What is the Shoulder
girdle?
What is the importance of
Shoulder Girdle
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Increase the ROM for Upper limb (up to 180°)
Provide More space to reach for upper limb
Provide an stable base for upper limb function
What are the Joints of the
Shoulder girdle?
Four interdependent linkages for Shoulder Complex
Functional Articulation: Scapulothorasic Joint (STJ)
Anatomical Articulation: Sternoclavicular Joint (SCJ)
Anatomical Articulation: Acromioclavicular Joint (ACJ
Anatomical Articulation: Glenohumeral Joint (GHJ)
Sternoclavicular
Joint
What is the role of Sternoclavicular
Joint within shoulder girdle?
Functional base for scapula
Movement in Clavicle and SCJ
Movement in Scapula Thoracic
Can You Describe the Sternoclavicular Joint?
Sternoclavicular Joint
Consists of two saddle-shaped surfaces but
A plane Synovial Joint
3 degree of freedom
Joint Capsule
3 Major Ligaments
A Joint Disc
4 joint’s area contact
Clavicle
Movement in SCJ is due to
Sternocalvicular
the change in contact area
Disc
between
Manuberium
Can you describe the function of
Sternoclavicular Disc Joint?
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A fibrocartilage joint disk, or meniscus, that increases
congruence between joint surfaces
Acts like a hinge or pivot point during clavicle motion.
Act like axis in the SCJ
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In Elevation/Depression
Clavicle move against Manuberium and Disc
 Upper part of Disc act like axis)
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In Protraction/Retraction
Disc and Clavicle Move against Manuberium
 Lower part of Disc act like axis
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the mechanical axis for these two movements
located not at the SC joint itself but at the more
laterally located costoclavicular ligament
How the disc Joint does provide
stability for SCJ?
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Disc has an Important Role in Joint Stability
By Creation congruent between Joint surface
 By absorption coming stresses to the lateral end of
clavicle
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Three-Compartment SC Joint
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Anatomic examination of the SC articulation has
led to the proposal that there are three
functional units
1. a lateral compartment between the disk and
clavicle for elevation and depression;
2. a medial compartment between the disk and
manubrium for protraction and retraction;
3. a costoclavicular joint for anterior and posterior
long axis rotation.
Sternoclavicular Joint Capsule
and Ligaments
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The SC joint is surrounded by a fairly strong fibrous
capsule but must depend on three ligaments for the
majority of its support. These are the
sternoclavicular ligaments,
Can you name the
Sternoclavicular Ligaments?
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Sternoclavicular Lig (Ant & Post)
Costoclavicular Lig (Ant & Post)
Inter Clavicular Lig
What is the function of Sternoclavicular Ligaments?
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Sternoclavicular (Ant & Post) Lig
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Costoclavicular (Ant & Post parts) Lig
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Strengthening of Ant and Post part of Joint
Prevent of Ant and Post Movements of Clavicle
Very strong Lig
Both parts resist against the 1) superior force from SCM and 2)
against elevation of the lateral end of clavicle
At the limit reach, they are responsible for inferior gliding of clavicle
Post part prevent of inward movement of clavicle (absorb of forces
acts on the Disc from arm)
Inter Clavicular Lig
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Control 1) Depression of clavicle, 2) superior gliding of clavicle and
protect subclavian artery and Brachial plexus and
Weight bearing of upper arm by help of upper capsule
Integrity of These elements
Clavicle
SCJ Disc Manuberium
Ligaments
Capsule
PROVIDS
Three Major functions for SCJ
1)Resist against Applied stress from Upper arm
2)Provide Mobility for Upper arm
3)Provide a Strength Base for Upper arm
What are the Sternoclavicular
Movements?
Motions of any joint are typically described by
identifying the direction of movement of the portion of
the lever that is farthest from the joint.
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Elevation/Depression
Protraction/Retraction
Anterior/Posterior Rotation
Can you describe
Elevation/Depression movements?
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Occur around the Ant-Post Axis which located in
Costoclavicula Lig
In the plan that convex surface of clavicle glide against
concave surface of manubrium and Disk
Opposite Movement of medial part of clavicle
Up to 48 degree Elevation and 15 degree Depression
Elevation of clavicle accompanied by elevation of
scapula and its upward rotation
Small magnitudes of medial-lateral translation and
superior/inferior translation in the medial aspect of
clavicle
Elevation and Depression
Can you describe the
Protraction/Retraction movements?
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Occur vertical axis locate in costoclavicula Lig
In the plan that concave surface of clavicle glide
against convex surface of manubrium
In protraction, lateral end rotate anteriorly, and
medial end slide anteriorly
15- 20 degree Protraction and 20-30 degree
Retraction
Pro/Ret of clavicle is accompanied by Pro/Ret
of scapula
Protraction and Retraction
Can you describe the
Anterior/Posterior Rotation?
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Occur around the longitudinal axis of clavicle
intersecting AC and SC Joint
An Spin movement saddle surface of medial part
of clavicle and manuberium/first costal cartilage
Movement start from neutral position only
toward posterior rotation
35-55 ° Post Rot and 10 ° available Ant Rot
It serve the last 30 degree of upward rotation of
scapula.
Posterior And Anterior Rotation
■ Sternoclavicular Stress Tolerance
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The Complex of bony segments, Capsuloligamentous
structure, and the SC disk produce a joint with dual functions
of mobility and stability.
The SC joint contribute to upper limb mobility, and
withstanding imposed stresses.
Although the SC joint is considered incongruent, the joint
does not undergo the degree of degenerative change
common to the other joints of the shoulder complex.
Dislocations of the SC joint represent only 1% of joint
dislocations in the body.
Acromioclavicular Joint
Acromioclavicular Joints
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Characteristics
Plan Synovial Joint
 3 rotational and 3 transitional degrees of Freedom
 Weak capsular joint
 Joint Disc
 Two Major Ligaments
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Superior & Inferior Acromioclavicular ligaments
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Integration of joint surface
Provide horizontal stability
Coracoclavicular Lig.
Its primary function included:
Primary function of ACJ
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Primary function
1. Allow the scapula additional range of rotation on the
thorax
2. Allow for adjustments of the scapula (tipping and
internal/external rotation) in order to follow the
changing shape of the thorax as arm movement
occurs.
3. Allows transmission of forces from the upper
extremity to the clavicle.
Articular Surface and Joint Disc of ACJ
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The articular facets, considered to be incongruent,
vary in configuration
Intra-articular movements for this joint are not
predictable.
A Joint disk with variable in size between individuals
exist in AC joint
It plays as a “meniscoid” fibrocartilage remnant within
the joint to develop each articulating surface during
upper extremitymovement
The Acromioclavicular Joint
Acromioclavicular Capsule
and Ligaments
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Capsule is weak and cannot maintain integrity of
the joint without reinforcement by ligaments
The superior acromioclavicular Lig are reinforced
by aponeurotic fibers of the trapezius and deltoid
muscles and assists capsule by
Apposing articular surfaces
 Controlling A-P joint stability. The fibers of the
superior AC ligament are
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the superior joint support stronger than the inferior
Acromioclavicular Capsule and Ligaments
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Coracoclavicular Ligaments which divided into:
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Lateral portion, the trapezoid ligament,
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provides the primary restraint for the AC joint in the superior and
inferior directions
Medial portion, the conoid ligament.
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Provides the majority of resistance to posterior translatory forces
applied to the distal clavicle.
They are separated by adipose tissue and a large bursa
 Both portions of the coracoclavicular ligament limit
upward rotation of the scapula at the AC joint
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Transfer Medially directed forces on humerus to the SCJ
 Transfer the rotational force of scapula to the clavicle and then
cause Posterior Rotation at SCJ
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When a person bears weight on the arm, a medially directed force up
the humerus (1) is transferred to the scapula (2) through the glenoid
fossa and then to the clavicle (3) through the coracoclavicular ligament
Acromioclavicular Motions
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The primary rotatory motions of AC joint are
Internal/external rotation,
 Anterior/ posterior tipping or tilting,
 Upward/downward rotation
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These motions occur around axes that are oriented to
the plane of the scapula rather than to the cardinal
planes.
Small translatory motions of AC joint included:
Anterior/Posterior,
 Medial/Lateral,
 Superior/Inferior.
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Plane of AC joint Movements
What movement does occur in
the Acromioclavicular joint?
1- Internal and External Rotation
Internal and External Rotation
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Occurs around an approximately vertical axis
through the AC joint
To Maintain contact of the scapula to horizontal
curvature of the thorax during Protraction and
Retraction
To orient the glenoid fossa toward the plan of
humeral elevation
30 degree the total ROM
An Anterior/Posterior translatory movement
Internal and External Rotation at
AC joint
Glenoid Fossa is the reference for naming the movement
Because of the thorax curvature, Internal/External Rotation
is a necessary movement for protraction and Retraction
Anterior and Posterior Tipping
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Occurs around an oblique “coronal” axis of joint
Ant. tipping will result in the acromion tipping forward and
the inferior angle tipping backward during downward
rotation and also Elevation of scapula
 Posterior tipping will rotate the acromion backward and the
inferior angle forward. during upward rotation and also
Depression of scapula
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To Maintain contact of the scapula with the contour
of the rib cage and orient the glenoid fossa during arm
flexion and abduction
30-40 degree the total ROM
A Superior/posterior translatory movement
Anterior and Posterior Tipping
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The superior aspect of scapula is the reference of naming the movement
The acromion has slightly translatory anteriorly/posteriorly movement
Upward and Down Ward Rotation at
AC Joint
Around an A-P axis
(perpendicular to scapula)
Direction of Glenoid Fossa
is the reference for the
naming the movement
Acromion has a small
medial/lateral Translatory
movement
3-Scapula Upward and Downward
Rotation
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Help to orient the glenoid fossa upward or
downward
Coraco-Clavicular Ligament limit this movement
Posterior rotation of clavicle lax the lig
So upward rotation can be done in the AC Joint
30 degree Upward Rot
17 degree Downward Rot
Acromioclavicular Stress Tolerance
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AC joint is extremely susceptible to both trauma and
degenerative change due to the
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its small and incongruent surfaces
Degenerative change is common from the second
decade with narrowed joint space by the sixth decade.
Treatment of sprains, subluxations, and dislocations
of this joint occupies a large amount of the literature
on the shoulder complex
Acromioclavicular Stress Tolerance
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Various classification of injury commonly
Type I injuries consist of a sprain to the AC
ligaments,
 Type II injuries typically have ruptured AC ligaments
and sprained coracoclavicular ligaments
 Type III injuries result in rupture of both sets of
ligaments,
 Types I, II, and III AC separations all involve
inferior displacement of the acromion in relation to
the clavicle caused by the loss of support from the
coracoclavicular ligaments
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Acromioclavicular Stress Tolerance
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Various classification of injury commonly
Type IV injuries have a posteriorly displaced lateral clavicle,
often pressing into the trapezius posteriorly, with complete
rupture of both the AC and coracoclavicular ligaments
 Type V injuries also involve an inferior displacement of the
acromion and complete rupture of both sets of ligaments
and are distinguished from type III by a severity of between
three and five times greater coracoclavicular space than
normal.
 Type VI injuries have an inferiorly displaced clavicle in
relation to the acromion, with complete ligament rupture
and displacement of the distal clavicle into a subacromial or
subcoracoid position.
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Scapulothorasic
Joint
Rotation at AC Joint
SCJ Elev/Dep and ACJ Rotation
are necessary movements for
Scapula Elevation and
Depression
ACJ Rotation and SCJ Elev and Post Rotation are the
necessary movements for Scapular upward Rot
Resting Position of scapula
Position of Scapula on the Thorax
2 inches from the midline
Between 2nd and 7th ribs
30-45 degree internally rotated from the coronal plane
10-20 degree anteriorly tipping from vertical
10-20 degree upward rotation, it is different among the individuals
What is the Movement of Scapula?
Elevation/Depression
Protraction/Retraction
Upward Rotation/Downward Rotation
Scapula Upward and downward Rotation
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Upward rotation of the scapula plays a significant role
in increasing the range of elevation of the arm
Approximately 60º of upward rotation is available.
Considering the closed-chain relationship between
the SC, AC, and ST joints, they contribute to scapula
upward/downward rotation by:
SC joint elevation/depression,
 SC joint posterior/anterior rotation
 AC joint upward/downward rotation
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Most often, scapular upward/downward rotation
results from a combination of the SC and AC
motions.
Scapula Upward and downward Rotation
Scapula Elevation/Depression
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Scapular elevation and depression can be isolated by
shrugging the shoulder up and depressing the
shoulder downward.
It is described as translatory motions
Scapular elevation, occurs by elevation of the clavicle
at the SC joint and requires Scapula adjustments in
anterior/posterior tipping
 internal/external rotation at the AC joint
 to maintain the scapula in contact with the thorax
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Scapula Elevation/Depression
Scapula Protraction/Retraction
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Scapula Protraction and retraction are described as
translatory motions of the scapula away from or
toward the vertebral column, respectively.
However, if protraction occurred as a pure translatory
movement, only the vertebral border of the scapula
would remain in contact with the rib cage.
In reality during protraction, scapula follows the
contour of the ribs by
rotating internally and externally at the AC joint and
 clavicular protraction and retraction at the SC joint
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So, glenoid fossa facing anteriorly with the full contact
of scapula with the rib cage
Scapula Protraction/Retraction
Scapula Internal/External rotation
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Scapular internal and external rotation are
normally not overtly identifiable on physical observation
 but are critical to its movement along the curved rib cage.
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The Movement normally accompany protraction/
retraction of the clavicle at the SC joint
Isolated Scapula Int rotation at the AC joint, cause
Prominence of the vertebral border of scapula
 Loss of contact of scapula with the thorax.
 Which is referred to clinically as scapular “winging”
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Excessive Int rotation may be indicative of pathology
or poor neuromuscular control of the ST muscles.
Pathologic Scapula Internal Rotation
Scapula Anterior/Posterior Tipping
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Anterior/Posterior tipping is
normally not obvious on clinical observation and
 yet is critical to maintaining contact of the scapula against
the curvature of the rib cage
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Movement occurs at the AC joint
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Isolated excessively Ant/Post Tipping at the AC joint
will result
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normally will accompany anterior/posterior rotation of the
clavicle at the SC joint
in prominence of the inferior angle of the scapula
Ant. tipped scapula may occur in pathologic situations
(poor neuromuscular control) or in abnormal posture.
Pathologic Scapula Anterior Tipping
What are the Scapulathorasic
Functions?
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Final function of this Joint
1. Adjustment of gelenoid direction
2. To Increased ROM for upper arm
3. To Provide an Strong Base to control Rolling and
gliding Movements for Humorous Surface
Scapulothorasic Stability
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Scapula Stability on the thorax is provided by
1. The structures that maintain integrity of the linked AC
and SC joints such as ligaments, capsule and joint disc.
2. The muscles that attach to both the thorax and scapula
maintain contact between these surfaces
3. These muscles also provide stabilization by pulling or
compressing the scapula to the thorax.
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The scapula, with its associated muscles and linkages,
performs mobility and stability functions so well that
it serves as a premier example of dynamic stabilization
in the human body