The brachial plexus is a network of nerves formed by the lower cervical and upper thoracic spinal nerves that provides motor innervation to the muscles of the upper limb and sensory innervation to the skin of the upper limb. It is divided into 5 parts - roots, trunks, divisions, cords, and branches. The document proceeds to describe each part in detail and lists the minor branches of the brachial plexus, their spinal root contributions, and motor and sensory functions. The blood supply of the brachial plexus is also summarized.

1. Brachial Plexus
Anatomy
 Abdulaziz R. Alanzi
 Medical Student, Al-Imam University
 Riyadh, Saudi Arabia

2. Bones of Upper Limb

3. Blood Supply of Upper Limb

4. Definition of Brachial Plexus
The brachial plexus (plexus brachialis) is a somatic
nerve plexus formed by intercommunications among the
ventral rami (roots) of the lower 4 cervical nerves (C5-C8)
and the first thoracic nerve (T1). The plexus, depicted in
the images below, is responsible for the motor
innervation of all of the muscles of the
upper extremity, with the exception
of the trapezius and levator scapula.

5. Cont’d
The brachial plexus is divided into 5 parts;
Roots – Trunks – Divisions – Cords – Branches
(a good mnemonic for this is
Read That Damn Cadaver Book).

6. Parts of Brachial Plexus
1- Roots:
The ventral rami of spinal nerves C5 to T1 are referred to as the
"roots" of the plexus. The roots emerge from the transverse
processes of the cervical vertebrae immediately posterior to
the vertebral artery.
2- Trunks:
• Superior trunk: A combination of C5 and C6 roots.
• Middle trunk: A continuation of C7.
• Inferior trunk: A combination of C8 and T1 roots.

8. Parts of Brachial Plexus
3- Divisions: each trunk splits into an anterior division and a
posterior division.
4- Cords: The cords are formed by recombination of the six
divisions to three nerve fibres. They are named by their position
relative to the axillary artery.
Lateral Cord:
formed by anterior
division of the superior
trunk & anterior division
of the middle trunk
Posterior Cord:
formed by posterior division of
the superior trunk, posterior
division of the middle trunk &
posterior division of the inferior
trunk.
Medial Cord:
formed by the
anterior
division of the
inferior trunk

10. Minor branches of the brachial plexus

11. 1- Musculocutaneous Nerve
 Roots: C5, C6, C7
 Motor Functions:
Innervates the brachialis,
biceps brachii and
corocobrachialis
muscles.
 Sensory Functions: Gives
off the lateral cutaneous
branch of the forearm,
which innervates the
lateral half of the anterior
forearm, and a small
lateral portion of the
posterior forearm

13. 2- Axillary Nerve
 Roots: C5 and C6
 Motor Functions:
Innervates the deltoid,
teres minor and the
long head of the
triceps brachii
 Sensory Functions:
Gives off the superior
lateral cutaneous
nerve of arm, which
innervates the inferior
region of the deltoid
(“regimental badge
area”)

15. 3- Median Nerve
 Roots: C6 – C8 and T1
 Motor Functions: Innervates
most of the flexor muscles in
the forearm, the thenar
muscles, and the two lateral
lumbrical muscles that move
the index and middle fingers
 Sensory Functions: Gives off
the palmar cutaneous branch,
which innervates the lateral
part of the palm, and the
digital cutaneous branch,
which innervates the lateral
three and a half fingers on the
anterior (palmar) surface of
the hand.

17. 4- Radial Nerve
 Roots: C5-C8 and T1
 Motor Functions:
innervates the triceps
brachii, and the
extensor muscles in the
posterior compartment
of the forearm.
 Sensory Functions:
Innervates the posterior
aspect of the arm and
forearm, and the
posterior, lateral aspect
of the hand.

19. 5- Ulnar Nerve
 Roots: C8 and T1
 Motor Functions:
Innervates the muscles
of the hand (apart from
the thenar muscles and
two lateral lumbricals),
flexor carpi ulnaris and
medial half of flexor
digitorum profundus
 Sensory Functions:
Innervates the anterior
and posterior surfaces of
the medial one and half
fingers, and associated
palm area

21. Blood Supply of the Brachial Plexus
 The blood supply of the brachial plexus is based largely on the
subclavian (which becomes the axillary) artery and its branches,
and variations exist.
 Generally, the vessels involved are the vertebral, the ascending
and deep cervical, and the superior intercostal arteries.
The cord and roots:
supplied by the anterior
and posterior spinal
branches of the
vertebral artery.
The trunks of the plexus:
supplied by muscular branches
of the ascending and deep
cervical arteries and superior
intercostals, and occasionally by
the subclavian itself.[

22. References
 Medscape Reference
 http://teachmeanatomy.info/

23. Thank You
AbdulazizROA@gmail.com
@Azizocyte