Human Anatomy Vol 1

by the anterior fibres of the deltoid, and superiorly

by the clavicle.

8 The tip of the coracoid process of the scapula lies

2-3 cm below the clavicle, overlapped by the

anterior fibres of the deltoid. It can be felt on deep

palpation just lateral to the infraclavicular fossa.

9 The acromion of the scapula (acron = summiq omos =

shoulder) is a flattened piece of bone that lies

subcutaneously forming the top of the shoulder. The

posterior end of its lateral border is called the

acromial angle,where it is continuous with the lower

lip of the crest of the spine of the scapula. The

anterior end of its medial border articulates with

the clavicle at the acromioclavicular joint.

1O The deltoidistriangalar muscle with its apex directed

downwards. It forms the rounded contour of the

shoulder, extending vertically from the acromion

to the deltoid tuberosity of the humerus.

LL The axilla (Latrn armpit) is a pyramidal space

between the arm and chest. When the arm is raised

(abducted), the floor of the axilla rises, the anterior

and posterior folds stand out, and the space becomes

more prominent. The qnterior axillary fold contains

the lower border of the pectoralis major, andposterior

axillary fold contains the tendon of thelatissimus dorsi

winding round the fleshy teres major.

The medial wall of the axilla is formed by the upper 4

ribs covEed by the seftatus anterior. The narrow

lateral wa\l presents the upper part of the humerus

covered by the short head of the biceps, and the

coracobrachialls. Axillary arterial pulsations can be

felt by pressing the artery against the humerus. The

cords of the brachial plexus can also be rolled against

the humerus. The head of the humerus can be felt

by pressing the fingers upwards into the axilla.

12 The midaxillary line is avertical line drawn midway

between the anterior and posterior axillary folds.

The superficial fascia (Latin a bond) of the pectoral
region is visualised after the skin has been incised. It
contains moderate amount of fat, and is continuous
with that of surrounding regions.The mammary gland,
which is well developed in females, is the most
important of all contents of this fascia. The fibrous septa
given off by the fascia support the lobes of the gland,
and the skin covering the gland.

Conlenls

Irr addition to fat, the superficial fascia of the pectoral
region contains the following.
i. Cutaneous nerves derived from the cervical plexus
and from the intercostal nerves.

PECTOBAL REGION

ii. Cutaneous branches from the internal thoracic and

posterior intercostal arteries.

iii. The platysma (Greek broad)

iv. The breast.

Dissection

Mark the following points.

i. Centre of the suprasternal notch,

ii. Xiphoid process,

iii. 7 o'clock position at the margin of areola,

iv. Lateral end of clavicle (Fig. 3.2).

Give an incision vertically down from the first point

to the second which joins the centre of the suprasternal

notch to the xiphoid process in the midsagittal plane.

From the lower end of this line, extend the incision

upward and laterally till you reach to the third point on

the areolar margin.

Encircle the areola and carry the incision upwards

and laterally till the anterior axillary fold is reached.

Continue the line of incision downwards along the

medial border of the upper arm till its junction of upper

one-third and lower two-thirds. Extend this incision

transversely across the arm.

Make another incision horizontally from the xiphoid

process across the chest wall till the posterior axillary

fold.

Lastly give horizontal incision from the centre of

suprasternal notch to the lateral (acromial) end of the

clavicle.

Reflect the two flaps of skin towards the upper limb.

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Fig. 3.2: Points and lines of incision a