This document provides an overview of peripheral nerve anatomy, focusing on the radial, median, and ulnar nerves. It describes the origin, course, branches, and innervation of each nerve. The radial nerve originates from the brachial plexus and provides motor innervation to muscles of the posterior arm and forearm. The median nerve originates in the axilla from the brachial plexus and provides motor innervation to muscles of the anterior forearm and hand. The ulnar nerve originates from the medial cord of the brachial plexus and provides motor innervation to muscles of the medial forearm, hand, and fingers.

1. Dr Ditesh Jain
Dept of Orthopedics

2. Introduction
 Basic Nerve Anatomy
 Radial nerve
 Ulnar nerve
 Median Nerve

3. Nerve anatomy
 A whitish fibre or bundle of fibres in the body that
transmits impulses of sensation to the brain or spinal
cord, and impulses from these to the muscles and
organs.

4.  Basic unit of any nerve is axon of neurons.
 Axons are arranged in bundles known as nerve fibre
and is covered with endoneurium..
 Group of nerve fibre form a fasciculi which is intern
covered with perineurium.
 Group of these fasciculi form a nerve which is covered
with areolar membrabe known as epineurium

5.  The epineurium is a loose connective tissue layer. The
outer condensation of this layer comprises
the external epineurium. The portion of this tissue
that extends into the substance of the nerve and
defines fascicular groups is the internal epineurium.

7.  The peripheral nerve surgeon, Hanno Millesi, in the
1970’s described mesoneurium. This overlooked bit of
connective tissue is what makes a nerve feel slippery or
flick away when palpated. The nerve slides in this
sheath during movement .

8.  Vasa nervorum are small arteries that provide blood supply
to peripheral nerves.
 These vessels are tortuous to allow for considerable freedom
of translational movement of peripheral nerves. More
numerous near joints.
 These form anastomoses at intervals throughout the course of
the nerve, reinforcing the blood supply within the
epineurium.
 Where a considerable interval between the supplying
nutrient vessels occurs, there will be a natural “watershed”
area of a nerve that may experience stress from ischemia.

11. Radial Nerve
 Origin
 Course and relation
 Branches

12. Radial Nerve:- Origin
 Terminal Branch of posterior cord of Brachial plexus
 Contains C5, C6, C7, C8 & T1 roots.
 Its largest branch of brachial plexus

14. Course
 The nerve arises in the axilla region, where it is
situated posteriorly to the axillary artery. It exits the
axilla inferiorly (via the lower scapulartriangular
interval), and supplies branches to the long and
medial heads of the triceps brachii along with
posterior cutaneous nerve of arm

16.  The radial nerve then descends down the
arm, travelling along with deep brachial artery in
the radial groove/ musculospiral groove/ radial
sulcus/ spiral groove .
 Branches to lateral head of triceps , anconeous and
inferior lateral cutaneous nerve of arm

18.  Through lateral inter-muscular septum 10-12 cm above
lateral condyle and comes to anterior comprtment of
arm
 Runs between brachialis and brachioradialis
 Gives accessory branch to brachialis , large branch to
brachioradialis and ECRL just above the elbow

19.  Radial nerve enters the forearm anterior to lateral
epicondyle.
 At around 3 cm interval devides in to superficial radial
and deep radial nerve with continues as posterior
interosseous nerve after entering the supinator canal

22.  PIN Course :
 Arcade of Frosche at radial head
 dives under supinator at arcade of Frohse (thickened edge of
between heads of supinator)
 Forearm posterior compartment
 winds around radial neck within substance of muscle to
posterior compartment of forearm
 Interosseous membrane
 reaches interosseous membrane of forearm

23. Branch
Cutaneous Branches:
1. Posterior cutanous
n/v of arm
2. Lower lateral
cutanous n/v of arm
3. Posterior cutanous
n/v of forearm
4. Superficial Radial
sensory nerve

24. Branch
Muscular branches
above elbow:
1. Triceps
2. Anconeous
3. Brachioradialis
4. ECRL

25. Branch
Muscular branches
below elbow:
1. ECRB
2. Supinator
3. Posterior
interosseous nerve
(PIN)
Superficial PIN:
EDC, EDQ, ECU
Deep PIN:
APL, EPL, EPB, EIP

26. Median Nerve
 Origin
 Course and relation
 Branches

27. Median Nerve (C5,6,7,8 & T1)
Arise in axilla from 2 roots lateral and medial:
1. Lateral root from lateral cord C567
2. Medial root from medial cord C8 T1

28. 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 side of axillary artery

29. In arm
• Median nerve continues to run on the lareral side of brachial artery
till the middle of arm , where it crosses infront of the artery and
passes anterrior to the elbow joint into forearm

30. In forearm
• Enters to the forearm b/w two heads of pronator teres .
• Then deep to fibrous arch of flexor digitorum
superficialis , in proximal third
• In mid forearm descends b/w flexor digitorum
superficialis and flexor digitorum profundus .
• About 5 cm above wrist , it comes to lie on the lateral side
of the flexor digitorum superficialis , becomes superficial
just above wrist

32. In hand
• Nerve passes deep to the flexor
retinaculum and enters the palm
• Muscular braches supply muscles of
thenar eminence ( abductor pollicis
brevis , opponens pollicis and flexor
pollicis brevis )

33. • Finally divides into 4 to 5 palmar
digital branches supplying lateral
three and half digit and their nail
beds
• Also , motor braches are given to
the first and second lumbrical
muscles

34. Branches
 In arm : vascular branches to the brachial
 In the forearm : muscular branches to all superficial flexor
muscles ( pronator teres , flexor carpi radialis , palmaris
longus and flexor digitorum superficialis )
 Anterior interosseous, 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
and central part of palm

35. Ulnar nerve
 Origin
 Course and relation
 Branches

36. Origin
• Ulnar nerve is the continuation of medial cord of
brachial plexus which arises from the anterior
Division of the lower Trunk.
• Root Value: C8 & T1

37. Course of UlnarNerve
• Course From Cord to Axilla.
• The Ulnar nerve runs between the Axillary artery
and vein in the axilla.

38. • Course from Axilla to Arm
 From the axilla it enters in the arm and stays
between the brachial artery and vein

39. • Course from Arm to Elbow
• The nerve runs inferior and posterior medial
aspect of humerus bone till it enters the
cubital tunnel.
• In the arm throughout the course the nerve
runs superficially gives medial cutaneous
n/v of arm and innervates no any muscle.

40. Cont’d
Course from Elbow to Forearm
• At the elbow the ulnar nerve lies in
Retrocondylar groove which is formed by
medial epicondyle humerus and olecranon
process of ulna.
• The ulnar nerve is trapped between the bone
and the overlying skin at this point.
It enters the forearm through the aponeurotic
arcade (Cubital Tunnel).

42. Ulnar Nerve In Forearm
• The ulnar nerve enters the anterior (flexor)
compartment of the forearm through the two
heads of flexor Carpi ulnaris and runs alongside
the ulna bone.
• There it innervates the Flexor Carpi Ulnaris
(FCU) muscle & medial half of Flexor Digitorum
Profundus III & IV (FDP) muscle.
• No further muscle is supplied by the ulnar nerve in
the medial forearm until it enters the wrist through
Guyon canal.

44. •

45. Course from forearm to wrist
•Dorsal Cutaneous Innervations of the Ulnar Nerve
•In the forearm it runs distally on the ulnar artery, and about
five to eight centimeters proximal to the wrist , the dorsal
ulnar cutaneous sensory branch exits to supply sensation to
the dorsal medial hand and the dorsal little finger as far
distally as the nail & the 4 digit.
•Palmar Cutaneous Innervations of the Ulnar Nerve
• At that level of the ulnar styloid the Palmer Cutaneous
sensory branch originates to supply sensation to the
proximal medial palm.

47. Dorsalcutaneousbranch

48. Palmarcutaneousbranch

49. At the wrist, the ulnar nerve and artery lie in a
canal formed by the pisiform bone medially and the
hook of hamate laterally (Guyon’scanal).
• In this region the nerve divides into two
superficial and deepbranches.
• TheSuperficial Branch
• TheDeepMotor Branch

51. • The superficial branch, sensory supply to
distal palm, fifth and half of the fourth
digit.
• Motor supply palmaris brevis.
• The deep branch gives off motor
innervation to the hand muscles. ..

52. Ulnar InnervatedMuscles
• Forearm:
• Flexor Carpi Ulnaris (C7, C8, T1)
• Flexor Digitorum Profundus III & IV (C7,
C8)
• Thenar:
• Hypothenar Muscles (C8, T1)
• Adductor Pollicis (C8, T1)
• Flexor Pollicis Brevis (C8, T1)
• Fingers:
• Palmer Interosseous (C8, T1)
• Dorsal Interosseous (C8, T1)
• III & IV Lumbricles (C8, T1)
• Digiti Minimi:
• Abductor Digiti Minimi (Quinti) (C8, T1)
• Opponens Dgiti Minimi (C8-T1)
• Flexor Digiti Minimi. : ( C8-T1)

53. Thank you