Brachial Plexus Block
Above the Clavicle
Edited by
Dr. M Dorgham
Under supervision of
Proff Dr. Amr Abdelfattah
Objectives
Review the Anatomy of brachial plexus
Neurostimulation guided approaches
Sonoanatomy and Ultrasound guidance
Complications
Advantages of ultrasound guidance
Anatomy of Brachial Plexus
•The brachial plexus is a network of nerve fibers , running from the spine,
formed by the ventral rami of the lower four cervical and first thoracic nerve
roots (C5-T1). It proceeds through the neck, the axilla (armpit region), and
into the arm.
•The brachial plexus is responsible for cutaneous and muscular innervation
of the entire upper limb, with two exceptions:
The trapezius muscle innervated by the spinal accessory nerve (CN XI)
and
An area of skin near the axilla innervated by the intercostobrachial
nerve.
Anatomy of Brachial Plexus
The brachial plexus is divided into
Roots
Trunks
Devisions
Cords
Branches
Anatomy of Brachial Plexus
Nerve
Roots
Muscles
Roots
Dorsal scapular
nerve
C5
Rhomboid
Levator scapulae
Roots
Long thoracic nerve
C5 C6 C7 Serratus anterior
Cutaneous
Anatomy of Brachial Plexus
Nerve
Roots
Upper
Trunk
Nerve to subclavius
C5 C6
Upper
Trunk
Suprascapular nerve C5 C6
Muscles
Subclavious
Supraspinatous
Infraspinatous
Cutaneous
Anatomy of Brachial Plexus
Nerve
Roots
Muscles
Cutaneous
Lateral
cord
Lateral pectoral
nerve
C5 C6 C7 Pectoralis Major
By
communication
with Medial
Pectoral Nerve
Lateral
cord
Musculocutaneous
nerve
C5 C6 C7 Coracobrachialis Become the
Brachialis
Lateral
cutaneous
Biceps brachii
nerve of
forearm
Lateral
cord
Lateral root of
median nerve
C5 C6 C7 Fibres of Median
nerve
Anatomy of Brachial Plexus
Nerve
Roots
Muscles
Cutaneous
Medial
cord
Medial pectoral Nr
C8 T1
Pectoralis major
Pectoralis minor
Medial
cord
Medial root of
median Nr.
C8 T1
Fibres to
median nerve
Medial
cord
Medial cutaneous
nerve of arm
C8 T1
front and medial
skin of the arm
Medial
cord
Medial cutaneous
nerve of forearm
C8 T1
medial skin of
the forearm
portions of hand
not served by
ulnar or radial
Anatomy of Brachial Plexus
Medial
cord
Ulnar Nr.
C8 T1
1. Flexor carpi
ulnaris
2. the medial
two bellies of
flexor
digitorum
profundus,
3. the intrinsic
hand muscles
except the
thenar muscles.
4. the two
most medial
lumbricals
the skin of the
medial side of
the hand
medial one and
a half fingers on
the palmar side
medial two and
a half fingers on
the dorsal side
Nerve
Roots
Muscles
Cutaneous
Post
cord
Upper subscapular
nerve
C5 C6
Sub scapilaris
(upper part)
Post
cord
Thoracodorsal Nr
(Middle subscapular)
C6 C7 C8
Latismus Dorsi
Post
cord
Lower scapular Nr
C5 C6
Subscapularis
(lower part)
Teres major
Post
cord
Axillary Nr.
C5 C6
Ant Br: Deltoid
& small area of
overlying skin
Post Br: Teres
minor &
Deltoid ms
Post Branch
continues as
upper Lateral
cutaneous Nr of
arm
Post
cord
Radial Nr.
C5 C6 C7
C8 T1
Triceps brachii
Supinator
Anconeus
Brachioradialis
Extensors of
forearm
Posterior
cutaneous
nerve of arm
INTERSCALENE BLOCK
ANTERIOR APPROACH
Superficial anatomy
Superficial anatomy
The sternal head of the sternocleidomastoid muscle (1) is anterior to its
clavicular head (2), which forms the anterior border
of the posterior triangle of the neck.
The accessory nerve (3) is superficial to the fascial floor of the posterior triangle
of the neck and originates close to the
lesser occipital nerve (4).
The superficial cervical plexus (5) is superficial to the fascial floor
of the posterior triangle of the neck and gives rise to the
supraclavicular nerves (6). The superficial cervical plexus originates
from C2 and supplies the ipsilateral skin of the neck, shoulder and occipital area
with sensory fibers.
The trapezius muscle (7) is innervated by the accessory nerve (3), and the
nerve to levator scapulae innervates the levator scapulae muscle (8).
Deep anatomy
Deeper anatomy
A view of the anatomy with the sternocleidomastoid muscle removed shows the position
of the
internal jugular vein (1) (cut off here). Deep to the internal jugular vein is the
thoracic duct (2) on the left side of the neck and adjacent to that the
Anterior scalene muscle (3). Posterior to that is the
middle scalene muscle (4) and more posterior,
the posterior scalene muscle (5). Posterior to the posterior scalene muscle is the
levator scapulae muscle (6) with the
nerve to the levator scapulae muscle (7).
The accessory nerve (8) as well as the
trapezius muscle (9) can be seen. Also note the
vagus nerve (10), which is situated in close relationship to the
carotid artery (11), and the
phrenic nerve (12), which is situated on the belly of the anterior scalene muscle (3). The
brachial plexus (13) is situated between the anterior and middle scalene muscles. The
suprascapular nerve (14) and the
dorsal scapular nerve (15) (which innervates the rhomboid muscles) branches from the
brachial plexus. Note that the
subclavian artery (16) lies anterior to the brachial plexus.
Surface anatomy
1 = Phrenic nerve
2 = Brachial plexus
3 = Dorsal scapular nerve (to rhomboid
muscles)
4 = Nerve to levator scapulae
POSTERIOR APPROACH (OR
CONTINUOUS CERVICAL PARAVERTEBRAL BLOCK)
The continuous cervical paravertebral block is ideal for relief of postoperative pain
following shoulder surgery, especially arthroscopic shoulder surgery.
This approach sometimes does not involve the nerves of the superficial cervical plexus
and the skin around the shoulder area will therefore not be anesthetized.
Although not yet evaluated by formal research, the experience of this author is that loss
of resistance to air as well as nerve stimulation may be used for the placement in this
block. If proven successful, this should make this block ideally suited for postoperative
use, and when severely painful conditions such as fractures of the shoulder are present
where nerve stimulation is not advisable or impractical.
Anatomy
The brachial plexus (1) is situated between the anterior (2) andmiddle (3) scalene
muscles, while the vertebral artery (4) is guarded by the bony structures of the
vertebrae.
The posterior approach for ISB is antero-lateral to the trapezius muscle (5) and
postero-medial to the levator scapulae muscle (6).
Anatomy
The point of needle entry is in the apex of the “V” formed by the
trapezius muscle posterior and the levator scapulae muscle anterior –
the “B”-spot
Surface anatomy
Needle entry should be at the level of C6 and just antero-lateral to the trapezius muscle
and postero-medial to the levator scapulae muscle in the apex of the “V” formed by
these two muscles.
Needle placement
The nerve stimulator is clipped to the needle and a loss-of-resistance to air device is
placed on the needle. The needle is directed , anteriorly and caudad, aiming for the
suprasternal notch.
The needle is carefully “walked off” the transverse process of C6 and loss of
resistance to air and muscle twitches of the shoulder girdle appear
simultaneously.
Ultrasound guided
Interscalene Brachial plexus block
The patient is in semi-sitting supine
position with the head facing away from the
side to be anesthetized.
The premedication of an adult, average
size patient typically consists of
2-4 mg of midazolam;
250mcg -500mcg of alfentanyl
administered just before insertion of the
needle
TIP: Visualization of the brachial plexus in
the interscalene grove can be challenging
in patients who are tense, moving or
exhibit guarding. Proper sedation can go a
long way toward obtaining quality images.
The ultrasound probe (10-12MHz) is
applied in the axial oblique plane
closer to the midline and angled to first
visualize the carotid artery
Note the position of the internal jugular vein (IJ) as the pressure on the
ultrasound probe is lightened. The internal jugular vein is positioned slightly
superficially and lateral to the carotid artery. Changing the pressure on the
probe causes the IJ to open and close.
The ultrasound probe is then moved slightly laterally to visualize the
brachial plexus in the interscalene grove between anterior and middle
scalene muscles.
The roots/trunks (N) of the brachial plexus are seen stacked between the
scalene muscles usually as round, hypoechoic structures
Sliding or angling the ultrasound probe slightly more inferior allows
visualization in the low-interscalene position in which the brachial plexus
is positioned in proximity to the subclavian artery
After the brachial plexus is identified
on the image, a 50 mm (max)
stimulating needle is inserted
perpendicular to the long axis of the
ultrasound probe. The needle is
inserted at the point on the probe that
corresponds to the location of the
brachial plexus on the screen
The needle insertion results in
shadowing of the ultrasound image
which indicates the path of the needle
TIP: Make sure to estimate the exact
depth of the brachial plexus (typically
0.5-1.5 cm) before inserting the
needle. The needle should never be
inserted deeper than the depth
indicated on the ultrasound image.
Injection of local anesthetic is made with monitoring of the dispersion of
the injectate. If the injectate does not appear to fill the lower
compartment of the interscalene space, the needle is slightly
advanced (0.5-1cm) and additional injection is made at a slightly
greater depth (0.5-1cm deeper).
Local anesthetic is injected slowly and with frequent aspirations, while
avoiding excessive injection pressures (<20 psi).
Thirty to forty ml of local anesthetic is more than adequate for
reliable blockade of the brachial plexus.
Typical indications for this block are surgery on the shoulder, lateral
clavicle, acromioclavicular joint, proximal humerus and elbow (with low
interscalene block).
Supraclavicular
Brachial Plexus Block
The trunks divide
behind
the clavicle into
anterior
and posterior
divisions,
which separate the
innervation of the
ventral and dorsal
halves of the upper
limb.
Classic Kulenkampff technique
In 1988 Brown described the plumb-bob technique
Ultrasound guided
Supraclavicular Brachial Plexus Block
POSITIONING
• The patient is placed supine
• The patient’s head is turned toward the
contralateral side
• The operator is positioned on the
ipsilateral side
• The ultrasound machine should be
placed on the contralateral side
SONOANATOMY.
The
subclavian
artery
appears hypoechoic and pulsatile
and the individual nerves
as
hypoechoic small circles.
It is very important to identify
the pleura while performing this
block so as to avoid pneumothorax.
The first rib acts as a backstop to
prevent pleural puncture, which
means that the needle tip is in the
same plane
the "chimney" effect as local anesthetic is forced to spread up between the
anterior and middle scalene muscles, unable to go down because the first rib is in the
way.
Pre injection
Post injection
•The major advantage of the supraclavicular approach is that the nerves
are very tightly packed, so that the onset is fast and the blockade deep,
leading to this technique being nicknamed “the spinal of the arm”.
•Ultrasound guidance, the pleura can be visualized, and as long as proper
technique is used, i.e. if the needle, and especially the needle tip, is
visualized at all times, pneumothorax should not occur.
•Typical Indication : For surgeries below the mid-humerus level.
It will not diffuse to the lower roots of the cervical
plexus, and thus will not block the upper aspect of
the shoulder.
•Twenty to Forty mls local anaesthetic is adequate for reliable block
Possible Complications
•Peripheral Nerve Injury
Most nerve injury presents as residual paresthesia, hand or forearm hypoesthesia,
and rarely as permanent Paresis
The overall incidence of long-term nerve injury ranges between 0.02% and 0.4%
•Vascular Injury
The risk of hematoma immediately after brachial plexus techniques is small (0.001 to
0.02%)
•Muscle Injury
Myonecrosis from local anesthetics at concentrations typically achieved at the site of
injection is well proven and characteristic of all local anesthetics, with bupivacaine
producing the most intense effect. Because damage is dose related, continuous
local anesthetic administration may worsen injury.
•Hemidiaphramatic Paresis
The proximity of the phrenic nerve to the interscalene groove frequently leads to
unintended local anesthetic block and resultant diaphragmatic dysfunction.
The incidence of hemidiaphragmatic paresis (HDP) is 50-100% after interscalene
brachial plexus block
•Pneumothorax
The reported incidence of pneumothorax after supraclavicular block is 0.5% to
6.1%
•Intravascular Injection
local anesthetic injected directly into the vertebral or carotid artery, or retrograde
flow of local anesthetic via the subclavian artery, may proceed directly to the
brain.
•Subarachnoid or Epidural Injection.
Interscalene brachial plexus block has been linked to unintended subarachnoid
block and to cervical or thoracic epidural block.
•Cervical Sympathetic Chain.
•Excessive local anesthetic spread can also affect the cervical sympathetic chain,
causing the patient to manifest Horner’s syndrome.
with20% to 90% incidence
•Recurrent Laryngeal Nerve.
•Hoarseness may transpire after interscalene block or after 1.3% of supraclavicular
blocks
Advantages of Ultrasound Guidance
Ultrasound guidance with real-time needle visualization in relation to anatomic
structures and target nerves makes regional anesthesia safer and more
successful.
With ultrasound guidance in experienced hands, brachial plexus blockade can
lead to
•Decreased block performance and onset time,
•Increased success rate and
•Decreased rate of complications.
These advantages result in increased operating room efficiency, as well as
increased patient satisfaction.
Thank You
The infraclavicular block is a
blockade of the brachial plexus
below the level of the clavicle and in
the proximity of the coracoid
process.
This block is uniquely well-suited for
hand, wrist, elbow, and distal arm
surgery. It also provides excellent
analgesia for an arm tourniquet.
As opposed to a supraclavicular
block, an infraclavicular block is
not a good choice for shoulder
surgery.
Anatomic structures of
importance. Pectoralis muscle
(shown cut to expose brachial
plexus)
clavicle (removed)
coracoid process
humerus
brachial plexus
subclavian/axillary artery and
vein
The boundaries of the infraclavicular fossa are the pectoralis minor and major
muscles anteriorly, ribs medially, clavicle and the coracoid process superiorly,
and humerus laterally. At this location, the brachial plexus is composed of
cords. The sheath surrounding the plexus is delicate. It contains the
subclavian/axillary artery and vein. Axillary and musculocutanous nerves
leave the sheath at or before the coracoid process in 50% of patients.
Consequently, the deltoid and biceps twitches should not be accepted as
reliable signs of brachial plexus identification.
The patient is in the supine position
with the head facing away from the
side to be blocked.
The anesthesiologist also stands
opposite to the side to be blocked to
assume an ergonomic position during
the block performance.
It is best to keep the arm abducted and
flexed in the elbow to keep the
relationship of the landmarks to the
brachial plexus constant.
Attention should be paid when the arm
is supported at the wrist to allow clear
unobstructed detection of the twitches
of the hand
Surface Landmarks
The following surface anatomy
landmarks are useful in
identifying the estimated site for
an infraclavicular block:
1.Sternoclavicular joint
2.Medial end of the clavicle
3.Coracoid process
4.Acromioclavicular joint
5.Head of the humerus
Anatomic Landmarks
Landmarks for the infraclavicular block
include:
1.Coracoid Process
2.Medial clavicular head
3.Midpoint of line connecting 1 and 2 and
3cm caudal
The needle insertion site is marked
approximately 3cm caudal to the
midpoint of the line connecting points 1
and 2.
TIP: Palpation of the bony prominence just medial to the shoulder,
while the arm is elevated and lowered, identifies the coracoid
process. As the arm is lowered, the coracoid process meets the
fingers of the palpating hand. This maneuver should be used to
identify the coracoid process in each patient planned for an
infraclavicular block
Needle insertion
A 10-cm long, 22-gauge
insulated needle, attached to a
nerve stimulator, is
Inserted at a 45-degree angle
to the skin and
Advanced parallel to the line
connecting
the
medial
clavicular head with the
coracoid process.
The nerve stimulator is initially set to deliver 1.5 mA. A local twitch of the
pectoralis muscle is typically elicited as the needle is advanced
beyond the subcutanous tissue. Once the pectoralis twitches disappear,
the needle advancement should be slow and methodical while looking
for the twitch of the brachial plexus
TIPS:
When the pectoralis twitch is absent despite appropriately deep needle
insertion, the landmarks should be checked as the needle is most likely
inserted too cranially (underneath the clavicle).
The bevel of the needle should be facing down to facilitate nerve stimulation
and reduce the risk of vascular puncture (subclavian or axillary artery and
vein).
Brachial plexus stimulation is typically obtained at a depth of 5 to 8 cm.
Twitches from the biceps or deltoid muscles should not be accepted,
since the musculocutaneous and axillary nerve, respectively, may depart
the brachial sheath before the caracoid process
Ultrasound guided
Infraclavicular Brachial Plexus Block