, teres major

Question 7

lateral rotation at shoulder joint

Answer 7

80°- infraspinatus, teres minor, posterior fibres deltoid

Question 8

elevation of arm- scapulohumeral rhythm

Answer 8

glenohumeral joint, scapulothoracic joint
0-30°- all glenohumeral movements- setting phase
30-80°- 2 humerus abduction and 1- scapula lateral rotation (scapulothoracic joint) ratio 2:1

Question 9

prime movers of muscles acting on shoulder joint

Answer 9

pectoralis major, latissimus dorsi, deltoid, teres minor, coracobrachialis

Question 10

the rotator cuff muscles (synergists)

Answer 10

supraspinatus, infraspinatus, teres minor, subscapularis, SITS- order of insertion into humerus

Question 11

pectoralis major origin and insertions

Answer 11

origin- clavicular attachment and sternocostal attachment (2 heads- conjoined tendons)
insertions- lateral lip of the intertubercular groove

Question 12

NS and actions pectoralis major

Answer 12

medial and lateral pectoral nerve (C5-8), actions- clavicular flex (clavicular head), sternocostal extension- from fully flexed position to neural, both heads adduction, medial rotation of humerus

Question 13

latissimus dorsi origin and insertion

Answer 13

origin- thoracolumbar fascia (inelastic and tough band of CT) from spinous process of T6-12 and all the lumbar and sacral vertebra, iliac crest, lower 4 ribs and inferior angle of scapula
insertion- floor of the intertubercular groove, lower 4 ribs and inferior angle of scapula

Question 14

latissimus dorsi NS and action

Answer 14

thoracodorsal nerve C6,7,8

action- extension, medial rotation, adduction of humerus

Question 15

deltoid origin and insertion (anterior, mid and posterior)

Answer 15

origin- lat 1/3 of clavicle (anterior-strap like), acromion (mid- bipennate), spine of scapula (post-strap like)
insertion- mid shaft humerus- deltoid tuberosity

Question 16

deltoid NS and action

Answer 16

NS- axillary nerve C5,6
action- anterior fibres flexion and extension, middle fibres- abduction, posterior fibres- extension and lateral rotation

Question 17

coracobrachialis origin and insertion

Answer 17

origin- tip of coracoid process, insertion- mid shaft of humerus

Question 18

coracobrachialis- NS and action

Answer 18

NS- musculotendinous nerve C5-6

Action- adduction and weak flexion of arm

Question 19

teres major- origin and insertion

Answer 19

origin- inferior angle of scapula

insertion- medial tip of intertubercular groove

Question 20

teres major- NS and action

Answer 20

NS- lower scapula nerve C5-6

action- adduction, MR of arm, assists extension of flexed arm

Question 21

teres minor- origin and insertion

Answer 21

origin- upper part of lateral borders of scapula

insertion- lowermost facet ( inferior) on greater tubercle of humerus

Question 22

teres minor NS and action

Answer 22

NS- axillary nerve C5,6

action- lateral rotation, extension and adduction of arm, main role is rotator cuff muscle

Question 23

subscapularis origin and insertion

Answer 23

origin- subscapular fossa, insertion- lesser tubercle of humerus

Question 24

subscapularis NS and action

Answer 24

NS- upper and lower subscapular nerves C5-7

action- MR of arm, controls unwanted slip or glide of head of humerus in glenoid fossa

Question 25

supraspinatus origin and insertion

Answer 25

origin- supraspinous fossa of scapula, insertion- uppermost facet on greater tubercle of humerus

Question 26

supraspinatus NS and action

Answer 26

NS- suprascapular nerve C5-6, action- assists abduction- initiating the first 20°, key role is rotator cuff group

Question 27

infraspinatus origin and insertion

Answer 27

origin- infraspinous fossa scapula | insertion- middle fact on greater tubercle

Question 28

infraspinatus NS and action

Answer 28

NS- subscapular nerve C5-6 | action- lateral rotation and adduction of arm, key role of rotator cuff group

Question 29

rotator cuff muscles- stabilize

Answer 29

the rotator cuff stabilizes the glenohumeral joint through force couples in both the coronal and transverse planes

Question 30

rotator cuff muscles- blend into capsule

Answer 30

Completely controls unwanted side and glide between head of humerus and glenoid fossa, steers the head of the humerus to allow the greater movement to be produced by prime mover muscles

Question 31

rotator cuff muscles- in transverse plane

Answer 31

subscapularis and infraspinatus

Question 32

rotator cuff muscles- frontal plane

Answer 32

supraspinatus and teres minor

Question 33

rotator cuff muscles- stabilising muscles

Answer 33

produce synergy movement

Question 34

origin and insertions of bicep brachii

Answer 34

origin- 2 heads- short- coronoid process, long- tubercle above glenoid fossa (through bicipital groove) insertion- to tuberosity of the radius and bicipital aponeurosis to soft tissue in medial aspect of proximal forearm

Question 35

NS and action bicep brachii

Answer 35

NS- musculocutaneous nerve C5-6 | flexion at shoulder/ elbow joint, supination of radioulnar joints

Question 36

origin and insertion for tricep brachii

Answer 36

origin- three heads- long- infra- glenoid tubercle, lateral- upper part of posterior surface of humerus, medial- lower part of posterior humerus insertion- posterior surface of olecranon process of ulna

Question 37

NS and action tricep brachii

Answer 37

NS- radial nerve C6,7,8 | action- extends the elbow, long head adducts and extends the shoulder

Question 38

axilla borders- lateral

Answer 38

costal surface of scapula with subscapularis

Question 39

axilla borders- anterior

Answer 39

inner aspect of pectoralis major

Question 40

axilla borders- medial

Answer 40

serratus anterior and thoracic cage

Question 41

axilla contents

Answer 41

brachial plexus- posterior, medial lateral and cord | axillary artery and vein