Human Anatomy Vol 1

INTRODUCTION

The shoulder or scapular region comprises structures
which are closely related to and surround the shoulder
joint. For a proper understanding of the region, revise
some features of the scapula and the upper end of the
humerus.

L a. The upper half of the humerus is covered on its

anterior, lateral and posterior aspects by the deltoid

muscle. This muscle is triangular in shape and

forms the rounded contour of the shoulder (Fig. 6.1).

lnferior angle

Medial epicondyle

-English Proverb

b. The greater tubercle of the humerus forms the

most lateral bony point of the shoulder.

The skin covering the shoulder region is supplied by:

a. The lateral supraclavicular nerve, over the uPPer

half of the deltoid;

b. The upper lateral cutaneous nerve of the arm, over

the lower half of the deltoid; and

c. The dorsal rami of the upper thoracic nerves, over

the back, i.e. over the scapula.

The superficialfascia contains (in addition to moderate

amounts of fat and cutaneous nerves) the infero-

lateral part of the platysma arising from the deltoid

fascia.

The deep fascia covering the deltoid sends numerous

septa between its fasciculi. The subscapularis,

supraspinatus and infraspinatus fasciae provide

origin to a part of the respective muscle.

Dissection

Define the margins of the deltoid muscle covering the

shoulder joint region. Reflect the part of the muscle

arising from spine of scapula downwards. Separate the

infraspinatus muscle from teres major and minor

muscles which run from the lateral scapular border

towards humerus. Axillary nerve accompanied with

posterior circumflex humeral vessels lies on the deep

aspect of the deltoid muscle.

Feolures

These are the deltoid, the supraspinatus, the

infraspinatus, the teres minor, the subscapularis, and

the teres major. The deltoid is described below. The

other muscles are described in Tables 6.1. and 6.2.

Fig.6.1 : Surface landmarks: Shoulder, arm and elbow regions

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