median nerve

Question 1

what cords of the brachial plexus form the median nerve?

Answer 1

lateral (musculocutaneous)
posterior (axillary & radial)
median (ulnar)
C5 - T1

Question 2

what does the sensory terminal branches of the median nerve supply?

Answer 2

thumb
index finger
middle finger
lateral half of ring finger

Question 3

what does the recurrent (motor) branch of terminal median nerve supply?

Answer 3

(LOAF)
lateral 2 lumbricals
oppenens pollicis
abductor pollicis brevis
flexor pollicis brevis

Question 4

what superficial flexors does the median nerve supply?

Answer 4

• pronator teres
• flexor carpi radialis
• palmaris longus
• flexor digitorum
  superficialis
  NOT flexor carpi ulnaris

Question 5

where does the median nerve pass through to enter lower brachium?

Answer 5

pronator teres

Question 6

where does ulnar nerve enter lower brachium?

Answer 6

flexor carpi ulnaris

Question 7

where does radial nerve enter lower brachium?

Answer 7

supinator

Question 8

what 7 muscles are innervated by the median nerve?

Answer 8

pronator teres
flexor carpi radialis
palmaris longus
flexor digitorum profundus
pronator quadratus
flexor pollicis longus
flexor digitorum
superificialis

Question 9

what cutaneous areas in the hand does the median nerve innervate?

Answer 9

palmar side of thumb
index finger
middle finger
half of ring finger

Question 10

what structures pass through the carpal tunnel?

Answer 10

median nerve
4 superficial flexor tendons
4 deep flexor tendons
flexor pollicis longus tendon ( most radial)

Question 11

why is feeling preserved in the hand with carpal tunnel syndrome

Answer 11

palmar cutaneous nerves runs over flexor retinaculum to supply palm of hand, APB, FPB, and OP, 1st & 2nd lumbricals

Question 12

what is the sign of benediction?

Answer 12

injury to median nerve at level of elbow or upper arm results in inability to flex DIP of index finger due to loss of innervation of lateral half of flexor digitorum profundus

Question 13

all muscles of the forearm are supplied by median nerve except for ?

Answer 13

half of flexor digitorum profundus

Question 14

what is the OK sign?

Answer 14

grossly verifies integrity of median nerve, specifically testing anterior interosseous nerve.
paralysis of flexor pollicis longus and flexor digitorum profundus (cannot flex PIP joint) cannot perform

Question 15

what structure above the elbow can compress the median nerve?

Answer 15

1% population have medial supracondylar spur ( 5 cm proximal to medial epicondyle). together with ligament of struthers can compress median nerve.

Question 16

describe presentation of pronator teres syndrome

Answer 16

parasthesia in radial 3.5 fingers
weakness in thenar muscles
dull aching pain over proximal forearm
no night symptoms
pronator teres tender to palpation
symptoms ++ with repetitve or forceful pronation
sensory disturbance to palm of hand & thenar muscles

Question 17

what structures are involved in pronator teres syndrome

Answer 17

in forearm (elbow) median nerve runs btn 2 heads of pronator teres muscle and then flexor digitorum superificialis & profundus; compressing median nerve

Question 18

what otho tests can help identify pronator teres syndrome

Answer 18

resisted pronation with elbow extension (tests compression btn 2 heads of pronator teres)
resisted elbow flexion with supination of forearm (test for compression at bicipital aponeurosis)
resisted contraction of FDS to middle finger (compresses FDS arch)

Question 19

2 differential diagnoses for pronator teres syndrome

Answer 19

c 5/6 radiculopathy
carpal tunnel syndrome

Question 20

what is the differentiating criteria in the hand between pronator teres and carpal tunnel syndrome

Answer 20

no symptoms are present when tinels performed at wrist for PTS
PTS causes thumb and index finger flexion weakness
both have weakness in thenar muscles
CTS has exacerbation of symptoms at night where PTS doesnt