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International Journal of Core Engineering & Management
Volume-6, Issue-11, 2021 ISSN No: 2348-9510
69
ROLE OF SCAPULAR RETRACTORS AND DEPRESSORS IN SCAPULAR HEALTH
Vidit Atul Phanse
Viditp1992@gmail.com
Madhushree Donde
madhudonde1992@gmail.com
Abstract
The shoulder complex is an intricate system that consists of the scapula, clavicle, and the
glenohumeral joint that plays a key role in maintaining shoulder health, it is a link between the
upper back and the upper extremity providing stability and range of motion to the shoulder. When
there is compromised scapular mobility, we see distinct number of shoulder issues and upper back
pain postural problems. In the clinical world where there are more rotator cuff injuries,
impingement syndromes, upper cross syndrome, and adhesive capsulitis and we see how
important it is to maintain scapular strength and motion. Poor scapular mobility can cause pain
and limit range of motion of the shoulder especially with overhead movement that limits the
ability to perform activities of daily living (ADL). The scapular retractors and depressors
especially assist with shoulder mobility and strength and weakness in these muscles can lead to
pain, decreased ROM and strength, injuries such as tears, poor posture, and spinal alignment. This
article dives into the deeper understanding of how scapular retractors and depressors can enhance
shoulder health, sports performance, and posture.
Keywords: Scapular Retractors, Scapular Depressors, Shoulder Health, Scapular Mobility,
Shoulder Complex, Shoulder strength, Scapular strength, Movement
I. INTRODUCTION
The shoulder complex is the connection of the upper extremity to the thoracic wall. It consists of
various structures such as ligaments, tendons and muscles of the scapula, humerus, sternum, and
clavicle that comprise of four joints, the Glenohumeral (GH) joint, Acromioclavicular (AC) joint,
scapulothoracic (ST) joint and sternoclavicular (SC) joint. These joints collectively work to offer the
extensive range of mobility of the shoulder complex [1]. The articular spheroid surface of the GH
joint especially contributes to allow for the greatest mobility of any joint in the body [2]. This
freedom of movement comes at the cost of stability. The tradeoff for stability, known commonly as
the mobility-stability trade-off. This intricate design that allows for greater mobility and function
also makes the shoulder complex susceptible to a wide range of injuries and instabilities [3]. The ST
joint functions to allow for the scapula to move on the thoracic wall offering stability to the shoulder
complex. This unique balance for function comes through dynamic forces that are active
stabilization forces from the muscles instead of the passive forces from the capsule and ligaments.
Thus, it is the muscles that secure the shoulder girdle to the thoracic wall and provide the stability
required for the shoulder to move freely and perform its dynamic movement [4]. The shoulder
complex has two groups of stabilizers the static stabilizers and the dynamic stabilizers. The static
stabilizers are the ligamentous structures, capsule and fascia structures around the shoulder
International Journal of Core Engineering & Management
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complex. The dynamic stabilizers are further divided into the glenohumeral and scapulothoracic
stabilizers [5].
1. Glenohumeral Stabilizers
The rotator cuff muscles (RTC), namely subscapularis, supraspinatus, teres major, infraspinatus,
and the deltoid, all stabilize the position of the humeral head in the glenoid fossa. These fine-tune
static postures and dynamic movements [6].
2. Scapulothoracic Stabilizers
Scapulothoracic stabilizers are vital for shoulder health and are often overlooked when
strengthening the shoulder complex. More emphasis is placed on strengthening the RTC muscles,
but overlooking the periscapular muscles will affect the scapulothoracic rhythm and will delay or
cause incomplete healing of the injury [7].
II. ANATOMY OF SCAPULAR MOVEMENT
The scapular motion is paired with motion in the shoulder. This biomechanical movement serves to
provide increased mobility to the shoulder girdle and stabilize the humeral head in the glenoid
fossa. Codman (1993) first published about the scapulothoracic rhythm [4]. The scapulothoracic
rhythm is the kinematic motion between the scapula and the humerus, this interaction is the link
between the GH joint and ST joint during shoulder elevation [9]. The GH and ST joint moves
simultaneously after the first 30 degrees of elevation motion at a 2:1 ratio. This rhythm serves two
main purposes:
1. It preserves the length-tension relation between the muscles and aids the muscles in sustaining
force through most of the shoulder range of motion [11].
2. The other function is prevention of shoulder impingement at the humeral and acromial head.
The difference in sizes of the glenoid fossa and the humeral head can cause impingement of
the shoulder if there is increased relative movement between the humerus and scapula. The
simultaneous movement between humerus and scapula during shoulder elevation can restrain
the relative movement [12].
The scapulothoracic joint is a floating joint and relies heavily on feedback from the stabilizing
muscles and a sense of muscular timing. The scapular elevators, depressors, protractors, and
retractors all work to minimize the dysfunction. Study by Struyf, et al. (2011) shows that during
shoulder elevation and reaching activities, there are multiple coupling forces on the floating joint,
and it is essential to study those to maintain shoulder health.
III. ROLE OF SCAPULAR DEPRESSORS AND RETRACTORS
Scapular retraction is the movement of pulling the scapula in towards the spine. Scapular
depression is the action of pulling the shoulder blades down.
1. Trapezius
The trapezius is a triangular muscle that has upper, middle and lower fibers extending from base
of skull to the lower thoracic vertebrae. The upper fibers help in scapular elevation, while the
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lower fibers help pull the scapula downwards and backwards. The middle trapezius muscle acts as
an antagonist to the force of serratus anterior and retracts the scapula [10].
2. Rhomboids
Located between the spine and medial border of scapula, the rhomboid major and minor are deep
muscles between the shoulder blades [14]. They primarily retract the shoulder but also assist in
depression of the shoulder blade through its anchor to the thoracic wall. Rhomboids along with
teres major muscle (proximally attached to scapula and distally to humerus act as scapular
retractors [13].
3. Levator Scapulae
The primary function of this muscle is scapular elevation, but it also acts as a force to stabilize the
scapula during depression movements. This muscle helps maintain the proper positioning of the
scapula during GH movements.
Understanding the interplay between these muscles is crucial for shoulder health. These muscles
not only stabilize the scapula on the thoracic wall but also assist the GH joint motion of adduction
and extension allowing neutral spine positioning. Adequate forces of the agonist, antagonist and
synergist muscles are required for smooth synchronous movement of the shoulder complex [14].
Deficits in these forces can lead to narrowing of the sub-acromial space leading to compression of
the soft tissue and tendons in this space and can lead to inflammation and pain [9].
IV. COMMON INJURIES AND CONDITIONS RELATED TO SCAPULOTHORACIC
DYSFUNCTION
Several known conditions arise due to dysfunction of the scapulothoracic rhythm and muscle
imbalance.
1. Shoulder Impingement Syndrome
This condition occurs when there are altered biomechanics of the shoulder complex. Abnormal
scapular position has been known to cause scapular dyskinesis, which can predispose an
individual to impingement syndrome [8].
2. Rotator Cuff Injuries
The RTC muscles are primary GH joint stabilizers. RTC injuries include tears, tendinitis, and
impingement. Inadequate or abnormal scapular movement can place a strain on the RTC muscles,
increasing their risk of tears [6].
3. Scapular Winging
This is a condition where the medial border of the scapula protrudes out posteriorly. Weakness or
dysfunction of the periscapular musculature can lead to winging. This can additionally affect
shoulder health by causing instability and pain in the GH joint [13]
4. Upper Cross Syndrome
Poor scapular control can lead to postural issues, namely upper cross syndrome. This condition is
characterized by forward neck posture, thoracic kyphosis (rounded shoulders), and muscle
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imbalances that can further lead to shoulder injuries, neck pain, and headaches. Good posture is
essential for maintaining optimal scapular function and health [7]
V. EXERCISES AND DOSAGE TO STRENGTHEN SCAPULAR MUSCLES
There are several exercises that can help strengthen the scapular muscles. These include seated
rows and shoulder extensions and their variations. There are several exercises that incorporate
scapular strengthening with scapulothoracic mobility “black burn exercises” (BME) used in
rehabilitation programs are aimed at improving muscle strength and muscle performance. These
exercises are divided into 3 positions: BME position I, II, III. Research by De Mey et al. (2013) in
their randomized controlled trial (RCT) concluded that the most effective exercise to activate and
strengthen the lower trapezius muscle and maximize its muscle activity was BME position II
exercises [5]. In a clinical setting, these exercises can help alleviate pain, improve function and
overall shoulder health. Following exercises will be divided into groups for the muscles used to
help strengthen shoulder muscles.
1. Shoulder extension
This can be performed using a resistance band or weights. Attach the resistance band to a stable
surface and hold the ends in both hands, pull the hands back towards the hips while keeping the
arms straight. This engages the trapezius and latissimus dorsi.
2. Seated rows
Use a resistance band or cable machine. Sit on a stable surface and secure the band or cable at feet
level. Pull the band or cable towards the chest, engaging the rhomboids, middle and lower
trapezius.
3. Prone Y and T
Lie face down on a bench or floor with arms extended overhead (Y position) or out to the sides (T
position). Lift the arms off the surface, squeezing the shoulder blades together, targeting the
trapezius and rhomboids.
4. Face pulls
Attach a resistance band to a stable surface at head level. Hold the ends in both hands and pull
towards the face while keeping the elbows high. This engages the rhomboids and trapezius.
5. Scapular wall slides
Stand with the back against a wall, arms at 90-degree angle. Slide the arms up the wall while
squeezing the shoulder blades together. This targets the trapezius and rhomboids.
6. Push-ups with scapular protraction and retraction
Perform a push-up and at the top of the movement, push the shoulder blades away (protraction)
and then squeeze them together (retraction). This engages the serratus anterior and rhomboids.
VI. CONCLUSION
1. Scapular health is fundamental to maintaining shoulder health. It is also essential for
improving athletic performance, preventing injuries, and enhancing postural alignment.
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2. Incorporating exercises that strengthen the scapular retractors and depressors into routine
shoulder strengthening programs can help address biomechanical inefficiencies and
imbalances in the shoulder complex.
3. Strengthening these muscles can also help maintain proper scapulothoracic rhythm, thereby
reducing the risk of injuries such as impingement syndromes, rotator cuff tears, scapular
winging, and postural deformities like upper cross syndrome.
4. For a better shoulder complex functioning it is not only important to have stronger shoulders
itself but a holistic approach of shoulder mobility, shoulder strength, scapular mobility,
thoracic mobility and strength is important.
5. It is important to identify the condition and the optimal muscle which might be acting as
agonist and the ones that might be acting as antagonist during motion and aggravating pain,
causing discomfort or leading to improper mechanics of the shoulder
6. Therefore, scapular muscle strengthening should be a core component of shoulder
rehabilitation and conditioning programs.
7. Further scope of study includes role of scapular depressors and retractors with their interaction
with thoracic muscles and range of motion in the shoulder joint.
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