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Flashcards in Brachial Plexus Deck (24):

What are the 5 components of the Brachial Plexus?

1st: Roots {Real}-ANT rami of C5-8 and T1
2nd: Trunks {Teachers}
3rd: Divisions {Drink}
4th: Cords {Cold}
5th: Branches {Beer}


What is the pathway of the Dorsal Scapular Nerve

Back of C5 root-->innervates lower part of levator scapulae -->and then also innervates BOTH Rhomboids


1) Long Thoracic Nerve comes from which Cervical nerves?

2) What does this innervate?
3) What does this nerve direct branch to ?

1) C5-7

2) Innervates Serratus Anterior
3) Direct branches to Scalene (C5-6)


A: Describe the location of Brachial Plexus [Trunk]s
B: Upper trunk is formed by a Union of __&___ and is the only trunk to have _____

C: Middle trunk is just a continuation of __
D: Lower trunk is formed by union between __ and ___

A: Trunks: formed near lateral border of Scalene muscles INSIDE Posterior Triangle

B: Upper trunk is formed by a Union between C5&C6 spinal n. and is only trunk to have its own branches

C: Middle TRUNK is a continuation of C7

D: Lower trunk is formed by union between C8 and T1


Describe these Brachial Plexus Cord formations
1. Lateral Cord

2. Medial Cord

3. Posterior Cord

1. formed by union between upper ANT divisions & middle trunks

2. formed by lower trunk ANT division & arises from
[C5-C8 and T1] combined

3. union of all 3 posterior divisions


Brachial Trunks are ___ and ___ into ___&___ divisions

Brachial Trunks are SHORT and SPLIT into Anterior & Posterior Divisions


1- How many branches stems from Brachial LATERAL Cord?

2- How many branches stems from Brachial MEDIAL Cord?

3- How many branches stems from Brachial POSTERIOR Cord

1- L= 3 Branches

2- M= 5 Branches

3- P= 5 branches


Where is the Cricoid cartilage located and what's special about it?

[ Cervical Vertebrae box #6 ] and where 2 roots (CN5 and 6) lies above and 2 brachial plexus roots (CN7 and 8) lie BELOW


1) Where are the TRUNKS of the Brachial Plexus located?

2) What about DIVISIONS of Brachial Plexus [3]

3) and how about CORDS of Brachial Plexus

1) inbetween the Scalene muscles, Medial to Clavicle Midpoint

2) BEHIND Clavicle midpoint, next to 3rd part of subclavian artery and at beginning of axillary artery

3) Extends laterally from Clavicle midpoint to inferomedial part of scapula coracoid process


1) What causes Erb's Palsy?

2) What are the sx of Erb's Palsy?

3) Name 3 CAUSES of Erb's Palsy?

1) UPPER Brachial Root Damage (CN5 & 6)
2) "waiters tip position" of UE

A: head forced to side during delivery
B: Pulled prolapsed fetal arm
C: Neck/Shoulder violently separated in fall


1- Median Claw is caused by what?

2) What are the sx of Median Claw?

1-Damage to Distal median nerve (after branch with
C5-7 n. has come off to feed forearm flexors)-->paralysis of LATERAL lumbrical muscles = this time 2nd and 3rd Digits are Clawed! = Median WEIRD Claw

2)WEIRD Claw hand/Collapsing of 2nd and 3rd(pointer and middle finger)


1) TRUE ULNAR Claw is caused by what?

2)How is this different from
"Papal-Popes Blessing Hand of Benediction"??

3) What are the sx of ULNAR Claw?

1) Distal Ulnar Nerve damage--> paralysis of medial lumbrical muscles--->4th and 5th digits CLOSEST TO body collapse
2) "P-Popes Blessing HOB" LOOKS SAME as true ulnar claw BUT instead caused by PROXIMAL MEDIAN n. damage
----->Can't PULL 2 lateral fingers down when trying to make fist [P for P]

3) Collapse of pinky and ring finger{True Ulnar} OR
unable to PULL 2 lat fingers down{POPE}


Klumpke's Total Claw

Lesion of [C8,T1 LOWER Brachial plexus trunk]--> damage to radial, median and ulnar n.-->
loss of ALL hand lumbricals = forearm finger flexors(median nerve with C5-7) & finger extensors (radial nerve) are unopposed


1) What happens when you CUT the Long Thoracic Nerve?

2) Humeral fractures typically result in ___nerve damage because this nerve _____. What happens when the RADIAL Nerve is damaged?

1) WINGED SCAPULA<--caused by no more innervation to Serratus Anterior

2) Humeral fractures typically result in RADIAL nerve damage because this nerve WRAPS WROUND HUMERUS. No Radial Nerve= NO THUMB SENSORY and NO FOREARM/POSTARM/EXTENSORS


FIVE FINGER pneumonic for Brachial Plexus Nerve Root Contributions:
[*Thumb= ___] and [pinky = ___ ]

1) 3 Musketters

5) TWO Unicorns

[Thumb = C5 n. ] [pinky= T1 n .] [ring finger=C8]

1) 3 Musketeers= thumb+pointer+middle= Musculocutaneous n.

2) ASSINATD=thumb+pointer=Axillary n.


5) TWO Unicorns=pinky+ring=Ulna n.


1) What 3 muscles does the Musculocutaneous [Brachial Plexus] Nerve innervate?

2) What nerve is associated w/ the funny bone?

1) Corochobrachialis(muscle it pierces thru) / Biceps / Brachialis

2) The ulna passes the funny bone to innervate MOST hand muscles and some forearm


Which artery is the LARGEST daughter of the Axillary artery?



Dermatomes are ___bands served by __ ___ ____

Dermatomes are SENSORY bands served by 1 DORSAL ROOT


A: What happens once the Vertebral Artery gets to C1 vertebrae?

B: Where does the Internal Jugular Vein lay?

C: Where does the CN11/(___) actually arise?

A: It hops onto the C1 vertebrae arch and travels up thru the foramen magnum to reach the brain

B: Lays RIGHT next to Common Carotid Artery

C: CN11(Spinal Accessory n.) arises from BEHIND Erbs point and is a decent Sized Nerve!


"Ape hand"

Damage to brachial plexus [PROXIMAL median nerve]
-->will lose [opponens pollicis muscle]-->inability to Oppose thumb = "ape hand" :-(


Facial Nerve is Cranial Nerve __ and where is the Facial ARTERY located?

ºFacial Nerve is Cranial Nerve 7
ºFacial ARTERY is underneath [mandible ramus] near the jaw's angle


A: Where does CN10 (___ ____) lay?

B: What is the LATERAL Antebrachial Cutaneous nerve [3]

C: Where does the Ansa Cervacalis of the __ __ nerve sit?

D: Middle Scalene muscle is ____[superficial/DEEP] to Brachial Plexus

A: CN10(Vagus Nerve) lays inbetween Common Carotid Artery and Internal Jugular Vein

B: Continuous from Musculocutaneous nerve of brachial plexus -->it travels inbetween biceps & brachialis---> innervates lateral forearm skin

C: Ansa Cervacalis of C1 Motor ventral rami SITS ON TOP OF INTERNAL JUGULAR VEIN

D: Middle Scalene muscle is BEHIND/DEEP the Brachial Plexus .
(ANT scalene and middle scalene muscles SANDWICHES the Brachial plexus)


Which is artery is bigger between ANT circumflex humeral artery and POST circumflex humeral artery

POST(has more words) circumflex humeral artery!


Etiology for WRIST DROP

Proximal (at or above elbow) Radial nerve damage---->loss of forearm's wrist extensor motor innervation