Muscles of the Pectoral Girdle and Arm (and Axilla)

Question 1

Name the medial, lateral, posterior, anterior borders of the axillary fossa.

Answer 1

anterior: pectorals major and minor
lateral: humerus
medial: ribs and serratus anterior
posterior: scapula and latissimus dorsi, subscapulares, trees major

Question 2

Name the two joints that make up the shoulder girdle.

Answer 2

sternoclavicular and acromioclavicular

Question 3

What are the movements of the sternoclavicular joint on its given 3 axes of movement?

Answer 3

AP- elevation and depression
vertical axis: protraction and reiteration
oblique axis: medial and lateral rotation

Question 4

What are the movements/ axes of the radioulnar joint?

Answer 4

pronation and supinations around the vertical axis

Question 5

What are the movements/axes of the acromioclavicular joint? How is it stabilized?

Answer 5

the acromioclavicular joint moves only slightly to allow smooth movement of the pectoral girdle as a whole, it is stabilized with the coracoclvicular ligament

Question 6

Where does the coracoacromial ligament run/ what is its purpose?

Answer 6

runs between the acromion process and the coracoid process of the scapula, helps to create the glenohumeral joint socket

Question 7

What joint is injured during a shoulder separation injury?

Answer 7

the acromioclavicular or supporting ligaments are damaged

Question 8

The tendon of which muscle projects directly into the glenohumeral joint?

Answer 8

the tendon of the long head of the biceps brachii

Question 9

Where is the weakest point of the glenoid cavity?

Answer 9

inferior and slightly anteriorly (there are no rotator cuff muscle attachment places at this location

Question 10

Name the two collateral ligaments of the elbow joint and what are their purpose(s).

Answer 10

the ulnar (medial) collateral (limits abduction) and radial (lateral) collateral (limits adduction)

Question 11

Which ligament stabilizes the proximal radioulnar joint?

Answer 11

the annular ligament

Question 12

Name the 3 radioulnar joints.

Answer 12

proximal radioulnar joint, middle radioulnar joint (interosseous membrane) and distal radioulnar joint

Question 13

Name the anterior and posterior muscles of the sternoclavicular joint (all attach to the scapula)

Answer 13

pectorals minor and serratus anterior (anterior) and levitator scapulae, rhomboids and trapezius (posterior)

Question 14

What are the actions of the pectorals minor?

Answer 14

depresses the shoulder girdle, protracts shoulder girdle and medially rotates the scapula (innervated by the lateral and medial pectoral nerves or the lateral and medial cords

Question 15

Where does the serattus anterior attach to the scapula?What is its action(s)?

Answer 15

medially and follows the rib cage anteriorly and inferiorly: protracts, depresses and lateral and laterally rotates

Question 16

How is the serattus innervated? Where is this nerve located?

Answer 16

innervated by the long thoracic n. which lays on top of the serratus muscle, fairly superficially near to the axilla (if damaged leads to winging of the scapula)

Question 17

What are the actions of the levator scapulae and rhomboids?

Answer 17

levitator scapulae: elevation

rhomboids: elevation, retraction and medial rotation

Question 18

What are the actions of the trapezius?

Answer 18

superior: elevation and lateral rotation
middle: retraction
inferior: depression and lateral rotation

Question 19

What are the axes and movements of the glenohumeral joint?

Answer 19

transverse: flexion/extension
AP:abduction and adduction
vertical: medial and lateral rotation

Question 20

Which are the muscles that anteriorly flex the glenohumoral joint?

Answer 20

pectorals major, coracobrachalis, biceps brachia and deltoid

Question 21

What is the action of the pectorals major?

Answer 21

flexion, adduction and medial rotation (Hugging muscle)

Question 22

What is the function of the fibrous capsule of the glenohumeral joint?

Answer 22

is loose and weak to permit free movement of the joint

Question 23

What is the glenoid labrum?

Answer 23

ring of fibrocartilage that surrounds the glenoid fossa and slightly depens and widens it

Question 24

What is the function of the subacromial dursa?

Answer 24

lays between the rotator cuff and the acromion process, reducing the friction between muscles and the adjacent bone or muscle

Question 25

Where do the tendons of the rotator cuff attach and what is their importance?

Answer 25

tendons of the rotator cuff attach to the greater and lesser tubercles and they provide most of the stability of the glenohumeral joint

Question 26

When the arm is in this particular position, it is at the highest risk for dislocation.

Answer 26

adducted and laterally rotated arm puts pressure on the inferior portion of the capsule which is not reinforced by the rotator cuff, to the capsule tears easily here

Question 27

What is innervated by the musculocutaneous n.?

Answer 27

motor to the muscles of the arm and cutaneous to the lateral forearm

Question 28

Name the 4 muscles of the posterior group of glenohumoral joint. (extend the humerus)

Answer 28

latssimus dorsi, teres major, triceps brachia and deltoid as well as the muscles of the rotator cuff.

Question 29

Name the 4 muscles of the rotator cuff. (SITS)

Answer 29

supraspinatus, infraspinatus, trees minor, subscapularis

Question 30

What are the actions of the latissumus dorsi and the teres major? (hand cuff muscles)

Answer 30

extension, adduction and medial rotation (handcuff muscles)

Question 31

Name the single motion of each of the rotator cuff muscles.

Answer 31

supraspinatus: abduction infraspinatus: lateral rotation (lateral) teres minor: lateral rotation (lateral) subscapularis: medial rotation (more medial)

Question 32

What is scapulohumoral rhythm?

Answer 32

the approximate ratio of 2 deg. at the glenohumeral joint for each 1 deg of movement at the sternoclavicular (120 deg at the glenohumeral joint and 60 deg at the sternoclavicular joint)

Question 33

What are the actions of the deltoid m.?

Answer 33

anterior portion: flexion, adduction and medial rotation lateral portion: abduction posterior portion: extension, adduction and lateral rotation

Question 34

What are the branches of the 1st portion of the axillary artery?

Answer 34

the superior thoracic

Question 35

What are the branches of the 2nd portion of the axillary artery?

Answer 35

the thoracoacromial trunk (acromial, pectoral, clavicular and deltoid a.) lateral throracic

Question 36

What are the branches of the 3rd portion of the axillary artery?

Answer 36

sub scapular (circumflex scapular, thoracodorsal) anterior humeral circumflex posterior humeral circumflex

Question 37

What are the branches that the brachial artery gives off?

Answer 37

deep brachial, radial and ulnar arteries

Question 38

Name 3 pairs of nerves that move with arteries.

Answer 38

supra scapular artery and nerve (scapular notch) posterior circumflex humeral artery and axillary nerve deep brachial artery and radial nerve (shaft of humerus) long thoracic nerve and lateral thoracic artery median nerve and brachial artery lower sub scapular nerve and circumflex scapular artery axillary nerve and posterior humeral circumflex artery radial nerve and deep brachial artery