MEDIAN NERVE- tests, transfers, injury
Terms in this set (69)
Median nerve - brachial plexus details
C5, 6,7,8,T1 anterior cords therefore volar muscles
Lateral cord root innervates forearm flexors & leads to the AIN motor branch= PQ, FDP 1/2, FPL C5-C7, no sensation here but PALMAR CUTANEOUS BRACH comes from LATERAL cord and provides sensation to lateral palm & digits
Medial cord root innervates LOAF muscles-lumbricals, opponenes pollicis, abductor pollicis brevis, flexor pollicis brevis (superficial/short) C8-T1
AKA RECURRENT MOTOR BRANCH OF MEDIAN (mill $)
Muscles of the lateral cord:
C5,C6,C7 Pronator teres, FCR, palmaris longus, FDS
AIN innervates FPL, pronator quad, FDP to IF/MF,
Muscles of AIN:
AIN innervates FPL, pronator quad, FDP to IF/MF
Muscles of Medial root of Median nerve: AKA RECURRENT MOTOR BRANCH OF MEDIAN
FPB, APB, OP, lumbrical 1&2, cutaneous to fingers
sensation to thenar muscle & recurrent motor nerve- "Million dollar nerve"
Median nerve syndromes:
Carpal tunnel, Pronator syndrome, AIN syndrome
High median nerve palsy:
lose pronator teres, FCR, PL, FDS, FDP 2&3, FPL, PQ, APB, OP, FPB superficial, lumbricals 2&3
Loss of sensation in the median innervated digits is also present.
ELBOW AND FA MUSCLES= HIGH
Low median nerve palsy:
lose OP, APB, FPB superficial head, lumbricals 1&2
(lose intrinsics to the thumb, index and long fingers) lose sensation to thenar area
Motor + Sensory syndromes:
Pronator, carpal tunnel
Carpal tunnel syndrome: compression site
COMPRESSION AT CARPAL TUNNEL
AIN syndrome: compression site
COMPRESSION AT TENDINOUS ORIGIN OF PRONATOR TERES AT THE MEDIAL EPICONDYLE
Pronator syndrome: compression site
COMPRESSION AT 1 OF 3 LOCATIONS
1. LIGAMENT OF STRUTHERS-above elbow
2. FDS ARCH
3. TWO HEADS OF PRONATOR TERES MUSCLE
4. Tendinous pronator area=Lacertus fibrosis
LIGAMENT OF STRUTHERS TEST
RESISTED ELBOW FLEXION AT 120-125- because the ligament is at the level of the elbow, therefore no pronation is needed, just elbow flexion- ARM TYPICALLY SUPINATED- true
- MEDIAN NERVE MAY BE DISPLACED MEDIALLY AND COMPRESSED BY LIGAMENT OF STRUTHERS AND SUPRACONDYLAR HOOK OF HUMERUS: TEST= COMPRESSION IS WORSENED W/ EXTENSION AND SUPINATION; (PER WHEELESS AND OTHERS)
Ligament of struthers compression- aka supracondylar process syndrome
*****pronator teres muscle would be weak as well as those by pronator syn. BECAUSE HIGH INJURY
FDS ARCH TEST
RESISTED MF PIP FLEXION- because this is the muscle you are testing
Per HUNTER: Resisted proximal interphalangeal flexion at the middle finger: If this results in symptom reproduction, the likely point of compression is the superficialis arch.
TWO HEADS OF PRONATOR TERES TEST
RESISTED PRONATION WITH ELBOW EXTENDED AND WRIST FLEXED because the muscle heads will enlarge with effort causing constriction of the nerve-true!
Per HUNTER: Resisted forearm pronation with elbow extension: The first test is performed with patient's forearm in the neutral position. The examiner resists forearm pronation as the elbow is gradually extended. A positive test reproduces the patient's symptoms and is indicative of median nerve compression at the PT.
TENDINOUS ORIGIN OF PRONATOR TERES TEST- AKA Lacertus Fibrosis tendon or bicipital aponeurosis
PROVOCATIVE TEST= RESISTANCE TO MAXIMALLY FLEXED ELBOW WITH RESISTED PRONATION (weiss citation) or possibly SUPINATION (Hunter/Rehab hand)
- lacertus IS TIGHTENED W/ PRONATION OF FOREARM ; PER MACKLIN- true!
Per HUNTER: Resisted elbow flexion: The second test reproduces pain and paresthesias if the median nerve is compressed at the level of the lacertus fibrosus. The examiner performs resisted elbow flexion with the patient's elbow flexed from 120 to 130 degrees and the forearm in full supination.
LOCATIONS OF MEDIAN NERVE ENTRAPMENT
LIGAMENT OF STRUTHERS, FDS ARCH, 2 HEADS OF PRONATOR TERES, TENDINOUS ORIGIN OF PRONATOR TERES(aka lacertus fibrosis,bicipital aponeurosis), CARPAL TUNNEL
Signs and symptoms of Pronator syndrome:
Altered sensation over the thenar eminence due to proximal compression that affects palmar cutaneous branch of median nerve (which isnt affected in CTS)
-SO ALTERED SENSATION ON WHOLE MEDIAN AREA OF HAND
Proximal FA aching pain- can refer to hand
Sensory symptoms but night uncommon
Tender over pronator teres
Symptoms exacerbated w/activity (FA rot, resist pro)
+ Tinel FA - Tinel wrist - Phalen wrist
weakness in muscles distal to ligament of struthers (ie forearm muscles)
compressed at one of locations-LS, FDS, 2 heads pronator, LF/BA
more common in women than men! 50's
Management of Pronator syndrome: pre-op
LAS elbow @90, wrist neutral, FA neutral to slight pronation x 2 weeks removing for gentle ROM only, anti-inflam, steroids, injection, act. mod
Signs and symptoms of Anterior Interosseous syndrome:
vague pain in proximal FA exacerbated by activity, no sensory symptoms, difficulty with pinch, loss of LOAF muscles
Management of Anterior Interosseous syndrome: pre-op
LAS elbow @90, FA neutral to slight pronation, wrist neutral, activity mod- do activities in supination
Signs and symptoms of Carpal Tunnel:
wrist/hand pain, numb/parasthesias, symptoms occur with sustained grip/pinch, repetitive wrist/awkward, symptoms worsen at night, cold sensitivity, females 40-60, thenar muscle weakness, clumsiness, + Phalen/ Reverse Phalen and + Tinel at wrist
- sensory fibres distal to carpal tunnel innervate medial thumb, second & third digits & lateral half of fourth digit (VOLAR AS WELL AS DORSAL ASPECT DISTALLY BEYOND DIP JOINT)
Management of Carpal Tunnel:
Splint neutral to slight ulnar deviation, MC 20-40 included if repetitively flex, modalities, stretching, cortizone shot, avoid positions that increase carpal pressure, avoid repetitive/prolonged grip/pinch
Why are AIN and Pronator syndrome splints and treatment the same?
Because both entrapped around level of pronator teres muscles (proximal), because both due to resisted pronation & wrist flexion
Functional deficits of a high median nerve injury?
Full loss of pronation, full loss of thumb opposition
Loss of thenar sensation + digit sensation
Weak wrist flex due to FCR & PL
Weak finger flexion due to FDS (all) FDP 1/2, lumbricals 2/3
Weak thumb flexion due to FPL
Weak thumb abduction due to APB-still have APL-weak
Functional deficits of a low median nerve injury?
Full loss of thumb opposition
Loss of lumbricals 2/3
Weak thumb flexion FPB superficial/short
Weak thumb abduction
Loss of digit sensation (NO thenar loss due to palmar cutaneous branch that arises prior to carpal tunnel)
Most common transfer for median nerve injury?
Opponensplasty common motors chosen:
flexors: FDS II or IV, PL,
extensors: EIP, ADM, EDM
Camitz Transfer for low median nerve injury:
Palmaris Longus to Abductor Pollicis Brevis
Excellent thumb abduction, limited thumb pronation
Splint: LAS opponens with wrist 20 flex & max palmar abduction under IF
high median to low median transfer
BUNNELL FDS of ring (IV) Transfer for low median nerve injury: also can use index finger
pulley at Pisiform for pron/sup of thumb
Splint: LAS opponens with wrist neutral to 20 flex & max palmar abduction under IF
high median to low median transfer
*most PREFERRED FOR OPPONENSPLASTY
Huber Transfer for low median nerve injury:
Abductor Digiti Minimi to Abductor Pollicis Brevis
(ADM to APB) for abduction of thumb
intrinsic transfer radial to median
Splint: Hand based opponens with max palm. abd.
Burkhalter EIP Transfer for low median nerve injury:
Extensor Indicis Proprius to Abductor Pollicis Brevis
(EIP to APB) for abduction of thumb
intrinsic transfer radial to median
What is the MOST COMMON tendon transfer surgery for long standing Carpal Tunnel syndrome?
Camitz Transfer - PL to APB for opposition of thumb
-uses a high median muscle to low median
High Median nerve transfers: common muscles used
1. ECRL/B to FDP for MCP flexion
SPLINT: DBS wrist neutral to flexed
2. Brachioradialis to FDS then FPL for MCP flexion
SPLINT: long arm dorsal blocking splint- elbow 90, wrist & thumb flexed, full palmar abduction- (treat like flexor tendon repair)
3. ECU also used for FPL for thumb flexion (Phalen-Miller)
Median nerve injury pre-op treatment:
Address thumb adducted and supinated contracture- webspace splints in full palmar abduction
Low median nerve injury post-op tendon transfer protocol:
0-3 weeks splint 24/7
3.5 weeks AROM IN splint to activate transfer
4 weeks AROM out of splint- active use of transfer, mobilize unaffected joints
6-8 weeks DC splint per MD, unrestricted AROM
8 weeks- resistance as allowed, prevent fatigue
12 weeks- no restrictions
*Wait longer to dc splint, wait til 8 for strength
High median nerve injury post-op tendon transfer protocol:
0-3 weeks splint 24/7
3.5 weeks AROM in splint to activate transfer
4 weeks AROM out of splint, NMES to activate (4-6 wk)
6 weeks DC splint, + PROM and Splinting for tightness
7-8 weeks progressive resistance
*NMES for long muscles, resistance & PROM earlier
Post op management of Pronator Syndrome:
Keep motion at the elbow limited to 90 flexion (due to its medial epicondyle origin) w/neutral FA x 5-10 days then motion as tolerated
Digits and wrist AROM as tolerated by patient
Post op management of AIN syndrome:
Splint if pronator elevated= elbow flexed, 45 pro and 45 wrist flex x 2 weeks, avoid full elbow extension
Digits and wrist AROM as tolerated by patient
Composite AROM & nerve/tendon glides at 3 weeks
Strengthening at 4 weeks
back to work 6-8 weeks
Post op management of Carpal tunnel release:
1- 14 days Digit AROM, nerve and tendon glides
2 weeks Sutures removed, wrist AROM, desensit, scar
3 weeks Strengthening
4 weeks Sensory eval, retraining, work hardening
Which branch of median nerve innervates the DEEP flexor group and what are the muscles?
Flexor digitorum profundus (only the lateral half)
Flexor pollicis longus
What muscles make up the superficial and intermediate muscle groups?
Superficial :Pronator teres,Flexor carpi radialis, PL
Intermediate group:Flexor digitorum superficialis
Course of Median nerve in Upper Arm:
Courses with brachial artery on medial arm between biceps brachii and brachialis. At first lateral to the artery, it crosses anteriorly to run medial to the artery in the distal arm and into the cubital fossa- it continues medial to the brachial artery at the fossa.
Course of Median nerve in forearm:
Arises from the cubital fossa and passes between the two heads of pronator teres. Travels between FDS and FDP before emerging between FDS and FDP.
The unbranched portion of the median nerve innervates muscles of superficial/intermediate groups except FCU.
The median nerve gives 2 branches through the FA:
1. AIN courses w/ anterior interosseous artery to innervate all the muscles of the deep group of the anterior compartment of the forearm except (ulnar) half of FDP. It ends with its innervation of pronator quadratus.
2.The palmar cutaneous branch arises at the distal FA, supplying sensory innervation to the lateral aspect of the skin of the THENAR/PALM (but not the digits).
Course of Median nerve in hand:
Enters the hand through the carpal tunnel for motor innervation to the first and second lumbrical muscles and then sends off several branches:
1. Recurrent branch to muscles of the thenar compartment (AKA "the million dollar nerve")
2. Digital cutaneous branches to
1. common palmar digital branch
2. proper palmar digital branch which supply the:
a) palmar digits 1-3
b) dorsal index, middle and ring finger
NOT TO THE THENAR AREA! That's palmar cut. branch
Where are the proper digital nerves in comparison to the corresponding arteries?
the proper digital nerves, as they run along the fingers, are placed SUPERFICIAL to the corresponding arteries.
(same in the shoulder, ie axillary, where axillary artery is surrounded by cords of brachial plexus
Proper versus Common digital nerves:
proper and then common digital nerves- first(distal) its proper, superficial and first-run along sides of fingers
then common(proximal), deep is second- more proximal in the palm
common branches into 2 that form the distal proper superficial nerves around the digits
3 proper palmar digital nerves of median nerve :
two of these supply the sides of the thumb,
third gives a twig to the first Lumbrical and is distributed to the radial side of the index finger.
2 common palmar digital nerves of median nerve:
The first of these divides into two proper digital nerves for the adjoining sides of the index and middle fingers;
the second common palmar digital nerve splits into two proper digital nerves for the adjoining sides of the third and forth digits; then courses to the pulp and the nail-
* split into a Y shape as become proper digital nerves to go around sides of digits
Way of remembering site of AIN compression:
TAIN- tendinous origin for AIN syndrome
resisted pronation w/supinated elbow in maximum flexion- AIN arises in the cubital fossa near the flexor tendons
Where is a low median nerve injury begin?
at wrist level, therefore only intrinsic muscles of the hand, no AIN muscles- loss of DIGIT sensation, but not loss of thenar sensation since the palmar cutaneous branch branches before the carpal tunnel- on top of it
ULTT for median nerve: ALSO MC AND AXILLARY NERVES TOO
shoulder abduction & ER,
cervical contralateral flexion
Other name of AIN syndrome:
Kiloh- Nevin syndrome
What is the prime muscle of thumb opposition?
Abductor pollicis brevis- it is the muscle that most tendon transfer attach to b/c it is the primary mover
Royle-Thompson transfer for low median:
Ring finger FDS to thumb MPJ
What thumb posturing should you expect with median nerve damage?
Adduction due to intact AP (ulnar)
Supination due to loss of opponens & APB
Thumb pronation appears as_____:
away from the plane of the digits 2-5, as a component of opposition
Return order of median nerve:
Pronator teres, FCR, Palmaris Longus, FDS (PFPF)
FDP, FPL, PQ
Abductor pollicis brevis, Opponens Pollicis, Flexor pollis brevis superficial, Lumbricals 1 & 2 (AOFL)
What does the ULTT look like for median?
Like youre getting a shot from the side OR
jumping jack position OR the end position of median nerve glide with contralateral neck flexion
Quick screen- jumping jack, or elbows extended w/wrist fingers extended and shldrs slight extension
sensation median general info: FA and Wrist
1. proximal to wrist , palmar cutaneous branch arises, running subcutaneously, (on top of but NOT within the carpal tunnel) supplying sensation to thenar eminence- not same nerve as recurrent motor branch
- 2. then enters wrist through carpal tunnel (bounded by carpal bones on three sides and roof formed by TCL)
- in the hand, muscular branches to Abductor pollicis brevis ('purest' median-innervated hand muscle), opponens pollicis, flexor pollicis brevis (superficial head) & first / second lumbricals
- sensory fibres distal to carpal tunnel innervate medial thumb, second & third digits & lateral half of fourth digit (volar as well as DORSAL aspect distally beyond DIP joint)
What happens with median nerve compression prior to carpal tunnel? Where is sensation still felt?
when proximal to wrist , the MEDIAN palmar cutaneous branch arises, running subcutaneously (and NOT within the carpal tunnel) it supplies sensation to thenar eminence- therefore if thenar sensation is lost, IT IS NOT compression within the carpal tunnel but more PROXIMAL (green)
-sensation is still felt in the dorsal and volar median innervated digits (yellow)
Retroposition vs opposition:**********
*retroposition is the elevating and abduction and supination of the thumb in a plane away from the palm- opp of opp.= ape hand position=COMBO MOVEMENT
-opposition is pronation of the thumb in the plane of the palm
results from a severed Median nerve at the level of the elbow or upper arm. The ability to flex the digits 2-3 at the MCPs, PIPs and DIPs is lost. Flexion at the PIP joints of digits 4-5 is weakened due to FDS loss, but flexion at the MCP joints and DIP joints remains intact.
TEST: The extensors are left unopposed and digits 2-3 remain extended WHEN PATIENT IS ASK TO MAKE A FIST.
Ulnar claw test: Deficit is most prominent at rest and WHEN THE PATIENT IS ASKED TO EXTEND HIS FINGERS.
Medial CORD innervations: NOT NERVE, CORD
Medial pectoral nerve branches off proximally and provides partial innervation to pectoralis major and full innervation to pectoralis minor.
2 Medial brachial cutaneous nerve supplies the medial aspect of the arm on its dorsal and volar surfaces.
3 Medial antebrachial cutaneous nerve of the forearm supplies the medial aspect of the forearm on its dorsal and volar surfaces.
4 Ulnar nerve motors the ulnar wrist flexors, ulnar digital flexors, and ulnar intrinsics in the hand. It provides cutaneous innervation to the skin overlying the ulnar half of IV and all of V.
5 Medial head of the median nerve innervates the median intrinsic muscles in the hand and the skin overlying I, II, III, and radial half of IV on the volar surface and distal to the proximal interphalangeal joints on the dorsal surface.
Weird AIN thing:****************************
Like the PIN, which is a motor branch off the radial nerve and runs with the superficial sensory radial branch that covers the dorsal radial digits, the AIN nerve is a motor branch off the main median nerve that runs alongside the palmar cutaneous branch of median nerve that covers the median palmar area
Where does palmar cutaneous brand arise and from what portion of the nerve?
The palmar cutaneous branch of the median nerve arises 5 to 7 cm proximal to the wrist crease
-from the main median nerve
Another clinical test that may aid in the diagnosis of PS is
the pronator compression test. The examiner exerts pressure over the PT muscle bellies, bilaterally, for 30 seconds. A positive test results in median nerve paresthesias in the involved extremity.
Muscles which Produce Thumb Retropulsion / Supination
Extensor Pollicis Brevis
Extensor Pollicis Longus
Muscles which produce thumb opposition / pronation
Abductor Pollicis Brevis
Abductor Pollicis Longus
Flexor Pollicis Brevis