Brachial plexus lecture

Question 1

brachial plexus is mad eup of

Answer 1

VENTRAL rami of cervical and thoracic spinal nerves (C5-T1)

Question 2

what parts of brachial plexus are supraclavicular?

Answer 2

roots and trunks

right at infraclavicular is where divisions are

Question 3

trunks in brachial plexus are

Answer 3

upper
middle
lower

Question 4

cords in Brachial plexus

Answer 4

medial
posterior
lateral
(in relation to axillary a.)

Question 5

Lateral cord comes from

Answer 5

the Anterior branches of C5-C7

Question 6

Medial cord comes from

Answer 6

anterior branch of T1

Question 7

posterior cord comes from

Answer 7

posterior branches of C5-T1

Question 8

nerves belonging to anterior compartment of brachial plexus

Answer 8

musculocutaneous
median
ulnar

Question 9

nerves belonging to posterior compartment of brachial plexus

Answer 9

radial

axillary

Question 10

the anterior and posterior compartments of the arm are divided by the
and forearm..

Answer 10

arm: medial and lateral intermuscular septa
forearm: interosseous membrane

Question 11

arm (brachium) main innervations for each compartment

Answer 11

ant. = musculocutaneous nerve (flexors of elbow joint)

post. = radial nerve (extensors of elbow joint)

Question 12

forearm (brachium) and hand innervations for each compartment

Answer 12

ant. = median & ulnar nerves.

post. = radial nerve

Question 13

excessive, forceful increase in angle between neck and shoulder
in adults from fall onto shoulder
what type of injury? s/s

Answer 13

Injuries to superior trunk (C5 &C6)
Upper/ superior trunk lesion = Erb’s palsey
-most common obstetric brachial plexopathy]
s/s: “WAITER’S TIP”
- arm abducted
- arm internally (medially) rotated at elbow
- pronation
- extension

Question 14

nerve deficits & affected muscles in erb’s palsey

Answer 14

C5 spinal nerve root

• axillary n. weakness in (deltoid and teres minor)
• suprascapular n. (weakness in supraspinatus and infraspinatus)
• musculocutaneous nerve (weakness in triceps)

C6 spinal root
- radial n. (weakness in brachioradialis and supinator)

Question 15

Klumpke’s palsey is often associated with

Answer 15

Horner’s Syndrome (T1 involvement causing preganglionic interruption of sympathetic pathways)

Question 16

an avulsion injury usually resulting from excessive, foreceful abduction of the arm
OR relatively rare obstetric injury when baby being pulled out

Answer 16

Klumpke’s Palsey

C8 and T1

Question 17

clinical presentation and nerves affected in Klumpke’s Palsy

Answer 17

median and ulnar n. affected
“CLAW HAND”
wrist - held in extremely extended posture (wrist flexors are unopposed)
hand and fingers
- all intrinsic muscles of hand affected
- joints between hand bones and finger bones hyperextended
- joints between finger segments will be flexed

Question 18

person using crutches imporerly
presentation -
weakness when trying to push something away with arm
difficulty extending the wrist
difficulty extending the fingers and opening the hand
“wrist drop” posture

Answer 18

injury to radial nerve (C5-T1) at the axillary region - nerve injured before it supplies triceps

Question 19

compression of radial nerve along midshaft of humerus in certain positions “sleep palsy/ saturday night palsy” or humeral fracture at midshaft
presentation
-difficulty extending the wrist
- difficulty extending or straightening the fingers and opening the hand
- triceps retain strength (why??)
also causes “wrist drop” posture”

Answer 19

injury to radial nerve (C5-T1) - injury at spiral groove of humerus
triceps okay because nerve fibers entering this muscle branch off proximal to mid shaft of humerus

Question 20

presentation - 
numbness in posterior deltoid region
difficulty abducting arm
diminshed lateral rotation of arm
deltoid muscle wasting (prolonged injury)
which nerve damaged and how?

Answer 20

axillary nerve (C5,C6)
causes
- fracture to surgical neck of humerus
- anterior dislocation of glenohumeral joint
- rotator cuff repair surgery

Question 21

penetrating wound to axillary region - stabbing maybe
surgical removal of axillary lymph nodes
presentation -
cannot raise arms above 90 degrees
“winged scapula”
nerve davaged? which muscle?

Answer 21

injuries to long thoracic nerve (C5,6,7)

innervation to serratus anterior muscles

Question 22

fracture to medial epicondyle of humerus/ entrapment of nerve in cubital tunnel
presentation:
- numbness/ tingling in 4th and 5th fingers (maybe worse when elbow is bent)
weakening of grip with some loss of flexion of fingers
- loss of ab- and adduction of fingers
nerve? what muscles involved?

Answer 22

ulnar nerve (C8, T1, and often C7) injured
damage involves flexors of wrist, digits and intrinsic hand muscles

Question 23

fracture of humerus above condyles/ entrapment of nerve by pronator teres/ inflammation or irritation in carpal tunnel (syndrome)
presentation -
pain & tenderness in anterior proximal region
decreased sensation along course of this nerve
numbness/ tingling along its course
inability to flex distal interphalangeal joint of digit 1
“hand of benediction” (unable to flex second and third digits when making a fist)
“ape hand” (thenar eminence atrophy and loss of thenar opposition)
loss of ab and adduction of fingers
which nerve injured?>

Answer 23

median!!!

Question 24

what are some places where median nerve can get entrapped?

Answer 24

under pronator teres

and carpal tunnel proximal to palm

Question 25

muscles paralyzed when median damaged?

Answer 25

lateral two lumbricals
lateral half of FDP
“hand of benediction”