Lecutre 7a: Shoulder Complex Fucntional Antomy And Biomechnasi Flashcards
What are the 4 joints of teh shoulder complex
• Gleno-humeral joint
• Acromio-clavicular joint
• Sterno-clavicular joint
• Scapulo-thoracic joint
What is the primary and secondary function of the shoulder
Primaryly position hand in space to permit upper limb to interact w environment
Secondary to suspect upper lift and serve as a fulcrum for arm elevation
What is the closed packed position and open packed position
• CPP: 90° of ABD (or full) and full ER
• OPP: 55° of ABD and 30° horz
adduction
What is the capsular pattern of the shoulder
ER > ABD > IR
Get IR back last
What are passive structures of the GH joint
- Labrum
- Capsule
- Ligaments
What are the active structures of the GH joint
- Rotator cuff mm.
- Scapular mm
What are the 5 key elements of GH stabilization
- ossesous structures : concavity of glenoid fossa
-glenoid labrum - capsule ligamentous structures
- muscular structures
- mechanoreceptors
What are the 3 things of the concavity of the glenoid fossa
- (-) intra-articular pressure
- Limited joint volume
- Adhesion / cohesion
Is the labrum avasualr or vascular
Avascular does not heal itself
The average depth of the glenoid fossa is doubled by what
Labrum
What is the stabilizing effect to limit translation in the labrum
Chock block
What does the glenoid labrum increase
Total surface area for articulation enhancing concavity compression effects
The labrum aids in attachment of what
GH ligaments to glenoid
How is the GH capsule
Large , loose and redundant
How much static stability does the GH capsule afford
Minimal
What is the normal fluid volume in **GH capsule ? **
Adhesive capsulitis
Capsular laxity
- Normal volume 10-15 ml
- Adhesive capsulitis 5-10 ml
- Capsular laxity up to 30 ml
What 2 ligaments are in the anterior complex of the GH
Superior GH ligament and middle GH ligament
When is the superior GH ligament taut
W arm by side (0° of abduction)
What is the superior GH ligaments covered by and what does it aid in
• Covered by coraco-humeral ligament
• Aids RC muscles to support suspended
humeral head
**
When the superior GH lig is incompetent how will the humeral head subluxa
Inferiorly
If the shoulder sublux anterior what ligament will be damaged
Middle GH lig
What is the middle GH lig a secondary restraint to
Anterior translation
What. Lig is in the inferior complex of the GH capsule
Inferior GH ligament
What complex is the main static stabilizer of an abducted shoulder
Inferior
When does the interior GH ligament become taut
Abduction
What happens to the inferior GH ligaments when the shoulder if rotated
Fans out to support humeral head
In the inferior complex the hammock like anatomy of the axillary pouch allows what
Reciprocal tightening of anterior and posterior structures w arm motin
What complex is there w no distinct capsular ligaments
Posterior complex
The majority of posterior stability comes from what
Dynamic stabilizers
What does the posterior band of the inferior GH lig provide
Stability to humeral head when arm is abducted 90° and IR
What are the 3 well recognized functions of the RC mm
• Control osteokinematic and
arthrokinematic motion
• Rotate humeral head
• Stabilize humeral head in glenoid (MAIN PURPOSE)
The RC mm has a force couple with w other mm
Deltoid
What is a force couple
2 or more mm or groups or mm are on opposite dies of the joint and work in concrete to add joint stability or movement of a joint
What are 3 examples for force couple in shoulder
• Rotator cuff – deltoid
• Upper/lower trapezius – serratus
anterior
• Anterior – posterior rotator cuff``
Dynamic stability of the GH joint is achieved thru what
Contraction of RC mm and biceps
What decreased capsular and ligamentous strain in the shoulder
Mm contraction of RC
For dynamic stability u want to reinforce ___ structures thru direct attached of ___ tendons
Passive
RC
How do u get NM control for dynamic stability
Via proprioception
How big is the sub acromion a space w the arm at side
10-11mm
What happens to the SA space as arm elevated
Narrows
Most narrow between 60-120°
What tendon is most invovled in over use syndromes
Supraspinatus
Why does the position of teh GH joint matters
Bc of the less and greater tubercle
What can increase superior migration of the t humeral head
Muscle imbalance and capsular stiffness which then can result in damage to labrum and/or soft tissue
Does IR or ER causes more stress on shoulder
IR
Can u actively control the AC joint ?
No bc no mm attach here
What kind of joint is the AC joint
True synovial , plane joint
What is the CPP of the AC joint
90° abduction
What are the passive structures of the AC joint
Capsule and ligaments
T/f: the AC joint is controlled by active structures
NNOOOOOO F
What is the main articulation that suspects UE from trunk
AC joint
What lig is the primary support of the AC joint
Coraco clavicular ligament
What are teh 2 parts of the coraco clavicaulr lig
Conoid and trapezoid
What is the CPP of the SC joint
Max elevation and protraction
What is the capsualr pattern for the SC joint
Extreme end ROM (especially elevation and horizontal ADD)
What are the passive structures of the SC joint
Capsule , ligament and articular disc
T/F the SC joint is controlled by active structures
NOOOOO NOOO NOOO
What is the only joint that connects that shoulder girdle to the axial Skelton
SC joint
Which dx is more common at the SC joint
Anterior dislocation
is the SC weak or strong
Weak
What is the SC secured by
Extremely strong ligaments
What kind of joint is the scapula thoracic joint
False joint
What is the OPP of the scapulo thoracic joint
W arm at neutral - scapular positioned 30-45° IR , slight upward rotation and 5-20° anterior tipping
Is teh scapula thoracic joint controlled by active or passive structures
Active
What does teh active structures of the ST joint link ? It also acts to do what ?
Links proximal trunk to UE
Acts to transfer energy through kinetic chain
When the humerus is in 70° of abduction how much rotation is there at the scap
20
When the humerus is elevated to 110° how much rotation is there at the scap
40°
What kind of pateitns is reverse scapulo humeral rhythm usually seen in
Adhesive capsulitis
RC tears
The nerve supply of the shoulder joint is from what nerves
C5-C8
Except for AC joint - C4
Where does the sympathetic nerve supply originate form
T2-T8
The vascular supply to shoulder complex is primarily from what
Branches off axillary artery
What artery supplies both heads of the biceps
Brachial artery
