The brachial plexus is formed by the ventral rami of cervical and thoracic spinal nerves C5-T1. It provides motor and sensory innervation to the upper limb. It forms trunks, divisions, and cords which branch into individual nerves that innervate specific muscles and skin areas. Anatomical variations are common and can impact techniques for brachial plexus blockade, which is used for surgeries on the shoulder, arm, elbow, and forearm. Injuries to different parts of the plexus can cause distinct nerve palsies like Erb's palsy or Klumpke's paralysis.

1. Dr. Ananya

2.  Anatomy
 Origin of brachial plexus
 Formation of brachial plexus
 Distribution of nerves
 Anatomical variations
 Anesthetic implications- brachial plexus
block

3. 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 –
from above the fifth cervical vertebra to underneath the
first thoracic vertebra(C5-T1).
It proceeds through the neck, the axilla and into the arm.
The brachial plexus is responsible for cutaneous and
muscular innervation of the entire upper limb.

4.  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, and therefore also to
the radial nerve.

5.  In the neck, the brachial plexus lies in the posterior
triangle, being covered by the skin, Platysma, and deep
fascia;where it is crossed by the supraclavicular
nerves, the inferior belly of the Omohyoideus, 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 eighth cervical and first thoracic is placed behind
the artery.

6.  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 first portion of
the axillary artery; it surrounds the second 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.

10.  FORMATION OF THE BRACHIAL PLEXUS
 Roots
 The ventral rami of spinal nerves C5 to T1 are referred to as
the roots of the plexus.
 Trunks
 Shortly after emerging from the intervertebral foramina
, these 5 roots unite to form three trunks.
–The ventral rami of C5 & C6 unite to form the Upper Trunk.
–The ventral ramus of C 7 continues as the Middle Trunk.
–The ventral rami of C 8 & T 1 unite to form the Lower
Trunk.

11.  •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.
 –The cords are named according to their position relative to
the axillary artery

12.  III. BRANCHES :Nerves that are branches from portions
of the brachial plexus usually contain only 1 type of
axon.
 From the Roots
 Dorsal Scapular nerve
Derived from C5 root
Motor nerve to the Rhomboideus major and minor
muscles
 Long Thoracic nerve
Derived from C 5,6,7
Innervates the serratus anterior muscle

13.  From the Upper Trunk
 Nerve to subclavius muscle
 Suprascapular nerve
Innervates supra and infraspinatus muscles
 From the Lateral Cord
 Lateral Pectoral nerve
Innervates the clavicular head of the pectoralis major
muscle
 From the Medial Cord
 Medial Pectoral nerve
Innervates the sternocostal head of the pectoralis
major muscle
Innervates the pectoralis minor muscle

17. From Nerve Roots Muscles Cutaneous
rhomboid
dorsal
muscles and
Roots scapular C5 -
levator
nerve
scapulae
long thoracic serratus
Roots C5, C6, C7 -
nerve anterior
nerve to the subclavius
Upper trunk C5, C6 -
subclavius muscle
supraspinatu
suprascapula
Upper trunk C5, C6 s and -
r nerve
infraspinatus

18. pectoralis
major (by
lateral communicati
Lateral Cord pectoral C5, C6, C7 ng with the -
nerve medial
pectoral
nerve)
coracobrachi becomes the
alis, lateral
musculocuta
Lateral Cord C5, C6, C7 brachialis cutaneous
neous nerve
and biceps nerve of the
brachii forearm
lateral root
fibres to the
Lateral Cord of the C5, C6, C7 -
median nerve
median nerve

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

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

21. Medial
Medial Pectoralis major and
pectoral C8, t1 -
cord pectoralis minor
nerve
Medial root Portions of hand not
Medial Fibres to the median
of the C8, t1 served by ulnar or
cord nerve
median nerve radial
Medial
Medial cutaneous Front and medial skin
C8, t1 -
cord nerve of the of the arm
arm

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

23.  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 .

24.  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.

25.  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.

26. Brachial
plexus
injury

27.  Named after augusta déjerine-klumpke,
 klumpke's paralysis 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.

28.  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."

29.  Erb’s Palsy – Nerves Affected

30.  BRACHIAL PLEXUS BLOCK-
 Techniques-
 Interscalene Brachial Plexus Block
 Supraclavicular(Subclavian)Brachial Plexus Block
 Infraclavicular Brachial Plexus Block
 Axillary Brachial Plexus Block

31.  Described by winnie in 1970.
 Indications-
 Surgery in shoulder ,upper arm and forearm.
 Post operative analgesia for total shoulder arthroplasty
 Blockade occurs at the level of the upper and middle
trunks.

33.  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.
 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.

35.  TECHNIQUE-
 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 is elicited.
 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.

36. After negative aspiration, 10 to 40 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.

37.  Complications
 Ipsilateral diaphragmatic paresis
 Severe hypotension and bradycardia (i.e., the Bezold-
Jarisch reflex)
 Inadvertent epidural or spinal block
 Nerve damage or neuritis
 intravascular injection with Seizure activity
 Horner’s syndrome with dyspnea and hoarseness of
voice.
 Puncture of the pleura may cause Pneumothorax.
 Hemothorax.
 Hematoma and Infection.

38.  Indications
 operations on the elbow, forearm, and hand. Blockade
occurs at the distal trunk–proximal division level.
 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.

41.  Technique-
 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.

42.  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 is elicited
or the first rib is encountered.
 If a syringe is attached, this orientation causes the needle
shaft and syringe to lie almost parallel to a line joining the
skin entry site and the patient's ear.
 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 .

43. Location of the artery provides a useful landmark; 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.
 Complications
 Pneumothorax
 phrenic nerve block (40% to 60%),
 Horner's syndrome and
 neuropathy.

44.  Indications- Hand, wrist, elbow and distal arm surgery
 Blockade occurs at the level of the cords of the
musculocutaneous and axillary nerves.
 Anatomical landmarks: The boundaries of the infraclavicular
fossa are
 pectoralis minor and major muscles anteriorly,
 ribs medially ,
 clavicle and the coracoid process superiorly,
 and humerus laterally.

45.  Technique-
 Classic approach
 The needle is inserted 2 cm below the midpoint of the
inferior clavicular border, advanced laterally and
directed toward the axillary artery
A coracoid technique consisting of insertion of the
needle 2 cm medial and 2 cm caudal to the coracoid
process has also been described

48.  Indications –
 include surgery on the forearm and hand. Elbow
procedures are also successfully performed with the
axillary approach.
 Blockade occurs at the level of the terminal nerves.
blockade of the musculocutaneous nerve is not always
produced with this approach.

50.  Landmark-
 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.

51.  Technique-
 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.
 A transarterial technique can be 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.
 Field block of the brachial plexus with a fanlike
injection of 10 to 15 mL of local anesthetic solution on
each side of the artery is a variation of the sheath
technique.

52.  Complications-
 Nerve injury and systemic toxicity
 intravascular injection
 Hematoma and infection are rare complications.

53.  Miller s anesthesia- 7th edition
 Barash s –textbook of clinical anesthesia
 Atlas of human anatomy- mac millans
 Chaurasia- textbook of human anatomy
 Internet references

54. THANK
YOU

55.  Some mnemonics for remembering the branches:
 Posterior Cord Branches
◦ STAR - Subscapular (upper and lower), Thoracodorsal,
Axillary, Radial
◦ ULTRA - Upper subscapular, Lower subscapular,
Thoracodorsal, Radial, Axillary
 Lateral Cord Branches
◦ LLM "Lucy Loves Me" - Lateral pectoral, Lateral root of
the median nerve, Musculocutaneous
 Medial Cord Branches
◦ MMMUM "Most Medical Men Use Morphine" - Medial
pectoral, Medial cutaneous nerve of arm, Medial
cutaneous nerve of forearm, Ulnar, Medial root of the
median nerve