ANATOMY OF BRACHIAL
PLEXUS
Dr.Shyam Sunder Reddy

Parts of Brachial Plexus
• R = ROOTS (ventral
rami)
• T = TRUNKS
• D = DIVISIONS
• C = CORDS
• B = BRANCHES
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ANATOMY

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 innervations of the entire
upper limb.
ANATOMY

• 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.

• 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.
RELATIONS

• the plexus next passes behind the clavicle, the
Subclavius, and the transverse scapular vessels,
and lies upon the first digitations 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.

FORMATION OF THE BRACHIAL PLEXUS

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 rami of C 7 continues as the Middle Trunk.
–The ventral rami of C 8 & T 1 unite to form the Lower
Trunk.

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

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

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

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

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

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

Posterior
Cord
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
Posterior
Cord
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
POSTERIOR CORD BRANCHES

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

Medial
Cord
Medial
Cutaneous
Nerve Of
The
Forearm
C8, T1 -
Medial Skin Of The
Forearm
Medial
Cord
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
MEDIAL CORD BRANCHES

Brachial
plexus
injury

• 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.
Klumpke s palsy

Lower Lesions of the Brachial Plexus
(Klumpke Palsy)
➢ traction injuries by excessive abduction
of the arm
➢ i.e. occurs if person falling from a height
clutching at an object to save himself or
herself.
➢ Can be caused by cervical rib.
➢ T1 is usually torn (ulnar and median
nerves)

Motor Effects: paralysis of all the
small muscles of the hand.
Sensory effects: loss of sensation
along the medial side of the
arm.
deformity: claw hand caused by
hyperextension of the
metacarpophalangeal joints and
flexion of the interphalangeal
joints.

Klumpke’s paralysis-
Site of injury
Cause of injury
Nerve roots involved
Muscles paralysed
Deformity
Disability

CLAW HAND

• 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."
Erb’s palsy

⦿ Upper Lesions of the Brachial
Plexus (Erb’s Palsy): resulting
from excessive displacement of the
head to opposite side and depression
of shoulder on the same side.
Brachial Plexus Injuries

⦿ This causes excessive traction or
even tearing of C5 and 6 roots of the
plexus. It occurs in infants during a
difficult delivery or in adults after a
blow to or fall on shoulder.

⦿ Effects:
Motor: paralysis of
➢ the supraspinatus,
➢ infraspinatus,
➢ subclavius,
➢ biceps brachii,
➢ part of brachialis,
➢ coracobrachialis;
➢ deltoid
➢ teres minor.
Sensroy: sensory loss on the lateral side of
the arm.

⦿ Deformity:
➢ waiter tip postion
a. limb will hang by the side,
b. medially rotated by sternocostal
part of the pectoralis major;
c. pronated forearm (biceps
paralysis)

ERB’S PARALYSIS
• Erb’s point
• Causes
• Nerve roots involved
• Muscles Paralysed
• Deformity
• Disability

Erb-Duchenne palsy (waiter's
tip)

LEFT SIDE PARALYSIS

• Erb’s Palsy – Nerves Affected

Causes:
➢ crutch pressing upward into the
armpit,
➢ Downward shoulder dislocations
➢ fractures of the surgical neck of the
humerus.
Axillary Nerve injury

• Motor effects:
➢Deltoid paralysis
➢teres minor paralysis.
• Sensory effects:
➢loss of sensation at lower ½ of deltoid
• Deformity:
➢Wasting of deltoid

AXILLARY NERVE
• Causes
➢crutch pressing upward into
the armpit,
➢Downward shoulder
dislocations
➢fractures of the surgical neck
of the humerus.
• Motor effects:
• Sensory effects:
• Deformity:

Injury in axilla :
⦿ crutch pressing up into armpit
⦿ drunkard falling asleep with one arm
over the back of a chair.
⦿ fractures of proximal humerus.
Radial Nerve injury

• Motor effects:paralysis of
➢ triceps
➢ Anconeus
➢ extensors of the wrist
➢ Extensors of fingers.
➢ Brachioradialis
➢ supinator muscle
• Deformity: Wrist and finger drop

RADIAL NERVE
Cause-
Site of injury-
Muscles paralysed-
Deformity
Disability

•Sensory effects :
➢small area of sensation loss at
arm and forearm
➢sensory loss over lateral part of
the dorsum of the hand (lat. 3.5
fingers without distal phalanges)

Injuries at Spiral Groove
➢Caused by fracture shaft of humerus.
• Motor effects: paralysis of
➢extensors of the wrist
➢Extensors of fingers

• Deformity:
➢Wrist and finger drop
• Sensory effects:
➢anesthesia is present over the
dorsal surface of the hand (lat. 3.5
fingers)

⦿Motor effects: paralysis of
➢ pronator muscles
➢ long flexor muscles of the wrist
and fingers,
➢ Exception:
a. flexor carpi ulnaris
b. medial half flexor digitorum profundus.
Median Nerve injury

Deformity:
⦿ apelike hand
1. thenar muscles wasted
2. thumb is laterally rotated and
adducted.
3. index and to a lesser extent the
middle fingers tend to remain
straight on making
4. Weakening of lat. 2 fingers

Sensory
⦿ Sensory loss on the lat. 3.5 fingers on
palmar side
⦿ Sensory loss over distal phalynges of
lat. 4 fingers on dorsal surface

MEDIAN NERVE –
Cause-
Site of injury-
Muscles paralysed-
Deformity
Disability
RIGHT SIDE

ULNAR NERVE
Causes-
Axilla- crutch pressure
Arm- # of shaft of humerus
Elbow- # of medial epicondyle
Forearm- penetrating injuries
Wrist- cut and stab wounds
Muscles paralysed-
Deformity
Disability

• Motor effects: paralysis of
➢ flexor carpi ulnaris
➢medial half of the flexor digitorum
profundus
➢All interossei
➢3-4 lumbricals
• loss of abduction and adduction of fingers
• Wasting of hypothenar
Ulnar nerve injury

•Deformity:
➢partial claw hand
•Sensory effects :
➢Sensory loss over 1.5 fingers
on both surfaces

LONG THORACIC NERVE
Causes - carrying Heavy load on
shoulder
Sudden pressure on shoulder
from above
Deformity – Winging of scapula
Overhead abduction not possible

• TUNNEL FORMED BETWEEN THE CONCAVITY OF THE
CARPAL BONES AND A LIGAMENT THAT COVERS THIS(
FLEXOR RETINACULAM)
• TENDONS OF THE FLEXORS PASS THROUGH
• MEDIAN NERVE ALSO PASSES THROUGH
• CROWDED TUNNEL
CARPAL TUNNEL SYNDROME
- CAUSED DUE TO COMPRESSION OF THE NERVE IN THE
TUNNEL
- CAUSES-
- 1. SWELLING OF THE TEDONS( OVERUSE)
- 2. PREGNANCY( EDEMA) 3. ARTHRITIS
SYMPTOMS- TINGLING OR NUMBNESS-LATERAL PART OF
HAND, WEAKNESS IN THUMB MOVEMENT
TREATMENT- REST, SPLINTING,ANTI-INFLAMMATORY
DRUGS, SURGERY.
CARPAL TUNNEL

• Relies mainly on clinical examination
• No specific lab. Studies
• CT myelography
• MRI
• Nerve conduction studies
Diagnosis