ANATOMY MUSKULOSKELETAL Cervical Plexus and Brachial Plexus

By : Hermizan Halihanafiah

COLLEGE OF ALLIED HEALTH AND SCIENCES

The Spinal Nerves31 pairs of spinal nerves (1st cervical above C1)

mixed nerves exiting at intervertebral foramenProximal branches

Dorsal (posterior) root is sensory input to spinal cordVentral (anterior) root is motor output of spinal cord

Distal branchesdorsal ramus supplies dorsal body muscle and skinventral ramus to ventral skin and muscles and limbsmeningeal branch to meninges, vertebrae and ligaments

Branches of a Spinal Nerve

Spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal.

Each has dorsal and ventral ramus.

Notice the branching and merging of nerves in this example of a plexus

Nerve Plexuses

Ventral rami branch and anastomose

repeatedly to form 5 nerve plexuses

cervical plexus

brachial plexus

Lumbar plexus

Sacral plexus

Coccygeal plexus

Spinal Nerve Roots and Plexuses

Nerves PlexusesThe ventral (anterior) rami of spinal nerves, except

for thoracic nerves T2-T12, do not go directly to the body structures they supply.

They form networks on the both the left and right sides of the body by joining with various numbers of axons from anterior rami of adjacent nerves.

Ventral rami branch and anastomose repeatedly to form 5 nerve plexuses

Nerves Plexus The principal plexuses are:

1. Cervical plexus

2. Brachial plexus

3. Lumbar plexus

4. Sacral plexus

5. Cocygeal plexus

Cervical PlexusFormed by the anterior (ventral) rami of the

cervical nerves C1-C4 with contribution C5.Supplies the skin and muscles of the head,

neck and superior part of the shoulders and chest.

Phrenic nerves arise from the cervical, innervate for the diaphragm muscles.

The Cervical Plexus

Terminal Branches Superficial branches (Sensory)1. Lesser occipital (C2) – skin of scalp

posterior and superior to ear.2. Great auricular (C2-C3) – skin anterior,

inferior, and over ear and over parotid gland.

3. Transverse cervical (C2-C3) – skin over anterior aspect of neck.

4. Supraclavicular (C3-C4) – skin over superior portion of chest and shoulder.

Transverse Cervical nerve

C2,C3

Supraclavicular nerve C2, C3

Greater Auricular nerve C2,C3

Lesser occipital nerve C2 (ventral

rami)

Greater occipital nerve

C2 (dorsal rami)

Deep Branches (Motor)1. Ansa cervicalis (superior root) – infrahyoid

and geniohyoid muscles of the neck.2. Ansa cervicalis (inferior root) – infrahyoid

muscles of neck.3. Phrenic nerve – diaphragm4. Segmental branches – prevertebral muscles

of the neck, levator scapulae and middle fiber of scalene.

Terminal Branches

Brachial PlexusThe anterior (ventral) rami of spinal nerves C5-C8

and T1 form the brachial plexus.

Extends inferiorly and laterally on either side of the last four cervical and first thoracic vertebrae through intervetebral foramen.

Passes above the first rib posterior to the clavicle and then enter the axilla (cervicoaxillary canal).

The brachial plexus provide the entire nerve supply

of the shoulder and upper limbs.

Five important nerves arise from brachial

plexus are:

1. Axillary nerve

2. Musculocutaneous nerve

3. Radial nerve

4. Median nerve

5. Ulnar nerve

Brachial Plexus

Nerve SupplyThe nerve that supplying

the structures in the arm

are all derivative from the

brachial plexus.

Brachial plexus is a

complex of intermingling

nerves that originate from

the neck (cervical and

thoracic origin)

Brachial plexus is formed by the ventral

(anterior) rami of the lower cervical nerves

and the first thoracic nerves. (C5, C6, C7, C8, T1)

Occasionally, there maybe a contribution from C4

or T2 or both.

Nerve Supply

Brachial PlexusThe anterior (ventral) rami of spinal nerves C5-

C8 and T1 form the brachial plexus.

Extends inferiorly and laterally on either side of

the last four cervical and first thoracic vertebrae.

Passes above the first rib posterior to the clavicle

and then enter the axilla (passes through

cervicoaxillary canal).

The brachial plexus provide the entire nerve supply

of the shoulder and upper limbs.

Five important nerves arise from brachial plexus are:

1. Axillary nerve

2. Musculocutaneous nerve

3. Radial nerve

4. Median nerve

5. Ulnar nerve

Brachial Plexus

Levels of Brachial PlexusRoots

Trunks

Divisions

Cords

Branches

Real

Trainers

Drink

Cold

Beer

RootsThe five roots are the five anterior(ventral) rami of

the spinal nerves, after they have given off their

segmental supply to the muscles of the neck.

These roots merge to form three trunks:

"superior" or "upper" (C5-C6)

"middle"(C7)

"inferior" or "lower" (C8-T1)

TrunkEach trunk then splits in two, to form six

divisions:

anterior division of the upper, middle

and lower trunks

posterior division of the upper, middle,

and lower trunks

Division and Cords

These six divisions will regroup to become the

three cords. The cords are named by their position

in respect to the axillary artery.

The posterior cord is formed from the three

posterior divisions of the trunks (C5-T1)

The lateral cord is the anterior divisions from the

upper and middle trunks (C5-C7)

The medial cord is simply a continuation of the

anterior division of the lower trunk (C8-T1)

Spesific BranchesOne can remember the specific branches of

lateral, posterior and medial cord using the mnemonic LML, ULNAR , M4U respectively.

LML - lateral pectoral nerve , musculocutaneous nerve , lateral root of the median nerve.

ULNAR - upper subscapular nerve , lower subscapular nerve , nerve to latissmus dorsi (thoracodorsal nerve) , axillary nerve , radial nerve.

M4U - medial pectoral nerve , medial root of the median nerve , medial cutaneous nerve of the arm , medial cutaneous nerve of the forearm , ulnar nerve.

Learn the Brachial Plexusin Five Minutes or Less!!

Draw two headless arrows to the right.

Add a headless arrow to the left

Add a “W “

Add an “X”

Add a “Y”. (Just a branch of the “Y”is added.)

Label C5 to T1.

Label the major branches:

More complex diagramming of the brachial plexus includes the four “3s.”

The first “3”is the branches to C5, 6, and 7 which form LTN = long thoracic nerve.

Next, each of the headless arrows has three nerves attached to it.To the top headless arrow, add its “3.”

Label these “3”:DSN = dorsoscapular nerve; SS = suprascapular nerve;LP = lateral pectoral nerve

Add the “3”to the middle headless arrow.

Label the second headless arrow “3”: SS = subscapular, TD = thoracodorsal nerve.

Add the final “3”on the bottom headless arrow

*Label the last “3.”MP = medial pectoral,MBC = medial brachial

cutaneous, and MABC = medial antebrachial cutaneous.

*Remember: the brachial cutaneous goes to the brachium or

arm, and the MABC goes to the antebrachium or forearm.

Label roots, trunks, divisions, cords, terminal branches.

Radiologists, neurosurgeons and thoracic surgeons need to know the nerve to the subclavius(SUB).

The complete brachial plexus diagram

From Nerve Root Muscles

Roots Dorsal scapular C5 Rhomboid minor, major and levator

scapulae

Roots Long thoracic C5, C6, C7

Serratus anterior

Superior trunk

Subclavian C5, C6 Subclavius

Superior trunk

Suprascapular C6, C6 Supraspinatus, infraspinatus

From Nerve Root Muscles

Lateral cord Lateral pectoral nerve

C5. C6, C7

Pectoralis major

Lateral cord Musculocutaneous nerve

C5. C6, C7

Coracobrachialis, brachialis, biceps

brachii

Lateral cord Lateral root of the median nerve

C5. C6, C7

Fibers to the median nerve

Posterior cord

Upper subcsapular nerve

C5, C6 Subscapularis

From Nerve Root Muscles

Posterior cord

Thoracodorsal nerve

C6, C7, C8 Latissimus dorsi

Posterior cord

Lower subscapular

C5, C6 Subscapularis

Posterior cord

Axillary nerve

C5, C6 Anterior branch: Deltoid

Posterior branch: Teres minor

Posterior cord

Radial nerve C5-C8, T1 Triceps brachii, supinator,

anconeus, extensor muscles move the

hand, brachioradialis

From Nerve Root Muscles

Medial cord Medial pectoral nerve

C8, T1 Pectoralis major, Pectoralis minor

Medial cord Medial root of median nerve

C8, T1 Fibers to the median nerve

Medial cord Medial cutaneous nerve of the arm (medial brachial cutaneous)

C8, T1 Skin of medial and posterior aspect of distal third of arm

Medial cord Medial cutaneous nerve of the forearm (medial antebrachial cutaneous)

C8, T1 Skin of medial and posterior aspects of forearm

From Nerve Root Muscles

Medial cord Ulnar nerve C8, T1 Flexor carpi ulnaris, flexor digitorum profundus, most of the small muscles of the hand

Summary1. Branches from the roots Nerves to the scalene and longus colli (C5, 6, 7,

8) A branch to the phrenic nerve (C5) Dorsal scapular nerve (C5) Long thorasic nerve (C5, 6, 7)

2. Branches from the trunks Nerve to subclavius / subclavian nerve (C(4), 5,

6) Suprascapular nerve (C(4), 5, 6)

3. There are no nerves arising from the divisions

4. Branches from the cords of the plexusi. Medial cord Medial pectoral nerve (C8, T1) Medial brachial cutaneous nerve (T1) Medial antebrachial cutaneous nerve (C8,

T1) Ulnar nerve (C(7), 8, T1) Medial part of the median nerve (C8, T1)

Summary

4. Branches from the cords of the plexusii. Posterior cord Upper subscapular nerve (C(4), 5, 6, (7)) Thoracodorsal nerve (C(5), 7. 8) Lower subscapular nerve (C5, 6) Axillary nerve (C5, 6) Radial nerve (C5, 6)

Summary

4. Branches from the cords of the plexusiii. Lateral cord Lateral pectoral nerve (C5, 6, 7) Musculocutaneous nerve (C5, 6, 7) Lateral part of the median nerve (C(5), 6, 7))

Summary