Gross Lecture 1

Question 1

During downward rotation of the scapula, what movement occurs at the sternoclavicular joint?

Answer 1

elevation of the medial end of the clavicle (upward with respect to the manubrium)

clavicle does the opposite of the scapula (scapula up, clavicle depressed; scapula adducted, clavicle moves anteriorly (protraction); scapula protacted (abducted), clavicle retracted)

Question 2

During pure protraction of the scapula, which muscle offsets the downward rotation caused by pectoralis minor?

Answer 2

serratus anterior

Question 3

During abduction of the shoulder beyond 90 degrees, what is the function of the rotator cuff muscles?

Answer 3

provide stability to the joint by keeping the head of the humerus applied directly to the glenoid fossa and pull the head of the humerus downward

(counteracting the tendency of the head of the humerus to move up towards the acromion and compress the structures btw the humeral head and acromion)

Question 4

List three muscles that cause medial rotation of the shoulder

Answer 4

subscapularis, teres major, latissimus dorsi

also the anterior portion of the deltoid

Question 5

Which two muscles are common boundaries for the triangular space, quadrangular space, and triangular interval?

Answer 5

Long head of the triceps and Teres Major

Question 6

Which artery branches from the first part of the axillary artery?

Answer 6

superior thoracic artery (supplying the first two intercostal spaces)

Question 7

The circumflex scapular artery anastomoses with which two arteries? Why is this important?

Answer 7

transverse cervical and suprascapular braches of the thyrocervical trunk
important bc: bring the first part of the subclavian artery into connection with the axillary artery - blood can still get to the arm, forearm and hand even if the terminal portion of the axillary artery were occluded

Question 8

At what landmark does the subclavian artery become the axillary artery?

Answer 8

the lateral border of the first rib

Question 9

At what landmark does the axillary artery become the brachial artery?

Answer 9

inferior border of the teres minor

Question 10

What are the three non-terminal branches coming off of the posterior cord?

Answer 10

1. upper subscapular nerve
2. thoracodorsal nerve
3. lower subscapular nerve

Question 11

Which muscles do the peripheral nerves coming directly off of the C5 root of the brachial plexus innervate?

Answer 11

dorsal scapular nerve; motor innervation to the rhomboid muscles

Question 12

Which roots of the brachial plexus contribute to the radial nerve? The ulnar nerve? The musculocutaneous nerve?

Answer 12

radial nerve: posterior cord - C5, C6, C7, C8 & T1
ulnar nerve: medial cord - C8, T1
musculocutaneous nerve: lateral cord - C5, C6, C7