INTRODUCTION:
• This the plexus formed from cervical enlargement.
• To study the entire upper limb Nerve supply via it, the formation, its components and
its nerve supply would help in understanding the nerves in an easy manner.
FORMATION:
i. Cervical Enlargement of spinal cord gives Brachial Plexus.
ii. Root value-C5, C6, C7, C8; T1 from anterior primary Ramus Gives Brachial plexus.
iii. Little Contribution also from C4, T2 spinal Nerves.
iv. If Contribution from C4 is larger, T2 is absent it is called as Pre-fixed Brachial
Plexus.
v. If Contribution from T2 is larger and from C4 is absent it is called as Post-fixed
Brachial Plexus.
COMPONENTS:
• 4 components of Brachial plexus
a. Roots
b. Trunks
c. Divisions
d. Cords
• Cords end up in forming terminal branches
ROOTS:
• 5 Roots of Anterior Primary Ramus (C5-C8; T1)-Located in Neck deep to scalenus
anterior muscle
TRUNKS:
• Located in Neck- Occupying cleft between scalenus medius behind and Scalenus
anterior in front
• Upper Trunk-Formed by C5, C6 Roots
• Middle Trunk-Root continues as Middle Trunk
• Lower Trunk-C8, T1 Roots joined to form lower trunk
DIVISIONS:
• Each Trunk-Upper, Lower, Middle Trunk has anterior and Posterior Divisions
located behind the clavicle.
CORDS:
• Present in Axilla
• Formations
a. Lateral - Anterior Divisions of Upper and Middle Trunk join to form the lateral
cord
b. Posterior-Posterior Division of Upper, Middle, Lower Trunk joins to form
Posterior cord
c. Medial-Anterior Division of Lower Trunk continues as Medial Cord (Ulnar Nerve)
• These Cords are named with respect to 2
nd part of the Axillary artery.
• These Cords Continue in Axilla
a. Lateral Cord-Musculocutaneous Nerve
b. Posterior Cord-Radial Nerve
c. Medial Cord-Ulnar Nerve
Medial Nerve: Contributed by Lateral and Medial Cords in Midline
BRANCHES:
FROM ROOTS:
1. LONG THORACIC NERVE (C5, C6, C7)
• Directed by roots in neck.
• Supplies Serratus Anterior.
2. DORSAL SCAPULAR NERVE(C5)
• Present in neck region.
• Supplies Scapular muscles in neck.
• Directly from C5 Root.
• Additionally,
➢ Contribution to phrenic Nerve (C5) supply diaphragm.
➢ Branches by roots to supply scalene muscles and Longus Colli (C5-C8).
FROM TRUNKS (ONLY FROM UPPER TRUNK):
1. SUPRASCAPULAR NERVE (C5, C6)
• Supplies Scapular muscles
2. NERVE TO SUBCLAVIUS (C5, C6)
• Branches from Roots and Trunks are Supraclavicular Branches of Brachial
Plexus.
• There are no specific branches from the divisions.
FROM CORDS:
A. FROM LATERAL CORD
1. Lateral Pectoral Nerve(C5-C7)
2. Lateral root of Median Nerve (C5, C6, C7)
3. Musculocutaneous Nerve(C5-C7)
B. FROM MEDIAL CORD
1. Medial Pectoral Nerve (C8, T1)
2. Medial Cutaneous nerve of Arm (C8, T1)
3. Medial Cutaneous Nerve of Forearm (C8, T1)
4. Medial Root of Median Nerve (C8, T1)
5. Ulnar Nerve (C8, T1)
C. FROM POSTERIOR CORD
1. Upper Subscapular Nerve(C5-C6)-supply Subscapularis
2. Lower Subscapular Nerve (C5, C6)-Supply Subscapularis (Hybrid Muscle)
3. Thoracodorsal Nerve / Nerve to Latissimus Dorsi (C6-C8)- Supply Latissimus
Dorsi
4. Axillary Nerve (C5, C6) - Supply Deltoid, Teres Minor
5. Radial Nerve (C5-C8; T1) - Nerve of Extension - Present in Radial Groove (Nerve
of Posterior Compartment
FROM TRUNKS (ONLY FROM UPPER TRUNK):
1. SUPRASCAPULAR NERVE (C5, C6)
• Supplies Scapular muscles
2. NERVE TO SUBCLAVIUS (C5, C6)
• Branches from Roots and Trunks are Supraclavicular Branches of Brachial
Plexus.
• There are no specific branches from the divisions.
FROM CORDS:
A. FROM LATERAL CORD
1. Lateral Pectoral Nerve(C5-C7)
2. Lateral root of Median Nerve (C5, C6, C7)
3. Musculocutaneous Nerve(C5-C7)
B. FROM MEDIAL CORD
1. Medial Pectoral Nerve (C8, T1)
2. Medial Cutaneous nerve of Arm (C8, T1)
3. Medial Cutaneous Nerve of Forearm (C8, T1)
4. Medial Root of Median Nerve (C8, T1)
5. Ulnar Nerve (C8, T1)
C. FROM POSTERIOR CORD
1. Upper Subscapular Nerve(C5-C6)-supply Subscapularis
2. Lower Subscapular Nerve (C5, C6)-Supply Subscapularis (Hybrid Muscle)
3. Thoracodorsal Nerve / Nerve to Latissimus Dorsi (C6-C8)- Supply Latissimus
Dorsi
4. Axillary Nerve (C5, C6) - Supply Deltoid, Teres Minor
5. Radial Nerve (C5-C8; T1) - Nerve of Extension - Present in Radial Groove (Nerve
of Posterior Compartment
APPLIED ANATOMY:
WINGING OF SCAPULA:
• Injury of Long Thoracic Nerve (Nerve to Serratus Anterior)
ERB'S PALSY
• It is an Upper Trunk Injury.
1. Axillary Nerve-Total Injury.
2. Musculocutaneous Nerve-Partial Injury - coracobrachialis alone spared.
3. Radial Nerve-Partial Injury-Brachioradialis paralyzed.
4. Suprascapular Nerve also injured.
CAUSES: Undue separation of head and Neck (Fall on shoulder, Birth Injury)
FEATURES: Policeman tip hand deformity (Sensory Loss on lateral aspect of upper
limb)
POSITION:
• Shoulder-Abduction and Medial rotation
• Elbow-Extension
• Radioulnar Joint-Pronation
KLUMPKEY'S PALSY
• It is a Lower Trunk Injury
• Median Nerve, Ulnar Nerve, T1-Sympathetic fibers -Involved
CAUSES
• Hyperabduction of arm (Holding a branch while fall from tree)
• Birth Injury)
CLINICAL FEATURES:
• Claw Hand Deformity (Metacarpophalangeal Extension, Interphalangeal Flexion)
• Horner Syndrome (Ptosis due to paralysis of Superior Tarsal Muscle) - Miosis due
to paralysis of Dilator Pupillae
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