Definition

• It is a pyramid shaped space between the upper part of the arm and the side of the chest

• Important Nerves, Blood and Lymph vessels travel through it from root of the neck to the upper limb

BOUNDARIES

BOUNDARIES :

APEX :• DIRECTED UPWARD AND

MEDIAL WARD, ENDING IN THE CERVICOAXILLARY CANAL, WHICH LEADS INTO POSTERIOR TRIANGLE OF NECK.

BOUNDARIES :• Anterior wall: By the pectoralis major,

Subclavius and pectoralis minor muscles

• Posterior wall: By the subscapularis,

Latissimus dorsi and teres major muscles

BOUNDARIES :• Medial wall: By the upper 4 or 5 ribs

and intercostal spaces covered by serratus anterior muscle

• Lateral wall: By the coracobrachialis

and biceps muscles in the bicipital groove of humerus

BOUNDARIES :

Base :The Base of axilla is

formed by the axillary fascia and the skin

stretching between the anterior and posterior walls

Contents of Axilla

• Axillary artery and its branches

• Axillary vein and its tributaries

• Lymph vessels and lymph nodes

• Important nerve plexus the “Brachial Plexus” which innervates the upper limb

Axillary Artery• Is a continuation of subclavian

artery• Begins at the lateral border of the

1st rib• Ends at the lower border of teres

major• It continues as the brachial artery• Closely related to brachial plexus

cords• Enclosed with them in the axillary

sheath• Axillary sheath is continuous with

the prevertebral fascia• Pectoralis minor divides it into 3

parts• Branches of axillary artery supply

the thoracic wall and the shoulder region

1st Part of Axillary Artery

• Extends from the lateral border of the 1st rib to the upper border of pectoralis minor

● Branches : Highest thoracic artery = superior thoracic artery

Relation

• Anterior: Pectoralis major, covering fascia, skin, cephalic vein

• Posterior: Long thoracic nerve

• Lateral: Three cords of brachial plexus

• Medial: Axillary vein

2nd Part of Axillary Artery

• Lies behind the pectoralis minor muscle

• Branches : Thoracoacromial and lateral

thoracic arteries

Relation

• Anterior: Pectoralis minor and major, covering fascia and skin

• Posterior: Posterior cord of brachial plexus

• Lateral: Lateral cord of brachial plexus

• Medial: medial cord of brachial plexus and axillary vein

3rd Part of Axillary Artery• Extends from lower border

of pectoralis minor to the lower border of teres major

• Branches : Subscapular artery, anterior

and posterior circumflex humeral arteries

Relation• Anterior: Pectoralis major, medial root of the

median nerve

• Posterior: subscapularis, latissimus dorsi and teres major

• Lateral: Coracobrachialis, biceps, humerus

• Medial: Ulnar nerve, axillary vein, medial cutaneous nerve of the arm

Branches of the axillary artery1• Send - Superior thoracic artery 2• The - Thoraco-acromial artery• Lord to - Lateral thoracic artery 3• Say - Subscapular artery• A - Anterior circumflex humeral artery• Prayer - Posterior circumflex humeral artery

AXILLARY VEIN• BEGINS AT UNION OF

BASILIC AND BRACHIAL VEINS AND TERMINATES AT 1ST RIB AS SUBCLAVIAN VEIN.

• LIES MEDIAL TO AND PARTLY OVERLAPS AXILLARY ARTERY WITH MEDIAL CORD AND ITS BRANCHES.

• RECEIVES TRIBUTARIES CORRESPONDING TO BRANCHES OF ARTERY PLUS THE CEPHALIC VEIN.

AXILLARY LYMPH NODES 1. ANTERIOR(PECTORAL) AXILLARY N - receive afferens from ant & lat thorax,

central & lat mammary gland - efferents go to 4 &5 2. LATERAL (BRACHIAL) AXILLARY NODES: - receive afferens from all upper

extremity except those nodes around cephalic vein

- efferents go to 4 & 5 3. POST(SUBSCAPULAR) AXILLARY NODES : - receive afferens from lower back of

neck and posterior wall of thorax - efferents go to 4 4. CENTRAL AXILLARY NODES : - receive afferens from all the above

nodes - efferents go to 5 5. APICAL (SUBCLAVICULAR) AXILLARY

NODES: - receive afferens from all the above

nodes - efferents go to trunci subclaviiangulus

venosus jugulum

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Brachial Plexus

Brachial Plexus

• Roots– C5– C6– C7– C8– T1

• Trunks– Upper 5,6– Middle 7– Lower 8,1

• Divisions– Anterior – primarily

flexors– Posterior – primarily

extensors

• Cords– Lateral C5,6,7– Posterior C5,6,7,8– Medial C8,T1

Parts of Brachial Plexus

• Really Tired? Drink Coffee Buddy!

• R = ROOTS (ventral rami)• T = TRUNKS• D = DIVISIONS• C = CORDS• B = BRANCHES

Roots join to form Trunks! (in neck)

• Ventral Rami Trunks

• C5 Upper Trunk• C6• C7 Middle Trunk• C8• T1 Lower Trunk

Trunks Split to form Divisions! (in neck)• Trunks Divisions

• Upper AnteriorPosterior

• Middle Anterior

Posterior

• Lower Anterior Posterior

Divisions Join to form Cords! (in axilla)

U A P

M A P

L A P POSTERIOR CORD

LATERAL CORD

MEDIAL CORD

Trunks DivisionsCords

Cords Give off Branches!! (in axilla)

• Lateral Musculocutaneous

Median

• Medial Ulnar

• Posterior RadialAxillary(thoracodorsal)(subscapular)

Relation of Spinal N. Roots to Vertebrae

• 1st cervical nerve exits ABOVE C1 vertebra– 2nd through 7th nerves exit above corresponding

vertebrae

• 8th cervical nerve exits BELOW C7 vertebra

Note: There are 7 cervical vertebrae

There are 8 cervical nerves

Brachial Plexus and its branches :

(1) Roots• C5

• C6

• C7

• C8

• T1

• (2) Long thoracic nerve :• Spinal Cord Segments

– C5, C6, C7• Muscles Innervated

– Serratus

(3) Dorsal scapular nerve :• Spinal Cord Segment

– C5 (C4 is variable)• Muscles Innervated

– Levator– Rhomboids

TRUNCUS SUPERIOR

(4) Nerve to subclavius :• Spinal Cord Segments

– C5, C6• Muscles Innervated

SC(5)Suprascapular nerve :

• Spinal Cord Segments– C4, C5, C6

(6) Anterior Divisions

• Innervates volar aspect of U.E.

• Spinal Cord Segments– C5– C6– C7– C8– T1

(7) Posterior Divisions

• Innervates the dorsal aspect of the U.E.

• Spinal Cord Segments– C5– C6– C7– C8– T1

(9) Lateral Cord• Gives rise to 2 ½ nerves• Spinal Cord Segments: C5, C6

&C7.

(8) Lateral pectoral nerve• Spinal Cord Segments– C5, C6, C7• Muscles Innervated

Pec. Maj.

(21) Musculocutaneous• Spinal Cord Segments– C5, C6, C7• Muscles Innervated– BB, CB, Brachialis

(11) Medial Cord• Gives rise to 5 ½ nerves• Spinal Cord Segments:C8-T1

(12)Medial pectoral nerve

(13)Muscles Innervated– Pec. Maj.– Pec. Min.

(16)Medial brachial cutaneous

(17) Medial antebrachial cutaneous

(18) Ulnar nerve• Muscles Innervated– FCU, FDP (4,5), PB, ADM,

ODM, FDM, ADD POL, FPB (deep head), Lum (4,5) DI, PI

Branches of Brachial Plexus Medial Cord:

• Money Makes Many Men Unhappy• • Medial pectoral nerve• • Medial branch of median nerve• • Medial cutaneous nerve of arm• • Medial cutaneous nerve of forearm• • Ulnar nerve

(22) Median nerve

• Spinal Cord Segments– C5, C6, C7, C8, T1

• Muscles Innervated– PT, FCR, PL, FDS,

FDP (2,3), FPL, FPB, APB, OP, PQ, LUM (2,3).

(10) Posterior Cord

• Gives rise to 5 nerves• Spinal Cord Segments: C5 – T1

(13) Upper subscapular nerve• Spinal Cord Segments : C5, C6• Muscles Innervated

Subscapularis

(14) Thoracodorsal nerve• Spinal Cord Segments : C6-C8• Muscles Innervated

Lat. D.

(15) Lower subscapular nerve• Spinal Cord Segments: C5, C6• Muscles Innervated– T. Maj.– Subscapularis

(10) Posterior Cord

(19) Axillary nerve• Spinal Cord Segments: C5, C6• Muscles Innervated– T. Min.– Deltoid

(20)Radial nerve

● Spinal Cord Segments– C5, C6, C7, C8, T1• Muscles Innervated– Triceps, Anconeous, BR,

Brachialis, ECRL

Brief Overview of Injuries

• Due to traction

• Traumatic injuries

– Contusion

– Disruption of blood supply

– Laceration

Injuries (Median)

• Fracture

• Dislocation

• Compression Sites

• Low lesion

• Ant. Interosseous lesion

• Lesion proximal to elbow

Injuries (Median)

• Fracture

• Dislocation

• Compression Sites

• Low lesion

• Ant. Interosseous lesion

• Lesion proximal to elbow

Median Nerve:Common Sites of

Compression

Median Nerve:Common Sites of

Compression

“Ape hand” Deformity

Wasting of the thenar eminence and unable to oppose the thumb

Ulnar Nerve Injuries

• Fractures

• Lacerations

• Low Lesions

• High Lesions

Ulnar Nerve: Compression Sites

Cubital tunnel

Guyon’s canal

Midpalm

Bishop’s or Benediction Hand

Wasting of hypothenar muscles, interossei, and two medial lumbricals

Radial Nerve Injuries

• Fractures

• Dislocations

• Posterior Interosseous Lesions

• Mid-humeral Lesion

• High Lesion

• Sensory Loss

Anatomy of the Radial NerveAnatomy of the Radial Nerve

Deltoid tuberosityDeltoid tuberosity

Radial GrooveRadial Groove(Spiral Groove)(Spiral Groove)

Drop Wrist Deformity

Wrist, thumb, and finger extensors weakness

Summary

• Brachial plexopathies require thorough

understanding of anatomy

• Specialized sensory and motor testing can

help localize the pathology

THANK YOU