Human Anatomy Vol 1

It gives off a large branch, the circumflex scapular

artery, which is larger than the continuation of the main

artery. This branch passes through the triangular

intermuscular space, winds round the lateral border of

the scapula deep to the teres minor, and gives a branch

to the subscapular fossa, and another branch to the

infraspinous fossa, both of which take part in the

anastomoses around the scapula (see Fig. 6.73).

Anostomoses ond Collolerol Cilculolion

The branches of the axillary artery anastomose with one
another and with branches derived from neighbouring
arteries (internal thoracic, intercostal, suprascapular,
deep branch of transverse cervical, profunda brachii).
When the axillary artery is blocked, a collateral
circulation is established through the anastomoses
around the scapula which links the first part of the
subclavian artery with the third part of the axillary
artery (apart from communications with the posterior
intercostal arteries) (see Fig. 6.13).

ILLARY VEIN

The axillary vein is the continuation of the basilic vein.
The axillary vein is joined by the venae comitantes of
the brachial artery a little above the lower border of
the teres major. It lies on the medial side of the axillary
artery (Fig. 4.9). At the outer border of the first rib, it
becomes the subclavian vein. In addition to the
tributaries corresponding to the branches of the axillary
artery, it receives the cephalic vein in its upper part.
There is no axillary sheath around the vein, which is
free to expand during times of increased blood flow.

IttARY TYMPH NODES

The axillary lymph nodes are scattered in the fibrofatty
tissue of the axilla. They are divided into five groups.
L The nodes of the anterior (pectoral) grouplie along the
lateral thoracic vessels, i.e. along the lower border
of the pectoralis minor. They receive lymph from the
upper half of the anterior wall of the trunk, and from
the major part of the breast (Fig. 4.11).
2 The nodes of the posterior (scapular) group lie along
the subscapular vessels, on the posterior fold of the
axilla. They receive lymph from the posterior wall
of the upper half of the trunk, and from the axillary
tail of the breast.
3 The nodes of the lateral group lie along the upper part
of the humerus, medial to the axillary vein. They
receive lymph from the upper limb.
4 The nodes of the central group lie in the fat of the
upper axilla. They receive lymph from the preceding
groups and drain into the apical group. They receive
some direct vessels from the floor of the axilla. The
intercostobrachial nerve is closely related to them.

AXILLA

Apical group

Anterior group

Lateral group

Central group

Posterior group

Pectoralis minor

Fig.4.11: The axillary lymph nodes

5 The nodes of the apical or infraclaaicular group lie deep

to the clavipectoral fascia, along the axillary vessels.

They receive lymph from the central group, from the

upper part of the breast, and from the thumb and its

web. The lymphatics from the thumb accompany the

cephalic vein.

The axilla has abundant axillary hair. Infection of

the hair follicles and sebaceous glands gives rise

to boils which are common in this area.

The axillary lymph nodes drain lymph not only

from the upper limb but also from the breast and

the anterior and posterior body walls above the

level of the umbilicus. Therefore, infections or

malignant growths in any part of their territory

of drainage give rise to involvement of the axillary

lymph nodes (Fig. 4.12). Bimanual examination of

these lymph nodes is, therefore, important in

clinical practice. Left axillary nodes to be palpated

by right hand. Right axillary nodes have to be

palpated by left hand.

An axillary abscess should be incised through the

floor of the axilla, midway between the anterior

and posterior axillary folds, and nearer to the

medial wall in order to avoid injury to the main

vessels running along the anterior, posterior and

Iateral walls.

Axiilary arterial pulsations can be felt against the

lower part of the lateral wall of the axilla.

In order to check bleeding from the distal part of

the limb (in injuries, operations and amputations)

the artery can be effectively compressed against

the humerus in the lower part of the lateral waII

of the axilla.

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