BRACHIALPLEXUS

BRACHIAL PLEXUS

The parts of the brachial plexus, from medial to lateral:

•  ROOTS•  TRUNKS•  DIVISIONS•  CORDS•  BRANCHES

The parts of the brachial plexus(from medial to lateral):

5 ROOTS Read3 TRUNKS The6 DIVISIONS Details3 CORDS Carefully,5 BRANCHES Bob

BRACHIAL PLEXUS 5 ROOTS

The roots of the brachial plexus are the anterior rami of C5 to T1

Therootsenterthe

posterio

rtriangleof the

neck bypassing

betweenthe

anteriorscalene

andmiddlescalenemusclesand lie

superior

andposterior to thesubclavi

anartery.

BRACHIAL PLEXUS 5 ROOTS 3 TRUNKS

The roots unite to form the trunks:

•  SUPERIOR TRUNK: C5+C6

•  MIDDLE TRUNK:

ONLY C7

•  INFERIOR TRUNK:C8+T1

BRACHIAL PLEXUS

5 ROOTS 3 TRUNKS 6 DIVISIONS

Each of the 3 trunks of the brachial plexus divides into 2 divisions:

•  anterior division

•  posterior division

The trunks pass troughthe posterior triangle of the neck. The trunks pass laterally over Ist rib,and enter the axilla.

BRACHIAL PLEXUS

5 ROOTS 3 TRUNKS 6 DIVISIONS

The trunks split into:

•  3 anterior divisions

•  3 posterior divisions

The 3 cords originate from the 6 divisions

BRACHIAL PLEXUS

5 ROOTS 3 TRUNKS 6 DIVISIONS3 CORDS

THE CORDS:

•  LATERAL•  POSTERIOR•  MEDIAL

are related to the second part of the axillary artery

BRACHIAL PLEXUS

5 ROOTS 3 TRUNKSè 6 DIVISIONSè 3 CORDS

The posterior cord occurs posterior to the second part of theaxillary artery.

The posterior cord originates as the union of all three posteriordivisions.

It contains contribu[ons from all roots of the brachial plexus (C5 to T1)

BRACHIAL PLEXUS

5 ROOTS 3 TRUNKSè 6 DIVISIONSè 3 CORDS

The lateral cord results from the union of the anterior divisions ofthe superior and middle trunks.

The lateral cord is placed lateral to the second part of the axillary artery.

BRACHIAL PLEXUS

5 ROOTS 3 TRUNKSè 6 DIVISIONSè 3 CORDS

The medial cord is the con[nua[on of the anterior division of the inferior trunk—it contains contribu[ons from C8 and T1.

The medial cord contains contribu[ons fromC8 and T1.

The medial cord is medial to the second part of theaxillary artery.

BRACHIAL PLEXUS SCHEMA OF THE BRACHIAL PLEXUS

BRACHIAL PLEXUS THE MUSCULOCUTANEOUS NERVE C5-C7

THE MUSCULOCUTANEOUS NERVE:

COURSE:•  exits axilla by piercing corarobrachialis•  descends between biceps brachii and brachialis (supply both)•  exits laterally in forearm as lateral cutaneous nerve of forearm

MOTOR INNERVATION:•  anterior flexor compartment of arm:

coracobrachialis, biceps brachii and brachialis muscles

SENSORY:•  skin of the lateral aspect of the forearm

BRACHIAL PLEXUS THE MUSCULOCUTANEOUS NERVE C5-C7

THE MUSCULOCUTANEOUS NERVE:

MOTOR INNERVATION:•  anterior flexor compartment of arm:

coracobrachialis, biceps brachii and brachialis muscles

INJURY:•  can not flex the elbow

BRACHIAL PLEXUS THE AXILLARY NERVE C5-C6

THE AXILLARY NERVE:

COURSE:•  exits axilla posteriorly•  runs posterior to the SURGICAL NECK

INNERVATION:•  glenohumeral (shoulder) joint•  teres minor•  deltoid muscle

SKIN:•  skin of the superolateral arm

BRACHIAL PLEXUS THE AXILLARY NERVE C5-C6

THE AXILLARY NERVE

MUSCLE INNERVATION:•  teres minor•  deltoid muscle

INJURY:

•  loss of abduc[on from 15-900

BRACHIAL PLEXUS SCHEMA OF THE BRACHIAL PLEXUS

BRACHIAL PLEXUS THE MEDIAN NERVE C6-T1

THE MEDIAN NERVE:

COURSE:•  lateral to axillary artery•  anterior to the elbow

THE MEDIAN NERVE: NO BRANCHES IN THE ARMOR AXILLA!

COURSE:•  supplies and passes between two heads of the pronator teres

muscle•  the nerve is closed to the surface of the wrist

BRACHIAL PLEXUS

THE MEDIAN NERVE:

INNERVATION

FOREARM:flexors of the wrist:

•  pronator teres,•  flexor carpi radialis,•  palmaris longus,•  flexor digitorum superficialis

THE MEDIAN NERVE C6-T1

Innervates most of the muscles in theanterior compartment of the forearm

(except for: the flexor carpi ulnarismuscle and the medial half of the flexordigitorum profundus muscle, which are

innervated by the ulnar nerve).

BRACHIAL PLEXUS THE MEDIAN NERVE C6-T1

THE MEDIAN NERVE:

THE BRANCHES (in the forearm):•  Anterior interosseous nerve (major branch in the forearm)•  Ar[cular branches•  Muscular branches•  Palmar cutaneous branch of the median nerve

BRACHIAL PLEXUS THE MEDIAN NERVE C6-T1

THE MEDIAN NERVE

INNERVATION:HAND:•  two lateral lumbricals: 1st and 2nd•  thenar eminence via the reccurent branch: opponens pollicis,

abductor pollicis brevis

SENSORY•  lateral three and one-half fingers of palmar surface•  superior dorsal apects (three and one-half finger[ps)

BRACHIAL PLEXUS THE MEDIAN NERVE C6-T1

THE MEDIAN NERVE

INJURY•  carpal tunnel syndrome – reduced the size of the carpal tunnel•  lunate disloca[on•  supra-epicondylar fracture of humerus

BRACHIAL PLEXUS THE MEDIAN NERVE C6-T1THE MEDIAN NERVE

The carpal tunnel syndrome causes:

MEDIAN TRAP

Myxedema (hypothyroidism)EdemaDiabetesIdiopathicAcromegalyNeoplasmTrauma Rheumatoid arthri[s Amyloidosis Pregnancy

BRACHIAL PLEXUS THE MEDIAN NERVE C6-T1

THE MEDIAN NERVE

The carpal tunnel syndrome:•  any pathology that expands the contents of the tunnel will

compress the enclosed median nerve•  tendoni[s of the flexor re[naculum from overuse – median nerve

entrapment

Findings:•  numbness•  [ngling or sensory loss•  atrophy of thenar eminence

BRACHIAL PLEXUS THE MEDIAN NERVE C6-T1

THE MEDIAN NERVE

INJURY OF THE MEDIAN NERVEThe median nerve controls the 1st & 2nd lumbricals, three thenar muscles.

Addi[onally there may be thenar atrophy.

The hand of benedic[on is only apparent if the pa[ent is asked to makea fist - pa[ent will be able to flex the lihle and ring fingers.

POPE'S HAND (HAND OF BENEDICTION)

BRACHIAL PLEXUS SCHEMA OF THE BRACHIAL PLEXUS

BRACHIAL PLEXUS THE RADIAL NERVE C5-T1

THE RADIAL NERVE:

COURSE:•  posterior to brachial artery•  runs with the profunda brachii artery•  radial groove in humerus•  con[nues inferiorly in the anterior compartment of the arm•  between the brachialis and the brachioradialis•  to the level of the anterior part of the lateral epicondyle of

humerus

BRACHIAL PLEXUS THE RADIAL NERVE C5-T1

THE RADIAL NERVE:

MOTOR INNERVATIONS:•  triceps•  brachioradialis

MOTOR INNERVATIONS:•  extensors of the wrist - posterior compartment of forearm: extensorcarpi radialis longus, extensor carpi radialis brevis, extensor digitorum,extensor digi; minimi, extensor carpi ulnaris, supinator, extensor indicis, abductor policis longus, extensor policis longus, extensor policis brevis

BRACHIAL PLEXUS THE RADIAL NERVE C5-T1

THE RADIAL NERVE - INNERVATION OF THE SKIN:•  posterior arm and forearm•  on dorsal hand - below the finger[ps of the medial three and one-half fingers

THE RADIAL NERVE INJURY maybe due to:•  fracture of the body of humerus (radial groove)•  saturday night palsy (compression of the nerve)

THE RADIAL NERVEPa[ent is not able to extendINJURY

the wrist and fingers in the MPRESULT INjointsTHE WRIST DROP

BRACHIAL PLEXUS THE RADIAL NERVE C5-T1

DORSAL BRANCH OF ULNAR NERVESkin of medial aspect of dorsum of hand and proximal por[ons of lihle and medial half of ring finger

SUPERFICIAL BRANCH OF ULNAR NERVEPalmaris brevis & sensa[on to skin of the palmar and distal dorsal aspects of digit 5 and of the medial (ulnar) side of digit 4 and proximal por[on of palm

DEEP BRANCH OF ULNAR NERVEHypothenar muscles, lumbricals of digits 4 and 5, all interossei, adductor pollicis, and deep head of flexor pollicis brevis

BRACHIAL PLEXUS SCHEMA OF THE BRACHIAL PLEXUS

BRACHIAL PLEXUS THE ULNAR NERVE C7, C8-T1

THE ULNAR NERVE:

COURSE:•  passes on the medial side of the brachial artery•  descends between the medial intermuscular septum of the arm and

the medial head of triceps

THE ULNAR NERVE – NO BRANCHES IN THE ARM !

THE MEDIAN NERVE – NO BRANCHES IN THE ARM !

BRACHIAL PLEXUS THE ULNAR NERVE C7, C8-T1

THE ULNAR NERVE:

COURSE:•  passes posterior to the medial epicondyle and to the medial

olecranon to enter the forearm

•  passes superficial to the flexor re[naculum(the median nerve under the flexor re;naculum)

•  enters the hand by passing through a groove between the pisiform and the hook of the hamate – the ulnar canal (Guyon’s canal)

BRACHIAL PLEXUS THE ULNAR NERVE C7, C8-T1

THE ULNAR NERVE:

INNERVATION OF FOREARM:•  innervates medial flexors of the wrist: flexor carpi ulnaris and

medial part of the flexor digitorum profundus

INNERVATION OF HAND:•  hypothenar eminence: abductor digi; minimi, flexor digi; minimi

brevis, opponens digi;•  medial lumbrical muscles: 3rd and 4th lumbricals•  all interosseous muscles of the hand: 1st – 4th dorsal interossei,

1st-3rd palmar interossei

THE ULNAR NERVE:SKIN INNERVATION:•  dorsal and palmar apsect of the hand for medial 1 ½ fingers•  medial forearm

BRACHIAL PLEXUS THE ULNAR NERVE C7, C8-T1

THE ULNAR NERVE INJURY may be due to:•  medial epicondyle fracture•  fracture of the hook of hamate

THE ULNAR NERVE INJURYRESULTS IN:•  inability to abduct or adduct fingers•  hypothenar atrophy•  Ulnar Claw Hand:

•  loss of medial lumbricals•  pa[ent tries to open hand and cannot extend 4th and 5th digits

BRACHIAL PLEXUS

VSINJURY OF THE MEDIAN NERVE

POPE'S HAND(HAND OF BENEDICTION)

the pa[ent isasked to make afist: pa[ent willbe able to flex

the lihle andring fingers.

INJURY OF THE ULNAR NERVE

ULNAR CLAW HAND

pa[ent tries to open hand and cannot extend 4th and 5th digits

DUPUYTREN CONTRACTURE OF PALMAR FASCIA

•  Its cause is unknown•  The fibrous degenera[on of the longitudinal bands of the palmar

aponeurosis on the medial side of the hand pulls the 4th and 5th fingers into par[al flexion at the metacarpophalangeal and proximal interphalangeal joints

•  The contracture is frequently bilateral and is seen in some men > 50 years of age

BRACHIAL PLEXUS

SENSORY INNERVATION OF THE HAND