Brachial Plexus Flashcards
List rotator cuff muscles and their nerve supply
- Supraspinatus - innervated by suprascapular nerve (C5,6)
- Infraspinatus - innervated by suprascapular nerve (C5,6)
- Teres minor - axillary nerve
- subscapularis - subscapular nerve
dorsal scapular nerve innervates
C5
Rhomboid major
Rhomboid minor
Levator scapula muscle
Long thoracic nerve of Bell
C5- C7
Serrates anterior
suprascapular nerve
C5,6
- supraspinatus
- infraspinatus
nerve to subclavius
C5 ,6
- subclavian muscle
lateral pectoral nerve
C5,6,7
- pectorals major
inferior sub scapular nerve
subscapularis M
Teresa Major
C5,6,7
superior ubscapular nerve
C5,,6,7
- subscapular muscle
thoracic dorsal nerve
C5,6,7
- latissimus dorsal muscle
What nerves come off the medial division
- medial cutaneous nerve of arm
- medial cutaneous nerve of forearm
- medial pectoral nerve
- median nerve
- ulner nerve
what nerves come from posterior division
(C5, T 1
1. inferior sub scapular nerve
2.superior sub scapular nerve
3. thoracodorsal nerve
4. axillary nerve
5. radial nerve
what nerves come from lateral division
- lateral pectoral nerve
- musculocutanous nerve
- median nerve
what muscles does the musculocutanous nerve supplies
biceps brachii
brachialis
corocobrachialis
what muscle does the axillary muscle supply
teres minor
deltoid
median nerve - 5 sites of compression
- brachial artery aneurysm
- Struthers Ligamanet
- lacerates fibrosus
- Pronator Teres Syndrome
- Anterior interosseous nerve
- CTS
Struthers Ligamanet
Struthers’ ligament is a feature of human anatomy consisting of a band of connective tissue at the medial aspect of the distal humerus. It courses from the supracondylar process of the humerus (also known as avian spur) to the medial humeral epicondyle (compress median nerve) .
lacertus fibrosus
bicipital aponeurosis (AKA lacertus fibrosus) is a broad aponeurosis of the biceps brachii which is located in the cubital fossa of the elbow and separates superficial from deep structures in much of the fossa. The bicipital aponeurosis originates from the distal insertion of the biceps brachii.
motor supply of Median Nerve
PT
FCR
Palmer’s
FDS
AIN* ( unable to make okay sign)
LOAF
Palmar cutaneous branch - before going through carpal tunnel
AIN supplies
AIN branch of median nerve
Supplies
- FDP
- FPL
- PQ ( Pronator quadratus)
Sensory distribution of Median nerve
- medial palmar aspect of hand
- distal end of 1,2,3 digit and half of 4th
- palmar
- thenar eminence
Ulnar nerve branches
FCU
FDP ( 3rd ,4th)
Abductor DMinimi
Opposes DM
Flexor DM
Lumbricles
Interossei
FPB
abductor pollicus
dorsal ulnar cutaneous
digital branch
Ulnar sensory
- palmar aspect ( 1/2 4th, 5th)
- dorsal - 4th and 5th
Ulnar compression sites
- axillary artery
- Arcade of struther
- retrocondylar groove (medial epicotyl and olecranon
- Cubital tunnel in forarm ( 2 muscles FCU and PDP ) - medial
- Guyons Canal (hook of hamate and piriformis )
Arcade of struther
in middle of the arm, ulnar nerve pierces medial intermuscular septum and descends in front of the medial head of the triceps;
- in 70-80% of individuals, nerve passes under arcade of Struthers
radial nerve branches
- triceps
- Anoconeous
- Brachioradial
- ECRL
- ECRB
becomes the posterior interosseous nerve
posterior interosseous nerve branche
Suprascapular
ECU
ED comminus
EDMinimi
Abductor PL
EPL
EPB
EIP
Radial nerve compression
- Axillary artery - crutch
- long and medial head of triceps
- SPIRAL GROOCE
- Brachialis and brachioradialis
Saturday night Palsy
wrist drop
finger drop
spares elbow extension
Sensation of radial nerve
PCNA
PCNF
Inferior lateral Cutaneous N of arm
Superficial branch - dorsal of hand
innervation APL
radial C7-C8
APB
median C8, T1
Adductor policus
ulnar C8, T1
EPB
radial C7, C8
EPL
radial C7, C8
FPL
median C8, T1
FPB
median / ulnar C8, T1
Opponeous Polices
Median C8,T1
3 shoulder external rotators of the arm
infraspinatous
teres minor
posterior deltoid
Martan Guber Anastamosis
ulnar and median anastomosis
3 areas of compression in Thoracic outlet syndrome
- Scalene
- Costoclavicular syndrome - 1st rib and clavicle
- Cervical rib
Rieche cano anastamosis
deep branch of ulnar to recurrent branch of recurrent nerve
Romans ROber anastomosis
deep ulnar –> posterior interosseous nerve anastomosis
Ligament of Strutters
2 cm bone spur 3-6cm proximal to medial epicondyle
Clinical if LOS causes median nerve entrapment
before all muscles are given off
weak in all muscles
- weak grip FDS FDP
- wrist flexion (FCR)
- dull ache in forearm
EMG LOS causes median nerve entrapment
SNAP And CMAP - abnormal
treatment LOS causes median nerve entrapment
Rehab and surgery
Clinical if Lacerates Fibrosis causes median nerve entrapment
- all muscles will be affected
Pronator Teres Syndrome
muscle compresses nerve - either before or after it gives its innervation
Anterior Interosseous Syndrome cause
injury to the motor branch of the median nerve
Supplies (FDS, PQ, FPL)
- idiopathic
- fracture of the forearm or humerus
- laceration
- compression
Clinical appearance of Anterior Interosseous Syndrome
The patient may demonstrate a positive “OK” sign (Figure 5–85) or have difficulty forming a fist (Figure 5–86) because of an inability to approximate the thumb and index finger (FPL, FDP weakness). Sensation is spared.
.EMG finding of Anterior Interosseous Syndrome
Sensory - NORMAL
CMAP - possible abnormal activity to PQ
MILD Degrees of CTS
Mild
- numbness, paresthesias, or dysesthesias radiating to the first, second, third, and lateral fourth digits.
- exacerbated during sleep
- relieved with wrist shaking.
Moderate CT S
Moderate
- continuous sensory deficits in the median nerve distribution- the entire palm and radiating proximally
- ability to handle fine objects is impaired.
Severe CTS
complain of severe sensory loss and muscular atrophy of the thenar emi- nence.
Severe CTS
complain of severe sensory loss and muscular atrophy of the thenar emi- nence.
NCS findings for Mild CTS
SNAP: Prolonged latency
CMAP: Normal
EMG- normal
NCS for moderate CTS
SNAP: Plus a decreased amplitude
CMAP: Prolonged latency
EMG - normal
NCS for severe CTS
SNAP: Absent
CMAP: Plus a decreased amplitude
Emg - abnormal activity
Poor outcome with conservative management may occur with:
• Symptoms greater than 10 months in duration
• Constant paresthesias
• Positive Phalen’s Test in less than 10 seconds
• Weakness, atrophy
• Marked prolonged latency on NCS
• Abnormal spontaneous activity on EMG
indication for surgery
- muscle atrophy
- severe pain
- failed conservative measures
ulnar course before giving its branches
The nerve descends along the medial surface of the medial head of the triceps. It runs within a deep groove of thick fascia, the Arcade of Struthers. It continues posteriorly in a sulcus between the medial epicondyle and olecranon, called the retrocondylar groove.
• Arcade of Struthers (AOS)
fascial band that connects the brachialis to the triceps brachii.
What nerve can be injured with going through AOS
ULNAR nerve
clinical pictures of AOS entrapment of
- all ulnar nerve muscles will be affected
- may get radial deviation because weak FCU
- abnormal sensation in ulnar distribution
Ulnar claw hand
While the hand is at rest, an unopposed pull of the EDC causes partial finger flexion of the fourth and fifth PIP and DIP joint due to exten- sion of the MCP.
froment sign
This test demon- strates an inability to hold a piece of paper by the thumb and index finger with pure thumb adduction (adductor pollicis weakness). The patient substi- tutes the median innervated FPL muscle, causing flexion of the interphalangeal joint.
Wartenberg’s Sign:
nability to adduct the fifth digit. (Interossei weakness). Therefore digiti minimi lies abducted since unopposed
NCS for ulnar nerve entrapment at AofS
SNAP: Abnormal dorsal ulnar cutaneous (DUC) and ulnar nerve findings
CMAP: Abnormal
Tardy Ulnar Palsy
ulnar neuropathy that can occur months to years after a distal humerus fracture
- nerve can be injured secondary to a trauma that results in bone overgrowth or scar formation. Nerve traction can occur from an increased carrying angle due to a values deformity at the elbow
Cubital Tunnel Syndrome
most common site of elbow entrapment. It is bordered by the medial epicondyle and olecranon with an overlying aponeurotic band.
- nerve can be injured from compression beneath the prox- imal edge of the FCU aponeu- rosis or arcuate ligament.
What muscles involved in Cubital Tunnel Syndrome
ALL ulnar muscles - similar to simp of AOS
FCU may or may not be involve
Tingles sign - positive over cubital tunnel
NCS and EMG of Cubital Tunnel Syndrome
SNAP: Abnormal findings in
the dorsal ulnar cutaneous and ulnar nerve
CMAP: Approximately 10 ms drop of conduction velocity across the elbow
Shea’s System for calcification of ulnar nerve injury at guyots canal
Type 1 - hypothenar and deep ulnar branches
Type 1 : deep ulnar branches
Type 3: superficial ulnar sensory branch
NCS and EMG finding of Guyon canal ulnar nerve injury
NCS
SNAP: DUC nerve is spared, ulnar nerve to the fifth digit is abnormal
CMAP: Abnormal
EMG
Abnormal activity in the ulnar nerve innervates hand muscles
clinical finding of Guyon canal ulnar nerve injury
intrinsic muscles
- 4 dorsal interossei
- 3 palmar interossei
- 2 lumbricles
1 adductor polices
- 1/2 FPB
PLUS
- hypothenar muscle, opposes DM, abductor DM, Flexor DM
painless wasting of the FDI.
severe claw hand may occur (lumbrical weak- ness) while the FDP remains intact causing marked finger flexion.
Crutch Palsy
- damage to the radial nerve but can also involved median axillary and supra scapular nerve
Clinical Crutch palsy
- weakness in triceps
- sensation decreased over the posterior arm and forearm
crutch palsy NCS and EMg
SNAP - may or may not be abnormal
CMAP - may or may not be abnormal
EMG - abnormal activity in the radial nerve innervated muscle
Spiral Groove injury
Radial nerve injury
- also known as Saturday night Palsy or Honeymooner Plays
Clinical Spiral Groove injury
SPARES - triceps and anconeous (elbow extensors)
All other radial nerves involved - weakness of elbow flexion (BR weakness)
- supination (supinator weakness)
- wrist drop (ECRL, ECRB, ECU weakness
- finger extension (EDC weakness)
Sensory deficits may occur in the dorsal aspect of the hand and posterior arm
Differential Dx of Wrist Drop
- Diffuse polyneuropathy : LEAD
- Mononeuropathy - PIN, radial nerve
- Plexopathy - posterior cord, upper trunk, middle truck
Radiculogpthy C6 and C7
SCI/ TBI / CVA
PIN syndrome
- PURE MOTOR Syndrome
PIN syndrome cause
- injury to nerve at Arcade of Frohse
- Injury by lipoma, cyst, synovitis from RA or a Monteggia fracture
Clinical PIN
- normal function of Triceps, ancones, BR, ECRL and ECRB
Abnormal in all muscles supplied by PIN ECU, EDM, EDC, Abductor PL, EPL, EPB, EIP
- distal extensor weakness
pseudo claw hand deformity (finger extensor weakness)
PIN NcS and EMG
SNAP - normal
CMAP - abnormal finding in muscle innervated by PIN
EMG - abnormal activity innervated by PIN including supinator
Superficial Radial Neuropathy
also known as Cheiralgia Paresthetica or Wristwatch Syndrome
compression at the wrist from a wristwatch, tight hand-
cuffs, etc.
Pure sensory syndrome
Clinical Superficial Radial Neuropathy
- plain solely of sensory abnormalities including numbness, burning, or tingling on the dorsal radial aspect of the hand.
- Discomfort may be exacerbated with palmar and ulnar wrist flexion or forced pronation.
Treatment of l Superficial Radial Neuropathy
Interventions may include: rehabilitation and removal of the compressive irritant.
fucking of EDC
extension of MCPs
Lumbrical infection
Flexion MCP and PIP and DIP extension
Dorsal interossei
MCP abduction (DAB)
Palmar interosse
MCP abduction (PAD)
heavy backpack with R shoulder weakness no pain, found to have a very weak right shoulder ER
Rotator cuff tear
C5- C6 nerve root damage
C6-C7 NR injury
SUPRASCAPULAR nerve injury (backpackers palsy)
Impingement syndrome
Arcade of Suthers entrapment damages what nerve
Ulnar
Arcade of Frohse damages what nerve
Radial
Ligament of strutters damages
Median nerve
two special signs for ulnar neuropathy
Front sign
Waternberg sign
Tardy ulnar nerve palsy
after a fracture
- entrapment anywhere along elbow
Bilateral wrist drop but eaten their fingers
THINK: radial nerve damage - wrist drop
Extend fingers : lumbricles and interossi (innervated by ulnar and median nerve
Ulnar neuropathy on elbow what not to do
external compression of ulnar nerve (leaning on table)
Stop smoking
complains of painless wasting of the first dorsal interossei what does it mimic
MND
Ulnar neuropathy at Guyon’s canal - more specifically distal deep palmar motor lesion
Preserved strength of APB (C8-T1) muscles. In MND expect all C8 - T1 muscles to be equally
Saturday night palsy
Radial nerve damage at spiral groove
Sensory loss to back of hand , some supination problems
pronator syndrome sensory issue
median nerve in hand
Pin will always spare
ECR
BR
triceps
Ancones
neuralgic amyotrophy
Supra scapular nerve
thumb motor and sensory sensation
Motor - all three , PIN, AIN and ulnar
Sensory - medial and radial
Rhomboid weakness cause what type of winging
lateral winging and retraction
