Keywords
winging of the scapula - accessory nerve palsy - long thoracic nerve palsy - synchronized
swimming
Introduction
Winging of the scapula is a condition in which the medial border of the scapula is
raised from the chest wall, resulting in a wing-like protrusion of the scapula. Scapular
winging has been observed in scoliosis, deltoid contracture, Sprengel's deformity,
and infraspinatus muscle atrophy. It can also occur in dislocation of the shoulder,
as well as after muscle rupture or muscular dystrophy associated with trauma.[1]
[2] Frequently, winging of the scapula occurs because of denervation of the serratus
anterior muscle due to long thoracic nerve palsy, or because of the denervation of
the trapezius muscle due to accessory nerve palsy.[3]
[4]
[5]
[6]
[7] The severity of winged scapula is variable, and although pain is not seen in every
case, it will most often resolve with time, even when there is complete loss of muscle
function.
The cause of long thoracic nerve palsy may be traumatic or atraumatic.[8] Lesions to the long thoracic nerve may occur due to numerous and varied causes.[9] Generally, however, injury to the long thoracic nerve can follow excessive upper-limb
stretching, and may result from traction and/or compression between its cervical origin
and its distal terminal branches in the serratus anterior muscle, the anatomical structure
and innervation of which have been thoroughly described. Excessive upper-limb stretching
during sports activities appears to be a significant factor.[10]
[11]
[12]
[13]
[14]
A wide range of sports have been reported to cause long thoracic nerve palsy, including
archery, tennis, and basketball.[4]
[6]
[7]
[15]
[16]
[17]
[18]
[19]
[20]
[21] To our knowledge, this is the first report of long thoracic nerve palsy in aquatic
sports ([Table 1]).
Table 1
Cases of long thoracic nerve palsy due to sports, as reported in the literature
|
Author
|
Year
|
Age
|
Sex
|
Cause
|
Period until Improvement (mo)
|
|
Gregg et al[5]
|
1979
|
23
|
M
|
Tennis
|
1
|
|
47
|
F
|
Tennis
|
6
|
|
32
|
M
|
Ballet
|
14
|
|
23
|
M
|
Soccer
|
12
|
|
20
|
M
|
Ice hockey
|
12
|
|
27
|
M
|
Bowling
|
7
|
|
27
|
M
|
Golf
|
11
|
|
22
|
M
|
Gymnastics
|
4
|
|
11
|
M
|
Weightlifting
|
4.5
|
|
Sakamoto et al[16]
|
1981
|
14
|
M
|
Basketball
|
6
|
|
Isayama et al[17]
|
1982
|
20
|
M
|
Archery
|
1
|
|
Yasuda et al[18]
|
1982
|
12
|
F
|
Portball
|
Began recovering in 2 y
|
|
Foo et al[28]
|
1983
|
18
25
|
M
F
|
Tennis
Archery
|
12
Unknown
|
|
Ohno et al[19]
|
1984
|
21
|
F
|
Gymnastics
|
7
|
|
Fukuzawa et al[20]
|
1985
|
14
13
|
M
F
|
Basketball
Volleyball
|
6
5
|
|
Shimizu[3]
|
1990
|
20
|
M
|
Archery
|
Recovering
|
|
Toizumi et al[15]
|
1997
|
16
|
M
|
Javelin
|
7
|
|
Ebata et al[23]
|
2005
|
27
|
M
|
Weightlifting
|
Unknown
|
|
Present case
|
2013
|
14
|
F
|
Synchronized swimming
|
Began recovering in 1 y
|
Note: Previous studies have reported patients with long thoracic nerve palsy due to
sports other than aquatic sports.
Synchronized swimming is a sport in which athletes are subjectively scored on technical
merit and artistic expression during their aquatic performance. In the present study,
we report a rare case of winging of the scapula that occurred during synchronized
swimming practice.
Case Report
The subject was a 14-year-old female synchronized swimmer with chief complaints of
muscle weakness, pain, and paresthesia in the right scapula. She had no history of
neurological or muscular disease.
History of Present Illness
In mid-July 2011, while performing the butterfly stroke during synchronized swimming
practice, the subject experienced severe pain in the vicinity of the second dorsal
rib, as well as dislocation of the right glenohumeral joint. Thereafter, she discontinued
practice and underwent an orthopedic examination several days later.
Physical Findings upon Initial Examination
Right arm manual muscle testing (MMT) grades and right shoulder joint range of motion
(ROM) are listed in [Tables 2] and [3], respectively. In the left shoulder, MMT and joint ROM were normal. The subject
experienced paresthesia in the right shoulder girdle. In addition, when the diagnostic
wall press test (WPT) was performed (pressing hands against a wall in a leaning position),
distinct winging of the right scapula was observed. Due to drooping of her right shoulder,
it was immobilized in a sling for 2 to 3 months. In addition, she was diagnosed with
isolated paralysis of the serratus anterior muscle based on electromyography results.
Table 2
Results of the right arm manual muscle test before and after therapy
|
Initial examination
|
One year after beginning therapy
|
|
Shoulder flexion
|
2
|
4
|
|
Shoulder abduction
|
2
|
4
|
|
Shoulder extension
|
1
|
3
|
|
Scapular elevation
|
1
|
2
|
Table 3
Results of the right shoulder joint range of motion examination before and after therapy
|
Initial examination
|
One year after beginning therapy
|
|
Passive (degrees)
|
Active (degrees)
|
Passive (degrees)
|
Active (degrees)
|
|
Shoulder flexion
|
10°
|
5°
|
130°
|
130°
|
|
Shoulder abduction
|
20°
|
10°
|
90°
|
90°
|
|
Shoulder extension
|
5°
|
0°
|
40°
|
25°
|
Exercise Therapy
At 4 months postinjury, the subject discontinued shoulder immobilization and began
rehabilitation. Rehabilitation initially consisted of passive flexion, extension,
abduction, and external and internal rotation of the right glenohumeral joint; this
was followed by gradual transition to active movement, and ultimately progressed to
resistance exercises. In addition, the muscles surrounding the right shoulder were
stretched and massaged. Two or three rehabilitation sessions were performed per week,
with each session lasting ∼30 minutes.
Progress
One year after beginning therapy, the right shoulder girdle pain and paresthesia had
disappeared. MMT and joint ROM improved, although not completely. The subject's MMT
and ROM grades 1 year after beginning therapy are listed in [Tables 2] and [3], respectively. However, when shoulder abduction was 0 degree, downward rotation
of the right scapula was prominent. Furthermore, WPT resulted in a distinct dorsal
protrusion of the scapula, and winging of the scapula remained ([Fig. 1]).
Fig. 1 Winging of the scapula is apparent when the patient is pushing forward. The arrows
show winging of the scapula.
Discussion
The long thoracic nerve is primarily derived from the merging of the ventral rami
of branches from the fifth, sixth, and seventh cranial nerves (hereafter, “C5,” “C6,”
and “C7,” respectively); this nerve consists of pure motor fibers, which innervate
the serratus anterior muscle.[4]
[6]
[21]
[22]
[23]
[24]
[25] There are many variations in the components of the long thoracic nerve. However,
generally, the upper long thoracic nerve trunk, which is formed by C5 and C6, innervates
the upper portion of the serratus anterior muscle. C7, which constitutes the lower
long thoracic nerve trunk, merges with the upper trunk to form the common trunk, and
then innervates the middle and lower portions of the serratus anterior muscle. The
course of the long thoracic nerve is characterized by certain features. C5 and C6,
which form the upper nerve trunk, primarily run through the anterior and middle scalene
muscles; in 24 to 33% of cases, the middle scalene muscle is penetrated ([Fig. 2]).[26]
[27] When the common trunk of the long thoracic nerve descends behind the brachial plexus,
it angulates over the second rib, runs downward along the thoracic wall, and innervates
the middle and lower portions of the serratus anterior muscle; its total length is
∼24 cm.[3]
[21]
[22]
[28]
Fig. 2 Diagram of the long thoracic nerve in a cadaver. The serratus anterior muscle consists
of upper, middle, and lower portions. The upper portion is supplied mainly by the
C5 nerve root. The long thoracic nerve, consisting of the C6 and C7 nerve roots, innervates
the middle and lower portions. Image modified from Toizumi et al[15] with the permission from Igaku-shoin.
Based on this anatomical course, there are sites where tight facial bands of tissue
may cause a “bow-string” effect that could induce long thoracic nerve palsy. Furthermore,
there is also a possibility of traction injury of the nerve between the middle scalene
muscle and the lower portion of the serratus anterior muscle.[5]
[15]
[22]
[29]
[30]
Hamada et al[21] showed that the upper portion of the serratus anterior muscle runs in a posterior
direction, the middle portion in a posteromedial direction, and the lower portion
in a posterosuperior direction. Therefore, the upper, middle, and lower portions of
the serratus anterior muscle control the anterior tilt, abduction, and upward/internal
rotation of the scapula, respectively. The serratus anterior muscle was considered
to stabilize the scapula as follows: the upper portion of the serratus anterior muscle
attaches the superior angle of the scapula to the first and second ribs, the middle
portion attaches the medial border of the scapula to the thorax, and the lower portion
attaches the inferior angle to the thorax. Therefore, when the superior angle is attached
to the thorax and the medial border and inferior angle of the scapula are floating,
it is inferred that the nerve distal to the branch that arises from the upper nerve
trunk and innervates the serratus anterior is damaged. When the superior angle is
also floating, it is inferred that there is damage to the nerve proximal to the branch
described above. Winging of the scapula associated with paralysis of the serratus
anterior muscle is prominent during anterior arm elevation. The middle portion of
the serratus anterior muscle controls scapular abduction, while the lower portion
controls upward and interior rotation; in paralysis of the serratus anterior muscle,
these portions do not function, resulting in characteristic adduction and downward
rotation of the scapula. In other words, the upper portion of the serratus anterior
muscle is innervated by branches that arise directly from the upper long thoracic
nerve trunk, which is composed primarily of C5 and C6, while the middle and lower
portions of the serratus anterior muscle are innervated by the common trunk. Therefore,
winging of the scapula only occurs if there is paralysis of the middle or lower portions
of the serratus anterior muscle.
The present case demonstrated prominent winging of the scapula during anterior arm
elevation, as well as floating of the superior angle. Based on this observation and
the severe pain near the second dorsal rib, we believe the cause was damage to the
nerve proximal to the branch that arises from the upper nerve trunk and innervates
the serratus anterior muscle.
The case reported herein presented with severe pain and dysfunction of the serratus
anterior muscle while swimming the butterfly stroke during synchronized swimming practice.
The cause of these symptoms was considered to be compression of the long thoracic
nerve between the scapula and ribs during posterior rotation of the arm. However,
despite identical movements of the left and right arms in the butterfly stroke, the
left serratus anterior muscle was completely undamaged. Therefore, it is inferred
that frequent use of the dominant right arm in sports and activities of daily living
can result in traction injury to the long thoracic nerve.
Conclusion
We reported a case of long thoracic nerve palsy and winging of the scapula that occurred
during synchronized swimming practice. It was apparent that some improvement was evident
at a 1-year follow-up examination, but full recovery was not evident. This case shows
that severe functional loss can remain and therefore timely follow-up is necessary
to monitor for signs of reinnervation. Otherwise, surgical exploration and microsurgical
nerve decompression repair or nerve transfer might be indicated. Methods to consider
for monitoring of reinnervation are clinical examination, muscle magnetic resonance
imaging to determine resolution of denervation edema, and electromyogram of the serratus
to detect reinnervation.
