Anatomy of Brachial Plexus.

1. BRACHIAL PLEXUS
• By: Syed Irshad Murtaza
• Technologist CNPS AKUH Karachi
• Date: 13-05-2014

2. What is the Brachial Plexus?
• Introduction
• A network of spinal nerves that originates in the
back of the neck, extends through the axilla
(armpit) and gives rise to nerves to the upper
limb.
• The brachial plexus is a network of nerve fibers,
running from the spine, formed by the ventral
(Anterior) rami of the lower four cervical and first
thoracic nerve roots (C5-C8, T1).

5. Anatomy
• Brachial Plexus proceeds through the neck,
the axilla (armpit region), and into the arm. It
is a network of nerves passing through the
cervico-axillary canal to reach axilla and
innervates brachium (upper arm),
antebrachium (forearm) and hand.

7. Horns in the spinal Cord
• In the spinal cord the gray matter is present inside
and white matter I towards outside while in the
brain this distribution is vice versa.
• On cross section of the spinal cord gray matter in
spinal cord presents butterfly like structure from
which some projections like “Horns” are seen,
termed as
• Ventral/Anterior Horn (ventral/anterior/motor
root centre (Efferent Nerve)
• Lateral Horn (Preganglionic sympathetic neurons,
• Dorsal/posterior Horn (dorsal/posterior/sensory
root centre (Afferent Nerve)

9. Terms to define
• Ganglion: collection of the nerve cell bodies is called
ganglion. E.g Dorsal root ganglion (DRG)
• Ramu (Pl: Rami) Spinal nerve when exits from the
vertebrae , it divides into two branches termed as,
• 1. ventral/anterior primary ramus
• 2. dorsal/posterior primary ramus
• Ventral/anterior ramus: it is the ventral division of
spinal nerve outside the vertebrae, which supplies
to the skin, muscles on anterior body.
• Dorsal division supplies to the skin and muscles of
the back.

10. RTDCB
• Brachial plexus comprises of Root, Trunk,
Division, Cord and peripheral Branches.
• A mnemonic for remember the region of the
brachial plexus is:
• Real - Roots
• Teenagers - Trunks
• Drink - Divisions
• Cold - Cords
• Beer – Branches

11. Brachial Plexus

12. Anatomy of RTDCB
• Roots: (lying between the anterior and middle
scalene muscles),
• Trunks: (found in the posterior triangle of the
neck),
• Divisions: (lay posterior/behind the clavicle),
Cords: (found in axilla & named according to
their relationship with axillary/brachial artery ) &
• Branches: (the five main nerve fibers in the arm).

14. Formation of Roots & Trunk of the Brachial Plexus
The roots of the brachial plexus come from
branches of the spinal vertebrae C5-8 and T1.
The cervical roots, C5 and C6, fuse together to
form the Upper (Superior) trunk
The cervical root C7 goes on to become
the Middle trunk
The cervical roots, C8 and T1, fuse together to
form the Lower (Inferior) trunk

15. The Trunks & Divisions of the Brachial Plexus
• There are three trunks of the brachial plexus that
lie in the posterior neck triangle.
• Each of the Trunks has its two divisions
• Anterior Division
• Posterior Division
• (Anterior divisions of the upper, middle, and
lower trunks
• Posterior divisions of the upper, middle, and
lower trunks)
• These six Divisions further unite to form the
Cords.

16. The Divisions & Cords of the Brachial Plexus
• There are two divisions of the brachial plexus that
lie posterior to the clavicle. These divisions go on
to form the cords of the brachial plexus.
• Anterior divisions of Upper and Middle Trunks go
on to form the Lateral cord
• All Posterior divisions go on to form
the Posterior cord
• The Anterior division of the Lower Trunk goes on
to form the Medial Cord

17. The Cords and main Terminal (Peripheral) branches
of Brachial Plexus
• The cords of the brachial plexus divide and join
together to form the five main nerve branches of
the arm.
• The Lateral cord divides to become
the Musculocutaneous and Median Nerve
Branches.
• The Medial cord divides to become the Median and
Ulnar Nerve Branches
• The Posterior cord divides to become the Radial
and Axillary Nerve Branches

18. Branches from direct roots
• Dorsal scapular nerve-(c4-c5)- (levator
scapulae, rhomboids)
• Subclavian nerve(c5-c6)- (subclavian muscle
• Long thoracic nerve(c5-c7)- serratus anterior
muscle
• Branch from trunk
• Supra scapular nerve(c5-c6)- branch from
upper trunk.
• Supplies infra/supraspinatus

19. Branches and their Roots
• There are five "terminal" branches and numerous other "pre-terminal"
or "collateral" branches that leave the plexus at various
points along its length.
• Lateral cord-1) musculocutaneous nerve(c5-c7)
2) lateral head of median nerve(c5-c7)
• Medial cord-1) med.ant.thoracic nerve(c8-T1)
2) med. Cut. Nerve of arm(c8-T1)
3) med.cut. Nerve of forearm(c8-T1)
4) ulnar nerve(c7-T1)
5) med. Head of median nerve(c8-T1)
• Posterior cord-
1) subscapular nerve(upper, lower)(c5-c7)
2) thoraco dorsal nerve(c5-c7)
3) axillary nerve(c5-c6)
4) radial nerve(c5-c8)

22. TTHHAANNKKSS