AXIS Vol. 4, Issue 2 (Spring 2013) 1

Variation of Suprascapular Artery

Abduelmenem Alashkhama,b, Abdulrahman Alraddadia,c, Roger Soamesa

a Centre for Human Anatomy and Identification, University of Dundee, Dundee, UK

b Human Anatomy Department, Faculty of Medicine, University of Zawia, Zawia, Libya

c Human Anatomy Department, Faculty of Medicine, King Saud Bin Abdulaziz University for Health Sciences , Riyadh, Saudi Arabia.

Abstract

In a routine dissection of the left shoulder of a

62 years old female, the suprascapular artery

was observed to arise from the thyrocervical

trunk of the 1st part of the subclavian artery. It

passed anterior to scalenus anterior and ran

posterolateral anterior to the brachial plexus

and deep to the clavicle and subclavius. By

tracing its course the suprascapular artery

was found to accompany the suprascapular

nerve underneath the transverse scapular

ligament to reach the supraspinatus fossa and

then the infraspinatus fossa through the

spinoglenoid notch to share in the

anastomosis around the scapula. The right

suprascapular artery passed over the ligament

which is an important variation in cases of

suprascapular nerve compression.

Introduction

The suprascapular artery is a branch of the

thyrocervical trunk from the 1st part of the

subclavian artery (Palastanga et al., 2006;

Moore et al., 2010).

As the suprascapular artery arises from the

thyrocervical trunk of the 1st part of the

subclavian artery (Smith et al., 1983; Hall-

Craggs, 1990; Monkhouse, 2001) it runs

inferolaterally and posterior undercover of

sternomastoid crossing anterior to scalenus

anterior and the phrenic nerve to reach the

posterior triangle of the neck. It crosses the

3rd part of the subclavian artery, as well as the

brachial plexus, and descends posterior and

parallel to the clavicle and subclavius

undercover of the posterior belly of omohyoid

accompanied by the suprascapular nerve until

they approach the superior border of the

scapula. Once the suprascapular artery

reaches the superior border, it passes

superficial to the transverse scapular

ligament, separating it from the suprascapular

nerve, and enters the supraspinous fossa

deep to supraspinatus. It then emerges

through the spinoglenoid notch to reach the

infraspinous fossa and descends inferiorly as

far as the inferior angle of the scapula and

shares in the anastomosis around the scapula

(Gray, 1913; Sinnatamby, 2006; Faiz and

Moffat, 2006; Ellis, 2006).

AXIS Vol. 4, Issue 2 (Spring 2013) 2

The suprascapular artery normal gives 7

branches; (1) branches: which contribute to

the anastomosis around the scapula (Rogers,

1992; Abrahams et al., 2011), (2) Acromial

branch: emerges through trapezius to supply

the skin over the acromion and anastomoses

with the acromial branch of the

thoracoacromial artery (Gray, 1913); (3)

Nutrient branches: to the clavicle and scapula

(Gray, 1913); (4) Articular branches: to the

shoulder and acromioclavicular joints (Lumley

et al., 1995; Gray, 1913); (5) Muscular

branches: to sternomastoid, subclavius and

muscles of the shoulder girdle (Lumley et al.,

1995); (6) Suprasternal branch: supplies the

skin over the upper part of the thorax (Gray,

1913); (7) Subscapular branch: a small branch

arising at the transverse scapular ligament

which runs downwards into the subscapular

fossa to ramify in subscapularis (Gray, 1913;

Snell, 1995).

Various studies have evaluated the anomalies

of the suprascapular artery. Yang et al (2012)

demonstrated, in a study of 103 shoulders (53

right side and 50 left with a mean age 70.4

years: 28 males, 27 females paired shoulders)

that the presence of the suprascapular artery

can be classified into three types, type I: the

suprascapular vessels pass over the transverse

scapular ligament, observed in 59.4% of cases;

type II: the suprascapular vessels pass over

and beneath the scapular ligament, observed

in 29.7%; type III: all the suprascapular vessels

pass below the scapular ligament, observed in

10.9% of specimens. Yang et al (2012) also

noted that in 48.9% of specimens all types

were observed bilaterally. Mishra and Ajmani

(2003) reported that on the left side the

suprascapular artery originated from the

axillary artery from which it then ascended for

a short distance and then ran transversely

undercover of the clavicle, subclavius and the

lower trunk of the brachial plexus. Once the

suprascapular artery approached the superior

border of the scapula, it passed through the

suprascapular foramen accompanied by the

suprascapular nerve to reach the

supraspinatus fossa. Mahato (2010) reported

a case of a 68 year old male cadaver in which

the suprascapular arteries on both sides arose

from the third part of the axillary artery

instead the thyrocervical trunk of the

subclavian artery. Both ascended upwards to

lie between the lateral cord of the brachial

plexus anteriorly and the posterior cord

posteriorly. On both sides, the suprascapular

artery passed under the transverse scapular

ligament with the suprascapular nerve to

emerge into the supraspinatus fossa. In the

dissection of 30 cadavers Adibatti (2010)

reported a case where the left suprascapular

artery arose from the first part of the axillary

artery: it then ran upwards for a short

distance before passing posterior to the

clavicle and brachial plexus to approach the

suprascapular notch. The suprascapular artery

and nerve were observed to enter the

supraspinatus fossa through the

suprascapular notch under the transverse

scapular ligament. Chen and Adds (2011)

reported the case of a 94 year old female with

an accessory suprascapular artery arising from

the third part of the subclavian artery at the

outer border of scalenus anterior, where it

ran inferior to the inferior trunk of the

brachial plexus and deep to the transverse

scapular ligament with the suprascapular

nerve, while the classic suprascapular artery

took its ordinary course to pass over the

transverse scapular ligament. The

suprascapular and accessory suprascapular

arteries anastomosed in the supraspinatus

fossa undercover of supraspinatus. According

to Drake et al (2005) and Moore et al (2010)

the suprascapular artery may originate from

AXIS Vol. 4, Issue 2 (Spring 2013) 3

the 3rd part of the subclavian artery. Atsas et

al (2011) also reported a case of a 68 year old

male in which on the left side the

suprascapular artery originated from the

internal mammary (thoracic) artery just after

it arose from the subclavian artery. It passed

backwards posterior to the medial third of the

clavicle and then accompanied the

suprascapular nerve where it bridged the

transverse scapular ligament, while the

suprascapular nerve passed beneath.

Case report:

During routine dissection of a 62 year old

female the left suprascapular artery was

found to arise from the thyrocervical trunk. It

emerged between sternocleidomastoid

anteriorly and scalenus anterior posteriorly

where it ran lateral and posterior to pass

anterior to the third part of the subclavian

artery and brachial plexus, and posterior to

the clavicle and subclavius. Throughout its

course it was accompanied by the

suprascapular nerve. Once they approached

the superior border of the scapula they both

passed below the transverse scapular

ligament to the supraspinous fossa deep to

supraspinatus (Figure 1, 2). The suprascapular

artery then continued through the

spinoglenoid notch to the infraglenoid fossa

deep to infraspinatus, where it contributed to

the anastomosis around the scapula. During it

course, the suprascapular artery gave

muscular branches to sternocleidomastoid

supraspinatus, infraspinatus, trapezius and a

small branch before passing through the

suprascapular notch to the subscapular fossa

to ramify in subscapularis. In addition, 2 to 3

articular branches were given to the shoulder

joint within the supraspinatus fossa. Hence

knowledge of this suprascapular artery

variation is important in cases of either open

or arthroscopic suprascapular nerve

decompression. An awareness of this variant

may also help in management of

glenohumeral region disease due to

underlying circulation problems.

AXIS Vol. 4, Issue 2 (Spring 2013) 4

Figure (1): A and B anterior view of left scapula shows 1: Suprascapular artery, 2: Suprascapular

vein, 3: Suprascapular nerve.

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Figure (2): Superior view of the left scapula shows 1: Suprascapular artery, 2: Suprascapular vein, 3:

Suprascapular nerve

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