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CASE REPORT Eur J Anat, 28 (4): 511-515 (2024)
Luschka’s tubercle and snapping scapula
syndrome: an anatomical and clinical
discourse
Saad Ahmed1, Panchal Hiten2, Jain Prathmesh3, Karthikeyan P. Iyengar4, Rajesh Botchu5
1 Department of Orthopedics, Royal Orthopedic Hospital, Birmingham, UK
2 Sanyapixel diagnostics, Ahmedabad, India
3 Advance Hospital, Ahmedabad, India
4 Department of Orthopaedics, Southport and Ormskirk Hospitals, Mersey and West Lancashire NHS Trust, Southport, UK
5 Department of Musculoskeletal Radiology, Royal Orthopedic Hospital, Birmingham, UK
SUMMARY
Snapping Scapula Syndrome (SSS) is an un-
common orthopaedic disorder characterised by
audible crepitations and disrupted shoulder ki-
nematics due to pathological interactions within
the tissues between the scapula and ribcage. One
rare cause of SSS is the presence of Luschka’s Tu-
bercle, a bony prominence located on the costal
surface of the superior angle of the scapula. Diag-
nosis of SSS due to Luschka’s Tubercle (LT) can be
challenging, often eluding conventional imaging,
potentially leading to mismanagement and wors-
ening symptoms. This case series underscores
the signicance of LT detection, explores its role
in SSS, and discusses treatment options.
This series presents ve patients with posterior
shoulder pain and a palpable click indicative of
SSS over a six-month period. Three of these pa-
tients did not exhibit Luschka’s Tubercle (LT) on
3D CT scans, while the remaining two patients
had LT detected on the imaging. Arthroscopic re-
section successfully resolved symptoms in one of
the two patients with LT.
SSS is characterised by scapular snapping
during movement, often associated with anatom-
ical abnormalities such as Luschka’s Tubercle. A
comprehensive approach to diagnosis and man-
agement, including imaging, conservative mea-
sures, and, when necessary, surgery, is crucial
for alleviating symptoms and enhancing shoulder
function in affected individuals.
Key words: Shoulder – Orthopaedics – Scapula
– Shoulder pain – Ribs – Musculoskeletal diseases
INTRODUCTION
Snapping Scapula Syndrome (SSS) is an intrigu-
ing yet uncommon orthopaedic disorder char-
acterised by audible crepitations and disrupted
shoulder kinematics resulting from pathological
interactions within the tissues located between
the scapula and the ribcage (Lazar et al., 2009;
Kuhne et al., 2009; Carvalho et al., 2019; Vidoni et
al., 2022). The causes of SSS are diverse and can
include morphological alterations of the scapula
and rib cage, an imbalance in periscapular mus-
Shared corresponding authors:
Rajesh Botchur. Department of Musculoskeletal Radiology, Royal Ortho-
pedic Hospital, Birmingham, UK. E-mail: drbrajesh@yahoo.com
Submitted: October 14, 2023 Accepted: January 22, 2024
https://doi.org/10.52083/HVJP6884
Luschka’s tubercle and snapping scapula syndrome: an anatomical and clinical discourse
512
culature forces (dyskinesia), or neoplasia (bone
tumours or soft tissue tumours) (Carvalho et
al., 2019). This condition predominantly affects
young, active individuals, often with a history
of pain stemming from overuse, rapid shoulder
movements, or participation in sports activities
(Gaskill and Millett, 2013).
Among the rare causes of SSS is the presence of
Luschka’s Tubercle (Carvalho et al., 2019; Gallien,
1985; Estwanik, 1989; Dietrich et al., 2017; Somer-
son et al., 2024). Luschka’s tubercle, rst described
and illustrated by Gruber, Luschka and Sauser in
the years 1864, 1870 and 1936, is a bony protu-
berance found on the costal surface of the superior
angle of the scapula (Sauser, 1936). The tubercle
is distinct due to its hook-shaped morphology and
discreet location at the superomedial aspect of the
scapula. It occurs in approximately 3% of the gen-
eral population and signicantly inuences the
dynamics of the scapulothoracic articulation (To-
tlis et al., 2014). LTs can restrict normal shoulder
mobility, contributing to the symptomatic expres-
sion of SSS by reducing the scapular interspace
and increasing friction, thereby causing discom-
fort (Dietrich et al., 2017).
Diagnosis of SSS due to Luschka’s Tubercle
(LT) can be challenging, as it are often missed on
conventional imaging, potentially leading to mis-
management of SSS and worsening symptoms in
affected patients (Kuhne et al., 2009). This case
series aims to emphasise the importance of de-
tecting Luschka’s Tubercle (LT), to explore its role
within the context of SSS and to discuss the differ-
ent treatment options.
CASE SERIES
In this series, we report on ve patients with
a mean age of 40 years (ranging from 26 to 46),
comprising three females and two males. All pa-
tients presented with posterior shoulder pain,
associated with pain on passive movements of
adduction and forward exion, and a palpable
click, typical of Snapping Scapula Syndrome,
over a six-month period. There was no history of
trauma. The overlying skin over the scapula was
normal. Cross-sectional imaging was performed
to evaluate this further. Three out of the ve pa-
tients did not exhibit Luschka’s Tubercle (LT) on
a 3D CT scan (15 slice ACT revolution, GE ) and
further assessment by Magnetic Resonance Imag-
ing (MRI) (1.5T HDXT, GE MRI, T1 and STIR axial,
coronal and sagittal), and there was no oedema in
the scapulothoracic interval. The remaining two
patients, a 26- and a 39-year-old male, present-
ed with similar symptoms, with LT being detected
on the 3D CT scan. There was oedema of the soft
tissues between the LT and thoracic wall on MRI
(Fig. 1).
They were initially managed with analgesics
and physiotherapy. The 39-year-old male patient
had recalcitrant pain despite these, and hence
underwent arthroscopic resection of the tubercle
with complete resolution of symptoms at a six-
month follow up (Fig. 2). The other patient was
also offered surgical resection; however, he could
not proceed due to nancial constraints. Other
three out of the ve patients with LT were man-
aged conservatively, involving analgesia and ste-
roid injections.
Fig. 1.- Axial STIR (a) showing edema between the Luschka’s tubercle and posterior chest wall (arrow). Sagittal CT showing Lusch-
ka’s tubercle (b) (arrow) and 3D reconstruction showing Luschka’s tubercle (c). H (humeral head), S (scapula).
Saad Ahmed et al.
513
DISCUSSION
Snapping Scapula Syndrome (SSS) is a fasci-
nating condition thought to originate from an
abnormal scapulothoracic articulation (Lazar et
al., 2009; Carvalho et al., 2019). The scapula, a
triangular bone situated between the second and
seventh ribs, exhibits distinctive surfaces, bor-
ders, and angles. Its connection with the ribcage
lacks conventional joint structures and is instead
surrounded by a complex array of muscles, cate-
gorised into supercial, intermediate, and deep
layers (Kuhne et al., 2009; Lazar et al., 2009; Car-
valho et al., 2019). These encompass the trape-
zius, latissimus dorsi, rhomboids, levator scapu-
lae, serratus anterior and subscapularis. Precise
scapular positioning and control are essential
for optimal glenohumeral joint function, neces-
sitating synchronised actions of various scapular
muscles (Lazar et al., 2009; Carvalho et al., 2019).
These muscles collaborate to enable a range of
movements, including abduction, adduction, el-
evation, depression, and rotation. Any disruption
to the biomechanics of scapulothoracic move-
ments can give rise to SSS.
SSS is characterised by an audible pop or click-
ing of the scapula during scapulothoracic joint
movements, often associated with inammation
and irritation of the bursa in the serratus anterior
space (Vidoni et al., 2022). Patients with SSS typ-
ically present with painful snapping, grinding, or
popping of the shoulder during adduction, exion
or extension movements, often accompanied by
crepitus and feelings of fullness in the posterior
shoulder region. The pain worsens with overhead
movements, heavy lifting, and repetitive use (Gas-
kill and Millett, 2013; Vidoni et al., 2022).
SSS has diverse causes, encompassing scapu-
lothoracic bursitis, ribcage or scapula deformi-
ties, and congenital anomalies such as Sprengel’s
deformity. Occupational factors, particularly re-
petitive overhead motions, can also contribute
to SSS (Kuhne et al., 2009). Notably, Luschka’s
Tubercle (LT) plays a pivotal role in SSS. LT, char-
acterised as a unique bony protrusion with a dis-
tinctive hook-shaped structure located along the
superomedial edge of the scapula, often proves
challenging to detect by conventional imaging,
posing a diagnostic challenge (Sauser, 1936; Le-
htinen et al., 2005; Totlis et al., 2014; Dietrich et
al., 2017). Despite the surrounding musculature
providing support to the scapulothoracic joint, it
is crucial to recognise that specic scapular ar-
eas, including the superomedial and inferomedi-
al angles, along with the medial border, possess
relatively less muscular and bursal coverage. LT
develops around the superior angle of the scapu-
Fig. 2.- Arthroscopy images (a, b) showing surface marking of scapula, insertion of arthroscopic ports (a) and image after resection
of Luschka’s tubercle (b), highlighted area between the arrows.
Luschka’s tubercle and snapping scapula syndrome: an anatomical and clinical discourse
514
la, remaining unsupported by musculature, thus
disrupting signicantly normal shoulder move-
ment. This disruption leads to the development of
SSS by narrowing the space between the scapula
and ribcage, resulting in heightened friction and
accompanying symptoms (Totlis et al., 2014; Di-
etrich et al., 2017).
Understanding the embryological development
of Luschka’s Tubercle (LT) presents challenges
due to its rarity in reported literature. The process
begins with undifferentiated mesenchymal tis-
sue, and the scapula’s primary ossication centre
emerges around the seventh week of gestation.
During this intricate process, various areas of the
scapula undergo differentiation, including the area
where Luschka’s tubercle eventually forms (Huang
et al., 2006). Osteoblasts play a crucial role in de-
positing bone matrix in this specic region, giving
rise to the tubercle. Secondary ossication centres
also develop in other scapular areas, further con-
tributing to its growth and maturation. As postnatal
growth ensues, and the scapula continues to trans-
form in shape and structure, with Luschka’s tuber-
cle becoming more distinct (Totlis et al., 2014). It
is important to note that genetic factors and the
complex processes of bone formation during em-
bryonic development can inuence the presence
and characteristics of this anatomical feature.
Diagnosing snapping scapula primarily relies on
patient history and physical examination. Some
researchers have suggested the use of CT scans
as a helpful adjunct in the diagnostic process for
snapping scapula cases (Mozes et al., 1999; Kuhne
et al., 2009). CT images can provide supplemen-
tary information to support clinical assessment.
Nevertheless, due to the limited clarity in exist-
ing literature regarding the scapular morphology
in individuals with snapping scapula, diagnosing
this syndrome remains challenging for diagnos-
tic radiologists. In our study, detection for LT was
made through CT scans (Mozes et al., 1999). MRI
is crucial in the visualisation of surroundings soft
tissues but often misses bony anomalies. The use
of ultrasound in these cases can be challenging
(Conduah et al., 2010).
The treatment approach for Snapping Scap-
ula Syndrome (SSS) associated with Luschka’s
Tubercle (LT) remains variable and subject to
controversy. While some studies have found no
conclusive link between LT and SSS (Dietrich et
al., 2017), our case series highlights the diversity
in management strategies. In our study, two pa-
tients with SSS and LT were managed different-
ly. One patient opted for conservative treatment,
which involved pain management through anal-
gesia and steroid injections, coupled with phys-
iotherapy to restore scapular control and muscle
strength. However, in cases where symptoms per-
sist, surgical intervention may become necessary,
as demonstrated in one of our patients. In this
instance, arthroscopic debridement of Luschka’s
Tubercle resulted in the complete resolution of
the patient’s symptoms, highlighting the poten-
tial efcacy of surgical intervention in selected
cases. Scapulothoracic arthroscopy offers several
advantages, including safe and straightforward
access to the superomedial corner of the scapula,
improved visibility for bursa and superomedial
corner resection, enhanced cosmesis compared
to open procedures, and minimal muscle dissec-
tion, resulting in reduced pain and quicker reha-
bilitation. Various approaches can be employed
for this procedure. However, the chicken wing po-
sition, with the patient in a prone posture and uti-
lizing the 3-portal technique (comprising superi-
or, medial, and inferior portals with blunt trocars
for scapular access), is notably effective. Initial
access to the scapulothoracic space involves two
superiorly positioned portals, one proximal and
one medial to the superomedial angle of the scap-
ula. Gaining access to the superomedial corner of
the scapulothoracic interspace is a procedure that
can be carried out in a straightforward and repro-
ducible manner. However, it is crucial to be aware
of the potential complications, such as the risk of
injuring the dorsal scapular nerve or vessels, as
well as the possibility of iatrogenic damage to the
suprascapular nerve. Failing to insert the portal
trocars toward the costal surface of the scapula
may lead to perpendicular insertion into the tho-
racic wall and cavity (Saper et al., 2015).
CONCLUSION
SSS is a condition characterised by scapular
snapping during movement, often linked to an-
atomical abnormalities like Luschka’s Tuber-
Saad Ahmed et al.
515
cle. Proper diagnosis and management involve a
multidisciplinary approach, including imaging,
conservative measures, and, in some cases, sur-
gery, to alleviate symptoms and improve shoulder
function in affected individuals.
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