1. The Median Nerve and CTS
“Anatomy”
Mohamed Elsayed Elsebaey, MD
Neurosurgery Fellow
Benha Teaching Hospital
The General Organization for Teaching Hospitals and Institutes
(GOTHI)

5. Abductor +add
Flexor
Opponens pollicis

6. Abductor
Flexor
Opponens digiti minimi

7. Crosses the brachial artery anteriorly
Passes over it.
Runs along the medial aspect between the brachialis muscle and the medial intermuscular
septum.

9. • Median nerve arises from contribution from the
lateral and medial cords.
• Motor filaments come from medial cord.
(Except C7 filaments pronator and flexor carpi radialis
come from lateral cord)
• Sensory filaments pass through the lateral cord.

10. At the Elbow,
Median nerve passes under the bicipital aponeurosis (lacertus
fibrosus)
This aponeurosis is radiated ulnarly across the antibrachial fossa.

11. Then enters through
pronator teres muscle
Usually passes in-between the superficial and deep heads of it.
But,
May pass deep to the both heads
or
May also pass through the superficial head.
1

12. 3 – 6 cm above the medial epicondyle,
there is bony process called
“the supracondylar process” or “
alveolar spur”
Fibrous bands called “ ligament of
struthers” are attached between it and
the medial epicondyle and producing
tunnel.
At this point of the bony spur, the
median nerve separated from the
surrounding vessels and passes inside
the tunnel beneath the bony spur.
In clinical practice, requiring X ray over the elbow and humerus shows the spur and if
related fractures and surgeon correlate those data with clinical examination of the motor
power of the fingers, wrist, forearm.

13. X ray of left elbow showing the bony spur and relevant anatomy

14. Then
passes between the FDS &
FDP
Then
becoming more superficial in
distal forearm.

15. At the level of elbow
4 groups of muscles receive branches from the
median nerve.
1. Pronator teres muscle
2. Flexor carpi radialis muscle
3. Palmaris longus muscle
4. Flexor digitorum superficialis muscle

20. Surgical NB.
The nerve branch to pronator muscle is:
1. Most proximal.
2. Arising from the anterior surface of Median N proper.
Other branches : (FCR, PL, FDS)
1. Deep.
2. Arising from the ulnar side of median N proper
AIN
1. About 3 cm distal to the intercondylar line.
2. Arising from the radial side from the median N proper

21. AIN
• Arises from the radial side from median nerve
• Innervates
1. Flexor digitorum profundus (FDP) arises from ulnar side of AIN
2. Flexor pollicis Longus (FPL) arises from radiaL side of AIN
3. Pronator quadratus (PQ)
• From the topographic view,
1. The group of fibres of the AIN is separated long distance before its emerge.
2. It was in ulnar side in Arm, and turns to be radial at level of proximal
forearm.
Important in issues of nerve
transfer

25. What is the clinical significance of
identification of nerve
topography??
How to use the sural nerve in grafting?
How to repair the median nerve ?

27. Palmar cutaneous branch of median nerve

28. Carpal tunnel transverse section

30. Median nerve sensation

31. In 1977, Lanz et al described 4
categories of median nerve
variations
• Category 1: variations of the recurrent median N.
• Category 2:bifid or duplicated median nerve
• Category 3:accessory median nerve passes
proximal to the carpal tunnel.
• Category 4: 3:accessory median nerve passes
distal to the carpal tunnel.

32. In details,
• Category 1:
Recurrent median nerve (take off)
1. Extraligamentous
2. Subligamentous
3. Transligamentous
4. Arise from the ulnar side of the median N

33. Extraligamentous distal take off (radial side of median n)

34. Subligamentous take-off (radial side of median N)

35. Transligamentous take-off (radial side of median N)

36. Ulnar side take-off subligamentous

37. Subligamentous take-off
Ulnar course
Distal emergence
Linear horizontal pathway to the thenar muscles
The most reliable
type for injury

38. Double thenar branches

39. Extra-ligamentous
Sub-ligamentous
Trans-ligamentous

40. • Category 2:
Bifid or duplicated median N
(High division of median N)
Separated by persistent median artery or muscle.
When be found, the radial half of the median
nerve mostly pass through separate compartment
of the carpal tunnel

41. High division of the median nerve with median artery in-between

42. High division of median nerve

43. • Category 3 :
The accessory median nerve
When takes off proximally,
Can pass accompanying the median N within the
same canal inside the carpal tunnel.
Or
May perforate the ligament and lie volar to the
flexor retinaculum.

44. Anatomical variations of the median N within the carpal tunnel 1995

45. ‫فى‬ ‫الزندى‬ ‫العصب‬ ‫و‬ ‫األوسط‬ ‫العصب‬ ‫بين‬ ‫وصلة‬
‫اليد‬ ‫راحة‬ ‫منطقة‬
‫كانييو‬ ‫ريتش‬ ‫وصلة‬
Riche-cannue motor anastomosis
Ulnar to median motor anastomosis in the palm
results in preservation of the thenar muscles
bulk and contour even if there is severe median N
compression or median N injury.
And
We can suspect it clinically.

46. Riche-Cannieu anastomosis
A- between thenar br. Of median N and deep br. Of ulnar N.
B- between thenar br. And deep br. Of ulnar N.

48. Facts
• In 1854, Dr Paget, was first to describe
manifestations of the CTS.
• In 1924, Dr Gallowoy did the first release of the
CT.
Complicated by post Op. pain.
Reoperated and was found nerve was adherent to
the scar tissue at the incisional line.
• In 1966, Dr Phalen publised the largest CTS series
study, (654 hands) of 439 patients over 17 years.

49. Management
Clinical examination
Inspection of thenar bulk
Motor
Sensory
Electrophysiology tests
Motor latency > 4.5 ms
Sensory latency > 3.5 ms
Follow up
Conservative
ttt+ splinting
Surgical release
Clinical examination as fresh
plus
Distinguish it is
1. Persistent
2. Recurrent
3. New insult
Electrophysiology tests
Medico-legal important only
Follow up
Generally (1,2) is conservative
(3) Is surgical

50. Etiology
• Compression.
• Impaired nerve blood circulation.
=====================================
Sub-synovial connective tissue fibrosis 
compression  nerve ischemia
Or
Dynamic ischemia of median nerve  certain
positions of hand  cause nocturnal paresthesia
This group shows rapid recovery after carpal tunnel
release.

51. • In 2006, amdio et al concluded that shaking
the hands that result in marked relief of the
hand symptoms is pathognomonic to CTS.
• In 2007, McCabe, suggested that positioning
the wrist in neutral position between flexion
and extension, in lateral position, in night 
relief CTS.

52. • CTS is most presented in females and in
increased BMI.
• CTS is strongly related to the repetition, force
and vibration.
• Certain careers:
1. Dental care providers
2. Key boarding using the mouse > 20 h/week
3. Heavy work workers
(claimed that hypertrophied lumbricals that
originate from the side of the FDP tendons distal
to the TL, causes median nerve compression)

53. • In 1973, Taleisnik described the standard carpal carpal tunnel release surgery.
• Long curvilinear incision in the palm that extended to the distal one third of
forearm.
• Incision be about 5 mm ulnar to inter-thenar depression to avoid injury of the
palmar cutanous branch of median nerve.
• Cutting the median nerve in the ulnar side preventing scar formation over the
median nerve.
• So avoiding adherence and adhesion and compression over median nerve.
• Divide the palmar aponeurosis in longitudinal fashion.
• Distal extent is the (V) point between the thenar and hypo-thenar muscles.
• If the thenar mm are atrophied, open in meticulous way and search for the
recurrent motor branch of median N.
• Visualization of the median nerve is the insurance of achieving full decompression.
• Hemostasis.
• Wound irrigation.
• Skin closed in simple interrupted way.
• Finger motion and light hand motion are encouraged.
• Wrist splint at night for 2-3 weeks to prevent bow shortening and stiffing of the
tendons over the median nerve after TL release.
• Gradual return to the full activity is allowed after 6 weeks from surgery.
• Internal neurolysis is not recommended at all.
• In obese patients, use longer skin incisions with zigzag fashion extended proximal
to the wrist flexion crease.

54. • Prolonged compression  demyelination 
axonal loss
• So, if patients come after 6 months of onset of
symptoms, about 4 months are needed for
resolving as time of re-myelination.

55. Complications
• Mild, moderate, severe.
Pillar pain: post-op pain located to the thenar and hypothenar
areas and is away from the incisional pain and Not well
understood.
• MacKinnon claimed that ulnar based incisions near total free
from the pillar pain.
• Suggested causes of pillar pain:
1. Alteration if the TL
2. Change in position & stability of thenar & htypothenar mm.
3. Edematous origin.
4. Micro-neuroma of the cutaneous branches.

56. If revision surgery needed
• Must distinguish between
1. Persistent symptoms as pre previous surgery.
2. Recurrence: same previous symptoms with
interval of improvement.
3. Added deficit: new symptoms different than
pre previous surgery.

57. Causes of complain
• Incomplete cut of TL.
• Intraneural scarring
• Median N. adherent to TL.
• Median N adherent to incisional scar.
• PCM injury.
• Recurrent motor branch injury.

63. ‫صدق‬ ‫مخرج‬ ‫أخرجنى‬ ‫و‬ ‫صدق‬ ‫مدخل‬ ‫ادخلنى‬ ‫و‬ ‫كله‬ ‫عملى‬ ‫تقبل‬ ‫اللهم‬
‫ارحمنى‬ ‫و‬ ‫عنى‬ ‫اعفو‬ ‫و‬ ‫لى‬ ‫اغفر‬ ‫اللهم‬
‫الخاتمة‬ ‫حسن‬ ‫ارزقنى‬ ‫اللهم‬
‫اد‬ ‫ارحم‬ ‫اللهم‬
/
‫حسن‬ ‫نبيل‬
,
‫كل‬ ‫و‬ ‫اجعلنى‬ ‫و‬ ‫الفردوس‬ ‫جنه‬ ‫ارزقه‬ ‫و‬ ‫ارحمه‬ ‫و‬ ‫له‬ ‫اغفر‬ ‫و‬
‫حسناته‬ ‫ميزان‬ ‫فى‬ ‫زمالئى‬