Orthopaedics & Traumatology: Surgery & Research 100 (2014) 515–519
Available online at ScienceDirect www.sciencedirect.com
Original article
The suprascapular vein: A possible etiology for suprascapular nerve
entrapment and risk of complication during procedures around the suprascapular foramen region
a b c c d a,∗
M. Podgórski , M. Sibinski´ , A. Majos , L. Stefanczyk´ , M. Topol , M. Polguj
a
Department of Angiology, Chair of Anatomy, Medical University of Łód´z, Narutowicza 60, 90–136 Lodz, Poland
b
Clinic of Orthopaedic and Pediatric Orthopaedics, Medical University of Łód´z, Łód´z, Poland
c
Department of Radiology and Diagnostic Imaging, Medical University of Łód´z, Łód´z, Poland
d
Department of Normal and Clinical Anatomy, Chair of Anatomy, Medical University of Łód´z, Łód´z, Poland
a r t i c l e i n f o
a b s t r a c t
Article history: Introduction: Nerve can be compressed when traveling through any osteo-fibrous tunnel. Any eventual
Accepted 13 May 2014
anatomic structure limiting this passage increases the risk of neuropathy. During dissection of the shoul-
der region we recognized a vein travelling on the inferior border of the suprascapular notch together
Keywords: with the suprascapular nerve. The aim of this work was to evaluate the morphological characteristics of
Anatomical variation
this vein in cadaveric material.
Suprascapular notch vein
Materials and methods: The suprascapular notch (SSN) region was dissected in 60 cadaveric shoulders.
Suprascapular nerve entrapment
The course, number and diameter of nerve and vessels in the suprascapluar notch region were evalu-
Superior transverse scapular ligament
ated. Length, proximal and distal width of the superior transverse scapular ligament were measured.
Suprascapular notch
Photographic documentation was taken to evaluate the suprascapular nerve passage area.
Anterior coracoscapular ligament
Results: The vein identified was named as the suprascapular notch vein. It was present in 58.3% of shoul-
ders. In 11 specimens, it was double. Its mean diameter was 1.7 mm (SD 0.7 mm) and did not correlate
with the suprascapular nerve passage area. A suprascapular notch vein co-occurred more often with
the anterior coracoscapular ligament (ACSL). In comparison with the SSN without the ACSL, it has a
significantly greater diameter (2 mm; SD 0.7 mm vs 1.5 mm; SD 0.6 mm, respectively; P = 0.021).
Conclusions: The suprascapular notch vein was a common structure that did not replace the suprascapular
vein. Its presence correlated with the occurrence of the ACSL and was independent of body side, STSL
type and SSN type.
Type of study: Observational anatomic study.
© 2014 Elsevier Masson SAS. All rights reserved.
1. Introduction suprascapular nerve (SN) and the suprascapular vein. The supras-
capular artery only occasionally runs below the STSL [2,3]. The
The suprascapular notch (SSN) is the incisure at the upper border suprascapular nerve innervates the supraspinatus and infraspina-
of the scapulae. It is bridged by the superior transverse scapu- tus muscles and also provides sensory branches to joints
lar ligament (STSL) creating an osteo-fibrous tunnel whose area (acromioclavicular and glenohumeral); ligaments (the coraco-
2 2
ranges from 4.6 mm to 85.4 mm [1]. Anterior coracoscapular humeral and coracoacromial); subacromial bursa [4] and to a
ligament (ACSL) is independent fibrous band extending on the ante- variable area of the overlying skin and soft tissues [5].
rior side of the suprascapular notch, below the superior transverse Structures passing below the STSL through the osteo-fibrous
scapular ligament (Fig. 1). Such structured tunnel usually holds the tunnel may increase the risk of neuropathy by limiting the space
available for the SN. This can result in suprascapular nerve entrap-
ment syndrome which was described in 1936 by André Thomas’a
[6] and usually occurs in the SSN [7].
During dissection of the shoulder region, we found an unusual
∗ vein that passed through the SSN on its inferior border. Because this
Corresponding author. Tel.: +48 42 63 04 949.
vein may restrict the passage for the SN, we aimed to determine its
E-mail addresses: [email protected], [email protected]
(M. Polguj). morphology and the prevalence.
http://dx.doi.org/10.1016/j.otsr.2014.05.008
1877-0568/© 2014 Elsevier Masson SAS. All rights reserved.
516 M. Podgórski et al. / Orthopaedics & Traumatology: Surgery & Research 100 (2014) 515–519
2. Materials and methods
The shoulder region was dissected in 60 formalin-fixed cadav-
eric shoulders, 30 left and 30 right, derived from a Polish population
(age and sex unknown). The humeral attachment of the subscapu-
laris muscle was cut and the muscle was retracted medially. The
fasciae were cleaned, revealing the anterior side of the scapula.
When the SNV was present, its course was traced from the SNN to
the upstream veins. The arrangement of the suprascapular artery,
vein and SN was also noted. Afterwards, the posterior aspect of
the SSN was exposed. The attachment of the trapezius and del-
toid muscles were separated from the spine of the scapulae. The
supraspinatus muscle was cut distally and bluntly dissected from
the supraspinatus fossa. The suprascapular notch vein was followed
to the site of its emptying.
The dissected scapulae were fixed at a standardized distance
from the camera, and their anterior aspect was photographed in
the coronal plane. The ten millimeter long scale was placed at
the level of measured structures and served for further calibration
of measuring tool. The dimensions of the STSL, the anterior cora-
coscapular ligament (ACSL) and the areas of the SSN and the SN
passage were measured using MultiScanBase 18.03 software (Com-
puter Scanning System II, Warsaw, Poland). The diameter of the SN,
Fig. 2. The representative example of the suprascapular notch vein (SNV) that passes
suprascapular vessels and SNV were also evaluated. In further anal- through the suprascapular notch together with suprascapular nerve (SN) and vein
ysis, the STSL was classified as either fan- or band-shaped [1] and (SV). Suprascapular artery (SA) travels above the superior transverse scapular liga-
ment (STSL).
the SSN to one of the 5 types [8].
For the purposes of statistical analysis, P < 0.05 was regarded
as statistically significant. Data is presented as a mean ± standard
deviation, unless stated otherwise. A comparison of the prevalence
of SNV between body sides, STSL types and SSN with or without
2
the ACSL was performed with the test. Differences in SNV diam-
eter between those variables was estimated with Student’s t test
for independent samples. This test was also employed to compare
areas of the SSN and the SN passage between specimens with and
without the SNV. The relationship between SNV diameter and the
number of its upstream veins was evaluated by means of one-way
Anova with dedicated post-hoc tests. This method was also used
to compare SNV diameter between types of the SSN. Correlations
of the SNV diameter and areas of the SSN and the SN passage were
evaluated by means of the Spearman’s rank correlation coefficient.
3. Results
The suprascapular notch vein was present in 35 shoulders
Fig. 3. Double suprascapular notch vein (SNV1 and SNV2) that passes through the
(58.3%) (Fig. 2). In 11 specimens, it was double (Fig. 3). It originated suprascapular notch together with suprascapular nerve (SN). Suprascapular artery
(SA) and vein (SV) travel above the superior transverse scapular ligament (STSL).
from 3 veins in 20 cases, 4 veins in 11, 2 veins in 3, and 5 veins
in 1 case. Veins of origin arose on the anterior side of the scapula,
inferior to the SSN, from a bone-nutrient vein of the scapula and/or
veins laying beneath the fascia of the subscapularis muscle. All SNVs
emptied into the suprascapular vein immediately after passing the
SSN. After exclusion of a single case with five upstream veins, the
diameter of the SNV differed significantly between three groups
(P = 0.0274) and tended to increase as the number of upstream veins
increased (Table 1) (Fig. 4).
In all cases, the SN (diameter = 2.1 mm; SD = 0.4 mm) travelled
below the STSL. The diameters of the suprascapular artery and vein
were 2.3 mm (SD = 0.6 mm) and 3.4 mm (SD = 0.7 mm), respectively.
In two cases, the suprascapular artery accompanied the SN beneath
Table 1
P value for post-hoc test.
Number of veins 2 3 4
2 – 0.3449 0.0493
3 0.3449 – 0.1018
Fig. 1. Schematic arrangements of the superior transverse scapular ligament (STSL)
4 0.0493 0.1018 –
and anterior coracoscapular ligament (ACSL) at suprascapular notch.
M. Podgórski et al. / Orthopaedics & Traumatology: Surgery & Research 100 (2014) 515–519 517
Fig. 6. Suprascapular notch vein (SNV) that reaches the suprascapular notch pass-
ing under anterior coracoscapular ligament (ACSL). SN: suprascapular nerve; SA:
suprascapular artery; SV: suprascapular vein; STSL: superior transverse scapular
ligament.
Fig. 4. Plot depicting differences in SNV diameters according to the number of veins
the presence of the SNV (P = 0.3601 and P = 0.7022, respectively).
of origin.
The differences in SNV diameter between body sides, STSL types
and SSN types were also insignificant (data not presented). How-
ever, the SNV co-occurred more often with the ACSL (P = 0.0001)
the STSL. The suprascapular vein passed below the STSL in 40 cases.
(Fig. 6). In those cases, diameter of the SNV was greater than in SSNs
A double suprascapular vein was found in 15 specimens. In 11 of
without the ACSL (2 mm; SD 0.7 mm vs 1.5 mm; SD 0.6 mm, respec-
them, one vessel passed inferior to the STSL and the other superior.
tively; P = 0.021). Table 2 shows differences in the prevalence of the
In the remaining 4 shoulders, both veins ran over the STSL. Fig. 5
SNV according to the body sides and the arrangement of structures
depicts the arrangement of SN and suprascapular vessels when the
occupying the SSN.
SNV was present.
2 2
The SSN area was 87.5 mm (SD = 33 mm ) and area of SN
2 2
passage was 25.3 mm (SD = 15.9 mm ). The diameter of the SNV 4. Discussion
ranged from 0.5 mm to 3 mm (mean = 1.7 mm; SD = 0.7 mm) but
did not correlate with neither the SSN area (P = 0.645) nor with The arrangement of vascular structures in the SSN is highly vari-
the SN passage area (P = 0.8686). Furthermore, the areas of the able. The suprascapular artery incidentally travels together with
SSN and the SN passage did not differ significantly according to the SN below the STSL. We observed this pattern in 3.3% of the
Fig. 5. Relationship of SNV with other neurovascular structures in SN region. N: suprascapular nerve; A: suprascapular artery; V: suprascapular veins; V1,V2: suprascapular
notch veins.
518 M. Podgórski et al. / Orthopaedics & Traumatology: Surgery & Research 100 (2014) 515–519
Table 2
Differences in prevalence of the SNV between: body sides, types of the STSL, occurrence of the ACSL and presence of the suprascapular vein below the STSL.
Compared parameters SNV present [Number] SNV absent [Number] P
Body sides [Number] Right (30) 16 14 0.60
Left (30) 19 11
STSL type [Number] Fan-shaped (29) 17 12 0.97
Band-shaped (31) 18 13
ACSL [Number] Present (31) 27 4 0.0001
Absent (29) 8 21
Suprascapular vein below the STSL [Number] Present (40) 29 16 0.16
Absent (20) 8 12
STSL: superior transverse scapular ligament; ACSL: anterior coracoscapular ligament; SNV: suprascapular notch vein.
cases. Tubss et al. [3] found this arrangement in 3 out of 120 cadav- The anterior coracoscapular ligament may also play an ambigu-
eric shoulders (2.5%) and Reinceck et al. [2] in 3 of 100 specimens ous role in the development of SN neuropathy. On the one hand,
(3%). it may increase the risk of SN neuropathy by obstructing the nerve
Variations in suprascapular vein anatomy occur more often. passage [17]. On the other hand, the ACSL separates the SN from
Yang et al. [9] reported that the SN was accompanied either by the the bone and prevents the SNV from intruding into the SN passage
suprascapular vein or artery in 25.2% of 103 cadaveric shoulders, space. Moreover, the presence of an ACSL was not found to decrease
and by both vessels in 14.6%. Furthermore, a double suprascapular the SN passage area [18].
vein was present in 19.4% of shoulders and a triple one in 1.9%. As Considering all the above we suppose that the SNV, together
far as the suprascapular vein is concerned, our results are similar, with the ACSL, may support a cushion mechanism for the SN, pro-
however, Yang et al. [9] did not describe any vein resembling the tecting it against repeated micro-trauma.
SNV. It is possible that, in this case, the SNV could have remained The limitation of this study is that no conclusions can be derived
unrecognized as the SSN had been dissected from the posterior regarding the symmetry of SNV occurrence, as separate limbs were
aspect. dissected and the data for left and right sides was pooled. How-
The suprascapular notch vein is common, however it is not well ever, Yang et al. [9] reported that body side is not associated with
studied because more attention is generally paid to the posterior different frequencies of vascular anomalies. Our observation that
aspect of the scapulae. In this location, the SN is often compressed SNV prevalence is non-side specific supports this theory. Another
by a mass (e.g. ganglion/labral cyst, tumor) [10,11] or retracted and limitation is that veins were not injected with medium, decreasing
irritated due to a rotator cuff tear [12]. It can also be entrapped in accuracy of vein diameter measurements. However, in formalin-
a spinoglenoid notch by the spinoglenoid ligament [13]. fixed shoulders, that we used, veins of a small diameter were
The previously-described variations of the suprascapular vein filled with clothed blood that was not flushed during embalming
concern mainly the number of vessels and their arrangement in procedure. Clothed blood distended vein lumen enabling reliable
the SSN. Usually, the suprascapular vein starts in the infraspinatus measurements. Finally, proposed protective role of the SNV and
fossa, approaches the supraspine fossa through the spinoglenoid the ACSL against the SN irritation cannot be confirmed based on
notch and ascends to the SSN. After passing the SSN, typically under anatomic description and should be further tested in clinical set-
the STSL, it travels with the suprascapular artery and finally emp- ting.
ties into the external jugular vein. It drains the same region as the Information about the relationship between the SN and ves-
corresponding artery, however the dorsal scapular vein and the cir- sels in the SSN region is of paramount importance for classical
cumflex scapular branch of the subscapular vein may also receive [19,20] and endoscopic surgical approaches [21,22]. Awareness
blood from this region [14]. In contrast to the suprascapular vein, of anatomical variations in this region has become vital due to
the SNV originates from veins emerging directly from bony foram- the increasing number of ultrasound-guided SN block procedures
ina on the anterior side of the scapula (nutrient veins) or veins [23,24], combined with the placement of a perineural catheter
running under the fascia of the subscapularis muscle. Moreover below the STSL [24,25]. Sonoanatomy of the SSN region has been
the SNV, traveling from anterior to posterior, crosses the SSN in recently described, however, the precise orientation of anatomical
the opposite direction to the suprascapular vein. Finally, the SNV landmarks is challenging and results of examination are subjec-
was always found to co-occur with the suprascapular vein, never tive [22,24]. In those procedures, the transducer is placed over the
replacing it. All the above implies that the SNV is not a variant of SSN in almost coronal plane. If the transducer is too anterior, the
the suprascapular vein but a separate structure. ACSL, together with the SNV below it, may be mistaken with the
Although the SNV was usually found to have a small diameter, in suprascapular vein passing below the STSL. Thus, the needle might
4 specimens it was wider than the suprascapular vein. Despite the be inserted too deeply, injuring the SN or suprascapular vessels.
fact that a suprascapular artery travelling together with the SN can This likelihood is even more increased by the limited visibility of
cause its neuropathy [15], it is uncertain whether a large notch vein the SN in the SNN requiring neighbouring structures to be used as
might increase this risk. Carroll et al. [16] reported the presence of landmarks in estimating the localization of the SN [26].
a venous varix in the spinoglenoid notch in six patients with symp-
toms of suprascapular nerve entrapment syndrome. Furthermore,
mechanical nerve irritation by venous dilatation has been described 5. Conclusions
in patients with tarsal tunnel syndrome [16]. These reports indicate
that the distended vessel can compress the nerve when the two The suprascapular notch vein is a common structure that was
structures travel together through the osteo-fibrous tunnel. How- found in 58.3% of the cases. It never replaces the suprascapular vein
ever, the diameter of the SNV did not correlate with the SN passage and courses against it. Its presence correlates with the occurrence
area and no varix of the SNV was found. Hence, the smooth wall of the ACSL and is independent of body side. Although its role in
of the SNV, which lines the bony floor of the SSN, might protect the development of SN neuropathy remain uncertain, knowledge
against the irritation of the SN that is kinked by the border of the about it may help to prevent unexpected bleeding while performing
SSN. procedures around the SSN region.
M. Podgórski et al. / Orthopaedics & Traumatology: Surgery & Research 100 (2014) 515–519 519
Disclosure of interest [13] Pecina MM, Krmpotic-Nemanic J, Markiewitz AD. Tunnel syndromes. Periph-
eral nerve compression syndromes. 3rd ed. Boca Raton: CRC Press; 2001. p.
49–55.
The authors declare that they have no conflicts of interest con-
[14] Pyrgakis P, Panagouli E, Venieratos D. Anomalous origin and course of the
cerning this article. suprascapular artery combined with absence of the suprascapular vein: case
study and clinical implications. N Am J Med Sci 2013;5(2):129–33.
[15] Houtz C, McCulloch PC. Suprascapular vascular anomalies as a cause of supras-
References
capular nerve compression. Orthopedics 2013;36(1):42–5.
[16] Carroll KW, Helms CA, Otte MT, Moellken SM, Fritz R. Enlarged spinoglenoid
[1] Polguj M, Jedrzejewski˛ K, Podgórski M, Majos A, Topol M. A proposal for classi- notch veins causing suprascapular nerve compression. Skeletal Radiol
fication of the superior transverse scapular ligament: variable morphology and 2003;32(2):72–7.
its potential influence on suprascapular nerve entrapment. J Shoulder Elbow [17] Avery BW, Pilon FM, Barclay JK. Anterior coracoscapular ligament and supras-
Surg 2013;22(9):1265–73. capular nerve entrapment. Clin Anat 2002;15(6):383–6.
[2] Reineck JR, Krishnan SG. Subligamentous suprascapular artery encountered [18] Polguj M, Jedrzejewski˛ K, Topol M. Variable morphology of the ante-
during arthroscopic suprascapular nerve release: a report of three cases. J rior coracoscapular ligament – a proposal of classification. Ann Anat
Shoulder Elbow Surg 2009;18(3):e1–3. 2013;195(1):77–81.
[3] Tubbs RS, Smyth MD, Salter G, Oakes WJ. Anomalous traversement of the [19] Gosk J, Rutowski R, Wiacek R, Reichert P. Experience with surgery for
suprascapular artery through the suprascapular notch: a possible mechanism entrapment syndrome of the suprascapular nerve. Orthop Traumatol Rehabil
for undiagnosed shoulder pain? Med Sci Monit 2003;9(3):BR116–9. 2007;9(2):128–33.
[4] Moen TC, Babatunde OM, Hsu SH, Ahmad CS, Levine WN. Suprascapu- [20] Kim DH, Murovic JA, Tiel RL, Kline DG. Management and outcomes of
lar neuropathy: what does the literature show? J Shoulder Elbow Surg 42 surgical suprascapular nerve injuries and entrapments. Neurosurgery
2012;21(6):835–46. 2005;57(1):120–7.
[5] Boykin RE, Friedman DJ, Higgins LD, Warner JJ. Suprascapular neuropathy. J [21] Bhatia DN, de Beer JF, van Rooyen KS, du Toit DF. Arthroscopic supras-
Bone Joint Surg Am 2010;92(13):2348–64. capular nerve decompression at the suprascapular notch. Arthroscopy
[6] Pecina M. Who really first described and explained the suprascapular nerve 2006;22(9):1009–13.
entrapment syndrome. J Bone Joint Surg Am 2001;83-A(8):1273–4. [22] Meyer M, Graveleau N, Hardy P, Landreau P. Anatomic risks of shoulder
[7] Zehetgruber H, Noske H, Lang T, Wurnig C. Suprascapular nerve entrapment. A arthroscopy portals: anatomic cadaveric study of 12 portals. Arthroscopy
meta-analysis. Int Orthop 2002;26(6):339–43. 2007;23(5):529–36.
[8] Polguj M, Jedrzejewski˛ K, Podgórski M, Topol M. Morphometric study [23] Harmon D, Hearty C, Peng PW, Wiley MJ, Liang J, Bellingham GA. Ultrasound-
of the suprascapular notch: proposal of classification. Surg Radiol Anat guided suprascapular nerve block technique. Pain Physician 2007;10(6):743–6.
2011;33(9):781–7. [24] Peng PW, Wiley MJ, Liang J, Bellingham GA. Ultrasound-guided suprascapu-
[9] Yang HJ, Gil YC, Jin JD, Ahn SV, Lee HY. Topographical anatomy of the lar nerve block: a correlation with fluoroscopic and cadaveric findings. Can J
suprascapular nerve and vessels at the suprascapular notch. Clin Anat Anaesth 2010;57(2):143–8.
2012;25(3):359–65. [25] Børglum J, Bartholdy A, Hautopp H, Krogsgaard MR, Jensen K. Ultrasound-
[10] Cummins CA, Messer TM, Nuber GW:. Suprascapular nerve entrapment. J Bone guided continuous suprascapular nerve block for adhesive capsulitis: one case
Joint Surg 2000;82-A:415–24. and a short topical review. Acta Anaesthesiol Scand 2011;55(2):242–7.
[11] Sherman PM, Sanders TG, De Lone DR:. A benign soft tissue mass simulating [26] Yücesoy C, Akkaya T, Ozel O, et al. Ultrasonographic evaluation and mor-
a glenoid labral cyst on unenhanced magnetic resonance imaging. Mil Med phometric measurements of the suprascapular notch. Surg Radiol Anat
2004;169:376–8. 2009;31(6):409–14.
[12] Shi LL, Freehill MT, Yannopoulos P, Warner JJ:. Suprascapular nerve: is it impor-
tant in cuff pathology? Adv Orthop 2012;2012:516985.