anatomy

ScienceInfoopk.com

ScienceInfopk

 QUESTION 1

     

        DESCRIBE MEDIAN NERVE ACCORDING  TO THE FOLLOWING

A )  ORIGIN

B)   ROUTE VALUE

C)   RELATIONS

QUESTION 2

 DESCRIBE THE CLINICAL IMPORTANCE OF MEDIAN NERVE.

QUESTION 3

HOW MEDIAN NERVE ENTER AND LEAVE FORE ARM.

 QUESTION 4

    

     DIFFERENCE BETWEEN  

 1. high median nerve palsy

 2.low median nerve pasy

QUESTION 5

 EXPLAIN THE FOLLOWING

1)    PHALEN’S MANEUVER

2) TINEL’S SIGN

MEDIAN NERVE ANATOMY

Root value: 

  C5, 6, 7,8 and T1 As it runs in the 

median plane of the forearm, so its 

called median nerve. > it arises in the 

axilla by 2 roots 1) Lateral (from lateral cord of brachial plexus) 2) 

Medial root (from the medial cord of 

the brachial plexus) .

IN AXILLA

 Median nerve is formed by lateral 

root from lateral cord and medial root 

from medial cord of brachial plexus.

  Median nerve runs  lateral to axillary artery.

IN ARM

 Median nerve continues to run on the

 lateral side of brachial artery till the 

middle of arm, where it crosses infront 

of the artery and passes anterior to the 

elbow joint into forearm.

IN FOREARM
Median nerve enters to the forearm by 

passing between two heads of pronator 

teres,then deep to fibrous arch of 

flexor digitorum superficialis,in 

proximal third of fore arm.

   In mid forearm, descends between 

flexor digitorum superficialis and flexor digitorum profundus.

     About 5cm above wrist, it comes to lie on the lateral side of the flexor 

digitorum superficialis, becomes 

superficial just above wrist.

IN HAND

Median nerve passes deep to the 

flexor retinaculam and enters 

the palm of hand.Here its muscular 

branches supply muscles of thenar 

eminence (abductor pollicis brevis,

 opponens pollicis and flexor

pollicis brevis).

  Finally it divides into 4 to 5 palmar digital branches

 supplying lateral three and half digit and their nail 

beds. Also, motor branches are given to the first and 

second lumbrical muscles.

BRANCHES

In arm: vascular branches to the brachial(arm)
 In forearm:    muscular branches to all superficial 

flexor muscles(pronator teres, flexor carpi

 radialis, palmaris longus and flexor 

digitorum superficialis).

 Anterior interosseous:

     which comes off the median nerve supplies lateral half of flexor digitorum 

profundus, flexor pollicis longus and

pronator quadratus.

 Articular branches :

       supply the elbow joint and proximal ulnar joint.

 Palmar cutaneous branch :

        supply skin over thenar eminence andcentral part of palm.





 Motor Functions.

 The median nerve innervates the majority 

of the muscles in the anterior forearm, and some intrinsic hand muscles.

 IMPORTANCE OF MEDIAN NERVE :

 Median nerve is most commonly injured 

near the wrist or high up in the fore arm

 AND CAUSE
 1. high median nerve palsy
 2.low median nerve pasy



1      LOW MEDIAN NERVE PALSY:

 Injury in the distal third of the forearm

 Cuts infront of wrist or by carpal  dislocation.

 There will be sparing of the forearm 

muscles, but the muscles of the hand will 

be paralysed.

  Thenar eminence is wasted and thumb 

abduction and opposition are 

weak,Sensation is lost over the radial and 

half digits and changes may be seen.

2    HIGH MEDIAN NERVE PALSY:

 Injury proximal to the elbow generally due to forearm features or elbow 

dislocation trauma may damage the nerve 

at any level.

This will cause paralysis of all the muscles supplied by the median nerve in the forearm and hand.

FLEXOR POLLIS LONGUS :

This muscle is tested by holding

 thumb  at its base and patient asked to 

bend the  terminal phalanx

FLEXOR DIGITORUM SUPERFICIALIS AND
PROFUNDUS :

When the patient is asked to clasp the hands the index finger of

affected side fail to

reflex.

FLEXOR CARPI RADIALIS :

The hand deviates to ulnar side when it is flexed against resistance.

 ABDUCTOR POLLICIS BREVIS :

The patient is asked to lay his hand flat on 

the table, a pen is held above the palm and 

the patient is asked to touch the pen with 

his thumb(Pen test).

OPPONENS POLLICIS

Bring the tip of the thumb towards the tipsof other fingers.                                                  CLANICALS
PHALEN’S MANEUVER :

1.  Diagnostic test for carpal tunnel syndrome
(inverse praying position to achieve maximal wrist flexion).

2. A person holds his or her forearms horizontally 

and then pushes backs of the hands together 

TINEL’S SIGN

Tinel's sign is positive when lightly 

banging (percussing) over the nerve 

elicits a sensation of tingling, or 'pins 

and needles in the distribution of the nerve.

DIRECT COMPRESSION OVER TRANSVERSE LIAGAMENT FOR 30 SECONDS.

Role of median nerve:

 In forearm, median nerve directly 

innervates muscles in the superficial and 

intermediate layers,superficial 

layer,Pronator teres, flexor carpi radialis 

and palmaris longus.

 INJURY TO THE MEDIAN NERVE:

 MUSCLES ARE TESTED

CARPAL COMPRESSION TEST