Axillary Art

8/8/2019 Axillary Art

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Now that we have identified the structures making up the various walls of

the axilla, it is time to take a look at its contents. We will first examine the

blood vessels, then the nerves and finally, the lymphatics, in that order.

Axillary Artery

The axillary artery begins at the lateral border of

the first rib as a continuation of the subclavianartery. It changes its name to brachial artery at

lower (inferior) border of the teres major muscle.

For purposes of description, it is broken up into

three parts by its relation to the pectoralis minormuscle. The first part is between the lateral

border of the first rib and the medial border of

the pectoralis minor, the second part is behind

the pectoralis minor and the third part is between

the lateral border of the pectoralis minor and theinferior border of the teres major.

Branches

FirstPart

(1branch

)

Second Part

(2branches)

ThirdPart

(3branche

s)

1

superio

r

thoracica.

(supre

me

thoracica.)

(highes

t

thoracic

a.)

2

thoracoacro

mial a.

3 lateralthoracic a.

4subscapul

ar a.

5 anterior

humeral

circumflex a.

6

posterior

humeralcircumfle

x a.


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y 4a thoracodorsal branch

of subscapular

y 4b scapular circumflex

branch of subscapulary 8 brachial artery

(continuation of theaxillary) below lower

border of teres major (tm)

Axillary Vein

The axillary vein lies along the medial side of the artery and is a continuation

of the basilic vein. It begins at the inferior border of the teres major m. and

ends at the lateral border of the first rib, where it becomes the subclavian v.It receives tributaries that parallel the branches of the axillary artery. Thecephalic v. joins the axillary v. just before it becomes the subclavian. We

won't give any further details here. This doesn't mean that it isn't important

for maintaining proper function of the upper limb. I may be injured in sports

as well as when a person uses a crutch. Penetrating wounds in the largerupper part are serious because air might enter into the venous system.

Vena comitans

The veins that run with their corresponding arteriesare frequently multiple

(2 or 3 interconnected veins). This interconnected

venous network is

called the vena commitantes.

Axillary Walls

Brachial

Plexus


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HomeTable of Contents for Upper Limb & Back

This is copyrighted1999 by Wesley Norman, PhD

TABLE OF MUSCLES OF PECTORAL REGION

MUSCLE ORIGIN INSERTION ACTIONNERVE

SUPPLY

pectoralis

major

medial half of

clavicle

sternum

costal cartilages

aponeurosis of

external oblique

muscle

lateral lip of

intertubercular

groove of humerus

flexes, adducts,

and rotates arm

medially

medial and

lateral pectoral

nerves

brachial plexus

pectoralis

minor

anterior aspect of

2nd-5th ribs

coracoid process of

scapula

protracts thescapula

pulls it forward

and down

medial pectoral

nerve

brachial plexus

subclavius

junction of the 1st

rib with

its costal cartilage

inferior surface of

clavicle

pulls clavicle

towards the

sternum

nerve to

subclavius

brachial plexus

Vessels & Nerves of Pectoral Region

Superficial Veins of

Upper Limb


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Table of Contents for Upper Limb & Back

This is copyrighted 1999 by Wesley Norman, PhD, DSc

Axillary Artery Diagram

Key to Diagram:

First division - one

branch: (1) Supreme

Thoracic Artery

Second division - two

branches:

(2)Thoracoacromial (with

four smaller branches)

A. Pectoral

Branch

B. Deltoid

Branch C. Acromial

Branch

D. Clavicular

Branch (3) Lateral Thoracic Artery

Third division - three branches:

(4) Subscapular Artery (branches to the Circumflex Scapular Artery and the Thoracodorsal Artery)

(5) Anterior Humeral Circumflex Artery


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(6) Posterior Humeral Circumflex Artery (which passes through the

quadrangular space)

Reference Netter Plates 398 and 405.

Nerves in the Axilla

Brachial Plexus

With one exception, all of the muscles of the upper limb are supplied by branches of

the brachial plexus. The exception is the trapezius m. which is supplied by the

cranial nerve (XI), spinal accessory.

Although only part of the brachial plexus is found in the axilla, we will

present a general layout of the plexus before covering the parts that arefound in the axilla. Whoever first described the brachial plexus must havebeen a nature lover, or at least a tree lover, because the various parts of the

plexus are named according to various parts of a tree, starting from the

roots.


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The brachial plexus starts in

the neck from the ventral rami

of spinal nerves C5 - T1 (5th

cervical to 1st thoracic spinal

cord segments). These rami

are called roots. The roots will

continue through the neck and,

some of them merge, to form

trunks. C5 and C6 form the

upper trunk, C7 continues as

the middle trunk and C8 and

T1 for the lower trunk. While

still in the neck, the trunks

divide into anterior and

posterior divisions. The

divisions then reunite in

different patterns. The anterior

divisions of the upper and

middle trunks merge to form

the lateral cord. The anterior

division of the lower trunk

continues as the medial cord.

The posterior divisions of all

trunks merge to form the

posterior cord. At this point,

the cords are in the axilla. The

cords are named according to

their relationship with the

axillary artery. Medial to it,

lateral to it or posterior to it.

Finally, the cords give rise to

various branches that supply

the upper limb structures. I

want to point out that although

most of the branches to the

upper limb muscles arise from

the plexus in the axilla, some

arise from the cervical (neck)

part of the plexus. These

nerves are the dorsal scapular,

nerve to subclavius, long


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thoracic, and suprascapular.

Needless to say, the brachial

plexus is a very importantstructure in the axilla and

can be injured here throughvarious types of trauma

(athletic injuries, humeraldislocations, crutch injuries,

surgical injuries),

carcinomas and other

pathological problems.

Branches of Brachial Plexus

RootsTrunks Cords

Lateral MedialPosterior


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dorsal

scapular (2)

long

thorac

ic (1)

nerve

to

subcla

vius

(3)

suprasca

pular (4)

lateral

pectoral (5)

lateral head

of median

n. (6)

musculocut

aneous

medial

pectora

l (8)

medial

cutaneo

us of

arm (9)

medial

cutaneo

us of

forearm

(10)

medial

head of

median

n.(11)

ulnar(1

2)

upper

subscapula

r(14)

thoracodor

sal(15)

lower

subscapula

r

axillary(17)

radial(18)

Axillary Arteries & Veins

Axillary

Lymph Nodes

HomeTable of Contents for Upper Limb & Back

This is copyrighted1999 by Wesley Norman,

PhD, DSc


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Muscle DetailsMuscle Origin Insertion Nerve supply Action

pectoralis

major

medial half of

clavicle

sternum

costal cartilages

aponeurosis of

external oblique

lateral lip of

intertubercular

sulcus

medial and

lateral

pectoral

nerves

flexes, adducts,

and rotates arm

medially

pectoralis

minor

anterior surface

of

2nd thru 5th ribs

coracoid process

of

scapula

protractsscapula

pulls it

forward

onto the

thorax

elevates ribs

when scapula

is held steady

medial pectoral

nerve

subclaviuscostal cartilage

of first rib

lower surface of

clavicle

nerve to

subsclavius

depresses lateralend of clavicle

pulls clavicular

head into

sternoclavicular

joint

serratus

anterior

lateral surface of

1st to 8th or 9th

ribs

vertebral (medial)

border of scapulalong thoracic

protract scapula

pulls it forward

rotates scapula

laterally

teres minor

axillary (lateral)

border of

scapula

inferior aspect

greater tubercle

of humerus

axillaryrotates arm

laterally

teres major posterior aspect

inferior angle of

crest of lesser

tuberclelower

adducts and

rotates arm


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scapula of humerus subscapular medially

latissimus

dorsi

spinous

processes

lower 6 vertebra

thoracolumbarfascia

iliac crest

floor of

intertubercularfossa thoracodorsal

adducts, extends

medially rotateshumerus

Bones of the Arm and ForearmThe arm bone is the humerus and the forearm bones are the radius and ulna.


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The details of the humerus are

shown in the adjacent

diagram.

The structures you should be

able to identify are:

y heady anatomical necky greater tubercley lesser tubercley crest of the greater

tubercley crest of the lesser

tubercley intertubercular sulcus

(groove)y deltoid tuberosityy medial epicondyle

y lateral epicondyley capitulumy trochleay coronoid fossay olecranon fossa


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The details of the radius and ulna areshown in the diagram.

The structures you should be able to

identify are:

Radius

y heady necky radial tuberosity

y styloid process

Ulna

y coronoid processy olecranon processy ulnar tuberosityy slyloid process

Interosseous Membrane

Summary of Items in Axilla

Muscles of

Anterior Arm

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This is copyrighted 1999 by Wesley Norman, PhD, DSc

Axillary Art

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