Axillary Dissection 
Peter Bird 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
Introduction:  
Lymph node status in breast cancer is one of 
the most important prognostic factors. Axillary 
dissection – not to be called an axillary clearance – is 
an operation used primarily to assist in staging a 
patient, and secondarily in controlling the axilla and 
avoiding local recurrence. It has not been proven to 
improve survival in itself, although if not done - or 
not done correctly - it could under-call axillary 
involvement and thus result in a patient receiving 
inadequate adjuvant therapy. Patients with early 
breast cancer – Stage 1 or 2 disease – can often avoid 
an AD as staging can be done by sentinel lymph node 
biopsy.  
Informed 
consent 
must 
be 
obtained, 
including a discussion of potential complications, 
such as bleeding, infection, seroma, lymphedema, 
neuralgia, sensory loss in the upper medial arm and 
shoulder dysfunction. 
The incision for a stand-alone axillary 
dissection will lie horizontally across the lower axilla 
but not coming medial up over the anterior axillary 
fold. The incision can curve in a vertical direction 
just behind the anterior axillary fold. Make it large 
enough to do the operation safely, usually about 8 to 
10cm in length. An axillary dissection done in 
conjunction with a mastectomy will be done after the 
breast is fully mobilized off the chest wall and 
usually taken en bloc with the breast. You will need 
a variety of retractors, some wide and deep. 
DO NOT allow the anesthetist to paralyze the 
patient as you’ll want to know when you are 
dissecting close to important motor nerves. Dissect 
with diathermy on a low setting. Cauterize even 
medium sized vessels. Don’t waste time tying off 
vessels, unless large, or big tributaries close to the 
axillary vein. Use scissors and blunt dissection and 
tie off all vessels if diathermy is unavailable or you 
are unfamiliar with its use. 
 
In general, the steps of axillary dissection are:  
● Medial dissection: Incision of the clavipectoral 
fascia, exposure of the pectoralis minor and 
median pectoral neurovascular bundle, and 
dissection of the serratus anterior muscle  
● Lateral dissection: Elevation of a skin flap down 
to the lateral edge of the latissimus dorsi 
● Superior dissection along the inferior edge of the 
axillary vein.  
● Mobilizing tissue from Level II or occasionally 
Level III.  
● Identification of the long thoracic nerve and 
further medial dissection 
● Further 
mobilization 
of 
axillary 
tissue 
downwards 
with 
identification 
of 
the 
thoracodorsal nerve  
● Completion of the dissection laterally and 
inferiorly, and removal of the specimen 
● Drain placement and closure 
 
Schematic of the right axilla. Labeled structures are: 1. 
Pectoralis major, the anterior border of the axillary space. 2. 
Pectoralis minor. 3. Serratus anterior, the medial border. 4. 
Subscapularis, the posterior border (with 8.) 5. Latissimus 
Dorsi. 6. Biceps brachii. 7. Triceps brachii. 8. Teres major, the 
posterior border (with 4.) 9. Coracobrachialis. 10. Retractor in 
the apex of the axillary space. Source: Primary Surgery Vol. 1 
: 
Non 
Trauma 
https://global-help.org/products/primary-
surgery/  
  
Axillary Dissection 
Peter Bird 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
The right axilla. Pectoralis major (1) has been partly removed 
to expose the axillary contents. 11. Coracoid process, origin of 
the Pectoralis minor (2.) 12. Long thoracic nerve. 13. 
Thoracodorsal nerve. 14. Lateral Pectoral nerve.  
Lymph node locations are according to their relation to the 
Pectoralis minor (2.) Nodes lateral to its lateral border (Red 
line) are in Level I. Nodes directly underneath it (between the 
Red and Orange lines) are in Level II. Nodes medial to its 
medial border (Orange line) are in Level III. Source: Primary 
Surgery Vol. 1 : Non Trauma 
https://global-help.org/products/primary-surgery/   
 
Steps: 
1. Position the patient supine with the arm abducted 
to 90 degrees. Prepare and drape the shoulder and 
axilla, going posteriorly to below the level of the 
latissimus dorsi fold. It is not necessary to drape 
the arm in a way that allows it to be mobilized 
during surgery, but some surgeons prefer this 
method of draping.  
2. Make a horizontal incision across the lower axilla 
but not coming medial up over the anterior 
axillary fold. This incision should be about 8-
10cm in length, immediately below the axillary 
hair if this is visible. 
3. Start by finding the lateral border of pectoralis 
major inferiorly and dissect towards axilla, 
identifying pectoralis minor. It runs deep to and 
more vertically than pectoralis major (by about 
30⁰). 
 
Right axillary dissection, head is to the left in this picture. 
Retracting the pectoralis major, divide the fascial attachments 
to its lateral surface until you see the pectoralis minor muscle 
(not yet visible in this photo.)  
 
4. Divide the clavipectoral fascia just lateral to 
pectoralis minor. Note the difference in fat 
(bigger globules under this fascia). 
 
As you divide the clavipectoral fascia, the pectoralis minor 
(Black arrow) becomes visible.  
 
5. Dissect superiorly along pectoralis minor and 
find the medial pectoral nerve neurovascular 
bundle wrapping around its lateral margin. In 
10% of cases, it will perforate directly through 
pectoralis minor. Follow the medial pectoral 
nerve neurovascular bundle directly down to the 
axillary vein taking care not to damage either 
structure. 
Axillary Dissection 
Peter Bird 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
The medial pectoral nerve neurovascular bundle (Black arrow) 
wraps around the lateral border of the pectoralis minor muscle. 
The serratus anterior muscle is becoming visible (under the tip 
of the diathermy pencil) as dissection proceeds posteriorly. 
 
6. Start dissecting down the medial wall of the 
axilla on the serratus anterior, dividing cutaneous 
nerves and vessels. Don’t go past the mid-
axillary line at this time. 
 
Below the pectoralis minor (Black arrow) you’ll encounter the 
medial border of the axilla,  the serratus anterior muscle 
(Purple arrow.) Do not dissect deeper than the point shown in 
this picture at this time. Note that the diathermy tip is touching 
the white fascial band of the serratus anterior, the “false nerve” 
described below in Step #13. The true long thoracic nerve will 
be much deeper.  
 
7. Go laterally now and dissect down the skin flap 
(make it quite thick) and find the lateral edge of 
latissimus dorsi, dissecting along it towards the 
axilla 
 
Create the lateral border of your axillary dissection by 
dissecting a plane deep to the skin, lateral to your incision, 
preserving fat on the skin, until you reach the lateral border of 
the latissimus dorsi muscle.  As you follow the plane (shown by 
the Dashed Black arrow) you will encounter perforating vessels 
and nerves, which can be safely treated with diathermy. 
 
 
Completed dissection of the lateral axilla. The lateral border of 
the latissimus dorsi is not visible in this photo but is just beneath 
the Dashed Black arrow. Do not dissect further on the surface 
of the latissimus dorsi muscle at this time.  
 
 
Photograph from a completed axillary dissection on a different 
patient, showing the position of the thoracodorsal nerve and 
Axillary Dissection 
Peter Bird 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
vessels (Black arrow,) medial to the lateral edge of the 
latissimus dorsi.  
 
8. Go superiorly across the top of the dissection and 
incise across the tissue, lateral to medial, parallel 
with the arm, extending deeply down to the 
axillary vein. You’ll encounter at least one 
significant vessel here. Expose the axillary vein 
along its inferior border, noting any vein 
tributaries entering at right angles from below, 
looking for the thoracodorsal vein lying deeply. 
Usually there is a tributary directly superficial to 
the thoracodorsal vein that needs dividing first. 
 
Dissect from medial to lateral along the inferior border of the 
axillary vein. Usually you can see the axillary vein by pulling 
gently down on the axillary fat. If you can not, dissect carefully 
in this area until the vein is seen. A large vein in the superficial  
lateral axillary fat is usually seen (Black arrow) roughly 
indicating the location of the thoracodorsal vein beneath it.  
 
9. Dissect medially up to the junction between the 
medial pectoral nerve neurovascular bundle and 
the axillary vein. There is a fat pad on top of the 
axillary vein just distal to this junction which 
often harbors a node or two. Bluntly take it in 
continuity with the specimen. 
 
The medial pectoral nerve neurovascular bundle is seen under 
the Black arrow. The forceps grasp the fat pad, which can now 
be bluntly dissected downwards and included in the specimen.  
 
10. Dissect up along the lower edge of the axillary 
vein towards the Level II/III junction.  Be careful 
to 
preserve 
the 
medial 
pectoral 
nerve 
neurovascular bundle. Various small & medium 
veins will need to be divided so as to take the 
fat/nodes en bloc. 
11. Go back to the medial wall and dissect medially 
up towards the apex of the axilla. 
12. Choose where to stop dissecting superiorly – 
usually at the medial border of pectoralis minor 
for a Level II axillary dissection - and divide the 
axillary fat here, sweeping the tissue down. If 
nodes are involved in Level III, take these en 
bloc, using a wide retractor and a strong assistant 
to pull the pectoral muscles medially and give 
access (If these nodes are involved it would be 
wise to feel for and remove any enlarged 
interpectoral nodes - Rotter’s nodes - between 
pectoralis major and minor.) The goal at Level III 
is to remove palpable disease, not to “clear” the 
level. 
 
Dissection of the superior medial aspect of the axillary fat, at the 
level II/III junction. allows downward mobilization of the axillary 
contents from the area you have stopped dissecting superiorly.  
 
13. Dissect down serratus anterior carefully, looking 
for the long thoracic nerve innervating it. You 
will come across the intercostobrachial nerve 
first – divide it, having already explained to the 
patient about the resultant upper medial arm 
numbness which will eventually be insignificant.  
The long thoracic nerve will be very deep down 
on the medial wall of the axilla, NOT running 
directly on serratus anterior, but a few 
millimeters away from it. Find it by looking for 
the vasonervorum.  Don’t be fooled by the white 
fascial band of serratus anterior, the “false 
Axillary Dissection 
Peter Bird 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
nerve.” The long thoracic nerve lies close to the 
floor of the dissection, the subscapularis muscle. 
Sweep it bluntly back to the medial wall and 
follow it superiorly. 
 
Dissecting carefully along the serratus anterior, find the long 
thoracic nerve adjacent to its vessels (Solid Blue arrow.) This 
can be distinguished from the “false nerve” (Open Blue arrow) 
by the fact that it usually runs with a vessel, as seen here. As 
with all nerves,  there will be a vasa nervorum, a tiny blood 
vessel, running on its surface. 
 
14. As you sweep down, find the thoracodorsal 
nerve, coming out from under the axillary vein at 
about the same depth as the long thoracic nerve, 
joining the thoracodorsal vein and artery, usually 
medially. 
 
The depth of the long thoracic nerve (Solid Blue arrow) helps 
you to identify the thoracodorsal nerve and vessels (Dashed 
Blue arrow) as you mobilize the tissue downwards. Here, the 
thoracodorsal nerve has not been definitely identified yet but its 
large accompanying vein allows the surgeon to mobilize the 
tissues downwards and locate it.  
 
15. Sweep down all the fat/nodes lying on 
subscapularis (floor of the axilla) taking care to 
see the thoracodorsal nerve and long thoracic 
nerve at all times! The long thoracic nerve gets 
pulled into the specimen easily. 
 
Continue downward mobilization of the specimen between the 
long thoracic nerve (Solid blue arrow) and the thoracodorsal 
nerve (Dashed Blue arrow.)  
 
16. You will now come across the serratus anterior 
vascular branches coming off the thoracodorsal 
vessels.  These go across the subscapularis and 
join with the long thoracic nerve to enter serratus 
anterior. This marks the inferior extent of the 
axillary dissection. 
17. Now dissect lateral to the thoracodorsal nerve 
neurovascular bundle from the axillary vein 
down to the serratus anterior vascular branches. 
There is often an involved node(s) lateral to the 
axillary vein – thoracodorsal vein junction. 
18. Continue dissecting the fat/nodes en bloc until 
reaching the lateral border of latissimus dorsi 
where the dissection ends. 
 
Completed dissection shows the clear apex of the axilla 
underneath the pectoralis major and minor (Black arrow) and 
the preserved long thoracic (Solid Blue arrow) and 
thoracodorsal (Dotted Blue arrow)  
 
19. Stop all bleeding, place an 16-18F closed suction 
drain into the space and close with 2/0 
subcutaneous interrupted absorbable suture, and 
3/0 absorbable subcuticular continuous suture.  
Place the dressing and then prime the suction, 
Axillary Dissection 
Peter Bird 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
release it and make sure the axilla concavity 
sucks in. 
20. Ensure the nursing staff keep the drain’s suction 
primed and sucking at all times. Leave it in until 
it produces 30-50cc or less in 24 hours. This may 
take 7-10 days.  
21. Have the patient move the shoulder immediately 
and give adequate analgesia to allow this. Have 
physiotherapy help with this and be sure 
exercises are given on discharge. Frozen 
shoulder must be avoided!  
22. If a seroma develops days after the drain tube is 
removed, it can be easily aspirated in the clinic, 
using meticulous sterile technique to prevent 
infection of the seroma.  
 
Pitfalls 
● A postoperative hematoma can result if a tie slips 
off a large branch of the axillary vein. If this is 
large enough to limit mobility it will need to be 
re-explored and evacuated. Briefly re-inspect all 
ties that have been placed on large veins prior to 
closing.  
● A postoperative seroma is a very common 
complication. Our practice is to use a closed-
suction drain in the axillary space and remove it 
after the drainage is consistently less than 30-
50cc in 24 hours. Sometimes the patient will need 
to go home with this drain and instructions on 
how to care for it and measure its output. If a 
seroma occurs after drain removal, aspirate in a 
strict sterile manner and repeat until the seroma 
does not reaccumulate.  
● Numbness of the axilla and sometimes the 
proximal medial arm is an expected outcome of 
this surgery, as the intercostobrachial cutaneous 
nerves run through the specimen. The discomfort 
associated with this numbness will decrease over 
time.  
● Frozen shoulder is much more difficult to treat 
than to prevent. Physiotherapy should see the 
patient as early as postoperative day 1 and 
instruct shoulder range of motion exercises. 
Reinforce these instructions by telling and 
demonstrating exercises to increase shoulder 
abduction, such as grabbing on to a high object 
(a doorframe or laundry frame) and passively 
stretching the arm over the head as much as 
possible. Verify the patient’s shoulder range of 
motion on every postoperative visit to reinforce 
this important concept.  
● Lymphedema of the arm occurs after up to 10% 
of axillary dissections. Preoperative counseling 
about this complication is important. Its 
incidence can likely be decreased by avoiding 
dissection into Level III. If there is no grossly 
palpable disease in Level III, an axillary 
dissection should only include Levels I and II. If 
there is palpable disease in Level III, try to 
remove only this, rather than attempting to 
“clear” all lymphatic tissue at this level. Once 
this complication has occurred, the only real 
treatment is a compression stocking on the 
affected arm to decrease swelling and attendant 
wound healing problems.  
 
Lymphedema of the right arm years after right Modified 
Radical mastectomy.  
 
 
 
Axillary Dissection 
Peter Bird 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
Peter Bird, MBBS, FRACS 
AIC Kijabe Hospital 
Kenya 
