Anatomy of median nerve by Dr. Bipul Borthakur

1. MEDIAN NERVE
By:
Dr. Bipul Borthakur,
Professor,
Dept of Orthopaedics, SMCH

2. Anatomy of Median nerve
• Condensation of lateral
and medial cords of
brachial plexus
o Root value :C5,C6,C7,C8,T1
o Mixed nerve
o Also known as Labourers
nerve

4. Median nerve in arm
• Enters arm from axilla at inferior margin of
teres major
– Passes vertically down on medial side of
arm in anterior compartment
• related to brachial artery throughout its
course:
• Proximaly - lies immediately lateral to
brachial artery
• Distally - crosses the brachial artery
-descends on its medial side
- passes anterior to elbow joint.
• No branches in arm

5. Median nerve in forearm
• Median nerve passes into forearm anterior to elbow
joint b/w 2 heads of pronator teres.
o Supplies FDS, FCR and Palmaris longus ,pronator
teres.
• Its branches innervates most of the muscles in
anterior compartment of forearm except
flexor carpi ulnaris, medial half of FDP, which are
innervated by ulnar nerve.
o Gives an Ant.Interosseous nerve at around 6-8 cm
from medial epicondyle ,supplies FPL,FDP of index
and middle fingers and pronator quadratus mules

6. Median nerve in hand
 Median nerve passes throughout carpal tunnel
,deep to flexor retinaculum the recurrent
motor branches supplies –thenar muscles i.e
abductor pollicis brevis,
opponens pollicis ,
superficial head of flexor pollicis brevis
.

7. Median nerve in hand
 Digital cutaneous branches provides sensation
to volar aspect thumb ,index,middle and radial
half of ring fingers.
• Palmer cutaneous branch of median nerve arises
proximal to wrist ,provides sensation to radial
palm
• Short motor branches supplies index and middle
finger lumbricals.

8. ANATOMY CARPAL TUNNEL
• Bounderies :
Volarly –transverse carpel ligament
Dorsaly-Carpel bones,deep volar carpel ligament and volar interosseous ligaments
Laterally-Scaphoid tuberosity and trapezium
Medially –Pisiform and hook of hamate
• Contents: 9 tendons –tendon of flexor pollicis longus,
4 tendons of flexor digitorum profundus ,
4 tendon of Flexor digitorium superficialis and
median nerve
Transverse carpel ligament :Flexor retinaculum :
- thick fibrous band from tuberosity of scaphoid & aportion of trapezium to the
pisiform and hook of hamate

9. CARPAL TUNNEL SYNDROME
• Most common entrapment neuropathy
• Entrapment of median nerve at wrist
• Most frequent cause of idiopathic CTS :
pathologic synovium
• Idiopathic variety is the most common
cause(95%)
• Affects 0.1-10% of general population.

10. CARPAL TUNNEL SYNDROME :Clinical presentation
• Pain: Dull aching pain,awakens patient at night
Intermittent course
Aggravated by activities that involve flexing or extending the wrist
Releived by changes in hand posture shaking the hand
• Tingling ,numbness of radial 3.5 fingers
• Paresthesia
• Weakness

11. Aetiology of carpal tunnel syndrome:
a)Idiopathic (95%)
b)Anatomic
c)Systemic
d)Exertional (Occupational )

12. Aetiology of carpal tunnel syndrome:
o Trauma
-post traumatic
swelling/hemorrhage/scar
-Post traumatic arthritis
-Carpel dislocation
-Distal radius malunion
o Small carpal canal
o Basal joint arthritis
• Anomalous structures muscles –
-palmaris profundus
-Anomalous slip of flexor pollicis
longus
-Reversed palmaris longus
• Vascular
-persistent /thrombosed median artery
• Masses/tumors
-ganglion
Lipoma
Fibroma/lipofibroma
Synovial sarcoma
Neuroma/neurofibroma/neurilemoma

13. Systemic
• Disorders affecting fluid balance
-Pregnancy
-Renal failure
-Thyroid disease
- Congesative heart failure
- Obesity
- Myxedema
-Acromegaly
• Neuropathic
diabetes
thyroid disease
vitamin nutritional defeciency
vitamin toxicity
Alcoholism
Medication(Lithium,beta blocker,ergot)
• Inflammatory condition
Rheumatoid arthritis
lupus
gout/pseudogout
scleroderma
dermatomyositis
amyloidosis
• Hemorrhagic disorders
leukemia
hemophilia
anticoagulation
• Infection
• Constitutional factors
Advancing age
female sex

14. Percussion test (Tinel sign)
• Gentle percussion along course of
median nerve from distal to proximal
direction
• Tingling sensation felt by patient in
distribution of nerve
• Importance:
– whether nerve interrupted
– In process of regeneration

15. Carpal tunnel compression test (Durkan test)
• Direct compression is applied to
median nerve for 30 seconds with
the thumbs.
o Patient with carpel tunnel syndrome
usualy have symptoms of
numbness,pain,or paresthesia in
median nerve distribution

16. Tourniquet test (Gilliat test)
• Arm tourniquet inflated above systolic pressure for 60 seconds.
• Numbness /tingling in the median nerve distribution

18. Investigation
• EMG /NCV: distal sensory latencies >3.2 ms or motor latencies >4.2ms considered
abnormal
• MRI not essential in preoperative diagnosis
• A positive Semmes weinstein monofilament test (most predictive sensory test) and a
consistent brigham hand diagram are features.

19. Treatment
• Splinting of wrist in neutral position especially night time and rest ,Nsaids, activity modification
must be initial management
• Corticosteroid injection into the carpal tunnel
is indicated when median nerve compression is
predicted to be temporary as in pregnancy or when
patient activity modified.
• Indication of surgery : any two of following
persistent symptoms,
positive physical examination
positive electrodiagnostic testing

20. • Absolute indication for surgery:
constant paraesthesia
thenar atrophy
markedly delayed median nerve conduction
velocity or abnormal EMG
• Open CTR or Endoscopic carpal tunnel release
• Recurrence rate after carpal tunnel release -20%
• Most common cause of recurrence –incomplete division of retinaculum.

21. THANK YOU
“vāsāṃsi jīrṇāni yathā vihāya
navāni gṛhṇāti naro’parāṇi
tathā śarīrāṇi vihāya jīrṇā-
nyanyāni saṃyāti navāni dehī”
“As a man casts off worn-out garments and
puts on others that are new,
so does the soul cast off its worn-out bodies
and enter into others that are new.”