Axilla,posterior shoulder and arm

Question 1

On return visit the patient complains that he cannot reach as far forward (such as to reach for a door knob) as he could before the injury. The nerve injured which caused these symptoms is the:

Answer 1

long thoracic n.

Question 2

A man suffers a penetrating wound through the anterior axillary fold, with resulting damage to one of the main terminal branches of the brachial plexus. Among the effects is a significant weakening of flexion of the elbow. One or more other effects to be expected is (are):

Answer 2

Weakening of flexion at the shoulder and loss of cutaneous sensation on

Question 3

abduction cannot be initiated

Answer 3

suprascapular nerve

Question 4

anastomosis in the shoulder occurs between the suprascapular artery

Answer 4

Circumflex scapular

Question 5

roots of the 5th and 6th cervical nerves had been torn away from the spinal cord.

Answer 5

loss abduction
Injuries to the upper roots of the brachial plexus (C5 and C6) are the most common types of injuries–resulting in a condition known as Erb-Duchenne Palsy. It affects especially the suprascapular, axillary, and musculocutaneous nerves, which causes paralysis of the rotator cuff muscles, biceps, brachialis, coracobrachialis, and deltoid.

Question 6

winging” of the right scapula.

Answer 6

Long thoracic

Question 7

Examination reveals no loss of hand function, but the skin on the thumb side of his palm is numb. Branches of which nerve must have been severed?

Answer 7

The median nerve provides sensory innervation to the skin of the radial 3.5 fingers of the palm.

Question 8

dorsal side of the hand between the first and second fingers, and the dorsal side of the forearm, arm, and lateral side of the shoulder are innervated by

Answer 8

cutaneous branches of the radial nerve.
The difficulty extending at the wrist and elbow is also consistent with a radial nerve injury (remember–the radial nerve innervates the extensors).

Question 9

but there must be an injury to the axillary nerve since deltoid cannot complete abduction.

Answer 9

axillary nerve

Question 10

posterior cord

Answer 10

axillary nerve - affected deltoid

radial nerve-affected extensors m.

Question 11

tip 3.5 fingers

Answer 11

median n.

Question 12

nerve

Answer 12

The axillary nerve provides cutaneous innervation to the lateral upper arm, and the musculocutaneous nerve provides sensory innervation to the lateral forearm with the lateral antebrachial cutaneous nerve. The radial and ulnar nerve provide sensory innervation to the hand–the radial nerve innervates the radial 2.5 digits on the dorsum of the hand, up to the nail bed. The ulnar nerve innervates the ulnar 2.5 digits on the dorsal side and 1.5 digits on the palmar side of the hand.

Question 13

central lymph

Answer 13

are defined as the group of lymph nodes situated deep to the pectoralis minor at the base of the axilla. The central nodes receive lymph from the lateral, subscapular and pectoral lymph nodes.

Question 14

The lateral nodes

Answer 14

are found on the lateral wall of the axilla

Question 15

subscapular nodes

Answer 15

are found on the posterior wall of the axilla

Question 16

pectoral nodes

Answer 16

are found on the anterior wall of the axilla

Question 17

lateral, subscapular,pectoral

Answer 17

These groups of lymph nodes are lateral to pectoralis minor

Question 18

apica lymph nodes

Answer 18

are medial to the medial border of the pectoralis minor

Question 19

lymph nodes posterior to the pectoralis minor muscle

Answer 19

central axillary nodes

Question 19

lymph nodes posterior to the pectoralis minor muscle

Answer 19

central axillary nodes

Question 20

The axillary nerve and radial nerve are both terminal branches from the

Answer 20

posterior cord.

Question 21

lateral cord

Answer 21

musculocutaneous nerve and contributes a branch to the median nerve.

Question 22

medial cord

Answer 22

ulnar nerve and a branch to the median nerve; it also gives off the medial pectoral nerve, the medial cutaneous nerve of the arm, and the medial cutaneous nerve of the forarm.

Question 23

brachial plexus

Answer 23

The C5 and C6 roots make the superior trunk of the brachial plexus. So, all the muscles innervated by nerves from the superior trunk of the brachial plexus will be denervated following the avulsion. Supraspinatus is innervated by the suprascapular nerve, which comes off of the superior trunk of the brachial plexus. This means that avulsing the C5 and C6 nerve roots would denervate supraspinatus and paralyze that muscle.

Latissimus dorsi is innervated by the thoracodorsal nerve, which comes off the posterior cord of the brachial plexus. The thoracodorsal nerve is made of contributions from C6, 7, and 8, so this nerve would be mostly intact. Pectoralis minor is innervated by the medial pectoral nerve, off the medial cord of the brachial plexus. It is made of contributions from C8 and T1. Trapezius is innervated by the accessory nerve – CN XI. This means that trapezius is not innervated by the brachial plexus. Finally, triceps brachii is innervated by the radial nerve. The radial nerve is a terminal branch of the posterior cord of the brachial plexus, and it is made of contributions from C5, 6, 7, 8, and T1. Triceps brachi would not be entirely paralyzed following an injury to the C5 and C6 nerve roots.

Question 24

fracture of the midshaft of the humerus, which artery is most likely to be injured?

Answer 24

The deep brachial artery is an artery in the deep arm, wrapping around the humerus in the radial groove. It is close to the humerus, so fracturing the humerus at mid-arm might result in damage to this vessel or the radial nerve.

Question 25

In a diving accident that severed the spinal cord below the sixth cervical vertebra, which muscle would be affected?

Answer 25

If the spinal cord was severed beneath the 6th cervical vertebra, all nerve roots below C6 would be affected. So, latissimus dorsi, which is innervated by the thoracodorsal nerve (C6, C7, C8) would be affected.

Deltoid is suplied by the axillary nerve (C5, C6). Infraspinatus is supplied by the suprascapular nerve (C5, C6). Levator scapulae is supplied by the dorsal scapular nerve (C5). Trapezius is supplied by the accessory nerve (CN XI). All of these nerves would be intact, so these muscles would not be affected after the accident.

Question 26

Which muscle is the strongest medial rotator of the arm?

Answer 26

Subscapularis is the only muscle listed that is a strong medial rotator. There are four muscles which are strong medial rotators of the arm: subscapularis, pectoralis major, teres major, and latissimus dorsi. Two of the muscles mentioned are the lateral rotators of the arm: teres minor and infraspinatus. Coracobrachialis flexes and adducts the arm. Supraspinatus is an important muscle for initiating abduction of the arm through the first 15 degrees.

Question 27

It was determined that the pain was caused by stretching of the lateral rotators of his arm during this motion. Which muscle was most likely involved?

Answer 27

Infraspinatus and teres minor are the two lateral rotators of the arm. These were probably the muscles that this patient had strained. Latissimus dorsi, teres major, subscapularis and pectoralis major are all important medial rotators of the arm. Supraspinatus is the muscle that initiates abduction of the arm through the first 15 degrees.

Question 28

supraspinatus tendon is sometimes ruptured where it blends with the capsule of the shoulder joint. Following this kind of injury one might expect

Answer 28

Supraspinatus is one of the four muscles that comprises the rotator cuff, along with infraspinatus, teres minor, and subscapularis. Supraspinatus is an essential muscle for initiating abduction of the arm, so if the supraspinatus tendon is injured, it will be difficult for a patient to begin abducting the arm. After the arm is abducted about 15 degrees, the deltoid will take over and continue abducting the arm.

Teres major is the muscle which adducts the arm. Biceps brachii and coracobrachialis flex the arm. The long head of the triceps brachii extends the arm. Finally, pectoralis major, teres major, subscapularis, and latissimus dorsi all medially rotate the arm.

Question 29

You deduce that the pain is due to stretching of the lateral (external) rotators of the shoulder.

Answer 29

Infraspinatus and teres minor are the lateral rotators of the shoulder. Infraspinatus is innervated by the suprascapular nerve and teres minor is innervated by the axillary nerve. Latissimus dorsi and teres major are both medial rotators of the arm. Supraspinatus initiates abduction of the arm for approximately the first 15 to 20 degrees–after that, deltoid takes over and allows the arm to continue abducting. Rhombiodeus major and minor are important for retracting the scapula.

Question 30

scapula forming the tip or point of the shoulder

Answer 30

The acromion is the part of the scapula that forms the point of the shoulder–if a patient can’t raise this, that means that there is a problem with either trapezius or the accessory nerve!

Question 31

Preganglionic sympathetic fibers come from

Answer 31

the lateral horn of the spinal cord between T1 and L2. They leave the spinal cord through the ventral root before entering the sympathetic chain. Since this injury happened at C5, there are no preganglionic sympathetic fibers coming through the spinal nerve at this level.