Brachial plexus
“Erb-Duchenne palsy, Erb-Charcot paralysis, Erb's point, Erb-Westphal symptom, Erb's spot”
2) Components
3) How are roots formed?
“formed by the anterior (ventral) rami of C5 to T1 spinal nerves”
Extent
- interscalene triangle (bounded by anterior scalene and middle scalene)
4) How do roots mix to form trunks?
C5 + C6 = upper trunk
- Erb’s point: confluence of C5&C6 at upper trunk
C7 = middle trunk
C8 + T1 = lower trunk
Extent
- interscalene triangle to supraclavicular space of posterior triangle
5) How do trunks divide to form divisions?
Each trunk splits into anterior and posterior divisions just behind and above the clavicle
Extent
- around and within cervico-axillary canal or apex of axilla
6) How do divisions form cords?
Post divisions of all 3 trunks= posterior cord (C5-T1)
Ant divisions of upper&middle trunks= lateral cord (C5-C7)
Ant division of lower trunks= medial cord (C8-T1)
*cords are named according to their relation to the 2nd part of axillary artery
7) How do branches arise from brachial plexus?
from cords and from divisions
8) How to draw a simple brachial plexus?
1st: roots
2nd: 3 letter Y’s
3rd: 2 letter E’s
4th: 1 letter X
9) 5th: rule of 3
10) Nerves from brachial plexus
Root, trunk, cord, and terminal branches
11) Root branches
“PLeaseD”
Phrenic (C3-C5)
Long thoracic nerve (C5-C7)
Dorsal scapular nerve (C4-C5)
12) Trunk branches
Subclavius (C5-C6)
Suprascapular (C5-C6)
13) Cord branches
Lateral cord – Look Miss Look
Medial cord – M4U
Posterior cord – ULTRA
14) Lateral cord branches
“Look Miss Look”
Lateral pectoral nerve (C5-C7)
Musculocutaneous nerve (C5-C7)
Lateral root of median nerve (C5-C7)
15) Medial cord branches
“M4U”
Medial Pectoral (C8-T1)
Medial cutaneous nerve of arm (C8-T1)
Medial cutaneous nerve of forearm (C8-T1)
Median root of median (C8-T1)
Ulnar (C7-T1)
16) Posterior cord branches
“ULTRA”
Upper Subscapular (C5-C6)
Lower Subscapular (C5-C6)
Thoracodorsal nerve (C6-C8)
Radial (C5-T1)
Axillary (C5-C6)
17) Terminal branches
“3 musketeers assassinated 5 rats, 5 mice and 2 unicorns!”
3 musketeers: Musculocutaneous nerve(C5, C6, C7)
Assasinated: Axillary nerve(C5-C6)
5 rats: Radial nere(C5, C6, C7, C8, T1)
5 mice: Median nerve(C5, C6, C7, C8, T1)
2 unicorns: Ulnar nerve(C8, T1)
18) Summary – mnemonic
19) Summary – table
20) Conditions
21) Erb & Klumpke palsy
'Erb' – 'up'per trunk
vs
Klumpke – lower trunk
22) Thoracic outlet syndrome
Compression of lower trunk (same as Klumpke) & subclavian vessels
23) Winged scapula
Medial scapular winging
- long thoracic nerve dysfunction
- serratus anterior muscle weakness
Lateral scapular winging
- spinal accessory nerve dysfunction
- trapezius muscle weakness
