Shoulder Flashcards
What is the reference point of the AC joint?
Front of the acromion
What is the ROM at the SC joint in the frontal plain?
45 degrees elevation
10 degrees depression
What is the ROM at the SC joint in the horizontal plane?
15-30 degrees protraction
15-30 degrees retraction
In retraction at the SC joint, the [convex/concave] clavicle moves on the [convex/concave] sternum. Disc moves with the clavicle to avoid bone to bone contact.
Concave; convex
Clavicular posterior rotation is associated with shoulder [abduction/adduction] and [extension/flexion].
Abduction; flexion
True or false:
There is active anterior rotation, but very little.
False. there is NO active rotation (just compression of the joint)
What is the ROM at the SC joint for posterior rotation?
20-35 degrees (sagittal plane)
What is the arthrokinimatic relationship occurring at the SC joint during elevation? what is the check reign lig. for this movement?
Convex clavicle rolls superior, and slides inferior on concave sternum; CCL
What is the arthrokinimatic relationship occurring at the SC joint during depression? what is the check reign lig. for this movement?
Convex clavicle rolls inferior and slides superior on concave sternum; SCL and ICL
With 2:1 scapulohumeral rhythm, active shoulder abduction of 180 degrees consists of 120 degrees ________ motion and 60 degrees of upward ______ rotation.
This describes Principle ___
Glenohumeral; scapular; 1
Principle 2: What is the result of 60 degrees of upward rotation of the scapula at the scapulothoracic joint during shoulder abduction?
simultaneous elevation at the SC joint combined with upward rotation at the AC joint
Principle 3: The clavicle _____ at the SC joint during abduction
retracts
Principle 4: The scapula at the AC joint ______ and _______ during full shoulder abduction
posteriorly tilts; externally rotates
Principle 5: The clavicle at the SC joint _______ around its own axis during abduction
posteriorly rotates
Principle 6: The GH joint ______ rotates during shoulder abduction
externally
What are the proximal stabilizers of the shoulder?
- Serratus anterior
2. Trapezius
What are the distal mobilizers of the shoulder?
- Biceps brachii
2. Deltiod
What are the distal mobilizers of the shoulder?
- Biceps brachii
2. Deltiod
With a rounded shoulder, what muscles get shortened? lengthened?
Shortened = Lats, Pec minor, Subclavius Lengthened = Lower trap
Name the scapulothoracic depressors.
- Lower trap
- Lats
- Pec minor
- subclavius
Name the scapulothoracic elevators
- Upper traps
- Levator scapula
- rhomboids
What is the only muscle capable of producing scapular upward rotation, posterior tilting and external rotation of the AC joint?
Serratus anterior
Name the scapulothoracic retractors
- Middle Trapezius
- Rhomboids
- Lower Trapezius
Elevation tendency of rhomboids neutralized by depression tendency of _____.
lower traps
Elevation of Arm requires cooperative effort from
- Glenohumeral m’s
- Scapulothoracic m’s
- Rotator Cuff Muscles
Name the muscles involved in upward rotation force coupling
- Upper Traps
- Lower Traps
- Serratus Anterior
Name the muscles involved in downward rotation force coupling
- Latissumus Dorsi
- Rhomboids
- Pectoralis Minor
What is needed for end range shoulder extension?
Anterior tilt of the scapular
Drives the superior roll of humeral head; Compresses the humeral head firmly against the glenoid fossa; Creates a semi-rigid spacer above the humeral head, restriction excessive superior translation of the humerus
Supraspinatus
Exerts a depression force on the humeral head
Infraspinatus, teres minor, and subscapularis
The medial end of the clavicle is usually _____ along its longitudinal diameter and _____ along its transverse diameter
Convex; concave
During abduction or flexion of the arm, how does the clavicle rotate and how many degrees does it rotate?
posteriorly; 20-35
What motions are you most likely to see winging?
IR and Ant tilt
Ligament that blocks posterior directed forces (humerus moving posterior)
Trapezoid ligament (of coracoclavicular lig)
Ligament that blocks superior directed forces (humerus moving superior)
Conoid lig (of coracoclavicualr lig
ST elevation = SC ___ + AC ___
Elevation; downward rotation
ST upward rotation = SC ___ + AC ___
Elevation; upward rotation
ST protraction = SC ___ + AC ___
Protraction; internal rotation
List the (3) functional importance of scapulothoracic upward rotation during arm elevation
- Projects the glenoid fossa upward and anterior-laterally to provide a good base for further motion of the humerus
- Preserves the optimal length-tension of the abductor muscles of glenohumeral joint
- Maintains the volume within the subacromial space to prevent impingement
What is the approximate angle of inclination of the humeral head? what is the retroversion of the head?
135; 30 degrees, posteriorly rotated
What is the scaption plane?
10 degrees anterior tilt
5-10 degrees of upward rotation
35 degrees IR
The position of the scapula on the throrax provides a base of operation for the ____ joint
GH
Ligament that stabilizes the SC joint through all motions, except depression of the clavicle
Costoclavicular lig
Separates the SC joint into distinct medial and lateral joint cavities
articular disc
What is the primary purpose of the 3 degrees of freedom at the SC joint?
to place the scapula at an optimal position to accept the head of the humerus
The AC joint is separated by a complete or incomplete articular disc. Why do some people have incomplete articular discs?
indicative of degeneration that affects this joint
A fully upward rotated scapula is an important component in arm elevation (⅓ of the 180 degrees of abduction or flexion). What 3 important functions does the upward rotation serve?
- projects the glenoid fossa upward and anterolaterally providing a base to maximize the upward and lateral reach of the UE
- Preserves optimal length-thesnion relationship of the abductor muscles of the GH joint
- maintains the volume within the subacromial space
What is the inferior portion of the GH joint capsule that appears slackened or redundant in an adducted position
axillary pouch
The AC’s flat joint surfaces make it vulnerable to ____
shearing forces
- sup and inf ligs provide structural stability
What part of the coracoclavicular ligament blocs posterior directed forces (humerus moving posterior on the body)? what part blocks superior directed forces?
trapezoid; conoid
What is the open packed position for the AC joint? close packed? capsular pattern?
arm relaxed by the side;
90 Abd; extremes of motion
What is the open packed position for the SC joint? close packed? capsular pattern?
Arm resting at side; arm elevated w/ posterior rotation, elevation at SC joint; extremes of motion
Which way is the inferior angle of the scapula moving in anterior tilt?
posteriorly
What are the motions at the SC joint?
Elevation/depression (frontal plane)
Protraction/ retraction (horizontal plane
posterior rotation (sagittal)
What are the motions at the AC joint?
Upward/ downward rotation (frontal plane)
Anterior/ post tilt (saggital plane)
IR/ ER (horizontal plane)
What are the motions at the scapulothoracic joint?
Upward/ downward rotation (frontal plane)
Protraction/ retraction (horizontal plane)
Elevation/ depression (frontal plane)
SC Elevation + AC downward rotation =
Scapulothoracic elevation
SC Elevation + AC up rot =
Scapulothoracic upward rotation
SC protraction + AC IR =
Scapulothoracic protraction
How much of the articular surface of the humeral head does the glenoid fossa cover?
1/3
Area not protected by the RTC mulches but reinforce by the long head of the biceps and coracohumeral ligament; located between the supraspinatus and subscapularis
rotator interval
What makes up 50 % of the depth of the glenoid fossa?
Glenoid labrum
What passive mechanisms provide stability at the GH joint?
- restrain provided by capsule, ligaments, aglenoid labrum and tendons
- mechanical support predicated on ST posture
- negative intracapsular pressure
What GH ligament limits extremes of ER?
middle GH lig
What GH lig restrains inferior and anterior-posterior translations of the humeral head and becomes taut in full adduction?
Superior GH lig
What GH lig is hammock-like, has three separate components, becomes taut in about 90 degrees of abd and becomes taut at extremes of ER and IR?
Inferior GH lig
- 3 parts = anterior band, posterior band, and axillary pouch (taut in abd)
What ligament is the strongest and thickest in the GH capsule?
anterior band of the inferior GH lig
- primary ligamentous restraint to anterior translation of the humeral head
What is ROM for arm abd
120 abd at GH j
60 scapular up rot
- 180 total
What is ROM for arm flexion?
120 flex at GH j
60 scapular upward rot
- 180 total
What is ROM for arm extension
65 degrees
What is ROM for arm ER? IR?
- 90 ER
- 70 IR
What is open pack position for GH joint? close pack? capsular pattern?
- OP = 55-70 abd, 30 horrid add, neutral rotation (splinting position to maximize blood flow to shoulder for healing)
- CP = max ER and abd (frozen shoulder)
- capsular = ER > Abd > IR