Human Anatomy Vol 1

(mdmrcog) #1
Supraspinatus
Acromion

Deltoid

Subacromial bursitis

Fig. 6.11: Subacromial bursitis

DISSECIION
The quadrangular intermuscular space is a space in
between the scapular muscles. The quadrangular space
is bounded by teres minor above and teres major below;
by the long head of triceps muscle medially and the
surgical neck of humerus laterally. The axillary nerve
accompanied with posterior circumflex humeral vessels
lie in this space. ldentify the nerve to the teres minor
muscle (Fig. 6.12).
Another intermuscular space, the upper triangular
space should be dissected. lt is bounded by the teres
minor muscle medially, long head of triceps laterally,
and teres major muscle below.
Now the remaining twothirds of deltoid muscle can
be reflected towards its insertion. ldentify subscapularis
muscle anteriorly.
Define the attachments of infraspinatus and cut
muscle at the neck of scapula and reflect it on both sides.
Dissect and identify the arteries taking part in the
anastomoses around scapula. These are suprascapular
along upper border, deep branch of transverse ceruical
(dorsal scapular) along medial border and circumflex
scapular along lateral border of scapula (Fig. 6.12).
Look for the structures covered with deltoid muscle.
ldentify a lower triangular space which is bounded
above by the lower border of teres major muscle,
medially by the long head of triceps brachii and laterally
by the medial border of humerus. The radial nerve and
profunda brachii vessels pass through the space.

INTRODUCIION


The long head of triceps brachii spans the length of the
arm arising from infraglenoid tubercle of scapula to the


SCAPULAR REGION

olecranon process of ulna. It lies medial to humerus.
Teres minor crosses posterior aspect of the shoulder
joint and origin of the long head as it passes from its
origin from scapula to the humerus. The muscle is
replaced by subscapularis on the anterior aspect of
shoulder joint. Teres major also crosses the long head
as it runs to bicipital groove for its insertion.
Thus potential spaces are formed between lateral
border of scapula, medial aspect humerus, long head
of triceps brachii, teres minor or subscapularis and teres
major muscles.
In the upper part there is a quadrangular space
laterally and upper triangular space medially. In the
lower part is the lower triangular space. Their
boundaries are as follows:

Quodrongulor Spoce
floum ries
Superior
i. Subscapularis in front.
ii. Capsule of the shoulder joint.
iii. Inferior border of teres minor behind.
lnferior: Superior border of teres major.
Medial: Lateralborder of longhead of the tricepsbrachii.
Lateral: Surgical neck of the humerus.

Cenlemfs
i. Axillary nerve (Fig.6.12)
ii. Posterior circumflex humeral vessels.

Upper Triongulor Spoce
Boun ries

Superior: Inferior border of teres minor.
Lateral: Medial border of long head of the triceps brachii.
lnferior: Superior border of teres major.

nfemfs
Circumflex scapular artery. It interrupts the origin of
the teres minor and reaches the infraspinous fossa for
anastomoses with the suprascapular artery.

Lower Triongulor Spoce
Soun ries
Medial: Lateral border of long head of the triceps brachii.
Lateral: Medial border of humerus.
Superior: Lower border of teres major (Fig. 6.12).

nfenfs
i. Radial nerve.
ii. Profunda brachii vessels.

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