Download Brachial Plexus

IN THE NAME OF GOD
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
12-3
The brachial plexus is divided into 5 parts;
Roots – Trunks – Divisions – Cords – Branches
(a good mnemonic for this is
Read That Damn Cadaver Book).
Relations - BP
• 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
• 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.
Relations - BP
• 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
• 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
PUT IT ALL TOGETHER…...
Minor branches of the brachial plexus
BRANCHES - Roots
• From the Roots
• Dorsal Scapular nerve
Derived from C5 root
Motor nerve to the
Rhomboideus major and
minor muscles
Roots
• Long Thoracic nerve
Derived from C 5,6,7
Innervates the serratus
anterior muscle
BRANCHES OF UPPER TRUNK
NERVE TO SUBCLAVIUS
Root value – C5,C6
SUPRASCAPULAR
NERVE
Root value – C5,C6
Branches – LC & MC
LATERAL PECTORAL NERVE
Root value- C5,C6,C7
MEDIAL PECTORAL NERVE
Root value- C8,T1
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
1- Musculocutaneous Nerve
• Roots: C5, C6,
C7
• Motor
Functions:
Innervates the
brachialis,
biceps brachii
and
corocobrachialis
muscles.
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.
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
• MEDIAL CUTANEOUS
NERVE OF
ARM
• Root value- C8,T1
• MEDIAL CUTANEOUS
NERVE OF FOREARM
• Root value – C8,T1
Medial Cord: Terminal Nerves
• Ulnar C8-T1
• Medial root of median
nerve C8-T1
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
ULNAR NERVE
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
• UPPER SUBSCAPULAR
• Root value-C5,C6
• LOWER SUBSCAPULAR
• Root value- C5,C6
• NERVE TO LATISSIMUS
DORSI
• Root value-C6,C7,C8
Posterior Cord Terminal Nerves
• Axillary nerve: C5-6
Motor: To deltoid and teres
minor muscles.
Sensory: Skin on arm over
deltoid muscle:
2- Axillary Nerve
• Roots: C5 and
C6
• Motor
Functions:
Innervates the
deltoid, teres
minor and the
long head of
the triceps
brachii
AXILLARY NERVE
Posterior Cord Terminal Nerves
• Radial nerve: C5-T1
Motor:
Posterior compartments of
arm and forearm.
Brachioradialis muscle
Sensory:
Back of arm, forearm, hand
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.
RADIAL NERVE
Cutaneous distribution
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 .
• 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.
• 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.
Begin with a letter “Y”, an “I” and a “Y”.
Add a “strike” and a “spare”
Draw “arches”.
Draw horizontal lines to separate the parts.
Roots
Trunks
Divisions
Cords
Branches
Begin labeling.
C6
C7
C5
C8
T1
Roots
Trunks
Upper
Middle
Lower
Medial
Posterior
Cords
Lateral
Divisions
Branches
Musculocutaneous
SLOW
Axillary
Median
Radial
Ulnar
Add details . . .
Branches off the posterior cord spell “ULTRA”
C5
C6
C7
C8
Roots
Trunks
Upper
T1
Middle
Lower
Upper subscapular
Lower subscapular
Thoracodorsal
Medial
Posterior
Cords
Lateral
Divisions
Branches
Musculocutaneous
SLOW
SLOW
Axillary
Median
Radial
Ulnar
“3M” comes off the medial cord.
C5
C6
C7
C8
T1
Roots
Trunks
Middle
Upper
Lower
Upper subscapular
Lower subscapular
Thoracodorsal
Medial
Posterior
Cords
Lateral
Divisions
Medial pectoral n.
Medial cutan. n. of arm
Medial cutan. n. forearm
Branches
Musculocutaneous
SLOW
SLOW
Axillary
Median
Radial
Ulnar
The lateral pectoral n. comes off the lateral cord.
C5
C6
C7
C8
T1
Roots
Trunks
Upper
Middle
Lower
Upper subscapular
Lower subscapular
Thoracodorsal
Medial
Lateral pectoral n.
Posterior
Cords
Lateral
Divisions
Medial pectoral n.
Medial cutan. n. of arm
Medial cutan. n. forearm
Branches
Musculocutaneous
Axillary
Median
Radial
Ulnar
There are 4 supraclavicular branches.
C5
C6
C7
C8
T1
Roots
Long
Thoracic n.
Trunks
Upper
N. to subclavius
Suprascapular n.
Lateral
Dorsal Scapular n.
Lateral pectoral n.
Middle
Lower
Upper subscapular
Lower subscapular
Thoracodorsal
Medial
Cords
Posterior
Divisions
Medial pectoral n.
Medial cutan. n. of arm
Medial cutan. n. forearm
Branches
SLOW
Musculocutaneous
Axillary
Median
Radial
Ulnar
That’s it!
The Brachial Plexus
C5
C6
C7
C8
T1
Roots
Long
Thoracic n.
Trunks
Upper
N. to subclavius
Suprascapular n.
Lateral
Dorsal Scapular n.
Lateral pectoral n.
Middle
Lower
Upper subscapular
Lower subscapular
Thoracodorsal
Medial
Cords
Posterior
Divisions
Medial pectoral n.
Medial cutan. n. of arm
Medial cutan. n. forearm
Branches
Musculocutaneous
Axillary
Median
Radial
Ulnar
THANK YOU VERRY MUCH