Human Anatomy Vol 1

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INTRODUCIION

The axilla (Latin armpit) is a pyramidal space situated
between the upper part of the arm and the chest wall.
It resembles a four-sided pyramid, and has the
following.
i. An apex
ii. A base
iii. Four walls: Anterior, posterior, medial and lateral.
The axilla is disposed obliquely in such a way that
the apex is directed upwards and medially towards the
root of the neck, and the base is directed downwards.

Dissection

Place a rectangular wooden block under the neck and

shoulder region of cadaver (Fig.4.1). Ensure that the

block supports the body firmly. Abduct the limb at right

angles to the trunk; and strap the wrist firmly on block

projecting towards your side. ln continuation with earlier

dissection, reflect the lower skin flap till the posterior

axillary fold made up by the subscapularis, teres major,

and latissimus dorsi muscles is seen. Clean the fat,

and remove the lymph nodes and superficial veins to

reach depth of the armpit. ldentify two muscles arising

from the tip of the coracoid process of scapula; Out of

these, the short head of biceps brachii muscle lies on

the lateral side and the coracobrachialis on the medial

side.

The pectoral muscles with the clavipectoral fascia

form anterior boundary of the region.

Look for upper three intercostal muscles and serratus

anterior muscle which make the medial wall of axilla.

Clean and identify the axillary vessels. Trace the

course of the branches of the axillary artery.

Reflect the upper skin flap on the arm till the incision

already given at its junction of upper one{hird and lower

two-third.

Fig. 4.1: Dissection of axilla

BOUNDARIES

Apex/Cervicooxillory Cono!

It is directed upwards and medially towards the root

of the neck.

It is truncated (not pointed), and corresponds to a

triangular interval bounded

i. Anteriorly by the posterior surface of clavicle,

ii. Posteriorly by the superior border of the scapula

and medial aspect of coracoid process.

iii. Medially it is bounded by the outer border of the

first rib.

This oblique passage is called the cervicoaxillary

canal (Figs 4.2ato c). The axillary vessels, axillary vein

and the brachial plexus enter the axilla through this

canal.

Lower skin flap

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