Download MBBS Anatomy PPT 85 Brachial Plexus Notes

Learning objectives


? Formation of brachial plexus

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? Components ? roots, trunks, divisions &

branches

? Relations ? cervical & axillary part

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? Main nerves of arm, forearm & hand
? Nerve course, injuries & applied aspects

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Wasted Thenar Muscles


Winging of scapula

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Winging of

scapula

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Wrist drop

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Week 7

Week 5

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RULE -
Limbs are outgrowths of ventral
body wall that undergo distal

growth and dif erentiation...5th

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Week

and rotation...7th week

Upper Limb

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Anterior

Muscle

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Compartments

Humerus

Arm

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Posterior

Anterior

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Forearm

Radius

Ulnar

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Posterior

Anterior

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Hand

5th metacarpal

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Anterior

Humerus

Arm

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Posterior

Few muscles of posterior
compartment are present in

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anterolateral aspect of

Anterior

forearm (*brachioradialis,

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supinator)

Forearm

*

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Radius

Ulnar

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Posterior

Anterior

Hand

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No posterior compartment in the hand

5th metacarpal

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Anterior

Musculocutaneous n.

Motor innervation

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Muscle Compartments

Humerus

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Radial n.

Posterior

Anterior

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Median n. & Ulnar n.

Radius

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Ulna

Radial n.

Posterior

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Ulnar n. & Median n.

Anterior

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5th metacarpal

Posterior

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Muscles of Arm: Cross elbow Move forearm

? Two compartments ? Anterior & posterior
? 1. Anterior: Flexors of forearm
? 2. Posterior: Extensors of forearm

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Anterior Compartment ? MCN + Axillary A & Brachial A

? Biceps brachii = Musculocutaneous nerve

? Brachialis = Musculocutaneous nerve

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? Coracobrachialis = Musculocutaneous nerve

? Brachioradialis = Radial nerve

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Posterior Compartment ? RN + Profunda Brachii Artery

? Triceps brachii = Radial nerve

? Anconeus = Radial nerve

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RULE : Ventral vs. dorsal limb mm.

Developmentally-dorsal muscles:

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? Lie posterior to the long bones in anatomical position
(* exceptions)

Developmentally-ventral muscles:

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? Lie anterior to the long bones in anatomical position

*

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Brachial plexus

? Supraclavicular part ? neck ? posterior

triangle b/w sclaneus anterior & sclaneus

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medius ? roots & trunks

? Infraclavicular part ? axilla ? divisions /cords

& branches

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? Cords ? named as per relation to second part

of axillary artery ? deep to pectoral minor

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? Lateral cord ? lateral , posterior cord ?

posterior & medial cord ?medial to 2nd part
of axillary artery

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Brachial Plexus
(right side; simplified)

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"Roots of BP"

(=ventral rami)

C5

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C6

Trunks

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C7

U

Divisions

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C8

M

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Cord

Terminal

Lat

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L

T1

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Branches

Post

Med

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Anterior (ventral) division

Posterior (dorsal) division

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Brachial Plexus
(right side; simplified)

"Roots of BP"

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(=ventral rami)

C5

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C6

Trunks

C7

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U

Divisions

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C8

M

Cord

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Terminal

Lat

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L

T1

Branches

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Post

Musculocutaneous n.

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Med

Median n.

Radial n.

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Anterior (ventral) division

Ulnar n.

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Posterior (dorsal) division

Brachial plexus - cords

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Lateral cord ? LML ? Lateral Pectoral n, Musculocutaneous

n, lateral root of Median n

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Medial cord ? MMMMU ? Medial pectoral n, Medial

cutaneous n of forearm, Medial cutaneous n of arm , Ulnar

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n & Medial root of median n.



Posterior cord ? LUNAR ? Lower subscapular n, Upper

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subscapular n , Nerve to latissimus dorsi, Axillary n & Radial
n.

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Brachial plexus - cords



1. Lateral cord ? LML ? Lateral Pectoral n,

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Musculocutaneous n, lateral root of Median n


2. Medial cord ? MMMMU ? Medial pectoral n,

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Medial cutaneous n of forearm, Medial

cutaneous n of arm , Ulnar n & Medial root of

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median n.


3. Posterior cord ? LUNAR ? Lower subscapular n,

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Upper subscapular n , Nerve to latissimus dorsi,

Axillary n & Radial n.

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Brachial plexus - cords

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1. Lateral cord ? LML ? Lateral Pectoral n,

Musculocutaneous n, lateral root of Median n

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2. Medial cord ? MMMMU ? Medial pectoral n, Medial

cutaneous n of forearm, Medial cutaneous n of arm ,
Ulnar n & Medial root of median n.

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3. Posterior cord ? LUNAR ? Lower subscapular n, Upper

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subscapular n , Nerve to latissimus dorsi, Axillary n &
Radial n.

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Brachial plexus ? supraclavicular

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branches - roots & trunks

? Branch to Phrenic nerve ?C5 ?anterior to sclaneus

anterior

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? Dorsal scapular n ? C5 ? pierces sclaneus medius,

supplies rhomboids & levator scapulae

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? Long thoracic n ? C5C6C7 ? (C7 ? may be absent) upper

two roots C5C6 pierce sclaneus medius , runs b/w
sclaneus ant & medius ? Supply - serratus anterior.

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? TRUNKS ? Upper
? Nerve to subclavius ? Erb's Point - C5 C6 ?subclavius (

gives - accessory phrenic nerve ?C5)

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? Suprascapular n- C5C6 ? supra & infraspinatus , articular

? shoulder, acromioclavicular,

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Brachial plexus-

? Lateral pectoral n- C5C6C7 ? LC -larger, pierces

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clavipectoral fascia ,ant to axillary art- pectoralis major
& minor.

? Medial pectoral n- C8T1-MC- , pierces pectoralis minor

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& supplies both pectoralis major & minor.

? Upper sub scapular n- smaller ? frequently double.
? Lower sub scapular n- subscapularis & teres major.
? Axillary n- ant branch ?deltoid & post branch- has

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pseudoganglion supplies teres minor ,cutaneous ? as-
upper lateral cutaneous nerve of arm .

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Brachial Plexus

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C5

(branches)

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C6

supraspinatus

suprascapular n.

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C7

& infraspinatus

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*

mm.

C8

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T1

**

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upper subscapular n.

subscapularis m.

axillary n. thoracodorsal n.

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latissimus dorsi

lower subscapular n.

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m.

deltoid & teres minor mm.

Brachial Plexus

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(branches)

rhomboid mm.

dorsal

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scapular n.

C5

C6

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suprascapular n.

C7

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*

C8

pectoralis mm. lateral pectoral n.

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serratus

T1 anterior m.

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musculoskeletal
n.

long

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thoracic n.

medial n.

medial pectoral n.

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pectoralis

**

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mm.

upper subscapular n.
thoracodorsal n.

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axillary n.

lower subscapular n.

ulnar n.

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radial n.


Brachial Plexus

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(all branches)

Dorsal
scapular n.

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C5

C6

Suprascapular n.

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C7

*

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C8

Lateral pectoral n.

T1

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Musculoskeletal n.

Long

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thoracic n.

Medial n.

Medial pectoral n.

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**

Upper & lower subscapular nn.
Thoracodorsal n.

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Axillary n.

Ulnar n.

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* Nerve to subclavius

Radial n.

** Medial brachial & antebrachial cutaneous nn.

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Brachial plexus - cords

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Lateral cord ? LML ? Lateral Pectoral n, Musculocutaneous

n, lateral root of Median n

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Medial cord ? MMMMU ? Medial pectoral n, Medial

cutaneous n of forearm, Medial cutaneous n of arm , Ulnar
n & Medial root of median n.

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Posterior cord ? LUNAR ? Lower subscapular n, Upper

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subscapular n , Nerve to latissimus dorsi, Axillary n & Radial
n.

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Brachial plexus - cords

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? Lateral cord ? LML ? Lateral Pectoral n,

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Musculocutaneous n, lateral root of Median n



? Medial cord ? MMMMU ? Medial pectoral n, Medial

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cutaneous n of forearm, Medial cutaneous n of arm ,
Ulnar n & Medial root of median n.

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? Posterior cord ? LUNAR ? Lower subscapular n, Upper

subscapular n , Nerve to latissimus dorsi, Axillary n &
Radial n.

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Nerve supply of Scapular Muscles

? Origin on Scapula:

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? Latissimus dorsi = Thoracodorsal nerve /N to

latissimus dorsi

? Subscapularis & Teres Major = Subscapular nerves

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? Supraspinatus & Infraspinatus = Suprascapular

nerves

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? Deltoid & Teres Minor = Axillary nerve

? Insertion on Scapula

? Levator Scapularis & Rhomboids = Dorsal Scapular

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nerve

? Pectoralis Minor = lat & medial Pectoral nn.

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? Serratus anterior = Long Thoracic n/nerve of bell

? Trapezius = Accessory spinal n.

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Branches - Posterior Cord

? Axillary Nerve ( w . Circumflex vs..)

? Supplies:

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? Deltoid & Teres minor (motor supply )

? Capsule of shoulder

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? skin of lower part covering deltoid (sensory

supply)

? Subscapular Nerves {C5,C6} : Subscapularis &

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Teres major

? Thoracodorsal Nerve : Latissimus dorsi

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Injury to axillary nerve


Waisting of shoulder

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Winging of the Scapula

Combined Axillary and Long Thoracic Nerve

Injuries

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Fore arm ?muscles
1. Flexor Compartment : Anterior

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(Superficial 5 + Deep 3) - supplied by
Median, Anterior Interosseous Nerve &
Ulnar nerves

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2. Extensor Compartment : Posterior

(Superficial + Deep)

Radial & Posterior interosseous nerve.

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Radial nerve injury in arm

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Wrist drop


Anterior Compartment Forearm = 5 +3

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1 Pronator teres

Median n

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2 Flexor digitorum superficialis Median n

3 Flexor carpi radialis

Median n

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4 Palmaris longus

Median n

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5 Flexor carpi ulnaris

Ulnar nerve

1 Pronator quadratus

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Anterior interosseous n-Median n

2 Flexor digitorum profundus

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Anterior interosseous n-Median n

& Ulnar nerve

3 Flexor pollicis longus

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Anterior interosseous n- Median n

Posterior Compartment Forearm ?
superficial - 7

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1 Anconeus

Radial n

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2 Brachioradialis

Radial n

3 Extensor carpi radialis longus

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Radial

4 Extensor carpi radialis brevis

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Posterior interosseous? Radial n

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5 Extensor digitorum

Posterior interosseous? Radial n

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6 Extensor digiti minimi

Posterior interosseous? Radial n

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7 Extensor carpi ulnaris

Posterior interosseous? Radial n

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Posterior Compartment Forearm ? deep - 5

1 Supinator

Posterior interosseous? Radial n

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2 Abductor pollicis longus

Posterior interosseous? Radial n

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3 Extensor pollicis brevis

Posterior interosseous? Radial n

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4 Extensor pollicis longus

Posterior interosseous? Radial n

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5 Extensor indicis

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Posterior interosseous? Radial n
Hand ? Median nerve - 5

Flexor pollicis brevis

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Median n

Abductor pollicis brevis

Median n

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Opponens pollicis

Median n

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1st lumbrical

Median n

2nd lumbrical

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Median n

Hand ? Ulnar nerve - 15

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Flexor digiti minimi

Ulnar n

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Abductor digiti minimi

Ulnar n

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Opponens digiti minimi

Ulnar n

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Interossei ? palmar & dorsal (8) Ulnar n



3rd & 4th lumbricals (2)

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Ulnar n

Palmaris brevis

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Ulnar n ? superficial branch

Posterior Compartment of Forearm

Muscle

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Nerve

? Superficial

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? Extensor carpi radialis Longus & Brevis

RN

? Extensor digitorum (communis) RN

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? Extensor digiti minimi

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RN

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? Extensor carpi ulnaris

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RN

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? Deep (post gp) - PIN

? Supinator

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Radial n + PIN

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? Abductor pollicis longus

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PIN

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? Extensor pollicis longus + brevis PIN

? Extensor indicis

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PIN

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An inability to oppose thumb to little finger

can result from injury to -

a) Axillary n

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b) Radial n

c) Ulnar n

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d) Median n


Hyperextension of proximal phalanges of

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little and ring fingers can happen due to
nerve injury of -

a) Ulnar

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b) Axillary

c) Radial

d) Median

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Inablity to abduction of arm can happen due

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to nerve injury of -

a) Axillary

b) Musculocutaneous

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c) Radial

d) Median

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Wrist drop can result from damage to -
a) Median n

b) Ulnar n

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c) Radial n

d) Anterior interosseous n

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