The document provides information about the anatomy of the brachial plexus. It begins with an introduction discussing the definition of a plexus and uses of peripheral nerve blocks. It then discusses the history and development of brachial plexus blocks. The majority of the document describes the anatomy of the brachial plexus in detail, including its formation, branches, relations, and variations. It also discusses brachial plexus injuries and techniques for performing brachial plexus nerve blocks.

1. ANATOMY OF BRACHIAL PLEXUS
PRESENTER – DR. SOURAV MONDAL
MODERATOR – DR. SUBHASH AGRAWAL (MD)
DEPT. OF ANAESTHESIOLOGY, SSMC, REWA , MP, INDIA

2. INTRODUCTION
• The word “PLEXUS” means a network of nerves
or vessels.
• Peripheral nerve blocks can be customized &
used for anaesthesia , post op analgesia and
diagnosis & treatment of chronic pain disorders.
• Blockade of the brachial plexus (C5-T1) at several
locations allows surgical anaesthesia of the upper
extremity and shoulder.

3. HISTORY
• 1884 – Carl Koller used cocaine in clinical practice.
• 1859 – 1922 – Karl Ludwig used infiltration
anaesthesia.
• 1880s – Halstead & Hall injected cocaine into
peripheral sites.
• 1912 – Kulen Kampff after experimenting on himself,
used supraclavicular technique.

4. • 1922 – Gaston Labott used axillary block.
• 1940 – MacIntosh and Mushin modified Kulen
Kampff block.
• 1964 – Alon P Winnie described perivascular
sheath and block.

5. ANATOMY OF BRACHIAL PLEXUS

6. ANATOMY

7. • The brachial plexus is an arrangement of nerve
fibres, running from the spine, formed by the
ventral rami of the lower cervical and upper
thoracic nerve roots.
• It includes C5-T1.
• Proceeds through the neck, the axilla and into the
arm.
• Responsible for cutaneous and muscular
innervation of the entire upper limb.

8. • The trunks pass laterally and lies around the
subclavian artery while passing over the first rib to
enter the axilla, between the clavicle and the
scapula.
• Behind the clavicle, each trunk splits into anterior
and posterior divisions. These recombine to form the
posterior , lateral and medial cords around the
axillary artery.
• The upper roots (C5–7) tend to stay lateral, the lower
roots (C8,T1) tend to stay medial and all roots
contribute to the posterior cord.

9. RELATIONS
• In the neck, the brachial plexus
lies in the posterior triangle,
being covered by the skin,
platysma & deep fascia; where it
is crossed by the supraclavicular
nerves, the inferior belly of the
Omohyoid, the external jugular
vein, and the transverse cervical
artery.
• When it emerges between the
Scaleni anterior and medius; its
upper part lies above the third
part of the subclavian artery,
while the trunk formed by the
union of the 8th cervical and 1st
thoracic, is placed behind the
artery.

10. • The plexus next passes
behind the clavicle, the
Subclavius, and the transverse
scapular vessels, and lies
upon the first digitation of the
Serratus anterior, and the
Subscapularis.
• In the axilla , it is placed
lateral to the 1st portion of
the axillary artery; it
surrounds the 2nd part of the
artery, one cord lying medial
to it, one lateral to it, and one
behind it; at the lower part of
the axilla it gives off its
terminal branches to the
upper limb.

11. FORMATION OF THE BRACHIAL
PLEXUS

12.  ROOTS
The ventral rami of spinal nerves C5 to T1 are referred
to as the roots of the plexus.
 TRUNKS
 The ventral rami of C5 & C6 unite to form the Upper
Trunk.
 The ventral ramus of C7 continues as the Middle Trunk.
 The ventral rami of C8 & T1 unite to form the Lower
Trunk.

13.  DIVISIONS
Each trunk splits into an anterior division and a posterior
division.
The anterior divisions usually supply flexor muscles
The posterior divisions usually supply extensor muscles.
 CORDS
The anterior divisions of the upper and middle trunks
unite to form the lateral cord.
The anterior division of the lower trunk forms the
medial cord.
All 3 posterior divisions from each of the 3 cords unite
to form the posterior cord.

14. From Nerve Roots Muscles Cutaneous
Roots
dorsal scapular
nerve
C5
rhomboid
muscles and
levator
scapulae
-
long thoracic
nerve
C5, C6, C7
serratus
anterior
-
Upper trunk
nerve to the
subclavius
C5, C6
subclavius
muscle
-
suprascapular
nerve
C5, C6
supraspinatus
and
infraspinatus
-
BRANCHES

15. Lateral Cord
lateral pectoral
nerve
C5, C6, C7
pectoralis
major (by
communicating
with the medial
pectoral nerve)
-
musculocutane
ous nerve
C5, C6, C7
coracobrachiali
s, brachialis and
biceps brachii
becomes the
lateral
cutaneous
nerve of the
forearm
lateral root of
the median
nerve
C5, C6, C7
fibres to the
median nerve
-

16. Posterior
Cord
upper
subscapular
nerve
C5, C6 subscapularis (upper part) -
thoracodorsal
nerve (middle
subscapular
nerve)
C6,
C7, C8
latissimus dorsi -
lower
subscapular
nerve
C5, C6
subscapularis (lower part )
and teres major
-

17. Axillary Nerve C5, C6
Anterior Branch:
Deltoid And A
Small Area Of
Overlying Skin
Posterior
Branch: Teres
Minor And
Deltoid Muscles
Posterior
Branch Becomes
Upper Lateral
Cutaneous
Nerve Of The
Arm
Radial Nerve
C5, C6, C7, C8,
T1
Triceps Brachii,
Supinator,
Anconeus, The
Extensor
Muscles Of The
Forearm, And
Brachioradialis
Skin Of The
Posterior Arm
As The Posterior
Cutaneous
Nerve Of The
Arm

18. Medial
cord
Medial
pectoral nerve
C8, T1
Pectoralis major and
pectoralis minor
-
Medial root of
the median
nerve
C8, T1
Fibres to the median
nerve
Portions of hand not
served by ulnar or radial
Medial
cutaneous
nerve of the
arm
C8, T1 -
Front and medial skin of
the arm

19. Medial
Cutaneous
Nerve Of
The
Forearm
C8, T1 -
Medial Skin Of The
Forearm
Ulnar
Nerve
C8, T1
Flexor Carpi Ulnaris,
The Medial 2 Bellies Of
Flexor Digitorum
Profundus, The Intrinsic
Hand Muscles Except
The Thenar Muscles
And The Two Most
Lateral Lumbricals
The skin of the
medial side of the
hand
medial one and a
half fingers on the
palmar side
and
medial two and a
half fingers on the
dorsal side

20. CUTANEOUS DISTRIBUTION

21. • The plexus may include anterior rami from C4 or
T2 and these are designated as
Pre fixed- C4 added
Post fixed- T2 added.
• The connective tissue sheath that invests the
plexus especially in the axillary region has a
convoluted and septated structure that can lead
to non uniform distribution of local anaesthetics .
ANATOMIC VARIATIONS

22. • The musculocutaneous nerve may fuse to or have
communications with the median nerve , which can
result in its absence from within the coracobrachialis
muscle.
• Communication between median and ulnar nerves is
common in the forearm with the median nerve
replacing the innervations to various muscles
normally supplied by the ulnar nerve.
• Variations with respect to vessels within the arm may
be present like double axillary veins , high origin of
radial artery and double brachial arteries.

23. • The interscalene groove may have variations in the
relationship between the plexus roots and trunks
and the muscles.
For eg.- the C5 or C6 roots may traverse through or
anterior to the anterior scalene muscles.
• In many specimens no inferior trunk exists , a single
cord or a pair of cords may develop. In some cases
no discrete posterior cord forms , with the posterior
divisions diverging to form terminal branches.

24. BRACHIAL PLEXUS INJURY

25. KLUMPKE’S PALSY
• Named after augusta déjerine-klumpke, it
is a variety of partial palsy of the lower
roots of the brachial plexus.
• Results from a brachial plexus injury in
which C8 and T1 nerves are injured .
• Affects, principally, the intrinsic muscles
of the hand and the flexors of the wrist
and fingers.
• The classic presentation of klumpke's
palsy is the “claw hand” where the
forearm is supinated and the wrist and
fingers are hyperextended with flexion at
interphalangeal and metatarso phalangeal
joints.

26. ERB’S PALSY
• Erb's palsy (Erb-Duchenne
Palsy) is a paralysis of the arm
caused by injury to the upper trunk
C5-C6.
• Signs of Erb's Palsy
 include loss of sensation in the arm
and paralysis and atrophy of the
deltoid, biceps, and brachialis
muscles.
 the arm hangs by the side and is
rotated medially; the forearm is
extended and pronated. commonly
called "waiter's tip hand."

27. BRACHIAL PLEXUS BLOCK

28. TECHNIQUES FOR LOCALIZING
NEURAL STRUCTURES
• PARESTHESIA TECHNIQUES
Reliant on patient cooperation & participation to
guide the local anaesthetic injection accurately
Only small doses of sedation medication are
recommended
Highly dependent on the skill of practitioner.
• ULTRASOUND GUIDED REGIONAL ANAESTHESIA
Allows visualization of the nerve target , the
approaching needle & the deposition of local
anaesthetic around the nerves

29. • PERIPHERAL NERVE STIMULATION
PNS transmit a small electric current to the end of
a stimulating needle, causing depolarisation &
muscle contraction when the needle is in close
proximity to a neural structure.
Allows patients to be more heavily sedated during
block placement.
It is necessary to attach cathode (-ve terminal) to
the stimulating needle & the anode (+ve terminal)
to the surface of the patient because

30. depolarisation occurs as the cathode allows
current to flow from the needle to the adjacent
nerve.
Current flows away from the needle causing
hyperpolarization if the terminals are reversed.
Most current stimulating electrodes are coated
with a thin layer of insulation along the needle
with exception of the tip as it allows for a more
discrete field of stimulation only at the tip of
needle.

31. Higher current output (>1.5 mA) is more likely to
stimulate neural structures through tissue or
fascial planes & can be associated with painful ,
vigorous muscle contractions.
After localization of the correct motor response,
the current is gradually decreased to a current of
0.5mA or less.
A motor response at a current of approximately
0.5mA is appropriate when used to facilitate the
location of the injection of local anaesthetic or
catheter placement.

32. PERIPHERAL NERVE STIMULATOR

33. Interscalene Block
Supraclavicular Block
Infraclavicular Block
Axillary Block
BRACHIAL PLEXUS BLOCK-
TECHNIQUES

34. INTERSCALENE BLOCK
• Described by Winnie in
1970.
• Blockade occurs at the
level of the superior and
middle trunks
• Blockade of inferior trunk
is incomplete & requires
supplementation.
• Indications-
 Surgery in shoulder ,upper
arm and forearm.
 Post op analgesia for total
shoulder arthroplasty

35. TECHNIQUES
PERIPHERAL NERVE STIMULATION OR
PARESTHESIA
 Positioning- supine position with the head turned
away from the side to be blocked.
 The posterior border of the sternocleidomastoid
muscle is palpated by having the patient briefly lift
the head.
 The interscalene groove can be palpated by rolling
the fingers posterolaterally from this border over the
belly of the anterior scalene muscle into the groove.

36.  A line extended laterally from the cricoid cartilage
and intersecting the interscalene groove indicates
the level of the transverse process of C6. The
external jugular vein often overlies this point of
intersection.
 Under sterile precautions and development of a skin
wheal, a 22- to 25-gauge, 4-cm needle is inserted
perpendicular to the skin at a 45-degree caudad and
slightly posterior angle. The needle is advanced until
paresthesia or nerve stimulator response is elicited.

37.  If bone is encountered within 2 cm of the skin, it is
likely to be a transverse process, and the needle may
be “walked” across this structure to locate the nerve
 After negative aspiration, 10 to 30 mL of solution is
injected incrementally, depending on the desired
extent of blockade.
 Contraction of the diaphragm indicates phrenic nerve
stimulation and anterior needle placement; the needle
should be redirected posteriorly to locate the brachial
plexus.

38. ULTRASOUND GUIDED
 A supraclavicular view of the subclavian artery &
brachial plexus is obtained & the plexus is traced up
the neck with the probe until the plexus trunks are
visualized as hypoechoic structures between
anterior and medial scalene muscles.
 The needle is then advanced either in an “out-of-
plane” or an “in-plane” approach.
 After –ve aspiration , local anaesthetic is infiltrated
into brachial plexus.
 Small volume is required.

40. COMPLICATIONS
 Inadvertent epidural or intrathecal block
 Ipsilateral diaphragmatic paresis
 Severe hypotension and bradycardia
 Nerve damage or neuritis
 Intravascular injection
 Horner’s syndrome with dyspnea and hoarseness of
voice.
 Pneumothorax.
 Hemothorax.
 Hematoma and Infection.

41. SUPRACLAVICULAR BLOCK
• Location- The three trunks
are clustered vertically over
the first rib
cephaloposterior to the
subclavian artery. The
neurovascular bundle lies
inferior to the clavicle at
about its midpoint.
• Blockade occurs at the distal
trunk–proximal division
level
• Indications
 operations on the elbow,
forearm, and hand.

42. PERIPHERAL NERVE STIMULATON OR
PARESTHESIA
 Positioning-in supine position with the head turned away
from the side to be blocked.The arm to be anesthetized is
adducted, and the hand should be extended along the side
toward the ipsilateral knee as far as possible.
 In the classic technique, the midpoint of the clavicle is
identified . The posterior border of the sternocleidomastoid is
felt. The palpating fingers can then roll over the belly of the
anterior scalene muscle into the interscalene groove, where a
mark should be made approximately 1.5 to 2.0 cm posterior
to the midpoint of the clavicle. Palpation of the subclavian
artery at this site confirms the landmark.
TECHNIQUES

43.  After appropriate preparation and development of a skin
wheal, the anesthesiologist stands at the side of the patient
facing the patient's head.
 A 22-gauge, 4-cm needle is directed in a caudad, slightly
medial, and posterior direction until a paresthesia or motor
response is elicited or the first rib is encountered.
 If the first rib is encountered without elicitation of a
paresthesia, the needle can be systematically walked
anteriorly and posteriorly along the rib until the plexus or
the subclavian artery is located .

44.  The needle can be withdrawn and reinserted in a
more posterolateral direction, which generally results
in a paresthesia or motor response.
 On localization of the brachial plexus, aspiration for
blood should be performed before incremental
injections of a total volume of 20 to 30 mL of
solution.

45. ULTRASOUND GUIDED
• Allows the practitioner
to see the brachial
plexus structures , as
well as the subclavian
artery and pleura, just
below the 1st rib.
• Has more inherent
safety features.

46. COMPLICATIONS
Pneumothorax
Phrenic nerve block (40% to 60%)
Horner's syndrome
Neuropathy.

47. INFRACLAVICULAR BLOCK
• Landmarks: The boundaries of
the infraclavicular fossa are :
pectoralis minor and major
muscles anteriorly,
ribs medially ,
clavicle and the coracoid
process superiorly, &
 humerus laterally.
• Blockade occurs at the level of
the cords.
• Indications- Hand, wrist,
elbow and distal arm surgery

48. PERIPHERAL NERVE STIMULATION OR
PARESTHESIA
Classic approach
• The needle is inserted 2 cm below the midpoint of
the inferior clavicular border & advanced laterally,
using a nerve stimulator to identify the plexus.
• An incremental injection of 20- 30 ml of solution
,after -ve aspiration, is sufficient.
Coracoid technique
• consists of insertion of the needle 2 cm medial and
2 cm caudal to the coracoid process, has also been
described
TECHNIQUES

49. ULTRASOUND GUIDED
Frequently used to
visualize the
neurovascular bundle
& ideally , local
anaesthetic spread
should be visualized
around the axillary
artery.

50. COMPLICATIONS
Inadvertent intravascular injection
Pneumothorax

51. AXILLARY APPROACH
• Blockade occurs at the level
of the terminal nerves.
• Blockade of the
musculocutaneous nerve is
not always produced with
this approach.
• Indications –
 Surgery on the forearm
and hand.
 Elbow procedures are also
successfully performed
with the axillary approach.

52. • Landmarks-
The axillary artery is the most important landmark;
the nerves maintain a predictable orientation to the
artery.
 The median nerve is found superior to the artery,
the ulnar nerve is inferior, and the radial nerve is
posterior and somewhat lateral
 At this level, the musculocutaneous nerve has
already left the sheath and lies in the substance of
the coracobrachialis muscle.
The intercostobrachial artery , is usually blocked by
the skin wheal overlying the artery.

53. TECHNIQUES
PERIPHERAL NERVE STIMULATION OR PARESTHESIA
• Positioning- The patient should be in the supine position
with the arm to be blocked placed at a right angle to the body
and the elbow flexed to 90 degrees , the dorsum of the hand
rests on the bed or pillow.
• The axillary artery is then palpated as far as proximaly as
possible , fixed against the humerus by the index & middle
fingers of the left hand , & a skin wheal is raised directly over
the artery at a point in the axilla approximating the skin
crease
• A transarterial technique is used whereby the needle pierces
the artery and 40 to 50 mL of solution is injected posterior to
the artery. Alternatively, half of the solution can be injected
posterior and half injected anterior to the artery.

54. • Classically, upon completion of the injection ,the arm
should be adducted & returned to the patient’s side
to prevent the humeral head from obstructing
proximal flow of the local anaesthetic solution
• However , maintaining the arm in abduction
decreases onset time & prolongs both sensory &
motor block

55. ULTRASOUND GUIDED
• Ultrasound guidance
with visualization of
local anaesthetic spread
around the 4 nerves
decreases block onset
time & can reduce the
number of needle
redirections.
• Only small volume is
needed.

56. COMPLICATIONS
• Nerve injury
• Systemic toxicity
• Neuropathies
• Inadvertent intravascular injections

57. CONTINUOUS CATHETER TECHNIQUES
• First described during 1940s.
• Offer ingenious solutions for the placing & securing
of the needle & the catheter.
• Especially applicable in patients with –
Upper extremity or digit replantation
Total shoulder or elbow arthroplasty
Reflex sympathetic dystrophies

58. • ADVANTAGES
Prolongation of surgical anaesthesia
Decreased risk of toxicity (lower incremental
doses)
Post op analgesia
Sympathectomy

59. • DISADVANTAGES
Catheter kinking
Displacement
Leakage
Bacterial colonization

60. CHOICE OF LOCAL ANAESTHETIC
• Prolonged blockade for up to 24 hrs often
occurs with long-lasting LA . They results in
superb post-op pain relief but may be
undesirable for the ambulatory pt because of
risk of nerve & tissue injury in partially
blocked limb .
• A short or medium acting LA is more
appropriate in outpatient settings.

61. • Vasoconstrictors, usually epinephrine, can be
added to the chosen local anesthetic to
improve onset of action, to decrease drug
uptake, and to prolong action.

62. COMMONLY USED LA IN MAJOR NERVE BLOCK