S2_L2: Kinesiology of the Shoulder Complex Flashcards
TRUE OR FALSE: The muscle that is parallel to the movement is the one that is most activated. It’s always about the line or plane of movement to muscle fiber.
True
TRUE OR FALSE: Elevation of the arm is always in relation to the trunk unless stated otherwise.
True
Note: As long as the trunk does not participate in the motion, the degree of elevation of arm from vertical and elevation of arm relative to the trunk will be the same.
TRUE OR FALSE: The scapulohumeral rhythm is a combination of concomitant glenohumeral and scapulothoracic motion. It varies among individuals and external constraints, but in reality, there is no definitive scapulohumeral rhythm.
True
It is the only muscle capable of producing simultaneous scapular upward rotation (prime mover), posterior tilting, and external rotation, and has the largest moment arms of any of the scapulothoracic muscles.
Serratus anterior
Note: It is also the primary stabilizer of the inferior angle and medial border of the scapula.
Paralysis of this muscle results to scapular winging
serratus anterior (boxer’s muscle)
____ occurs to maintain the contact of the scapula with the contour of the rib cage and to orient the glenoid fossa.
Scapular tilting
During normal flexion or abduction of the arm, the scapula ____ tilts on the thorax as the scapula is upwardly rotating.
posteriorly
TRUE OR FALSE: The orientation of the glenoid fossa is important for maintaining congruency with the humeral head; maximizing function of glenohumeral muscles, capsule and ligaments; maximizing stability of the glenohumeral joint; and maximizing available motion of the arm.
True
TRUE OR FALSE: Elevation of the scapula in the thorax (e.g., shoulder shrug) can result in anterior tilting or tipping of the scapula.
True
The greatest shear forces during humeral elevation typically occur between ___ degrees of elevation.
30-40
Painful arc of motion between ___ degrees of elevation (flexion & abduction) may indicate the rotator cuff or biceps as the primary source of pain.
60-120
Note: Pain later in the range of motion may indicate acromioclavicular degeneration as the primary source of pain.
TRUE OR FALSE: A force component parallel to the long bone has a stabilizing effect because the parallel component contributes to joint compression.
True
Most frequently dislocated joint in the body
glenohumeral joint
TRUE OR FALSE: Shoulder dislocations are usually anterior-inferior, but multi-directional.
True
Most common because of the weakness of the rotator interval capsule, foramen of Weitbrecht, weak rotator cuff muscles, and tendency of humerus to shift anteriorly (anteversion of the scapula).
A. anterior shoulder dislocation
B. posterior shoulder dislocation
C. inferior shoulder dislocation
A. anterior shoulder dislocation
Brought about by the pull of gravity, and weak supraspinatus, deltoids, rotator interval capsule support, and area on the superior aspect.
A. anterior shoulder dislocation
B. posterior shoulder dislocation
C. inferior shoulder dislocation
C. inferior shoulder dislocation
A potential space between the superior and middle glenohumeral ligaments; thus accounts for the weak capsular region and anterior dislocations.
Foramen of Weitbrecht
Area between the middle and inferior glenohumeral ligaments that is not a common problematic area
Foramen of Rouviere
Enumerate the components of the rotator interval capsule (RIC)
superior glenohumeral ligament, superior joint capsule, and coracohumeral ligament
Most functional activities of the shoulder happen in this shoulder motion
scaption/scapular abduction
This structure is the osteoligamentous vault over the humeral head that forms the subacromial space, suprahumeral space, or supraspinatus outlet.
Coracoacromial/Suprahumeral Arch
Note: It is 10mm in healthy subjects with an adducted arm, 5mm in arm elevation.
Enumerate the contents of the subacromial space, the region between the suprahumeral/coracoacromial arch and humeral head
- subacromial bursa
- rotator cuff tendons
- portion of tendon of the long head of the biceps brachii
Note: These structures are protected superiorly from direct trauma by the coracoacromial arch. Contact of the humeral head with the undersurface of the arch can cause painful impingement or mechanical abrasion of the structures within the subacromial space.
These bursae are very important in the shoulder complex because they separate the supraspinatus tendon and humeral head from the acromion, coracoid process, coracoacromial ligament, and deltoid muscle.
Subacromial and subdeltoid bursae
Note: The bursae are commonly continuous with each other and are collectively known as subacromial bursa.
TRUE OR FALSE: The subacromial bursa permits smooth gliding between the humerus and supraspinatus tendon and surrounding structures. Interruption or failure of this mechanism is a common cause of pain.
True
TRUE OR FALSE: The subacromial space is considered as a component of the glenohumeral joint rather than a separate joint.
True
Note: The subacromial or suprahumeral joint (or space) is also described as a functional joint which is formed by movement of the head of humerus below the coracoacromial arch.
This structure is a false joint formed by the coracoid process, acromion, coracoacromial ligament, and inferior surface of acromioclavicular joint. It acts as a physical barrier to superior translatory forces acting on the humeral head, preventing it from dislocating superiorly.
Coracoacromial/Suprahumeral Arch
Note: The coracoacromial ligament connects the acromion and coracoid process and creates the subacromial space below these structures.
This condition occurs with a narrowed subacromial space. It occurs most commonly secondary to inflammation or degeneration of the supraspinatus tendon.
Subacromial bursitis
TRUE OR FALSE: In shoulder impingement syndromes due to a narrowed subacromial space, the supraspinatus tendon (supraspinatus impingement syndrome), subacromial bursa, or long head of biceps are the ones usually impinged.
True
Note: There is no one single reason why people develop impingement syndromes, there are multiple factors involved. If the reason is anatomical, surgery is the solution.
TRUE OR FALSE: Below 60º or above 120º in relation to the painful arc of shoulder motion, the supraspinatus tendon has yet to rotate past the overlying acromion or has already rotated past it, respectively. In these ranges, the pain is minimized or decreased.
True
Note: Beyond 120º, the space is less narrowed (opening further) because the scapula moves more superiorly with clavicular elevation, which is why there is no more pain/reduces the pain for the patient.
Enumerate the 3 functional reasons for a narrowed subacromial space
- Repetitive shoulder motion (Leads to inflammation, fibrosis, and thickening of soft tissues; e.g., throwers & swimmers)
- Abnormal scapular mechanics (E.g., inadequate posterior tilting or upward rotation of the scapula)
- Poor humeral mechanics (I.e., inadequate rolling or gliding movements, excessive superior or anterior translation of humeral head)
Enumerate the 4 anatomical reasons for a narrowed subacromial space
- Shape of acromion process (a curved or hooped shape causes narrowing compared to a flat shape)
- Another object occupies the space (e.g., bony spurs or osteophytes)
- Large coracoacromial ligament (congenital)
- Disproportionately large humeral head
This muscle is the prime mover of glenohumeral flexion
Anterior deltoid
These muscles are the prime movers of glenohumeral abduction
deltoid and supraspinatus
Most vulnerable rotator cuff muscle to tensile overload and chronic overuse because it is either passively stretched or actively contracting; it also participates in humeral elevation.
Supraspinatus
It is the combination of scapular, clavicular, and humeral motion that occurs when the arm is raised either forward or to the side; including sagittal plane flexion, frontal plane abduction, and all the motions in between.
Elevation
This movement is a combination of upward rotation of the scapula, external rotation of the shoulder, and posterior tilting of the scapula.
Abduction
TRUE OR FALSE: Motion of the scapula on the thorax normally contributes about one-third of the total shoulder complex motion necessary for arm elevation, whereas the glenohumeral joint contributes about two-thirds of the total motion.
True
TRUE OR FALSE: Any motions of the scapula will influence glenohumeral joint function.
True
modified T/F on shoulder complex
TRUE joints are glenohumeral, acromioclavicular & sternoclavicular jount
FALSE joints are scapulothoracic, subacromial space & suprahumeral joint
TT
- false joints have no anatomical relationship with each other
modified T/F on shoulder complex
It is made up of humerus, scapula & clavicle for mobility/motion & not for stability
It is from the scapula through the acromion process & lateral aspect of clavicle
TT
modified T/F
sternoclavicular joint is the articulation of medial aspect of clavicle & manubrium of sternum
It is a saddle joint (double condyloid joint)
TT
modified T/F on sternoclavicular joint
the concave part is for protraction & retraction
the convex part is for elevation & depression
TT
match the ff ligament
- between 2 clavicle, touches manubrium & supports superior aspect of joint that restrict too much depression of the clavicle
- found anterior & posterior that prevent too much ant/pos displacement of clavicle
- found inferior to clavicle to prevent too much elevation of the clavicle
A. sternoclavicular ligament with capsule
B. costoclavicular ligament
C. interclavicular ligament
- C
- A
- B
which of the ff are true about sternoclavicular joint
A. Has THREE ROTATIONAL Degrees of freedom
B. Elevation / Depression (z axis)
C. Protraction / Retraction (y axis)
D. Anterior (when protracting) / Posterior (when elevating shoulder) Rotation (x axis)
E. All of the above
E
- B&C are osteokinematic (observable)
- D is arthrokinematic (not observable)
modified T/F on Sternoclavicular Joint:
Clavicular rotation aids in scapular upward rotation and shoulder elevation
If there’s no clavicular rotation, then it limits shoulder complex elevation
TT
modified T/F on Sternoclavicular Joint:
Controls for clavicular elevation & depression
Costoclavicular ligament controls elevation while superior interclavicular ligament controls depression
TT
modified T/F
Sternoclavicular Joint have THREE TRANSLATORY Degree of freedom:
Anterior / Posterior, Superior / Inferior, Lateral / Medial
During horizontal abduction of shoulder, there’s a lateral translation while during horizontal adduction of shoulder, there’s a medial translation
TT
modified T/F
acromioclavicular joint articulates in the acromion process of scapula & lateral aspect of clavicle
It allows scapular rotation/movement & is the site of force transmission from the UE going to the clavicle
TT
modified T/F on coracoclavicular ligament
conoid is lateral & anteriorly located
trapezoid is medial & posteriorly located
FF
trapezoid is lateral & anteriorly located
conoid is medial & posteriorly located
modified T/F
acromioclavicular (AC) capsule has weaker support & easily tears than sternoclavicular capsule
acromioclavicular joint is connected with AC capsule & prevents too much depression of scapula/clavicle
TT
modified T/F on acromioclavicular disk
fibrocartilagenous disk that prevents friction & for shock absorption, lubrication, & inc. joint congruency
It is found between joints & not oblique shaped unlike sternoclavicular disk
TT
which of the ff are true about Acromioclavicular Joint:
A. Has THREE ROTARY Degrees of Freedom(DOF)
B. Internal / External Rotation (y axis) [30°of motion]
C. Anterior / Posterior Tilting or Tipping (x axis) [60°of motion]
D. Upward / Downward Rotation (z axis) [30°of motion]
E. All of the above
E.
modified T/F
anterior tilting/tipping is where the superior aspect of scapula moves backward
posterior tilting/tipping is where the superior aspect of scapula moves forward
FF
anterior tilting/tipping is where the superior aspect of scapula moves FORWARD
posterior tilting/tipping is where the superior aspect of scapula moves BACKWARD
T/F
Acromioclavicular Joint has THREE TRANSLATORY DOF: Anterior / Posterior, Superior / Inferior &
Lateral / Medial
T
which of the ff are true about Scapulothoracic Joint:
A. Articulation of scapula with the thorax
B. Not a true anatomic and synovial joint
C. Interdependent with AC and SC joints
D. all of the above
D
the ff are resting position of Scapulothoracic Joint, EXCEPT:
A. 5cm from midline through 2nd-7th ribs
B. Internally rotated (35-45°) from coronal plane
C. Anteriorly tilted (10-15°) from vertical
D. Upwardly rotated (5-10°) from vertical
E. None of the above
E
which of the ff are functions of the Scapulothoracic Joint:
A. Increases shoulder ROM for greater reach
B. Maintains favorable length-tension relationships for deltoid to function above 90° shoulder elevation for stability while moving
C. Provides GH stability (glenoid and humeral head alignment) for overhead activities
D. Shock absorption for FOOSH & Permits elevation of body (e.g. seated push-up, ambulating with crutches)
E. All of the above
E
modified T/F on Scapulothoracic Joint:
THREE ROTARY DOF
- Upward / Downward Rotation
- Internal / External Rotation
- Anterior / Posterior Tilting/Tipping
TRANSLATORY DOF
- Elevation / Depression
- Protraction / Retraction
TT
which of the ff are true about glenohumeral joint:
A. articulation is at the humeral head & glenoid fossa of scapula
B. Ball-and-Socket Synovial Joint (universal joint)
C. More Mobility than Stability which is why it’s prone to instability
D. Anteverted scapula with Humeral head in superior, medial, posterior direction
E. All of the above
E
- the direction of humeral head with anteverted scapula (resting position of scapula) will contribute to the stabilization of glenohumeral joint
match the ff
- Axis through humeral head and neck in relation to longitudinal axis through humeral shaft
- 130-150° (120°) in frontal plane
- Axis through humeral head and
neck in relation to an axis through humeral condyles - 30° posterior
A. ANGLE OF INCLINATION
B. ANGLE OF TORSION
- A
- A
- B
- B
modified T/F on GLENOID LABRUM
Enhances the depth and concavity of the glenoid fossa by 50%
Fibrous connective tissues are covered by cartilaginous tissue
TT
the ff are Functions of glenoid labrum, EXCEPT:
A. Resistance to humeral head translation
B. Reduction of joint friction
C. Dissipation of joint contact forces
D. Attachment site of ligaments, joint capsule and tendons
E. None of the above
E
modified T/F on GLENOHUMERAL CAPSULE
Taut superiorly to prevent humerus sliding downward & slack anteriorly and inferiorly with arm at dependent side to give more room to elevate shoulder
Tight at adduction and IR (close-packed position)
TF
Tight at ABDUCTION and ER (close-packed position)
which of the ff are part of the GLENOHUMERAL LIGAMENTS
A. Superior, Middle, & Inferior Glenohumeral Ligaments
B. Foramen of Weitbrecht which is the space between superior & middle GH ligament that can cause anterior dislocation because of the weak joint capsule
C. Foramen of Rouviere which is the space between middle & inferior GH ligament
D. Coracohumeral Ligament from coracoid to humerus that prevents humerus from being pulled downwards & maintains the stabilization of the humerus in the joint
E. All of the above
E
which of the ff are true about rotator interval capsule (RIC)
A. consists of superior GH ligament, superior joint capsule, & coracohumeral ligament
B. acts to stabilize humerus in place, prevents humerus from inferiorly sliding
C. bridges the space between supraspinatus & subscapularis muscles
D. no muscular support, so no dynamic stabilization, only static stabilization
E. all of the above
E
which of the ff statements are incorrect
A. bursa prevents excessive frictional forces
B. acromion bursa is found below acromion process
C. subdeltoid bursa is found between deltoid & humerus
D. Subcoracoid bursa is found between subscapularis & coracoid process
E. Without the bursa, the muscles will generate too much friction when they contract & result in muscle tear
B.
*subacromial bursa is found below acromion process
which the ff are true on Motions of Glenohumeral Joint:
A. Has THREE ROTATIONAL DOF
B. Flexion (90-120°) / Extension (50°) [sagittal]
C. Abduction / Adduction (arms in neutral/IR versus arms in ER) [frontal]
D. External / Internal Rotation → 130° of rotation at 90° abduction [transverse]
E. All of the above
E
modified T/F
SCAPTION / SCAPULAR ABDUCTION is the Shoulder elevation in the plane of scapula
It occurs along sagittal & transverse planes when abducting shoulder diagonally
TF
It occurs along sagittal & FRONTAL planes when abducting shoulder diagonally
- most functional activities happen in caption
modified T/F
Coracoacromial/Suprahumeral Arch forms the subacromial space
Subacromial bursa, Rotator cuff tendons & Long head of biceps
brachii can also be seen in the Coracoacromial/Suprahumeral Arch
TT
modified T/F
Narrowed subacromial space causes Impingement syndromes, Subacromial bursitis & bicipital tendinitis.
painful arc is between 50-130°
TF
painful arc is between 60-120°
which of the ff are anatomical factors that narrows subacromial space
A. shape of acromion process (curved, flat, hooked)
B. when another object occupies the space (bony spurs/osteophytes)
C. in born large coracoacromial ligament
D. large humeral head that push up the structures & narrows the space
E. All of the above
E
the ff are functional factors that narrows subacromial space, EXCEPT:
A. repetitive motion like swimmers, throwers
B. abnormality of scapular mechanics (not moving properly/rhythmically with humerus)
C. poor humeral mechanics ( concave-convex function of humeral head is altered, inadequate rolling/gliding movements can narrow the area)
D. None of the above
D
modified T/F
static stabilization is provided by ligaments, joint capsules & rotator interval capsule (RIC)
In the dependent arm position, the negative pressure creates a suction effect that’s created by the joint capsule & allows the static stabilization of the GH joint & maintain stability of the joint
TT
which of the ff are true about Dynamic Stabilization in dependent arm position
A. relies on the muscle
B. capable of stabilizing humerus by counteracting inferior forces of gravity
C. supraspinatus is found superiorly that dynamically stabilizes humerus & prevents downward pull
D. The line of force is inwards to compress together the humeral head to glenoid fossa to provide stabilization
E. All of the above
E
modified T/F
the short head of the biceps brachii tendon stabilizes the humerus & prevents the downward pull
Others are born with laxed rotator cuffs, deltoids, long head of biceps that results in the instability of the shoulder so they rely on dynamic stabilizers & need to further strengthen the muscles
FT
the LONG head of the biceps brachii tendon stabilizes the humerus & prevents the downward pull
modified T/F on shoulder impingement syndrome
painful in 60-120° arc because it narrows the subacromial space that could impinge the bursa, long head of biceps & supraspinatus tendon
pain is reduce but is still there in less than 60° & more than 120°
TT
modified T/F on AC joint degeneration/destruction of the cartilage & disc
there’s a direct bone to bone contact & it’s very painful
when its compressed by crossing arms in front/ sidelying on that side, it becomes very painful
TT
which of the ff are true about bicipital tendonitis
A. attaches inferiorly in superior labrum & rim of glenoid fossa
B. inflamed when narrow subacromial space
C. injured by torn in superior labrum (SLAP lesion)
D. Done by repetitive movements & if the bursa is absent then the tendon will have a direct frictional force wit the bone & will tear/degenerate the tendon
E. if the transverse humeral ligament is torn then the tendon can easily be moved sideways that create friction with he tubercles
A.
attaches SUPERIORLY in superior labrum & rim of glenoid fossa
modified T/F
anterior shoulder dislocation is common due to weak RIC, foramen of weitbrecht, & rotator cuff in which the anterversion of the scapula easily push humerus anteriorly
Inferior dislocation is due to pull of gravity, & weak supraspinatus, deltoid, RIC
TT
- most people with shoulder dislocation is antero-inferior
which of the ff are SCAPULOHUMERAL
FUNCTION
A. Shoulder complex (especially GH and ST) acts in coordinated manner
B. Distributes motion between joints for greater ROM with less compromise in stability
C. Maintains glenoid fossa in optimal position in relation to humeral head to increase congruency
D. Permits good length-tension relationship of muscles (prevents active insufficiency of shoulder muscles)
E. All of the above
E
which of the ff are true about SCAPULOHUMERAL RHYTHM
In shoulder elevation:
A. GH contributes 100-120° (flexion); 90-120° (abduction)
B. ST contributes 50-60°
C. Combined is 150-180° elevation
D. Overall ratio of 2° for GH and 1° for ST (2:1 ratio)
E. all of the above
E
match the ff phase to its SCAPULOHUMERAL RHYTHM
- Initial 60° of flexion; 30° of abduction (3:1 ratio)
- Scapula seeking a position of stability (GH joint only, scapula isn’t moving)
- At 30° abduction, 2:1 ratio begins
- ST joint movement is increased with GH joint motion reduced (approaching 1:1)
- More scapular motion at 80-140° abduction
A. Setting Phase
B. Mid portion phase
C. Later Phase
According to Inman et. al.
- A
- A
- B
- C
- C
which of the ff are true about SC & AC
CONTRIBUTIONS
A. Contributes to 60° of scapular upward rotation since when we elevate GH complex, the scapula needs to move too
B. ST elevation results in SC
elevation & clavicular posterior rotation
C. SC in retraction
D. AC in internal rotation
E. All of the above
E
identify the wrong statement
A. upper part of trapezius is an upward scapula rotator
B. levator scapula is a downward rotator with retraction of scapula
C. serratus anterior is an upward rotator with protraction of scapula
D. if same muscles are contracting on the same direction, they’ll move/create motion
E. if same muscles are contracting on the opposite direction, they’ll create stabilization on the scapula
B.
rhomboids is a downward rotator with retraction of scapula
modified T/F
when upper trapezius & serratus anterior contract, the scapula will move upward
If you have a serratus anterior movement with the co-contraction of rhomboids, then the scapula is stabilized due to the stabilizing synergistic function of the muscles
TT
modified T/F
SHOULDER COMPLEX DEPRESSION is when there’s a forceful downward movement of arm in relation to trunk (scapula rotates downward and adducts)
the shoulder complex is depressing while elevating trunk when lifting body in seated position, seated push-up (inc. tone of latissimus dorsi)
TT
match the ff muscles
(can have multiple answers)
- agonist in shoulder complex depression
- synergist with latissimus dorsi
- secondary agonist
- aside from rotating scapula downward & adducting, the humerus will extend, adduct & IR
- adducts & IR humerus
A. Latissimus Dorsi
B. Pectoralis Major (Sternal)
C. Teres Major
D. Rhomboids
E. Pectoralis Minor
- A
- D
- B, C, E
- A
- B
match the ff muscles
- secondary role that anteriorly tilts scapula only for assistance
- downward rotator of scapula, scapular downward rotation & adduction together with GH extension, adduction, IR which is a synergistic action
- extensor, adductor, IR of humerus (secondary actor because it only activates if there’s resistance)
A. Latissimus Dorsi
B. Pectoralis Major (Sternal)
C. Teres Major
D. Rhomboids
E. Pectoralis Minor
- E
- D
- C
