Human Anatomy Vol 1

PECTORAL REGION

Figs 3.18a to c: Self-examination of breast

Fig. 3.19: Mammogram showing cancerous lesion Fig. 3.20: Fine needle aspiration cytology

Muscle

Pectoralis major

(Fig. 3.21)

Pectoralis minor

(Fig. 3.25)

Subclavius

(Fis. 3.12)

Table 3.1: Muscles of the pectoral region

Origin from

. Anterior surface of medial two-thirds of clavicle
. Half the breadth of anterior surface of manubrium and
sternum up to 6th costal cartilages
. Second to sixth costal cartilages, sternal end of 6th rib
. Aponeurosis of the external oblique muscle of abdomen
. 3, 4,5 ribs, near the costochondral junction
. lntervening fascia covering external intercostal muscles
First rib at the costochondral junction

lnsertion into

It is inserted by a bilaminar tendon on the

lateral lip of the bicipital groove in form of

inveded'U'

The two laminae are continuous with each

other inferiorly

Medial border and upper surface of the

coracoid process

Subclavian groove in the middle one-third

of the clavicle

The anterior lamina is thicker and shorter than the
posterior. It receives two strata of muscle fibres:
Superficial fibres arising from the clavicle and deep
fibres arising from the manubrium (Fig. 3.21).

The posterior lamina is thinner and longer than the

anterior lamina. It is formed by fibres from the front of

the sternum , 2nd-6th costal cartilages, sternal end of

6th rib and from the aponeurosis of the external oblique

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