Shoulder Complex Flashcards
The shoulder girdle is composed of what three things?
scapula
clavicle
manubrium
Mobility is at the expense of ______ _______
structural stability
What joint is the only bony joint connecting the upper limb to the trunk?
sternoclavicular
Labrum deepens socket by __%
50%
Glenoid fossa is tilted __ degrees upward relative to vertebral border
5
vertebral (medial) border is located between?
T2-7
The forward convexity at the sternal end of the clavicle is the path for what?
upper extremity neurovascular bundle
How is the head of the humerus oriented inside the labrum?
faces medially, superiorly and is rotated posteriorly
What is the angle of inclination of the humerus and what is is measured relative to?
135 degrees; measured relative to the long axis of the shaft
Angle of torsion in humerus is retroverted ___ degrees in transverse plane
30
The condyles of humerus are located _____ relative to head of humerus. What does this allow?
anteriorly; allows head to be in scapular plane while elbow is in neutral and it also allows for greater ROM in abduction and external rotation before impingement occurs
Pectoral girdle joints consists of 2 bony articulations and 1 false articulation. What are they?
- Acromioclavicular
- Sternoclavicular
False:
-Scapulothoracic
Classification of sternoclavicular joint
- synovial, complex, modified stellar
- can also be classified as planar with multiplanar motion
- 3 DOF
What are the two articulations of the sternoclavicular joint?
manubrium and sternal end of clavicle
Movements of the sternoclavicular joint?
- elevation/depression
- protraction/retraction
- rotation
osteokinematics of sternoclavicular joint?
swing
________ ligament prevents upward displacement of the clavicle
interclavicular ligament
ARTHROKIN:
-Elevation of clavicle = _____ clavicular roll with ____ clavicular slide
superior
inferior
ARTHROKIN:
-Protraction of clavicle = _____ roll and slide
anterior
classification of acromioclavicular joint
- planar synovial joint
- multiplanar motion
osteokinematics of acromioclavicular joint?
translation
what muscular connections move the AC joint?
none!
Primary function of the AC joint?
assist the scapula in maintaining thoracic contact throughout ROM
Two articular surfaces of the AC joint?
acromial end of the clavicle and medial margin of the acromion of the scapula
What is the AC joint lined with?
fibrocartilage
2 accessory ligaments for the AC joint?
acromioclavicular and coracoclavicular ligaments
Which is stronger: coracoclavicular or acromioclavicular ligament
coraco
What is the coracoclavicular ligament composed of, and what stability do they provide?
Trapezoid - prevents lateral mvmt of clavicle on acromion
Conoid - checks superior mvmt of clavicle
GH joint has limited _____ stability
osseous
Approximately __% of head of humerus fits into glenoid cavity
25%
REMEMBER: THERE IS A DIFFERENCE BETWEEN GLENOID LABRUM AND GLENOID CAVITY
labrum deepens the cavity.
transverse ligament goes from lesser to greater tuberosity and creates a tunnel for what?
tendon of biceps brachii muscle
The GH ligaments reinforce the ___ and ___ joint capsule ; most common point of dislocation is at __ or __ o’clock.
anterior and inferior
4 or 5 - more to do with the mechanism of injury than anything else
Part of coracohumeral ligament blends with tendon of the ____ on lesser tubercle
subscapularis
How does the coracohumeral ligament strengthen the capsule?
Strengthens the superior capsule counteracting downward pull of the arm
Superior and middle GH ligaments assist the coracohumeral ligament in strengthening the capsule how?
counteracting downward pull of arm
The ____ ____ ligament converts the intertubercular groove of humeral head into a tunnel for the tendon of the long head of biceps brachii
transverse humeral ligament
What soft tissue structures are stretched with external rotation?
anterior capsule
GH ligament
What soft tissue structures are stretched with internal rotation?
external rotators
posterior capsule
(no ligaments back there)
What soft tissue structures are stretched with extension?
flexor muscles
anterior capsule
ligaments
How is PROM limited in elevation thru abduction when internally rotated?
180 degrees with no rotation is limited to 120-140 degrees when internally rotated
Why is the scapulothoracic joint not considered a ‘true’ joint?
it represents an articulation between the shoulder blade and the thorax
What is between the scapula and thorax? (4)
bursa
serratus anterior
subscapularis
fascia
How does the scapulothoracic joint provide GH stability?
for overhead work; also prevents impingement
Where does the scapulothoracic joint prevent impingement?
under the acromion - if you can’t rotate acromion out of the way then your greater tuberosity bangs on the acromion and squishes anything in that space
scapulohumeral rhythm is approximately what ratio?
2:1
GH:Scapula
Phase 1 of scapulohumeral rhythm?
Humerus: 30 degrees abduction
Scapula: minimal movement - this is the setting phase
Clavicle: 0-5 degrees
Phase 2 of scapulohumeral rhythm?
Humerus: 40 degrees abduction
Scapula: 20 degree rotation, minimal protraction
Clavicle: 15 degrees elevation
Phase 3 of scapulohumeral rhythm?
Humerus: 60 degrees abduction and 90 degrees lateral rotation
Scapula: 30 degrees rotation
Clavicle: 30-50 degrees posterior rotation and up to 15 degrees elevation
When you are i n 90 degrees of abduction, how much is with humerus and how much is with scapula?
70 degrees humerus and 20 degrees scapula
What is happening to scapulohumeral rhythm ratio if rhythm is faulty?
frozen shoulder or torn rotator cuff can lead to faulty rhythm - in this case, most of mobility generally comes from scapula movement, so GH movement is lacking
How does the subscapular bursa communicate with joint capsule?
via synovial fluid
Impingement of subacromial/subdeltoid bursa can be due to? (4)
-inflammation due to tendon damage
-Ca+ deposit
-faulty scapulohumeral rhythm
humerus not staying centered on glenoid
____ bursa overlies the anterior joint capsule
subscapular
The subscapular tendon lies beneath the tendon of what muscle?
subscapularis
What bursa communicates with the joint capsule, helping to maintain negative pressure within the joint that contributes to GH joint stability?
subscapular bursa
What nerves supply the trapezius?
CN XI, C3 and C4
Reverse OI for Trap?
extend
ipsilateral flexion
contralaterally rotate neck
nerve supply for levator scapulae?
dorsal scapular nerve
reverse OI for levator scapulae?
extend
ipsilateral flexion
ipsilateral rot. of neck
How do you stretch the levator scapulae?
contralateral flexion and ipsilateral rotation - double check in lab manual
nerve supply for rhomboid?
dorsal scapular nerve
nerve supply for serratus anterior?
long thoracic nerve
Reverse OI for serratus anterior?
retracts trunk
elevates and depresses trunk
nerve supply for the pec minor?
medial pectoral nerve
What muscles upwardly rotate the scapula?
trapezius
serratus anterior
lower trapezius
What muscles downwardly rotate the scapula?
levator scapulae
rhomboid major & minor
pectoralis minor
nerve supply for pec major?
medial and lateral pectoral nerve
what nerve innervates the coracobrachialis?
musculocutaneous
what nerve innervates the deltoid?
axillary n.
what nerve supplies lats?
thoracodorsal nerve
what nerve innervates the teres major?
lower subscapular
what nerve innervates the teres minor?
axillary nerve
nerve that innervates supra- and infraspinatus?
suprascapular nerve
what nerve supplies the subscapularis?
upper and lower subscapular nerve
what nerve innervates the biceps brachii?
musculocutaneous nerve
what nerve innervates the triceps brachii?
radial
What three muscles insert at the intertubercular bicipital groove?
pectoralis major
latissimus dorsi
teres major
Muscles of the rotator cuff? SITS
Supraspinatus
Infraspinatus
Teres Minor
Subscapularis
What is the role of the rotator cuff muscles during arm movement?
hold head of humerus centered in the glenoid cavity
3 bony stabilizers of the GH joint?
- Glenoid
- coracoid process
- acromion
What are the 4 types of passive stabilizers in the GH joint?
- Bony (osseous) - minimal support
- Glenoid labrum
- articular capsule
- ligaments
The glenoid labrum is a _________ ring that deepens the socket by 50%
fibrocartilage
what does the articular capsule do?
allows greater elevation and provides stability for end ROM
Negative intraarticular pressure within the GH joint is influenced by communication with what?
subscapular bursae and intact labrum
What are the dynamic stabilizers of the GH?
muscles and tendons
At rest, the humeral head is suspended by?
ligaments (superior GH, coracohumeral) and negative intra-articular pressure
What happens when you have head forward posture?
hyper fires the traps - they become tight and overactive
What happens to scapula if you have tight levator scapulae?
it becomes difficult for scapula to upwardly rotate
the primary function of the rotator cuff muscles are that they are _____ ______
compressive stabilizers
How does biceps stabilize the shoulder?
compresses the humeral head
How does the deltoid function as a dynamic stabilizer?
- In initial elevation it shears the head of the humerus superiorly
- as elevation proceeds, deltoid compresses
- at full elevation, the deltoid and horizontal forces from RC provide stability
Brachial plexus is what nerve roots?
C5 C6 C7 C8 T1
Axillary nerve comes from what nerve root?
C5-6
Musculocutaneous nerve comes from what nerve root?
C5-7
Median nerve comes from what nerve root?
C5-T1
Ulnar nerve comes from what nerve root?
C8-T1
Radial nerve comes from what nerve root?
C5-T1
Dorsal scapular nerve supplies? (3)
Rhomboids Major and minor
levator scapulae
subscapular nerve supplies? (2)
infra- and supraspinatus
axillary nerve supplies? (2)
deltoid and teres minor
medial and lateral pectoral nerves supply? (2)
pec major and minor
long thoracic nerve supplies? (1)
serratus anterior
Upper subscapular nerve supplies? (1)
subscapularis
lower subscapular nerve supplies? (2)
teres major
subscapularis
thoracodorsal nerve supplies?
latissimus dorsi
musculocutaneous nerve supplies? (3)
biceps brachii
brachialis
coracobrachialis
radial, ulnar and median nerve supplies - look at slide 82
:)
what nerve supplies levator scapulae?
dorsal scapular n. (C3/4?)
What nerves roots supply the trapezius? (3)
CN XI
C3
C4
What muscles are working during crutch walking while you pull your GH joint from a flexed position to extended?
At the GH joint, extension and slight adduction are
occurring. Big muscles for this are Latissimus Dorsi, Teres Major, triceps (holding arm at elbow in extension), wrist co-contraction to create stability, rhomboids and lower scapula will depress scapula, need strong rotator cuff muscles that will hold humerus in glenoid cavity.
What muscles would be weak during a push-up? Raising and lowering phase?
Raising:
- -> GH is extended and abduct
- -> serratus anterior holds scapula in retraction
Lowering:
- -> GH is flexed and adducted: pec major
- -> same muscles but the are working eccentrically
What are the key muscles in the power phase of a butterfly swim stroke?
- Extension and internal rotation
- Latissimus Dorsi and Teres Major are the big ones.
With head forward posture and increased thoracic kyphosis, which movements would be limited?
Depression of scapula
Upward rotation of scapula - cause your downward rotators are tight
Go find which joints would have limited ROM and which muscles would be tight and weak?
What are the primary causes of impingement?
overloaded overhead activity
What are the secondary causes of impingement?
faulty scapulohumeral rhythm, rotator cuff/soft tissue imbalance
WHat cases a faulty scapulohumeral rhythm?
overactive right muscle and/or weak muscle
Poor stabilization of humerus in glenoid and altered arthrokinematics are caused by what weak muscles?
weak muscles - teres minor and infraspinatus
