Final Exam--Blue Boxes

Question 1

Paralysis of Serratus Anterior

Answer 1

Caused by injury to long thoracic nerve
Medial border of scapula moves laterally and posteriorly away from thoracic wall (winged scapula)
serratus anterior unable to rotate the glenoid cavity superiorly so upper limb cannot abduct above horizontal position

Question 2

Triangle of Auscultation

Answer 2

Gap in musculature that makes it easier to listen to lungs
Borders: superior Latissimus dorsi, medial scapula, inferolateral trapezius
Enlarged when crossing arms across chest
6th, 7th ribs, 6th intercostal space subcutaneous

Question 3

Injury of spinal accessory nerve (spinal accessory nerve palsy)

Answer 3

ipsilateral weakness when shoulders are elevated (shrugged) against resistance

Question 4

Thoracodorsal nerve injury (C6-C8)

Answer 4

At risk during surgery of inferior axilla, during mastectomies when axillary tail of breast removed, and during surgery on scapular lymph nodes
at posterior wall of axilla and enters at medial surface of Lat. dorsi
Paralysis of lats leads to being unable to raise trunk with upper limbs and unable to use axillary crutch bc shoulder is pushed superiorly by it (aka injury leads to loss of active depression of scapula)

Question 5

Injury to dorsal scapular nerve

Answer 5

nerve to rhomboids

scapula on affected side will be located farther from the midline than that on the normal side

Question 6

Injury to axillary nerve (C5-C6)

Answer 6

Deltoid atrophies, flattened shoulder, slight hollow around acromion, loss of sensation over lateral side of proximal arm (bc axillary n gives rise to lateral cutaneous nerve of arm)
usually injured when surgical neck of humerus is injured bc thats where this nerve wraps around; Can also be injured during dislocation of glenohumeral joint or by compression from incorrect crutches use

Question 7

Fracture–Dislocation of Proximal humeral epiphysis

Answer 7

caused by a direct blow or indirect injury of shoulder of child or adolescent bc joint capsule of glenohumeral joint, reinforced by rotator cuff (tendon of the SITS muscles) is stronger than epiphyseal plate
In severe fractures, shaft of humerus is displaced but humeral head retains its relationship with glenoid cavity of scapula

Question 8

Rotator Cuff Injuries

Answer 8

Supraspinatus tendon is most commonly ruptured
Rotator Cuff injuries resutl in instability of glenohumeral joint
Degenerative tendonitis of rotator cuff is common, esp in older people

Question 9

Variations of Brachial Plexus:
Aside from the normal C5-T1 contributions, what other nerve roots can contribute to the brachial plexus? What is each of the conditions called when a different nerve root contributes?

Answer 9

Anterior rami of C4 or T2 can contribute
If plexus goes from C4-C8=PREFIXED brachial plexus
if it goes from C6-T2=POSTFIXED brachial plexus=inferior trunk of plexus can be compressed by 1st rib producing neurovascular symptoms in upper limb

Question 10

Variations of Brachial Plexus: What other variations are seen?

Answer 10

Variations in trunks, divisions and cords or combination of branches
Ex: lateral or medial cords may receive fibers from anterior rami inferior or superior to usual levles, respectively

Question 11

Variations of Brachial Plexus:

What remains always the same regardless of the variations in brachial plexus?

Answer 11

Terminal branches remain unchanged
Also, even though a nerve (like the median nerve) may have two medial roots, the components of the nerve are the same (impulses arise from the same place and reach the same destination whether they go through one or two roots)

Question 12

Brachial plexus injuries: complete paralysis vs. incomplete paralysis

Answer 12

complete: no movement detectable
incomplete: not all muscles paralyzed so person can move but movements are weak

Question 13

Brachial plexus injuries: superior brachial plexus injuries (C5-C6)

Answer 13

caused by excessive increase in the angle between the neck and shoulder (thrown from motorcycle or horse and lands on shoulder that separates neck and shoulder. Then, shoulder hits something and stops while head and trunk continue moving)

Question 14

Injury to superior trunk of brachial plexus

Answer 14

waiter’s tip position–limb hangs by side in medial rotation

Upper brachial plexus injury can also occur in neonates when excessive stretching of neck occurs during delivery

Question 15

Consequences of Superior brachial plexus injury

Erb-Duchenne palsy

Answer 15

paralysis of muscles supplied by C5-C6: deltoid, biceps, brachialis
symptoms: adducted shoulder, medially rotated arm and extended elbow, loss of sensation to lateral elbow
heavy backpack can cause microtrauma to superior trunk causing motor and sensory deficits due to musculocutaneous and radial nerves

Question 16

Backpackers palsy

Answer 16

superior brachial plexus injury producing muscle spasms and severe disability in hikers who carry backpacks for long periods

Question 17

Acute brachial plexus neuritis (brachial plexus neuropathy)

Answer 17

neurological disorder of unknown cause characterized by sudden onset of severe pain around shoulder; pain starts at night and is followed by muscle weakness and atrophy (neurologic amyotrophy)

Question 18

Brachial neuritis

Answer 18

often preceded by URI, vaccination or trauma; nerve fibers are from superior trunk of brachial plexus

Question 19

Compression of cords of the brachial plexus

Answer 19

caused by hyperabduction of arm during overhead tasks like painting
cords impinged between coracoid process and pectoralis minor tendon
Symptoms: numbness, paresthesia, erythema and hand weakness, ischemia of upper limb and distension of superficial veins
Result from compression of AXILLARY nerve & vessels!!

Question 20

Klumpe paralysis: inferior brachial plexus injury (C8-T1)

Answer 20

occurs when uper limb suddenly pulled superiorly (ex: grasping something to break a fall or baby’s upper limb pulled excessively during delivery)
short muscles of hand are affected and CLAW HAND results!!

Question 21

Brachial plexus block

Answer 21

Anesthesia around axillary sheath
sensation blocked in all deep structures of upper limb and kin distal to middle of arm
combined with occlusive tourniquet technique and allows for operation on upper limb without general anesthetic
Can use interscalene, supraclavicular and axillary approach or block

Question 22

bicipital myotatic reflex

Answer 22

positive response confirms integrity of musculocutaneous nerve and C5,C6 spinal cord segments
Prolonged response indicates central or peripheral NS disease or metabolic disorders like thyroid disease

Question 23

Biceps Tendinitis

Answer 23

Inflammation of biceps tendon caused by repetitive microtrauma (throwing, tennis etc)
Tight, narrow or rough intertubercular sulcus may irritate and infame tendon producing tenderness and crepitus

Question 24

Dislocation of tendon of long head of biceps

Answer 24

occurs in young people during traumatic separation of proximal epiphysis of humerus
can also occur in older people with history of biceps tendinitis
popping or catching felt during arm rotation

Question 25

Rupture of tendon of long head of biceps

Answer 25

caused by wear and tear of inflamed tendon as it moves back and forth in intertubercular sulcus of humerus; can be caused by forceful flexion against excessive resistance (weights) but more likely caused by prolonged tendinitis
occurs in individuals older than 35; tendon is torn from its attachment at supraglenoid tubercle; snap/pop
detached muscle belly forms ball near center of distal anterior arm
repetitive overhead movements=swimmers, baseball pitchers

Question 26

Interruption of blood flow in brachial artery

Answer 26

best place to compress brachial artery to control hemorrhage=medial to humerus near middle of arm bc ulnar and radial arteries will still receive sufficient blood through the anastomoses around the elbow

Question 27

If there is collateral circulation around the elbow, why can it still be problematic if brachial artery is occluded?

Answer 27

bc it causes paralysis of muscles from ischemia of elbow and forearm within a few hours

Question 28

Ischemic compartment syndrome

Answer 28

Muscles and nerves can tolerate upto 6 hrs of ischemia. Then, fibrous scar tissue replaces necrotic tissue and causes muscles to shorten permanently producing flexion deformity
Flexion of fingers and wrist results in loss of hand power due to irreversible necrosis of forearm flexors

Question 29

Absence of Pectoralis muscles

Answer 29

Anterior axillary fold (formed by skin and fascia over inferior pec major) is absent and nipple more inferior than usual
Poland syndrome: Both pectoralis major and minor are absent; breast hypoplasia and absence of two to four rib segments also seen

Question 30

Injury to musculocutaneous n.

Answer 30

typically inflicted by weapon like a knife
results in paralysis of coracobrachialis, biceps, and brachialis
Weak flexion may occur at glenohumeral joint bc musculocutaneous n affecting long head of bicpes and coracobhacialis
Flexion of elbow and supination greatly weakened but not lost bc of brachioradialis and supinator (radial n)
Loss of sensation of lateral forearm supplied by lateral antebrachial cutaneous n supplied by musculocutaneous n.

Question 31

Injury to radial n in arm

Answer 31

causes paralysis of triceps, brachioradialis, supinator, and extensor muscles of wrist and fingers and loss of senstion in areas of skin supplied by radial n; if injured in radial groove, triceps not totally paralyzed bc only medial head and distal posterior forearm affected
WRIST DROP seen–inability to extend wrist and fingers at metacarpophalangeal joint; wrist assumes partly flexed position

Question 32

Venipuncture in cubital fossa

Answer 32

Cubital fossa=site for blood sampling, transfusion, IV injections bc of assessibility of veins–median cubital vein–crosses bicipital aponeurosis (grace Deux tendon)
median cubital vein also site for cardiac catheters to get blood samples from great vessels and chambers of heart and also can be used for coronary angiography

Question 33

Variation of veins in cubital fossa

Answer 33

20% of people: Median antebrachial vein (median vein of forearm) divides into median basilic v which joins basilic v of arm and median cephalic v that joins cephalic v
Creates an M by cubital veins; both median cubital and median basilic vein crosses SUPERFICIAL to BRACHIAL ARTERY from which it is separated by bicipital aponeurosis
good for drawing blood but NOT for injecting drugs bc of danger of injecting it into brachial a.