Download MBBS Anatomy PPT 96 Median Nerve And Its Lesions Notes

--- Content provided by‍ FirstRanker.com ---

Learning Objectives

1. Median nerve formation , root value and important

relations

--- Content provided by⁠ FirstRanker.com ---

2. Motor and sensory supply

3. Important sites of injuries/entrapment of nerve

--- Content provided by‍ FirstRanker.com ---

4. Effects of injury of median nerve

5. How to clinically test median nerve injury
MCQ

--- Content provided by FirstRanker.com ---

Q 1.Regarding the median nerve, all are correct

EXCEPT:

a. Arises from both the medial and lateral cords of the

--- Content provided by‍ FirstRanker.com ---

brachial plexus.

b. It crosses the brachial artery at the insertion of the

--- Content provided by⁠ FirstRanker.com ---

coracobrachialis.

c. In the cubital fossa, it lies lateral to the brachial

artery.

--- Content provided by FirstRanker.com ---

d. It enters the hand in the carpal tunnel.

e. Injury of the nerve causes ape-like hand.

--- Content provided by‌ FirstRanker.com ---

MCQ

Q 1.Regarding the median nerve, all are correct

EXCEPT:

--- Content provided by‌ FirstRanker.com ---

a. Arises from both the medial and lateral cords of the

brachial plexus.

--- Content provided by‍ FirstRanker.com ---

b. It crosses the brachial artery at the insertion of the

coracobrachialis.

c. In the cubital fossa, it lies lateral to the brachial

--- Content provided by‌ FirstRanker.com ---

artery.

d. It enters the hand in the carpal tunnel.

--- Content provided by‍ FirstRanker.com ---

e. Injury of the nerve causes ape-like hand.

Answer c
MCQ

--- Content provided by⁠ FirstRanker.com ---

Q 2. A 40 year tailor complains of pain numbness and

weakness of right hand for last 3 months. On

examination, there is hypoesthesia and atrophy of

--- Content provided by‌ FirstRanker.com ---

thenar eminence. Which of the following nerve is likely

to be involved?

--- Content provided by⁠ FirstRanker.com ---

A Ulnar nerve

B Median nerve

C radial nerve

--- Content provided by‍ FirstRanker.com ---

D Axillary nerve

MCQ

--- Content provided by‌ FirstRanker.com ---

Q 3 Injury to the median nerve in the arm would affect

all of the following movements except:

A. Pronation of the forearm

--- Content provided by​ FirstRanker.com ---

B. Flexion of the wrist

C. Flexion of the thumb

--- Content provided by‍ FirstRanker.com ---

D. Supination of the forearm
Anatomy

? Mixed nerve (contain motor & sensory fibers).

--- Content provided by⁠ FirstRanker.com ---

? Root value: C 5,6,7,8 & T1

? Runs in the median plane of the forearm , so

its called median nerve

--- Content provided by‌ FirstRanker.com ---

MEDIAN NERVE

? Formation:from two roots from

--- Content provided by​ FirstRanker.com ---

lateral cord

[C(5),6,7]&

from medial cord(C8,T1) of

--- Content provided by​ FirstRanker.com ---

brachial plexus

Before leaving axil a, C7 fibres

--- Content provided by​ FirstRanker.com ---

conveyed by median nerve are

handed over to Ulnar nerve

? These two roots embrace the third

--- Content provided by⁠ FirstRanker.com ---

part of axillary artery uniting

anterior or lateral to it

--- Content provided by‍ FirstRanker.com ---

In the arm

? Closely related to the

--- Content provided by​ FirstRanker.com ---

brachial artery through out

the course in arm

? In the upper part it is

--- Content provided by FirstRanker.com ---

lateral to artey

? In the middle part it

--- Content provided by⁠ FirstRanker.com ---

crosses the artery from

lateral to medial side

? Remains on the medial

--- Content provided by⁠ FirstRanker.com ---

side up to elbow
Branches in arm

? Branch to Pronator Teres just above elbow

--- Content provided by⁠ FirstRanker.com ---

? Branch to brachial artery
? Branch to elbow joint at or just below the

elbow
In the cubital fossa

--- Content provided by​ FirstRanker.com ---

? Descends medial to

brachial artery

--- Content provided by‍ FirstRanker.com ---

? Posterior to bicipital

aponeurosis

? Anterior to brachialis,

--- Content provided by FirstRanker.com ---

seperated by the

muscle from the elbow

--- Content provided by‍ FirstRanker.com ---

joint

? Leaves the cubital fossa by passing

between two heads of pronator teres

--- Content provided by‍ FirstRanker.com ---

In the forearm

? Enters the forearm between

the heads of pronator teres

--- Content provided by‍ FirstRanker.com ---

? Crosses the lateral side of

ulnar artery from which it is

--- Content provided by FirstRanker.com ---

seperated by the deep head

of pronator teres

? Gives branch to pronator

--- Content provided by FirstRanker.com ---

teres while passing between

the two heads

--- Content provided by FirstRanker.com ---

? Proceeds behind a

tendinous ridge

between the two heads

--- Content provided by‍ FirstRanker.com ---

of Flexor digitorum

superficialis and

--- Content provided by⁠ FirstRanker.com ---

anterior to Flexor

digitorum profundus

? Here it is accompanied

--- Content provided by FirstRanker.com ---

by median artery, a

branch of anterior

--- Content provided by FirstRanker.com ---

interosseous artery
? About 5 cm

proximal to flexor

--- Content provided by FirstRanker.com ---

retinaculum it

becomes

superficial

--- Content provided by⁠ FirstRanker.com ---

? Here it lies

between the

--- Content provided by‌ FirstRanker.com ---

tendon of

palmaris longus

and the flexor

--- Content provided by‌ FirstRanker.com ---

carpi radialis

muscle

--- Content provided by‍ FirstRanker.com ---

? Leaves the forearm and enters the palm of the

hand by passing through the carpal tunnel deep to

flexor retinaculum

--- Content provided by‍ FirstRanker.com ---

Branches in the forearm

? Muscular branches

to all the muscles

--- Content provided by⁠ FirstRanker.com ---

in the

superficial and

--- Content provided by​ FirstRanker.com ---

intermediate layer of

forearm except one

(FCU) originate

--- Content provided by‌ FirstRanker.com ---

medially from nerve

just distal to elbow

--- Content provided by FirstRanker.com ---

joint

? Anterior interosseous

nerve: originate between

--- Content provided by⁠ FirstRanker.com ---

two heads of pronator teres

? passes distally down the

--- Content provided by​ FirstRanker.com ---

forearm with the anterior

interosseous artery.

? Innervates the muscles of

--- Content provided by​ FirstRanker.com ---

deep layer (FPL, lateral half

of FDP (for index and middle

--- Content provided by‌ FirstRanker.com ---

finger) and pronator

quadratus)
?Palmar cutaneous branch: starts just proximal to flexor

--- Content provided by FirstRanker.com ---

retinaculum

?Lateral branches - thenar skin and connecting branch to

the lateral cutaneous nerve of fore arm

--- Content provided by‌ FirstRanker.com ---

?Medial branches - central palmer skin and connecting

branch to the palmar cutaneous branch of the ulnar nerve

--- Content provided by⁠ FirstRanker.com ---

? Communicating branch:

multiple

?Arise in the proximal forearm

--- Content provided by​ FirstRanker.com ---

? Pass medialy between FDP &

FDS and behind the ulnar artery

to join the ulnar nerve

--- Content provided by‍ FirstRanker.com ---

Median nerve in hand

? Proximal to flexor retinaculum it lies

between the tendons of FCR & FDS

--- Content provided by‍ FirstRanker.com ---

overlapped by palmaris longus

? Distally it lies between the retinaculum and

--- Content provided by‍ FirstRanker.com ---

the tendon in the retinaculum

? Site of compression

? Distal to retinaculum nerve enlarges and

--- Content provided by​ FirstRanker.com ---

flattens

? devides in to five or six branches
Branches in the hand

--- Content provided by‌ FirstRanker.com ---

Lateral branch: gives

Recurrent

--- Content provided by⁠ FirstRanker.com ---

muscular branch-

short and

stout, curls upwards

--- Content provided by⁠ FirstRanker.com ---

over the distal border

of flexor retinaculum

--- Content provided by​ FirstRanker.com ---

and FPL to supply

three thenar muscles

APB, FPB &OP

--- Content provided by FirstRanker.com ---

? Three palmer digital

branches- First two

--- Content provided by‌ FirstRanker.com ---

supply the skin of the

sides of the thumb ,its

web and distal part of

--- Content provided by​ FirstRanker.com ---

its dorsal surface.

? Third supplies the skin

--- Content provided by‌ FirstRanker.com ---

of the radial side of

index finger and the

first lumbrical muscle

--- Content provided by​ FirstRanker.com ---

through its superficial

surface
? Medial branch: gives

--- Content provided by FirstRanker.com ---

? Two common palmar digital

branches- lateral and

--- Content provided by FirstRanker.com ---

medial which descend to

the interdigital clefts

between the index, middle

--- Content provided by‍ FirstRanker.com ---

and ring finger

? Each nerve divides again

--- Content provided by‍ FirstRanker.com ---

into two to supply adjacent

sides of the fingers

? So in total it supplies skin of

--- Content provided by FirstRanker.com ---

lateral three and half fingers

including the skin on the

--- Content provided by​ FirstRanker.com ---

dorsal aspect of terminal

phalanges
Injuries

--- Content provided by​ FirstRanker.com ---

? High
? Low
Median Nerve Lesion in Elbow Region ? High Lesion

? Damaged in

--- Content provided by​ FirstRanker.com ---

supracondylar fracture

of humerus

--- Content provided by⁠ FirstRanker.com ---

? Muscles af ected are:
? Pronator muscles of

the forearm

--- Content provided by​ FirstRanker.com ---

? All long flexors of

wrist and fingers

except FCU and

--- Content provided by FirstRanker.com ---

medial half of FDP

Motor Effects:

--- Content provided by⁠ FirstRanker.com ---

Wasting

of thenar

? Loss of pronation. Hand is kept in

--- Content provided by​ FirstRanker.com ---

eminence

supine position

--- Content provided by‍ FirstRanker.com ---

? Wrist shows weak flexion, and

ulnar deviation

? Loss of flexion on interphalangeal

--- Content provided by FirstRanker.com ---

joints of the index and middle

fingers

--- Content provided by‌ FirstRanker.com ---

? Weak flexion of ring and little

finger

Ulnar deviation

--- Content provided by⁠ FirstRanker.com ---

? Thumb is adducted and lateral y

rotated, with loss of flexion of

--- Content provided by⁠ FirstRanker.com ---

terminal phalanx and loss of

opposition

? Wasting of thenar eminence

--- Content provided by‍ FirstRanker.com ---

? Hand looks flat ened and

"apelike", and presents an inability

--- Content provided by FirstRanker.com ---

to flex three most radial digits

when asked to make a fist.
? Sensory Ef ects: Loss of

--- Content provided by‍ FirstRanker.com ---

sensation from:

? The radial side of the palm
? Palmar aspect of the lateral

--- Content provided by​ FirstRanker.com ---

3? fingers

? Distal part of the dorsal

surface of the lateral 3?

--- Content provided by⁠ FirstRanker.com ---

fingers

? Trophic Changes:

--- Content provided by FirstRanker.com ---

? Dry and scaly skin
? Easily cracking nails
? Atrophy of the pulp of

fingers

--- Content provided by‍ FirstRanker.com ---

Median Nerve Lesion at Wrist

? Often injured by penetrating wounds (stab wounds or

--- Content provided by⁠ FirstRanker.com ---

broken glass) of the forearm.

? Motor:

? Thenar muscles are paralyzed and atrophy in time so thenar

--- Content provided by‌ FirstRanker.com ---

eminence becomes flattened

? Opposition & abduction of thumb are lost, and thumb and

--- Content provided by‌ FirstRanker.com ---

lateral two fingers are arrested in adduction & hyperextension

position .

? "Apelike hand"

--- Content provided by⁠ FirstRanker.com ---

? Sensory & trophic changes are same as in elbow

region injuries

--- Content provided by​ FirstRanker.com ---

Examination

? Flexor pol icis longus : Tested by holding

thumb at its base and patient asked to flex the

--- Content provided by‍ FirstRanker.com ---

terminal phalanx


Examination

--- Content provided by⁠ FirstRanker.com ---

? Flexor digitorum superficialis & profundus

(Ochsner's clasping test)
- Patient is asked to clasp the hands , the index

--- Content provided by​ FirstRanker.com ---

finger of af ected side fails to flex

Examination

--- Content provided by‌ FirstRanker.com ---

? Flexor Carpi radialis : Hand deviates to the

ulnar side when flexed against resistance
Examination

--- Content provided by‍ FirstRanker.com ---

? Muscles of Thenar eminance:

-abductor pol icis brevis (Pen test)
- hand laid flat on the table
-pen held above the palm and the patient is

--- Content provided by​ FirstRanker.com ---

asked to touch the pen with his thumb

Examination

--- Content provided by‌ FirstRanker.com ---

? opponens pol icis : brings the tip of the

thumb towards the tips of other fingers
Opponens pollices

--- Content provided by‌ FirstRanker.com ---

Benedict Sign

Lesion to upper arm area, just proximal to where motor

branches of forearm flexors originate, is diagnosed if the

--- Content provided by‍ FirstRanker.com ---

patient is unable to make a fist.

More specifically, the patient's index and middle finger

--- Content provided by⁠ FirstRanker.com ---

cannot flex at the MCP joint, while the thumb usually is

unable to oppose. This is known as hand of benediction or

Pope's blessing hand.

--- Content provided by‍ FirstRanker.com ---

Benedict Sign

Kiloh-Nevin syndrome and OK Sign

The Anterior Interosseus Nerve (AIN) syndrome

--- Content provided by‌ FirstRanker.com ---

Patients suffering from this syndrome have impaired distal

interphalangeal joint, because of which they are unable to

--- Content provided by​ FirstRanker.com ---

pinch anything or make and "OK" sign with their index finger

and thumb. The syndrome can either happen from pinched

nerve, or even dislocation of the elbow.

--- Content provided by‍ FirstRanker.com ---

Kiloh-Nevin syndrome OK Sign

MCQ

After history of stab wound on front of forearm ,

--- Content provided by​ FirstRanker.com ---

patient presents with impairment of the pincer

movement and is having difficulty picking up a small

--- Content provided by FirstRanker.com ---

item, such as a coin, from a flat surface. Which of the

following statement is correct ?

A Injury to anterior interroseous nerve of median nerve

--- Content provided by‌ FirstRanker.com ---

B injury to main median nerve as pincer movement

involves FDS

--- Content provided by‍ FirstRanker.com ---

C Injury to ulnar nerve

D. Injury to median nerve at level of wrist
Ape hand deformity

--- Content provided by FirstRanker.com ---

In "Ape hand deformity", the thenar muscles become

paralyzed due to impingement and are subsequently flattened.

it is seen only after the thenar muscles have atrophied. While

--- Content provided by​ FirstRanker.com ---

the adductor pollicis remains intact, the flattening of the

muscles causes the thumb to become adducted and laterally

--- Content provided by‍ FirstRanker.com ---

rotated. The opponens pollicis causes the thumb to flex and

rotate medially, leaving the thumb unable to oppose.

Ape Thumb

--- Content provided by FirstRanker.com ---

Median nerve Compression

Syndromes

? Carpal Tunnel ?nerve may be compressed due to

--- Content provided by FirstRanker.com ---

inflammatory condition of ulnar bursa or anterior

dislocation of lunate bone

--- Content provided by⁠ FirstRanker.com ---

? Pronator
? Interosseous

Carpal Tunnel Syndrome

--- Content provided by‌ FirstRanker.com ---

? Compressive neuropathy as the nerve passes through the

Carpal Tunnel

? Causes:

--- Content provided by​ FirstRanker.com ---

- Idiopathic

: Most common

--- Content provided by‌ FirstRanker.com ---

- Inflammatory : Rheumatoid Arthritis

: Wrist osteoarthritis

- Post traumatic : Bone thickening

--- Content provided by‍ FirstRanker.com ---

- Endocrine

: Myxoedema

--- Content provided by⁠ FirstRanker.com ---

: Acromegaly

- Pregnancy

- Gout

--- Content provided by‍ FirstRanker.com ---

- Repetitive wrist movts: Typists & Computer users
Carpal Tunnel Syndrome

? The commonest neurological

--- Content provided by⁠ FirstRanker.com ---

problem associated with median

nerve is compression beneath

--- Content provided by⁠ FirstRanker.com ---

flexor retinaculum at wrist.

? Motor: Weak motor function of

thumb, index & middle finger

--- Content provided by⁠ FirstRanker.com ---

? Sensory: Burning pain or `pins

and needles' along distribution

--- Content provided by⁠ FirstRanker.com ---

of median nerve to lateral 3?

fingers

No sensory changes over palm as palmer cutaneous branch

--- Content provided by​ FirstRanker.com ---

is given before median nerve enters carpal tunnel.

Symptoms

--- Content provided by​ FirstRanker.com ---

? Hand and wrist Pain

? Paraesthesia

? Hypoaesthsia

--- Content provided by⁠ FirstRanker.com ---

? Sparing of Palmar cutaneous branch supply

? Patient wakes at night with burning or aching

--- Content provided by⁠ FirstRanker.com ---

pain and shakes the hand to obtain relief and

restore sensation

? Aggravated by elevation of hand

--- Content provided by FirstRanker.com ---

? Thenar atrophy and weakness of thumb

opposition and abduction may develop late
Diagnosis

--- Content provided by​ FirstRanker.com ---

? History

? Clinical examination:

--- Content provided by‌ FirstRanker.com ---

- Thenar wasting

- Phalen's sign

- Tinel's sign

--- Content provided by‌ FirstRanker.com ---

- Carpal compression test

? Electro Diagnostic Studies:

--- Content provided by‌ FirstRanker.com ---

- Very reliable for evaluation

- Atypical cases may be present

Thenar atrophy

--- Content provided by​ FirstRanker.com ---

Phalen test

A positive Phalen test is highly suggestive of carpal tunnel

syndrome.

--- Content provided by‌ FirstRanker.com ---

Phalen's test is performed by having patients place their wrists in

complete unforced flexion for at least 30 seconds.

--- Content provided by​ FirstRanker.com ---

If the median nerve is entrapped at the wrist, this maneuver will

reproduce the symptoms of carpal tunnel syndrome.

--- Content provided by‍ FirstRanker.com ---

Tinel's Sign
Carpal Compression test/ Durkan's test

Pronator teres syndrome

--- Content provided by⁠ FirstRanker.com ---

? High Compression neuropathy

? It is rare compared to CTS and AIS

Pronator teres syndrome

--- Content provided by​ FirstRanker.com ---

The characteristic physical finding is tenderness over the

proximal median nerve, which is aggravated by resisted

--- Content provided by‌ FirstRanker.com ---

pronation of the forearm.

The flexor pol icis longus and FDP of the index finger are weak,

leading to impairment of the pincer movement. This reflects

--- Content provided by⁠ FirstRanker.com ---

involvement of the anterior interosseous nerve.

Sensory changes may be found in the first three fingers as well

--- Content provided by‍ FirstRanker.com ---

as in the palm, indicating impairment of the median nerve

proximal to the flexor retinaculum.
Symptoms & signs

--- Content provided by‌ FirstRanker.com ---

? Symptoms are similar to those of carpal tunnel syndrome

? Sensory disturbances

- Thumb & Index > Middle finger

--- Content provided by​ FirstRanker.com ---

? Night pain is unusual and forearm pain is more common

? Hand numbness on gripping

--- Content provided by‍ FirstRanker.com ---

? Phalen's test negative

? Double crush phenomena

? Symptoms provoked by resisted elbow flexion with forearm

--- Content provided by⁠ FirstRanker.com ---

supinated ( tightening of bicipital aponeurosis )

? By resisted forearm pronation with the elbow extended (

--- Content provided by​ FirstRanker.com ---

pronator tension )
Thank You