The brachial plexus is a network of nerves that originates from the lower cervical and upper thoracic spinal nerve roots and provides motor and sensory innervation to the upper limb. It has five roots, three trunks, divisions, cords and branches. The roots emerge from the spinal nerves C5-T1. The cords are named lateral, posterior, and medial based on their relationship to the axillary artery. The plexus gives rise to many branches that innervate specific muscles and skin areas of the upper limb. Variations commonly occur in the formation of the lateral cord. Injuries can happen at the level of the roots, cords or branches and cause different functional deficits depending on the location and extent of injury

1. SURGICAL ANATOMY OF
BRACHIAL PLEXUS
Sudhir suggala

2. ANATOMY
 A network of nerves starting from 5 nerve
roots in upper spine & ending in nerves that
control movement & sensation in the upper
limb.

3. ANATOMY contd…
 Located where neck joins shoulder behind
clavicle & between spine & upper arm just
distal to axilla.
 5 roots ant.primary rami after giving
segmental supply to prevertebral muscles
&scalene muscles.

4. Levels
 Roots
 Trunks
 Divisions
 Cords
 Branches

7. ROOTS
 THE ORIGIN NERVES ARE THE ANT.
PRIMARY RAMI OF5th TO 8th CERVICAL
VERTEBRAE AND T1.
 ROOTS EMERGE FROM THE
TRANSVERSE PROCESSES OF
CERVICAL VERTEBRAE IMMED. POST. TO
VERTEBRAL ARTERY
 T1:VULNERABLE IN FRACTURE AND
DISLOCATION OF FIRST RIB

8. NERVES FROM ROOTS .
 DORSAL SCAPULAR N. C5
 ARISES FROM C5 JUST LAT. TO LONG
THORACIC
 TRAV. POST TO Plx
 INNERVATES LEV.SCAPULAE, RHOMBOIDES

9. Brachial Plexus
Netter 2nd ed

11. ROOTS contd…
 LONG THORACIC N. OF BELL
C567
 IMMED. AFTER THEY ORIG. FROM
INTERVERTEBRAL FORAMEN
 ALSO PIERCES S.MED. AS IT PASSES
POST TO Plx

13. TRUNKS
 IN THE POST. TRIANGLE OF NECK
 C56: UPPER/SUPERIOR TRUNK
 C7; MIDDLE TRUNK
 C8 T1: LOWER/INFERIOR TRUNK
 TRUNKS LIE IN FRONT OF ONE
ANOTHER
 RELATION b/w C5 AND PHRENIC NERVE

15. NERVES FROM TRUNKS
 SUPRASCAPULAR N. C5,6
 SENSORY TO SHOULDER JT.
 MOTOR TO SUPRASPINATUS AND
INFRASPINATUS
 N.TO SUBCLAVIUS C5,6

16. DIVISONS
 LIE DEEP TO CLAVICLE
 POSTERIOR DIV. OF UPPER AND MIDDLE
TRUNK LARGER
 10% OF CASES NO POST. DIVISON OF
LOWER TRUNK

17. CORDS
 NAMED LAT. ,POST. AND MEDIAL ACC.
TO RELATION WITH AXILLARY ARTERY
 LATERAL CORD: ANT. DIV OF UPPER &
MIDDLE TRUNK
 MEDIAL CORD: ANT. DIV. OF LOWER
TRUNK
 POSTERIOR CORD:POST./DORSAL
DIVISONS OF ALL 3 TRUNKS

18. FROM LAT.CORD
 Lateral pectoral nerve- c5,c6,c7
 Pierce clavipectoral fascia.
 Communicate with medial pectoral across front
of 1st part of axillary art.
 Br. To P.major & P.minor
 No cut. Br.

19. FROM LAT. CORD contd…
 Musculocutaneous nr.-c5,c6,c7
 To biceps & brachialis.
 Becomes lateral cut. Nr. Of forearm.
 Lateral root of median nr.-c5,c6,c7
 Continuation of lat.cord

20. FROM MEDIAL CORD
Medial pectoral nr.- behind 1st part of ax.art
Perforates p.minor
No cut.br.
Medial root of median nr-. Crosses ax. Art to join lat root.
Medial cut.nr. Of arm – smallest & most medial.
Medial cut. Nr. Of forearm –
Large nr.
Runs down bet ax.art & ax. Vein in front of ulnar nr.
Ulnar nr.- largest br. C7 C8 T1
To most of the hand muscles.

21. FROM POST CORD contd…
 Radial nr. – c5,c6,c7,c8,T1
 Cont.of post cord
 Largest in the whole plexus
 Gives post cut nr. Of forearm.

22. FROM POST.CORD
 Upper subscapular- c5,c6
 Small nr.
 Enters upper part of subscapularis.
 Thoracodorsal – c6,c7,c8
 nr.to lat. Dorsi.
 A large nerve.
 Runs down post.ax. Wall.

23. FROM POST CORD contd…
 Lower subscapular –c5,c6
 To lower part of subscapularis
 Ends in teres major.
 Axillary nr. – c5,c6
 Circumflex nr.
 A large terminal br.
 No supply in axilla.
 Br.to shoulder jt.
 Ant. & post div.

24. FROM POST CORD contd…
 Radial nr. – c5,c6,c7,c8,T1
 Cont.of post cord
 Largest in the whole plexus
 Gives post cut nr. Of forearm.

25. VARIATIONS
 GREATEST VARIATION IN FORMATION
OCCURS IN LATERAL CORD
 10% OF CASES MUSCULOCUT. N. MAY
ARISE AS 2-3 BRANCHES
 LATERAL ROOT OF MEDIAN N. MAY
ARISE AS 2-3 BRANCHES

26. BLOOD SUPPLY
 From subclavian & vertebral art.
 Vertebral art.- c5, c6. & more proximal
cervical nerves
 C8, T1,- br. From costocervical trunk.

27. MICRO ANATOMY
 120,000-150,000 Myelinated fibres
 C5 &T1-least no. of myelin.fibres
 C8 –largest no. of myelin.fibres.
 Proportion of motor fibres highest in c5, then
c8 & least in c7 & t1.
 Sensory greatest in c7, then c6, then c8.
 Segregation of nr fibres well established
proximally.

28. PREFIXATION & POSTFIXATION
 PREFIXED: CONTRIBUTION FROM C4 IS
LARGE ,T2 IS OFTEN ABSENT
 POSTFIXED: CONTRIBUTION FROM T1
IS LARGE, T2 IS ALWAYS PRESENT,C4 IS
ABSENT,C5 IS REDUCED IN SIZE

31. Anatomy

32. BRACHIAL PLEXUS SHEATH
 C.t. of prevertebral fascia
 Blends with fascia of biceps & brachialis.
 C.t. septae compartmentalize components of
the sheath.
 Controversies – septae may limit spread of
solutions during BP block.

33. Brachial Plexus Branches &
Muscular Innervations
Dorsal Scapular N.
 Levator Scapulae
 Rhomboid Major/Minor
Lateral Pectoral N.
 Pectoralis Major/Minor
Suprascapular N.
 Infraspinatus
 Supraspinatus
Musculocutaneous N.
 Biceps Brachii
 Brachialis
 Coracobrachialis

34. Brachial Plexus Branches &
Muscular Innervations
Axillary N.
 Deltoid
 Teres Minor
Upper Subscapular N.
 Subscapularis
Middle Subscapular or
Thoracodorsal N.
 Latissimus Dorsi
Lower Subscapular N.
 Subscapularis
 Teres Major

35. Brachial Plexus Branches &
Muscular Innervations
Median N.
 Abductor Pollicis
Brevis/Longus
 Flexor Carpi Radialis
 Flexor Digitorum Superficialis
 Flexor Digitorum Profundus
(Lat. 2)
 Flexor Pollicis Brevis (Lat.) &
Longus
 Lumbricales (Lat. 2)
 Opponens Pollicis
 Palmaris Longus
 Pronator Quadratus
 Pronator Teres *
Radial N.
 Abductor Pollicis Brevis
 Anconeus
 Brachioradialis
 Extensor Carpi Radialis
Brevis/Longus
 Extensor Carpi Ulnaris
 Extensor Digiti Minimi
 Extensor Digitorum Communis
 Extensor Indicis
 Extensor Pollicis
Brevis/Longus
 Supinator
 Triceps Brachii

36. Brachial Plexus Branches &
Muscular Innervations
Ulnar N.
 Abductor Digiti Minimi
 Adductor Pollicis
 Dorsal Interossei
 Flexor Carpi Ulnaris
 Flexor Digiti Minimi
 Flexor Digitorum Profundus
(Med. 2)
 Flexor Pollicis Brevis (Med.)
 Lumbricals (Med. 2)
 Opponens Digiti Minimi
 Palmar Interossei
Long Thoracic N.
 Serratus Anterior
Medial Pectoral N.
 Pectoralis Major
Medial Brachial Cutaneous N.
(sensory)
Medial Antebrachial
Cutaneous N. (sensory)

37. FUNCTIONAL DISTRIBUTION MOTOR
 C5-SHOULDER ABDUCTION
 C6-WRIST EXTENSION
 C7-WRIST FLEXION AND FINGER
EXTENSION
 C8-FINGER FLEXION
 T1-FINGER ABDUCTION AND ADDUCTION

39. SENSATION
 C5-LATERAL ARM
 C6-LAT.FOREARM ,THUMB,INDEX
FINGER
 C7-MIDDLE FINGER
 C8-MEDIAL FOREARM,RING,SMALL
FINGER
 T1-MEDIAL ARM
 T2-AXILLA

48. TRANSITIONAL ZONE
 BERTHOLD (1993):JUNC. b/w ROOTS AND
SPINAL CORD
 A CENTRAL-PERIPHERAL TRANSITIONAL
ZONE
 2 TYPES OF INTRADURAL INJURY-
RUPTURE AND AVULSION

49. RUPTURE & AVULSION
 INTRADURAL RUPTURE IS TEARING OF
ROOTLETS AT OR PERIPHERAL TO T.Z
 AVULSION IS ROOTLETS ARE TORN
FROM SPINAL CORD ITSELF AND INJURY
IS CENTRAL TO TRANSITIONAL ZONE .

59.  UPPER PLEXUS INJURY (ERB’S
PARALYSIS)
 LOWER PLEXUS INJURY(KLUMPKE’S
PARALYSIS)
 INJURY AT LEVEL OF ROOTS

60. CORDS INJURY
 LATERAL
 POSTERIOR
 MEDIAL

61. NEOPLASTIC RADIATION

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