Brachial plexus - Made so Easy

Brachial plexus is one of the tough topic to remember by anyone undergoing MBBS course. This slide gives you in detail about the Origin / Course / Formation / Distribution / Anatomical variations & Applied anatomy & Made so easy to Remember & Draw as well.

1. BRACHIAL PLEXUS
Prof.Dr. U.Murali.M.S;MBA
Dept.Of Surgery
D Y Patil Medical College
Mauritius.

2. Contents of Discussion
Spinal Nerves
Nerve Plexus
BP – Origin & Relations
Formation
Parts of BP
Distribution - Nerve Supply – areas
Anatomical Variations
Applied Anatomy

3. Spinal Nerves
Spinal nerves attach to the
spinal cord via roots
Dorsal root
Has only sensory neurons
Attached to cord via rootlets
Dorsal root ganglion
Ventral root
Has only motor neurons
No ganglion - all cell bodies
of motor neurons found in
gray matter of spinal cord

4. Spinal Nerves
31 pair
each contains thousands of nerve fibers
All are mixed nerves have both sensory and motor
neurons
Connect to the spinal cord
Exit from SC – Supplying the muscles & structures
of the body

5. 8 pairs of cervical nerves from
C1 to C8
12 pairs of thoracic nerves
from T1-T12
5 pairs of lumbar nerves from
L1 to L5
5 pairs of sacral nerves from
S1 to S5
1 pair of coccygeal nerves
located at C zero (Co)
Spinal Nerves

6. 12-6
Formation of Rami
Rami are lateral branches of a
spinal nerve
Rami contain both sensory and
motor neurons
Two major groups
Dorsal ramus
Neurons innervate the
dorsal regions of the
body
Ventral ramus
Larger
Neurons innervate the
ventral regions of the
body
Braid together to form
plexuses (plexi)

7. 12-7
Nerve Plexuses
Nerve plexus
A nerve plexus is nothing more than a
system or network of connected nerve
fibers that link spinal nerves with specific
areas of the body . A network of ventral
rami.
Ventral rami (except T
2
-T
12
)
Branch and join with one another
Form nerve plexuses
In cervical, brachial, lumbar, and sacral regions
No plexus formed in thoracic region of s.c.

8. 12-8
Branches
of
Spinal
Nerves
Dorsal Ramus
Neurons within muscles of trunk and back
Ventral Ramus (VR)
Braid together to form plexuses
Cervical plexus - VR of C1-C4
Brachial plexus - VR of C5-T1
Lumbar plexus - VR of L1-L4
Sacral plexus - VR of L4-S4
Coccygeal plexus -VR of S4&S5
Communicating Rami: communicate
with sympathetic chain of ganglia
Covered in ANS unit

9. 12-9
Brachial Plexus - Origin
Formed by ventral rami of spinal
nerves C5-T1
Five ventral rami form
Roots / Trunks that separate into
Divisions that then form
Cords that give rise to Branches
Major nerves
Axillary
Radial
Musculocutaneous
Ulnar
Median

10. Brachial Plexus
15 cms long ,spinal column to
axilla.
Brachial plexus is responsible for
cutaneous (sensory) and
muscular (motor) innervation of
the entire upper limb & pectoral
girdle.
It proceeds through the neck, the
axilla and into the arm.

12. 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 Omohyoid,
the external jugular vein, and the
transverse cervical artery.
Relations - BP

13. Relations - BP
When it emerges
between the Scalene
anterior and medius
--* its upper part lies
above the third part of
the subclavian artery,
* while the trunk
formed by the union of
C8 & T1 is placed
behind the artery.

14. 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.
Relations - BP

15. Relations
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.

16. FORMATION OF THE BRACHIAL
PLEXUS

17. PUT IT ALL TOGETHER…...

18. ROOTS
Originates froms C5-C8 and most of T1
Receives gray rami communicates from the
symphathetic trunk.
Carry postganglionic symphathetic fibers
onto root for distribution of periphery.
Root and trunk enter posterior triangle of
neck by passing between anterior scalene
and middle scalene muscles and lies
between superior and posterior to subclavian
artery.

19. TRUNKS
C5,C6 roots pass down wards between
Scalenus medius and Scalenus anterior
muscles and unite to form SUPERIOR
TRUNK
C7 root pass between Scalenus muscles and
at laeral border of scalenus anterior emreges
as MIDDLE TRUNK
C8, T1 roots unite behind a fascial sheet
(sibson”s fascia) and beneath the subclavian
artery form LOWER TRUNK

20. DIVISION
Lateral to the 1
st
rib , where three trunks are
located behind the axillary artery ,they separate
into 3 anterior and 3 posterior divisions
The 3 anterior division form parts of brachial
plexus that ultimately give rise to peripheral
nerves associated with the anterior compartment
of arm or forearm.
The 3 posterior division combine to form parts of
the brachial plexus that give rise to nerves
associated with the posterior compartments.

21. CORDS
3 posterior divisions unite to form
posterior cord
Anterior divisions of upper and ,middle
trunks (C5-C7) unite to form lateral cord
Anterior division of lower trunk forms
medial cord(C8-T1)
Cords – named after their relation with AA
& passes through the thoracic outlet and
give off major branches

22. BRANCHES - Roots
From the Roots
Dorsal Scapular nerve
Derived from C5 root
Motor nerve to the
Rhomboideus major and
minor muscles

23. Roots
Long Thoracic nerve
Derived from C 5,6,7
Innervates the serratus
anterior muscle

24. BRANCHES OF UPPER
TRUNK
NERVE TO SUBCLAVIUS
Root value – C5,C6
SUPRASCAPULAR
NERVE
Root value – C5,C6

25. Branches – LC & MC
MEDIAL PECTORAL NERVE
Root value- C8,T1
LATERAL PECTORAL NERVE
Root value- C5,C6,C7

26. Lateral Cord
Direct branches:
Lateral pectoral nerve: C5-7
To clavicular head of pectoralis
major muscle
Terminal nerves:
Musculocutaneous: C5-7
Lateral root of median
nerve: C5-7

28. Medial Cord: Direct Branches
Medial pectoral nerve:
C8-T1
To sternal head of pectoralis
major muscle and pectoralis
minor muscle.
Medial cutaneous nerve to
arm
Medial cutaneous nerve to
forearm

29. MEDIAL
CUTANEOUS
NERVE OF
ARM
Root value- C8,T1
MEDIAL
CUTANEOUS
NERVE OF
FOREARM
Root value – C8,T1

30. Medial Cord: Terminal Nerves
Ulnar C8-T1
Medial root of
median nerve C8-T1

31. ULNAR NERVE

32. Posterior Cord Direct Branches
Upper subscapular nerve
C5-6
To subscapularis muscle
Thoracodorsal nerve:
C6-7
To latissimus dorsi muscle
Lower subscapular nerve:
C5-6
To subscapularis and
teres major muscles

33. UPPER
SUBSCAPULAR
Root value-C5,C6
LOWER
SUBSCAPULAR
Root value- C5,C6
NERVE TO
LATISSIMUS DORSI
Root value-C6,C7,C8

34. Posterior Cord Terminal Nerves
Axillary nerve: C5-6
Motor: To deltoid and teres
minor muscles.
Sensory: Skin on arm over
deltoid muscle:

35. AXILLARY NERVE

36. Posterior Cord Terminal Nerves
Radial nerve: C5-T1

Motor:
Posterior compartments of
arm and forearm.
Brachioradialis muscle
Sensory:
Back of arm, forearm, hand

37. RADIAL NERVE

39. Cutaneous distribution

40. Anatomic Variations
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 .

41. 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.

42. 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.

43. APPLIED ANATOMY

44. Brachial Plexus Injury
Obstetric palsy - Injury to all or portion of a child
brachial plexus occurring at that time of the
delivery.
Excessive lateral traction on the head so that the
head is pulled away from the shoulder.
Divide into :
Erb’s Duchenne Palsy
Klumpkee’s Palsy

47. Erb’sparalysis
•C5 -C6
•Birth injury / Trauma
•Arm hangs by the side
+ Rotate medially
•Forearm pronated +
extended
•Flexed wrist + fingers
•Deltoid/supraspinatus/
infraspinatus/biceps/
brachialis
. LOS – in arm

48. Erb’s Palsy – Nerves Affected

49. LEFT SIDE PARALYSIS

50. Klumpke’sparalysis
•C8 –T1
•Traction injuries / Fall
* Intrinsic muscles of the hand +
long flexors of the wrist & hand
paralysed
• Claw hand = extension at MPJ +
flexion at IPJ ( wrist & hand )
* Forearm – supinated
* LOS – medial side - am
•Cervical rib can cause paralysis
similar to Klumpke’sparalysis with
post-fixed T2 contribution

51. BRACHIAL PLEXUS BLOCK
Supraclavicular approach Axillary approach

52. Begin with a letter “Y”, an “I” and a “Y”.

53. Add a “strike” and a “spare”

54. Draw “arches”.

55. Draw horizontal lines to separate the parts.
Roots
Trunks
Divisions
Cords
Branches

56. Roots
Trunks
Divisions
Cords
Branches
Begin labeling.
C5 C6 C7 C8 T1
Upper Middle Lower
MusculocutaneousAxillary Median RadialUlnar
L
a
t
e
r
a
l
P
o
s
t
e
r
i
o
r
M
e
d
i
a
l SLOW

57. Add details . . .
Branches off the posterior cord spell “ULTRA”
Axillary Radial
C5 C6 C7 C8 T1
Roots
Trunks
Divisions
Cords
Branches
Upper Middle Lower
Musculocutaneous
Median Ulnar
L
a
t
e
r
a
l
P
o
s
t
e
r
i
o
r
M
e
d
i
a
l
Upper subscapular
Lower subscapular
Thoracodorsal
SLOW
SLOW

58. “3M” comes off the medial cord.
Axillary Radial
Roots
Trunks
Divisions
Cords
Branches
C5 C6 C7 C8 T1
Upper Middle Lower
Musculocutaneous Median Ulnar
L
a
t
e
r
a
l
P
o
s
t
e
r
i
o
r
M
e
d
i
a
l
Upper subscapular
Lower subscapular
Thoracodorsal
Medial pectoral n.
Medial cutan. n. of arm
Medial cutan. n. forearm
SLOW
SLOW

59. The lateral pectoral n. comes off the lateral cord.
Axillary Radial
Roots
Trunks
Divisions
Cords
Branches
C5 C6 C7 C8 T1
Upper Middle Lower
Musculocutaneous Median Ulnar
L
a
t
e
r
a
l
P
o
s
t
e
r
i
o
r
M
e
d
i
a
l
Upper subscapular
Lower subscapular
Thoracodorsal
Medial pectoral n.
Medial cutan. n. of arm
Medial cutan. n. forearm
Lateral pectoral n.

60. There are 4 supraclavicular branches.
Axillary Radial
Roots
Trunks
Divisions
Cords
Branches
C5 C6 C7 C8 T1
Upper Middle Lower
Musculocutaneous Median Ulnar
L
a
t
e
r
a
l
P
o
s
t
e
r
i
o
r
M
e
d
i
a
l
Upper subscapular
Lower subscapular
Thoracodorsal
Medial pectoral n.
Medial cutan. n. of arm
Medial cutan. n. forearm
Lateral pectoral n.
Dorsal Scapular n.
N. to subclavius
Suprascapular n.
Long
Thoracic n.
SLOW

61. That’s it! The Brachial Plexus
Axillary Radial
Roots
Trunks
Divisions
Cords
Branches
C5 C6 C7 C8 T1
Upper Middle Lower
Musculocutaneous Median Ulnar
L
a
t
e
r
a
l
P
o
s
t
e
r
i
o
r
M
e
d
i
a
l
Upper subscapular
Lower subscapular
Thoracodorsal
Medial pectoral n.
Medial cutan. n. of arm
Medial cutan. n. forearm
Lateral pectoral n.
Dorsal Scapular n.
N. to subclavius
Suprascapular n.
Long
Thoracic n.