Human Anatomy Vol 1

Fig.3.22: Clavicular head being made prominent by flexing the
arm to right angle

Fig.3.23: Sternocostal head being made prominent by abducting
arm to 60' and touching the physician's hand kept at the
opposite hip

PECTORAL REGION

investing layer of the deep cervical fascia and to the

axillary sheath. Inferiorly, the clavipectoral fascia splits

to enclose the pectoralis minor muscle (Fig. 3.25).

Medially it is attached to external intercostal muscle of

upper intercostal spaces and laterally to coracoid

process. Below this muscle, it continues as the

suspensory ligament which is attached to the dome of

the axillary fascia, and helps to keep it pulled up.

The clavipectoral fascia is pierced by the following

structures.

i. Lateral pectoral nerve (Figs 3.12a and b).

ii. Cephalic vein.

iii. Thoracoacromial vessels.

iv. Lymphatics passing from the breast and pectoral

region to the apical group of axillary lyrnph nodes

(Fig. 3.12a).

Serotus Anleilor

Serratus anterior muscle is not strictly muscle of the

pectoral region, but it is convenient to consider it here.

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Serratus anterior muscle arises by eight digitations from

the upper eight ribs in the midaxillary plane and from

the fascia covering the intervening intercostal muscles

(Fig.3.26).

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The muscle is inserted into the costal surface of the

scapula along its medial border.

The first digitation is inserted from the superior angle

to the root of the spine.

The next two digitations are inserted lower down

on the medial border.

The lower five digitations are inserted into a large

triangular area over the inferior angle.

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Fig.3.24= Pectoralis major being tested Fig" 3.25: The pectoralis minor and subclavius muscles a