Shoulder Complex Flashcards
The Shoulder Complex consists of
Sternoclavicular joint
Acromioclavicular joint
Glenohumeral joint
Scapulothoracic “joint”
The shoulder complex is designed for
Mobility with dynamic stability
The shoulder is susceptible to _________ due to competing ___________&_________ demands
Dysfunction and instability
Mobility and stability demands
Describe the sternoclavicular jt
Saddle joint between the medial clavicle and clavicular notch
The _____________ shaped articulating surfaces in the sternoclavicular jts are__________ . To help this the joint has a _____
Saddle
Incongruent
Disc
The sternoclavicular disc is made of ____________.
Fibrocartilage
Functions of the Sternoclavicular jt
Create 2 jt spaces Promotes stability (increase congruency, absorb forces, limits medial mvmt)
What limits A/P translation of the medial clavicle
Posterior fibrous capsule
A&P sternoclavicular ligaments
What ligament limits excessive depression and superior glide of the clavicle?
Interclavicular ligament
Functions of the Costoclavicular ligament include
Limit elevation of lateral clavicle
Contributes to inf glide of medial clavicle
Shock Absorption
Dynamic stabilization of the sternoclavicular jt
Scm
Subclavius
Pec major
Sternothyroid & sternohyoid
Osteokinematics of the sternoclavicular jt
Elev/dep
Protract/retract
Ant/post rot
Arthrokinematics of elevation at the sternoclavicular jt
Lateral clavicle rotates upward
Superior roll, inferior glide
Arthrokinematics of depression at the sternoclavicular jt
Lateral clavicle rotates downward
Inferior roll, superior glide
In elevation and depression at the sternoclavicular jt, the disc….
Does not move
During protraction/retraction in the sternoclavicular jt, the disc…
Moves with the clavicle
Describe Arthrokinematics of protraction at the sternoclavicular jt
Lateral clavicle moves anteriorly
Anterior roll and glide
Describe Arthrokinematics of retraction at the sternoclavicular jt
Lateral clavicle moves posteriorly
Posterior roll and glide
Anterior and posterior rotation at the sc jt occurs around the clavicles…
Longitudinal axis
Anterior/posterior rotation at the sc jt occurs as a ________ between articulating surfaces
Spin
During posterior rotation at the sc jt the inferior surface turns ____________ and during anterior rotation the inferior surface returns to ___________.
Turns anteriorly
Returns to inferior position
In the sc jt, posterior rotation is also described as ___________
Backward rotation
What is the closed packed position for the sc jt
Full posterior rotation (full arm elevation)
What is the open packed position of the sc jt
Arm resting at side
What is the capsular pattern of the sc jt
Pain at end range with arm overhead
Describe the acromioclavicular jt
Plane synovial jt between the lateral clavicle and acromion
In the ac jt, is there an articular disc?
Depends
May or may not be present
What ligament resists anterior clavicular/posterior acromion translation at the ac jt
The superior ac ligament
Trapezoid and Conoid ligaments are apart of what ligament?
Coracoclavicular ligament
What is the function of the coracoclavicular ligament
Limit superior clavicular/inferior scapular translation and posterior rotation of the clavicle
The jt capsule at the ac joint is
Weak
What are the passive stabilizers of the ac jt
Jt capsule
Superior and inferior ac ligament
Coraccoclavicular ligament
What is the primary function of the ac jt
Allows scapula to rotate during arm mvmt
Increases ue motion
Positions glenoid beneath humeral head
Maintains congruency of the scapula on the thorax
What are the Osteokinematics of the ac jt
Upward /downward rotation
Internal/external rotation
Anterior/posterior tilting (tipping)
Upward and downward rotation at the ac joint is important for…
Positioning glenoid fossa in optimal position
Upward rotation of the ac jt is a component of what shoulder movement? During this motion the scapula swings ….
Abd or flexion of the shoulder
Upward and outward rotation of the scapula
Downward rotation at the ac jt is associated with what movements of the shoulder? What happens with the scapula during this movement
Add and ext.
Brings scapula back to anatomical position
The internal/external rotation at the ac jt is important for
Maintaining contact of the scapula on curved thorax during protraction and retraction of the clavicle
Anterior/posterior tilting (tipping) at the ac jt is important for…
Maintaining contact of the scapula on curved thorax during elevation/depression of clavicle
What is the closed packed position for the ac jt
Arm abducted to 90
What is the open packed position for the ac jt
Arm resting at the side
What is the capsular pattern at the ac jt
Pain at end range with arm overhead
Scapulaothoracic “jt” is not a true anatomical jt. Therefore movement here depends on the
Integrity of the sc and ac jts
Primary Osteokinematics of the scapulothoracic “jt”
Elevation/depression
Protraction/retraction
Upward/downward rotation
Secondary movements at the scapulothoracic “jt” work to..
Keep congruency between the scapula and thorax
Secondary Osteokinematics of the scapulothoracic “jt”
Anterior/posterior tilt
Internal/external rotation
Elevation of the scapulothoracic “jt” is a combination of ……
This is observed in..
Sc jt elevation and ac jt downward rotation
A shoulder shrug
Protraction of the scapulothoracic “jt” is a combination of
Sc jt protraction and slight ac jt IR
Retraction at the scapulaothoracic “jt” is a combination of
Sc jt retraction and slight ac jt ER
depression of the scapulothoracic “jt” is a combination of
Sc jt depression and ac jt upward rotation
Upward rotation at the scapulothoracic jt is a combination of
Sc jt elevation and ac jt upward rotation
Upward rotation at the scapulothoracic jt is observed during
Flex/abd of the shoulder
Downward rotation at the scapulothoracic “jt” is a combination of
Sc jt depression and ac jt downward rotation
Describe the glenohumeral jt
Ball and socket jt between the glenoid fossa and head of the humerus
Angle of inclination at gh jt
130-150 in the frontal plane
Angle Between the head of the humerus and the shaft of the humerus
Angle of torsion at the gh jt
30 posterior in the transverse plane
Angle between the head of humerus and the condyles
Retroversion at the gh jt
Posterior orientation of the humeral head with regard to the condyles (angle of torsion)
30
glenoid labrum functions
Enhance concavity and increase articular surface
Resist humeral head translations, dissipate force, and protect bony edges
Attachment of the gh ligaments and tendon of biceps long head
The joint capsule in the gh jt is
Significantly lax which provides minimal stability
Reinforced by thicker external ligaments
The inferior portion of the joint capsule is slack in the _____________ position creating _______
Adduction
Axillary patch
The joint capsule of the GH jt is reinforced by
external ligaments and dynamic stability of the rotator cuff
External GH ligaments include
Superior, middle, and inferior GH ligaments
Coracohumeral lig.
What ligament limits ER, anterior and inferior translation at 0 abd and slackens when abd beyond 35-45
Superior GH lig
The middle GH Lig limits
Anterior translation from 45-90 abd and extremes of ER
The inferior GH lig has 3 components:
And is the primary stabilizer when?
Anterior band, posterior band, and axillary pouch
Primary stabilizer beyond 45 of abd or with combined abd and rotation
The coracohumeral ligament limits
Inferior translation and er of the humeral head with arm hanging at the side
The rotator cuff muscles reinforce the GH jt capsule by
Protecting and actively stabilizing the GH jt with dynamic activities
The rotator cuff muscles reinforce the GH jt everywhere except:
Inferiorly
The region btw subscapularis and Supraspinatus (rotator interval)
When the rotator cuff can not reinforce the GH jt at the rotator interval, it is instead reinforced by:
Long head of the biceps, coracohumeral lig, and superior/middle gh lig
Describe Arthrokinematics of flexion in the gh jt
Anterior roll and posterior glide
Describe Arthrokinematics of extension at the gh jt
Posterior roll and anterior glide
Flexion causes tension throughout the capsule of the gh jt. Therefore what may see __________ at end range flexion due to tension in the ____________
Slight anterior translation
Tension in posterior capsule
Describe Arthrokinematics of adduction at the gh jt
Inferior roll superior glide
Describe the Arthrokinematics of abduction at the gh jt
Superior roll inferior glide
To reach full abd rom at the gh jt will require
Some external rotation to move the humerus into a more optimal position (better pull and less bony blocks)
Inferior gh ligament _________ with abduction
Tightens
Describe the Arthrokinematics of IR at the gh jt
Anterior roll
Posterior glide
Describe the Arthrokinematics of ER at the gh jt
Posterior roll and anterior glide
What is the closed packed position of gh jt
90 abd and full er
or
full abd and er
What is the open packed position of the gh jt
Abd 55, horizontally abd 30, slight er
What is the capsular pattern of the gh jt
ER > ABD > IR
Scapulohumeral rhythm
For every 2 degrees of GH movement there is 1 degree of scapular motion during elevation/abduction
According to scapulohumeral rhythm the 180 degrees of ABD is comprised of
120 degrees of GH motion
And
60 degrees of Scapulothoracic upward rotation
Ideal shoulder girdle posture:
Slightly elevated and relatively retracted scapula
= slightly upward facing glenoid fossa
Pathologies that can reduce muscular support of the shoulder girdle
Stroke
Muscular dystrophy
Guillain-Barre
Nerve impingement
Effect of gravity on scapulothoracic posture
Depressed, protracted and excessively downwardly rotated scapula
“Rounded shoulders” what is it and what does this posture predispose you for
Slight depression, downward rotation, and protraction of scapula
Predisposes an individual to impingement
Causes for rounded shoulders
General laxity Muscle tightness Fatigue/weakness GH jt capsule tightness Abnormal cervicothoracic posture Habit
For a pure retraction what must happen?
With full retraction effort…
Elevation tendency of rhomboids neutralized by depression tendency of lower trap
If the deltoid is not working, can you achieve full abd? Why?
Supraspinatus can perform full abd but torque is significantly reduced
If the Supraspinatus is not working, is full abd possible? Why?
Not possible due to the weakness of the deltoid and altered Arthrokinematics
What muscles can contract simultaneously to produce upward rotation during GH abd?
Serratus anterior
Upper trap
Lower trap
Scapular winging
Excessive IR of the scapula visualized with attempted elevation of the arm
Describe the relationship between the Supraspinatus and Arthrokinematics of the GH jt
Drives superior roll of the humeral head
Compresses humeral head against glenoid
Creates a semirigid spacer above the humeral head, restricting excessive superior translation of the humerus
Describe how the infraspinatus, teres minor and subscap work together to impact the Arthrokinematics of the GH jt
Exerts a depression force on the humeral head
Describe how the infraspinatus and teres minor work together to impact the Arthrokinematics at the GH jt
ER humerus during arm motions
How does a reverse shoulder arthroplasy help the deltoid to increase ABD leverage?
It shifts the axis of rotation medially and inferiorly in relation to the scapula, increasing mechanical advantage of the deltoid
What 3 muscles work to stabilize the scapula?
Rhomboids downwardly rotate and retract the scapula during add and extension of the GH jt
Middle traps assist
And teres major
When the infraspinatus externally rotates the shoulder the _____________ acts to stabilize the scapula. If the scapula moves into IR, this would create _______ that effects the GH motion.
Middle trap
Dyskinesis
Scapular dyskinesis
Any abnormal position or movement of the scapula
Typically seen as reduced upward rotation, excess downward rotation, IR, anterior tilt or elevation of the scapula with the movement of the gh jt
