Ch 9 - Neuromuscular Flashcards
Which nerves originate proximal to the brachial plexus?
Dorsal scapular nerve and long thoracic nerve
Dorsal scapular nerve originates where and supplies what muscles?
C4- C5
Rhomboids and levator scapulae
Rhomboids have 4 sides, C4-5
Long thoracic nerve originates where and innervates what muscle?
C5-7
Serratus anterior
(medial) Scapular winging occurs with what?
Damage to serratus anterior (long thoracic nerve)
SALTy WING MEal
SA=serratus anterior, LT= long thoracic, ME=medial
What causes lateral winging of the scapula?
Damage to trapezius (CN11)
When is long thoracic nerve commonly injured?
Very superficial and runs supraclavicular, so can be injured by carrying heavy objects on ones shoulder or during mastectomy
Segments of brachial plexus?
Roots, Trunks, Divisions, Cords, Nerves
Republicans Think Democrats Cant Negotiate
Roots of brachial plexus?
C5-T1
Trunks of brachial Plexus?
Upper (C5-6)
Middle (C7)
Lower (C8-T1)
Divisons of the brachial plexus divide??
Anterior = travels to ventral arm
Posterior = dorsal arm
Cords of brachial plexus?
Lateral, Medial and posterior cords.
Lateral Cord of the brachial plexus?
Consists of anterior division of C5-C6 and middle from C7
C5-C7
Posterior Cord of the brachial plexus?
Consists of all divisions, C5-T1
Medial Cord of the brachial plexus?
C8-T1
Branches off the trunks of the BP?
suprascapular and nerve to subclavius
Suprascapular nerve supplies?
Supraspinatus and infraspinatus
Function of supraspinatus?Infraspinatus?
First 15 degrees of arm abduction
External rotation of the arm.
Branches of the lateral cord?
Lateral cutaneous nerve of the forearm
Lateral pectoral nerve
Musculocutaneous
Median Nerve*
*Medial cord also contributes to median nerve
Lesion of the lateral cord causes?
Sensory loss over the lateral forearm (LCN of forearm), and weakness of elbow and wrist flexion (musculocutaneous)
Lateral pectoral nerve (C5-7) supplies ? function?
clavicular head of pectoralis major muscle.
Pulls shoulder forward.

Musculocutaneous Nerve (C5-7) supplies what muscles? Function?
biceps, brachioradialis, coracobrachialis
supination of the forearm, elbow flexion, biceps reflex.

Median nerve is supplied by what cord (s)?
Lateral and medial cords

The part of the median nerve supplied by the lateral cord is responsible for sensation to?
Muscles?
Function?
Sensation to thumb, index, middle finger, (lateral ring finger is medial AND lateral cord)
pronator teres and flexor carpi radialis
pronator teres pronates the forearm, FCR flexes and abducts the wrist

Branches of the medial cord?
medial cutaneous nerve of the arm (C8-T1)
medial cutaneous nerve of the forearm (C8-T1)
Median Nerve (C8,T1 from medial cord, C5-T1 total)
Ulnar nerve (C7-T1)
Medial pectoral nerve (C8-T1)
Lesion of the lateral cord causes?
Sensory loss over medial forearm, weakness of long finger flexors, and weakness of intrinsic hand muscles.
Medial Pectoral Nerve innervates? function?
pec minor(lowers scapula and moves shoulder forward)
sternal head of pec major (adducts the arm and rotates medially)
Part of median nerve supplied by the medial cord supplies? Function of median nerve?
APB (C8-T1)
FDP 1 and 2 (C7-8)
FDS (C7-T1)
FPB (superficial head) (C8-T1)
lumbricals 1 and 2 (C8-T1)
Opponens pollicis (C8-T1)
Palmaris longus (C7-T1)
Pronator quadratus (C7-8)
Flexion of thumb, index, middle finger, flexion of wrist, opposition of thumb, pronation of the forearm, abudction of the hand.

APB function
abducts the thumb perpendicular to the hand
FDP 1 and 2 function
flexion of the terminal phalanges
FDS function?
flexes the middle phalanges of the second, third, fourth, fifth fingers.
Superficial FPB function?
flexes the proximal phalanx of the thumb
FPL function?
flexion of the terminal phalanx of the thumb
Lumbricals 1 and 2 function
flex the MCP joint and extend the procimal and distal interphalangeal joints of the 2nd and 3rd digits.
Opponens pollicis fxn
opposition of the thumb
palmaris longus fxn
flexes the wrist
pronator quadratus fxn?
pronates the forearm
Sensory branches of the median nerve supply
thenar emninence, proximal palm, palmar aspect of first 3 digits and half of fourth digit.

Anterior Interosseous Nerve (branch of median nerve) innervates?
FPL (C5-7)
FDP 1 and 2 (C5-7)
Pronator quadratus (C7-8)
Anterior interosseous nerve injury syndrome?
Pain in the arm/forearm
weakness in pronation (PQ)
weakness in flexion of the terminal phalanx of the thumb (FPL)
weakness in terminal phalanges of 2nd and 3rd digit (FDP 1 and 2)
normal sensation
(PURE MOTOR NERVE)
Cannot make OK sign => teardrop sign

Signs of CTS?
weakness in APB, decreased sensation in the median distribution with sparing of sensation of the thenar area because the palmar cutaneous branch arises proximal to the carpal tunnel.
Phalens - elicited with wrist PHlexion
Tinel - Tapping over median nerve at the wrist
What is the abnormal NCS finding in CTS?
prolonged distal latency in the median sensory
(NCS can be normal in CTS)
Function of the ulnar nerve?
Ulnar flexion at the wrist, flexion of 4th and 5th digits, opposition and abduction of the 5th digit, thumb adduction, finger abduction and adduction
Issues with ulnar nerve causes what deformity?
Claw hand - hyperextension of MCP joints with flexion at interphalangeal joints.
Ulnar nerve supplies sensation to?
Fifth and half of fourth digit
List of muscles supplied by the ulnar nerve?
Abductor digiti minimi (C8-T1)
Adductor pollicis (C8-T1)
Flexor carpi ulnaris (C7-T1)
Flexor digiti minimi (C8-T1)
Flexor digitorum profundus 3+4 (C7-C8)
Flexor pollicis brevis (deep head) (C8-T1)
Interossei (C8-T1)
Lumbricals III/IV (C8-T1)
Opponens digiti minimi (C8-T1)
Palmaris brevis (C8-T1)
Function of ADM?
abducts fifth digit
Function of adductor pollicis
adducts the metacarpal of the thimb
function of FCU
flexes the wrist and adducts the hand
function of flexor digiti minimi
flexes the fifth digit
function of flexor digitorum profundus III and IV
flexes the terminal phalanges of the fourth and fifth digits.
Function of deep head of flexor pollicis brevis
flexes and adducts the thumb
Function of the lumbricals III and IV?
flex the MCP joints and extend the proximal and distal IP joints of the third and fourth digits.
Function of interrosei?
flex the MCP joints and extend the proximal and distal IP joints.
Palmar interosei adduct the fingers, dorsal interossei abduct the fingers.
Function of opponens digiti minimi?
opposition of the fifth digit.
Best way to differentiate an ulnar nerve lesion from a T1 radiculopathy?
Test APB (C8-T1) however is innervated by the MEDIAN NERVE