The Scapula, colloquially known as theshoulder blade, is a distinct triangular Bone of the upper back that relays connection of the Upper Limb to the torso. This is done through providing an articular surface for several joints of The Shoulder Girdle and acting as the site of many Muscle , Connective Tissue and Fascia l attachments:
attachments listed underfunction
The Scapula is a thin-triangular Bone with a complex architecture that resides on the posterosuperior surface of the Thorax , forming the highly-mobile Scapulothoracic Joint . In lieu of a bony articulation, ligamentous structures of the Acromioclavicular Joint and suction forces formed by the Serratus Anterior and Subscapularis fix the Scapula to the Thorax . Additional stability is afforded by the Rhomboids , Levator Scapulae , Trapezius and the Rotator Cuff (SOURCE-3).The body of the Scapula is often so thin it appears translucent, while its borders are notably thicker to afford the attaching musculature a stable base (SOURCE-4).
The Anterior, orCostal, surface of Scapula is predominately concave to reciprocate the contour of the Thorax . This surface thickens superolaterally to form a longitudinal ridge near its border which helps withstand substantial forces generated from the Serratus Anterior .The remaining Costal surface, known as theSubscapular Fossa, is thin and serves as the extensive attachment site for the Subscapularis (SOURCE-8). In the absence of a bony articulation, this surface forms a functional articulation known as the Scapulothoracic Joint , along with the Thorax .
The Posterior, orDorsal, surface of Scapula features two fossae that are distinguished by an oblique bony ridge known as the Spine of Scapula:
Supraspinous Fossa- a thin triangular depression immediately superior of the Scapula Spine which accounts for the mediosuperior portion of the dorsal surface. The three points of the Fossa’s triangular shape are formed from theSuprascapular Notch(laterally), Superior Angle of Scapula (superiorly) and the upper third of the Medial Border of Scapula (medially)
Spine of Scapula- a ridge-like bony projection that is thickest laterally and progressively thins as it courses medially to where the two fossae meet. The spine has a slightly oblique orientation, coursing superolaterally. The edges of the ridge are rough for attachment of Muscle and associated Fascia (seeattachment sites). Followed to its most medial point, the SpinesRoot, should align with T3 in the transverse plane
Infraspinous Fossa- the larger more rhomboid-like segment of the dorsal surface that falls immediately below the Scapula Spine. This fossa accounts for the majority of the surface between the Medial Border, Lateral Border and Scapula Spine
Superior Border- a thin boundary that extends from the Suprascapular Notch (laterally) to the Superior Angle (medially) which serves as the attachment site for Muscle (see below) and the Suprascapular Ligament which forms a roof for the Notch, converting it into a foramen for the Suprascapular Nerve . The Suprascapular Notch is known to be highly variable, with some morphologies predisposing a greater risk of nerve Entrapment (discussed below) (SOURCE-25)
Medial Border- the thinner Medial Border spans from the Superior Angle (superiorly) to the Inferior Angle (inferiorly). This border is on average >6x thinner than its lateral counterpart (SOURCE-4) yet substantially more prominent.
Lateral Border- the thickest Scapula border spans between the Glenoid Fossa (superiorly) and Inferior Angle. While the entire section is thicker than the Scapula body with an average thickness of 46.1mm, the thicker superior portion forms theInfraglenoid Tubercle(SOURCE-8+4).
Inferior Angle- the most distal point of the Scapula formed by the union of the Medial and Lateral Borders, typically aligns with T7 in the transverse plane
Superior Angle- formed by the union of the Superior and Medial Borders and typically aligns with T2 in the transverse plane. While it is often not palpable posteriorly due to the overlying Trapezius , this angle can be accessed above and behind the Clavicle (SOURCE-8)
The Acromion, also known as theShoulder Cap, is the bony continuation of the lateral Spine of Scapula that extends an average of 4.3-4.8cm with an anterior bias beyond the Scapula Body (SOURCE-4+10). The underside of the Acromion is lined with Subacromial Bursa and while not a true joint, forms a ceiling for the Humeral Head, known as the Suprahumeral Joint . The anterior edge of the Acromion provides an articulation for the Clavicle , forming the Acromioclavicular Joint . The shape of the Acromion can be described in one of three ways based on its appearance from a lateral view:
Flat- also known astype-I- the least common morphology with a prevalence of 9% (SOURCE-10)
Curved- also known astype-II- found to be the most common morphology with a prevalence of 78.8% (SOURCE-10)
Hooked- also known astype-III- second-most common morphology with a prevalence of 12%, although some texts have found this number to be higher (SOURCE-10+23). Bony spurs, orOsteophytes, are more prevalent in the Hooked Acromion with Osteophytes on the anteroinferior surface affording its hooked-shape. Their formation has been attributed to degeneration and ossification of the Coracoacromial Ligament near its attachment in response to repetitive or excessive load during shoulder movement (SOURCE-10+23). This morphology predisposes the following conditions
Rotator Cuff Tear - increases risk (SOURCE-1 (31-33)), with roughly 70% of these tears associated with this morphology (SOURCE-23)
Subacromial Impingement - One study found patients with this variant were 6.2x more likely to develop impingement (SOURCE-10)
The distance between the Acromion and Coracoid Process varies between 2.2-3.9cm. The Subacromial Bursa may extend from the lateral end to as medially as the Acromioclavicular Joint (SOURCE-7)
TheScapula Neckis the region between the Supraglenoid Tubercle (superiorly), Infraglenoid Tubercle (inferiorly),Root of the Coracoid Process(anteriorly) and Costal Surface (posteriorly). A finger-like bony projection known as theCoracoid Process, reaches anteriorly and the laterally from the superior neck to the extent that it is palpable from the anterior shoulder. During overhead activity ( GH Joint - Abduction or GH Joint - Flexion ) the Subscapularis Tendon is bent around the undersurface of the Coracoid Process, creating a pulley-like effect that exacerbates GH Joint - Internal Rotation force produced by the muscle (SOURCE-8).
The lateral border of Scapula thickens at is superior end to form a cavity known as the Glenoid Fossa. This oval-shaped concavity is 20-30% larger in a vertical dimension than horizontally (SOURCE-9). This fossa represents the ‘socket’ in the ball-and-socket Glenohumeral Joint which articulates with the Head of Humerus . During articulation the smaller Glenoid Fossa is only in contact with roughly 25-30% of the larger Humeral Head. To improve joint congruency, the fossa is deepened by the Glenoid Labrum . In anatomical position the Fossa is orientated with a slight anterior and upwards (~11º) facing bias; however, this has been shown to vary with age and congenital morphologies (SOURCE-8+2 (21) +18). At its proximal and distal ends the fossa features two tubercles:
Supraglenoid Tubercle- this smaller tubercle defines the superior Glenoid margin and is in close proximity to the root of the Coracoid Process. It’s rough surface facilitates a proximal origin for the Long Head of Biceps
Infraglenoid Tubercle- this larger tubercle resides immediately inferior of the Glenoid Fossa and has an equally rough surface for the origin of the Long Head of Triceps
Scapula morphology can either be hereditary or an adaptation. An increase in age, for example, was correlated with Acromion morphology, indicating type-III Acromion’s may be a product of degenerative changes (SOURCE-10 +1 (31-33)).
Glenoid Hypoplasia
Suprascapular Notch - serval morphologies have been reported (SOURCE-25):
U-Shaped - most common, accounting for roughly half of all Scapulae
V-Shaped - accounts for roughly 1/5th of all Scapulae
J-Shaped - accounts for roughly 1/10th of all Scapulae
Other - L or W-Shaped, double foramen, complete ossification, or absent Notches were also described
The Scapula serves as a bony shield for the underlying posterior Thorax and forms passages for neurovascular structures such as the Brachial Plexus found below the Coracoid Process or soft tissues such as the Supraspinatus or Subacromial Bursa found under the Acromion. The Scapula also relays the connection between the torso and the Upper Limb . The Scapulothoracic Joint provides a stable base for movement that occurs at the Glenohumeral Joint and orients the Glenoid in a favourable position for muscles to act. Appropriate positioning of the Glenoid also allows the Upper Limb to achieve greater ranges of motion, such as those seen during Scapulohumeral Rhythm . The Scapula forms additional articulation with the Clavicle to form the Acromioclavicular Joint , which further serves to refine and amplify movement at The Shoulder Girdle .
The Scapular serves as the attachment site for many Muscle s:
Superior
Omohyoid - inferior belly inserts where the Suprascapular Notch meets the Superior Border
Suprascapular Ligament - provides a ceiling for the Suprascapular Notch, converting it into a foramen
Medial
Levator Scapulae - arises from the Medial Border of the Supraspinous Fossa between the Superior Angle and Spine
Rhomboid Minor - arises from the Medial Border below the Spine of Scapula
Rhomboid Minor - arises from the Medial Border, below the attachment of the Rhomboid Minor
Lateral
Long Head of Triceps - arrises from the Infraglenoid Tubercle
Teres Minor - both attachments are made on the middle half of the Lateral Border, separated by theGroove for Circumflex Scapular Artery
Teres Major - arises from the inferior portion of the Lateral Border
Latissimus Dorsi - often present scapular portion arises from the Inferior Angle
Supraspinatus - arises from medial two-thirds of Supraspinous Fossa, including the upper surface of the Spine
Trapezius - middle fibres attach to the Spines superior border
Deltoid - posterior fibres attach between the posterior Acromion and Scapula Spine’s inferior border
Infraspinatus - arises from the Infraspinous Fossa
Serratus Anterior - proximal portion inserts along the Costal Surface near the Medial Border while the distal 5-6 digitations attach near the Inferior Angle
Deltoid - posterior fibres attach between the posterior Acromion and Scapula Spine’s inferior border
Superior Biceps Aponeurosis- fibres that extend between the Coracoacromial Ligament and proximal Short Head of Biceps Tendon attach on the anterior Acromion and lateral Coracoid Process
Trapezoid Ligament - attaches anterior of the Conoid Ligament
Conoid Ligament - attaches to dorsal surface of Coracoid Process near where it courses laterally
Coracoacromial Ligament - anterior and posterior bands attach to the lateral border of the Coracoid Process
Costocoracoid Ligament - attaches to the Coracoid Process
Short Head of Biceps - inserts onto the medial portion of the Coracoid tip
Coracobrachialis - arises from the inferior surface of the Coracoid Process
Pectoralis Minor - attaches to the superior and medial borders of the Coracoid Process
Scapular Dyskinesis - the umbrella term for disturbed mechanics of the Scapula which may be derived from hindered muscle couplings of the Glenohumeral Joint and Scapulothoracic Joint , poor posture or tissue restriction (SOURCE-19):
While there are many muscles that directly and indirectly influence the position of the Scapula, there are two muscle couplings that are arguably most profound:
Serratus Anterior to Rhomboids , Levator Scapulae and Serratus Posterior Superior - these muscles determine the position of the Scapula on an obliquely medial to lateral axis where the Serratus Anterior draws the Scapula laterally and inferiorly while the remaining muscles antagonistically pull back towards the spine (medially and superiorly) (SOURCE-8+11)
Lower Trapezius - Pectoralis Minor : on an almost perpendicular axis the Lower Trapezius draws inferiorly and slightly medial on the Spine of the Scapula while the Pectoralis Minor draws on the Coracoid Process resulting in an anterior tilt of the Scapula (SOURCE-11)
The relative position of the Scapula may provide insight into which structures are either restricted (short) or weak (long) and require treatment.
Vertebral Column -exacerbated curvature of the proximal column has been shown to affect on Scapula posture, capacity of local musculature and consequently Shoulder - Active Range of Motion (SOURCE-5 (11,12)+6 (74)):
Thoracic Spine - the Thoracic Angle or extent of Kyphosis is known to disturb Scapula mechanics. At rest Scapular Winging (lateral translation) is more present when slouched (greater Thoracic Kyphosis), while those with erect posture have their Scapula sit medially at rest and translate a greater lateral distance between 0º and 90º GH Joint - Abduction . Significantly greater Scapulothoracic Joint - Elevation was displayed in the slouched group between 0-90º GH Joint - Abduction . In the healthy shoulder, both Internal Rotation and Posterior Tilting of the Scapula are expected to increase with Scapulothoracic Joint - Upward Rotation ; however, these mechanics are also expected to change with greater Thoracic Kyphosis. While similar from 0-90º, slouched posture demonstrated significantly less Upwards Rotation beyond 90º GH Joint - Abduction and significantly less Posterior Tilting and greater Internal Rotation through all GH Joint - Abduction ranges. Approaching full GH Joint - Abduction from 90º, the Scapula of both postures course medially to return to their at rest position.(SOURCE-16)
Cervical Spine - Scapular Dyskinesis is a common consequence when the neuromuscular structures associated with Forward Head Posture are disturbed (SOURCE-12 (4)). Individuals with Forward Head and Rounded Shoulder PostureFHRSPdisplayed greater Internal Rotation of the Scapula during reaching and flexing and on average 5º greater Scapulothoracic Joint - Upward Rotation when arm is elevated around 120º. Unsurprisingly this posture maintained a greater Anterior Scapular Tilting of ~3º when the arm is ascending and ~4º when descending. FHRSP may inhibit the Serratus Anterior , particularly during the ascending phase of shoulder elevation (SOURCE-13).
Aside from the Muscle discussed underMuscle Couplings, the position and mechanics of the Scapula can be influenced by many tissues. Forward positioning of the Scapula (ie excess Scapulothoracic Joint - Protraction and Anterior Scapular Tilting ) is associated with restricted Horizontal GH Joint - Adduction and tightness in the (SOURCE-14+24):
Posterior Glenohumeral Joint Capsule
Posterior Deltoid
Spiral Line - via Serratus Anterior and Rhomboids
Deep Back Arm Line - via several muscles including Levator Scapulae and Rotator Cuff
Deep Front Arm Line - via Pectoralis Minor and Biceps Brachii
Superficial Front Arm Line - via Latissimus Dorsi attachment
Dorsal Arm Chain - via multiple muscles including Latissimus Dorsi and Infraspinatus
Lateral Arm Chain - via Trapezius
The Dorsal Scapular Nerve is thought to cause forms of Scapular Dyskinesis through atrophy of the Rhomboids and/ or Levator Scapulae (SOURCE-17). These symptoms are likely to occur concomitantly with Pain between the Scapulae and radiating along the posterolateral arm. In a similar fashion injury to the Long Thoracic Nerve inhibits the Serratus Anterior , leaving the Trapezius unopposed. This results in excessive Scapulothoracic Joint - Elevation and Scapulothoracic Joint - Retraction and Scapular Winging that is most prominent during Scapulothoracic Joint - Protraction (SOURCE-38). Cranial Nerve XI (the accessory nerve) palsy inhibits action of the Trapezius to cause Lateral Winging while nerve blocks of the Suprascapular Nerve result in signficantly greater Scapulothoracic Joint - Upward Rotation and External Rotation (SOURCE-8+24+39).
Fractures of the Scapula are considered rare, accounting for 1% of all fractures and 3-5% of those to The Shoulder Girdle (SOURCE-21). The most commonly affected site is the Scapula Body, involved in just under half (45%) of all Scapula fractures (SOURCE-21). Other sites include the Scapular Neck (25%), Coracoid Process (15%), Glenoid Fossa (10-30%) and Spine of Scapula (5%) (SOURCE-21). The most common mechanism of injury is attirbuted to motorvehicle/ cycle accidents, followed by other forms of traumatic accidents (SOURCE-35). These fractures have been classified in several ways based on the implicated structures, such as the Processes, Body or Articular Segment (Glenoid Fossa and Articular Rim) (SOURCE-20+21):
14A - Extra-articular fractures that involve the
Coracoid Process - account for 3-7% of Scapula fractures and have been described based on their relations to the Coracoclavicular Ligament , which bares implications for surgery. Conservative treatment is typically sufficient unless intra-articular extension or 1cm of displacement occurs (SOURCE-22)
Acromion - represent 8-16% of Scapula fractures and respond well to conservative treatment in the absence of displacement (SOURCE-22). May be associated with Subacromial Impingement or luxation of the Acromioclavicular Joint
Spine of Scapula
14B - Extra-articular fractures that involve the Blade/ Body
14F - Intra-articular fractures that involve the Glenoid Fossa:
F0- also known as 14C0, a fracture that severs the Glenoid Fossa from any part of the Body
F1- a Rim, Transverse, or Oblique fracture through the Glenoid Fossa. Can be further divided into one of three sub-categories:
Simple anterior articular rim or oblique fracture
Simple posterior articular rim or oblique fracture
Simple transverse or short oblique fracture
F2- a multifragmnetary fracture of the Glenoid Fossa, leaving 3 or more articular fragments. Can be further divided into one of two sub-categories:
More than 1 fracture line exit point
Central-fracture dislocation with no exit line through the Rim
Low nonunion rates, particularly of the Body, are attributed to the myofascial support afforded by the Rotator Cuff whose highly vascular structure also relays effective blood flow (SOURCE-20). Conversely, fractures that involve the Articular Segment may disturb joint congruency, predispose a greater risk of Glenohumeral Instability and may require surgery (SOURCE-21).
Breathing - Mouth breathing is associated with greater Scapulothoracic Joint - Elevation in children (SOURCE-15)
There are many pathologies that are directly or indirectly related to the Scapula. The umbrella term Scapular Dyskinesis often presents as either Scapular Winging and/ or Scapular Tilting .
Forward Head Posture - Dyskinesis is a common consequence when the neuromuscular structures associated with FHP are disturbed (SOURCE-12 (4))
Subacromial Impingement - a narrowing of the space between the Head of Humerus and Acromion of Scapula that predisposes several shoulder pathologies
Thoracic Spine Kyphosis - roughly 15º of Thoracic - Extension is required for full bilateral arm elevation, while unilateral elevation requires ~9º (SOURCE-37). Thoracic Kyphosis is associated with Scapulothoracic Joint - Protraction , Scapulothoracic Joint - Downward Rotation and Anterior Tilting (SOURCE-37). Additionally, Kyphosis was associated with a significant reduction in Scapulothoracic Joint - Elevation (SOURCE-37). Similarly, a slouched posture leads to a significant reduction in Posterior Tilting of the Scapula and GH Joint - Abduction (SOURCE-37). These movement impairments may indirectly predispose Subacromial Impingement as thoracic mobility was found to be significantly less in those with impingement (SOURCE-36+37).
The following instability-related pathologies are associated with the Scapula:
Glenohumeral Instability - as the Glenoid Fossa forms a disproportionately small conguency with the Head of Humerus , maintaining optimal positioning of the Scapula is integral to its articulation. It is therefore unsurprising that Scapula instability (aka Dyskinesis) is ubiquitous with instability of the Glenohumeral Joint (SOURCE-3). Further, fractures that affect the Glenoid Fossa are often associated with instability (SOURCE-21). It has been suggested increased Scapular Internal Rotation may contribute to anterior instability (SOURCE-24)
Glenohumeral Dislocation / Subluxation - the natural progression of severe joint instability. Reccurent episodes may lead to dysfunctional muscle patterns which manifests as Scapular Dyskinesis . As dyskinesis is a signficant risk factor for instability, this creates a positive feedback-loop for further Scapula-related pathology. Glenoid Bone -loss is common following recurrent dislocations, particularly in adolesence (SOURCE-24)
The following pathologies are related to a fracture of the Scapula:
Clavicle Fracture - structural shortening from mal or non-union requires additional Anterior Scapular Tilting and Internal Rotation to maintain adequate Scapula mechanics (SOURCE-24). Clavicle fractures often occur concomitantly with fractures of the Scapula (SOURCE-35).
Ribs Fracture - the most common concomitant Thoracic injury with fractures of the Scapula (SOURCE-35)
Thoracic Spine Fracture - often occurs concomitantly with Scapula fractures (SOURCE-35)
Pneumothorax - often occurs concomitantly with Scapula fractures (SOURCE-35)
Pulmonary Contusion - often occurs concomitantly with Scapula fractures (SOURCE-35)
Pain over the Scapula may be the result of Referred Pain from local structures:
C3 - C6 Zygapophyseal Joints or Intervertebral Discs - refer over top half of Scapula from Medial Border to Lateral Acromion (SOURCE-6)
C8 Radiculopathy - refers over Inferior Angle (SOURCE-6)
Alternatively Pain between the Scapulae, known as theInterscapular Space, is often caused by (SOURCE-17):
The following details the normal resting position of the Scapula, for dynamic observation see Scapulothoracic Joint , Scapulohumeral Rhythm and Scapular Dyskinesis :
Spine of Scapula- should appear roughly horizontal with 5º of rotation in either direction considered normal (SOURCE-2 (20)).
Glenoid Fossa- typically has a slight upwards bias in older individuals and downwards bias in the young (SOURCE-2 (21))
Medial Border of Scapula- parallel to both the Thoracic Spine and opposing medial border of Scapula; however, it is not uncommon for the dominant side to sit slightly more inferolaterally (SOURCE-2 (22))
Superior Angle of Scapula- horizontally aligned with T3 - T4 (SOURCE-2 (4)).
Inferior Angle of Scapula- horizontally aligned with T7 , T8 , T9 or occasionally T10 (SOURCE-2 (4)).
Additionally the entire Scapula should have a ~40º bias towards the frontal plane and an anterior tilt of ~10º (SOURCE-2 (20)).
Due to several overlying muscles the Lateral Border is not often palpable (SOURCE-8). The upper-third of the Medial Border is similarly difficult to palpate, while the distal two-thirds are more easily identifiable (SOURCE-8). The Scapula Spine is typically palpable along its entire length.
Radiographs (X-Rays)- initial chest radiographs of Scapula fractures have low recognisability as they are superimposed by other structures (SOURCE-22). Therefore the following Scapula projections are recommended:
Scapula AP View - perpendicular to the plane of the Scapula with 90º GH Joint - Abduction and full Elbow - Flexion and Elbow - Supination
Grashey (AP Oblique) View - patient orientated 35-45º so that the body of the Scapula can be pressed against the imaging detector. Provides a clear image of the Glenohumeral Joint
Scapula Lateral View - Acromion, Coracoid and Body form a “Y” or “peace sign”, with the Head of Humerus ideally centrally positioned. Can be taken anteriorly or posteriorly:
AP - with patient supine, ipsilateral hand is placed over the opposing shoulder and torso is slightly rotated towards the ipsilateral side
PA - with patient standing, lateral Thorax positioned against the detector and hand either placed over the opposing shoulder or the is-lateral hip
True Axillary View - with patient lying supine, the ipsilateral arm is in up to 90º GH Joint - Abduction to clear the arm from the Thorax . Provides a clear view of the Glenohumeral Joint space, the Lesser Tuberosity may be visible as an inverted V over the Humeral Head
Computed Tomography (CT) Scan- provide exceptionally detailed, three dimentional images of osseous structures. For the Scapula this may be relevant for the detection of subtle or complex Fractures to sites such as the Glenoid, Scapular Neck or Body, Acromion or Coracoid Process and provide a precise insight into the extent and location of damage (SOURCE-31). The clarity of these images also enables practitioners to evaluate for the presence of congential abnormalities, lesions, Inflammation or other abnormalities, assess for degenerative bone loss and conduct pre/post-operative investigation (SOURCE-32+32+33+35).CT Arthropraphyutilises contrast injection to evaluate vasularity and damage to the associated soft-tissues. 3D Wing CT scans are highly reliable for the diagnosis and typing of Scapular Dyskinesis (SOURCE-28).
Ultrasonography (Ultrasound)- while restricted in their ability to visualise through osseous structures, can be used to identify Bone irregularities on the cortical surface. For the Scapula, Ultrasound may be indicated for the evaluation of associated soft-tissues and Nerves for their size, quality and any signs of deterioration (SOURCE-29+30). This may be relevant for understanding the eitology of conditions such as Scapular Winging (SOURCE-30). The ability of Ultrasounds to provide real-time feedback also permits dynamic assessment of the Scapula through functional movement.
Treatment of Scapular Dyskinesis is typically centred around restoring appropriate tone to relevant soft-tissues and/ or the nerves that innervate them. A similar strategy is implemented following a fracture and period of immobility where range of motion and Strength are likely affected. Often conservative treatment will suffice for these pathologies; however, severe instances such as Glenoid fractures may require surgery (SOURCE-22+22). More joint specific treatment protocols are found their pages Glenohumeral Joint / Scapulothoracic Joint .
From a musculoskeletal persepective, research suggests Stretching as an isolated treatment may not significantly improve Scapular posture either at rest or through motion (SOURCE-26). However when integrated with other treatment modailities such as strengthening, it may be more promising for addressing these kinematic issues. In either case, stretching appears to have a more consistent improvement on other markers such as Pain and disability (SOURCE-26). Intuitively stretching has the capacity to restore/ improve joint Range of Motion , though caution must be taken to ensure these improvements are relevant as it may lead to excessive ranges such as Scapulothoracic Joint - Elevation or Scapulothoracic Joint - Upward Rotation (SOURCE-26). Nevertheless, given the location of their attachments on the Scapula and tendency towards restriction, stretching of the following muscles has the potential to impact Scapula posture at rest and through motion:
Pectoralis Minor - when shortened leads to anterior tilt, Scapulothoracic Joint - Protraction and Scapulothoracic Joint - Downward Rotation
Serratus Anterior - when shortened leads to Scapulothoracic Joint - Protraction and Scapulothoracic Joint - Upward Rotation
Upper Trapezius - when shortened leads to Scapulothoracic Joint - Elevation altered Cervical Spine posture
Subscapularis - when shortened leads to increased Scapulothoracic Joint - Protraction and internal rotation
Levator Scapulae - when shortened leads to Scapulothoracic Joint - Elevation and Scapulothoracic Joint - Downward Rotation
Biceps Brachii - the two heads impact the Scapula in a similar fashion, though through diverging mechanisms. The Short Head of Biceps , via its Coracoid attachment, directly contributes to Scapulothoracic Joint - Protraction and Anterior Tilt. The Long Head of Biceps has a more indirect influence, as its tightness restricts Head of Humerus movement in the Glenohumeral Joint , forcing the scapula into compensatory patterns such as protraction
Infraspinatus - when shortened leads to excessive External Rotation and/ or compensatory Scapulothoracic Joint - Retraction
Teres Minor - when shortened leads to a similar Scapula posture to the Infraspinatus, likely with more pronounced Scapula distrubance when performing overhead motions
Latissimus Dorsi - when shortened may indirectly lead to altered Scapula mechanics during overhead movements
In a similar fashion to streching, exercise therapy fails to display a consistent positive effect on Scapular Dyskinesis yet appears to aid with associated Pain and disability (SOURCE-26). This may at least in part be attributed the standardisation of exercise protocols used in controlled studies that fails to meet the subjective needs of each test subject, a dysfunction of the Rotator Cuff is highly related to pathologies of the Scapula (SOURCE-3). Further, some studies have found strength training of the Scapulothoracic Joint musculature to improve position of the Scapula (SOURCE-2). Particularly in the initial phase, training volume should be monitored as training Scapular stabilisers to the point of fatigue may perpetuate its malposture (SOURCE-3). Generally speaking the following muscle groups should be emphasised with consideration to their function and relations (SOURCE-27):
Shoulder Depressors - Subscapularis , Infraspinatus and Teres Minor
Scapular Stabilisers - Trapezius , Serratus Anterior and Rhomboids
Primary Shoulder Movers - Pectoralis Major , Deltoid and Latissimus Dorsi
While Mobilisations to any of The Shoulder Girdle joints may be relevant in treatment of the Scapula, the following lists techniques that can be applied directly: Joint Play - techniques applied with the patient at rest
Mobilisation with Movement - techniques applied through an affected motion
Shoulder - MWM 1 - End-Range Elevation
Shoulder - MWM 2 - Mid-range Elevation in quadruped
SMWAM - when Radiculopathy is suspected
When a Radiculopathy is suspected, mobilisations may also be applied to the Cervical Spine with relevant techniques listed on its respective page.
Surgical indications following Scapula Fracture include (SOURCE-20+22):
Medial Displacement of Lateral Border - distance between corresponding fragments of Scapula Neck Fractures >25mm
Angular Deformity >45º - the angular difference between two corresponding fragments
Intra-articular step 3-5mm
Gleno-Polar Angle- used to evaluate a rotational malalignment of the Glenoid. 20-22º may indicate surgery with 30-45º considered normal
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