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sternoclavicular joint, acromioclavicular joint, scapulothoracic joint, glenohumeral joint
What are the 4 joints that make up the shoulder complex?
sternocalvicular (SC) joint
connects sternum and clavicle
acromioclavicular (AC) joint
connects clavicle and scapula
scapulothoracic joint
connects scapula and rib cage
glenohumeral joint
connects scapula and humerus
clavicle
connects upper extremity with axial skeleton
scapula
triangular flat bone that overlies ribs 2nd-7th posteriorly
superior, medial, and axillary borders
what are the three main borders of the scapula?
attachment for upper appendicular and axial skeleton
serve as the base for upper extremity movement
What are the 2 primary purposes of the pectoral girdle?
sternum (manubrium), clavicle, scapulae
what bones form the partial ring of the pectoral girdle?
humerus
what is the longest bone in the body?
sternoclavicular joint
the articulation between manubrium of the sternum and medial end of the clavicle
the sternoclavicular joint
what the only direct connection of the upper limb to the axial skeleton
articular disc
what improves joint congruency at the sternoclavicular joint?
fibrocartilage
what is the articular disc made of?
improve joint congruency and absorb shock
what is the purpose of the articular disc?
saddle joint (triaxial)
what kind of joint is the sternoclavicular joint?
elevation/depression, protraction/retraction, upward/downward rotation
what motions occur at the sternoclavicular joint?
anterior sternoclavicular ligament, posterior sternoclavicular ligament, interclavicular ligament, costoclavicular ligament
What ligaments support the sternoclavicular joint?
prevents excessive retraction and elevation
what actions occur at the anterior sternoclavicular ligament?
prevents excessive protraction and elevation
what actions occur at the posterior sternoclavicular ligament?
prevents excessive retraction and depression
what actions occur at the interclavicular ligament?
costoclavicular ligament
what actions occur at the costoclavicular ligament
during abduction or flexion of glenohumeral joint, the clavicle rotates upwardly. Opposite occurs during extension and adduction
what happens at the long axis of clavicular rotation
acromioclavicular joint
articulation between acromion process of scapula and lateral end of clavicle
plane synovial joint
what kind of joint is the acromioclavicular joint?
gliding, clavicle rotates when scapula elevates and depresses
What kind of actions occur at acromioclavicular joint?
acromioclavicular ligaments, coracoclavicular ligaments, and coracoacromial ligments
what 3 types of ligaments occur at the acromioclavicular joint?
superior and inferior thickening in the joint capsule
holds AC joint together
What is the purpose of acromioclavicular ligaments?
conoid ligament and trapezoid ligament
What 2 ligaments make up the coracoclavicular ligaments?
inferior aspect of clavicle to coracoid process of scapula
Where are the coracoclavicular ligaments located?
prevent excessive elevation of the clavice
What is the purpose of the coracoclavicular ligaments?
the coracoid process to the acromion process of the scapula
Where does the coracoacromial ligament run?
provides stability on superior aspect of GH joint
forms roof of coracoacromial arch
What is the purpose of the coracoacromial ligament?
coracoacromial arch
Osteoligamentous structure formed by acromion process, coracoacromial ligament, and coracoid process
prevents superior translation of humerus
what is the purpose of the coracoacromial arch?
glenohumeral joint
articulation between head of humerus and glenoid fossa of scapula
multi-axial ball and socket joint
what kind of joint is the glenhumeral joint?
sacrifices stability for mobility
What compromise does the glenhumeral joint make?
sagittal, frontal, transverse planes
what planes of motion does the glenhumeral joint act in?
flexion/extension, abduction/adduction, internal/external rotation, horizontal abduction/adduction, circumduction
what actions occur at the glenhumeral joint?
anterior, posterior, and inferior capsule
what are the main parts of the glenohumeral joint capsule?
3
how many distinct thickenings does the anterior capsule have?
none
how many thickenings does the posterior capsule have?
glenoid labrum
fibrocartilaginous rim around the perimeter of the glenoid cavity
deepens the socket
what is the primary function of the glenoid labrum
anterior glenhumeral ligaments
fibrous bands that run from glenoid to anatomical neck
superior, middle, and inferior
what are the 3 distinct bands of the anterior glenhumeral ligaments
prevents humerus from displacing anteriorly
what is the main function of the anterior glenhumeral ligaments?
runs from the lateral aspect of the coracoid process to greater tuberacle of the humerus
Where does the coracohumeral ligament run?
provides anterior stability to GH joint
what is the primary function of the coracohumeral ligament?
runs from the greater to the lesser tuberacles over the intertubercular groove and superficial to the long head of the biceps tendon
Where does the transverse humeral ligament run?
holds tendon in place
what is the primary function of the transverse humeral ligament?
bursa
flattened sac containing synocial fluid that reduces friction between two moving structures in the body
between the subscapularis tendon and the coracoid process
Where is the subscapular bursa located?
inferior to the coracoacromial arch and superior to the supraspinatus tendon
what is the subacromial bursa located?
subdeltoid bursa
what other bursa is the subacromial bursa continuous with?
atop the 2nd and 7th ribs
where does the scapulothoracic joint lie?
no joint capsule
no ligaments
muscles on anterior scapula prevent articulation of bones
why is the scapulothoracic joint not a true joint?
elevation/depression, protraction/retraction, upward/downward rotation
what motions occur at the scapulothoracic joint?
scapulohumeral rhythm
coordination of movements between the scapula, clavicle, and humerus
GH joint, ST joint, SC joint, and AC joint
what 4 joints must work together to ensure scapulohumeral rhythm?
2:1 ratio of GH:ST
what is the ratio of movement between glenohumeral and scapulothoracic joints?
120 degrees abduction/flexion of humerus
during 180 degrees of abduction of the arms, what happens at the glenohumeral joint?
60 degrees upward rotation of scapula
during 180 degrees of abduction of the arms, what happens at the scapulothoracic joint?
30 degrees elevation of clavicle
during 180 degrees of abduction of the arms, what happens at the sternoclavicular joint?
30 degrees upward rotation of clavicle
during 180 degrees of abduction of the arms, what happens at the acromioclavicular joint?
thoracoappendicular muscles
muscles that move the pectoral girdle
subclavius, pectoralis minor, serratus anterior
What are the anterior muscles that move the pectoral girdle?
serratus anterior
dysfunction of what muscle causes winging of the scapula?
trapezius, levator scapulae, rhomboid major, rhomboid minor
what posterior muscles move the pectoral girdle?
humerus
what bone does the rotator cuff muscles work to move?
supraspinatus, infraspinatus, teres minor, subscapularis
what muscles make up the rotator cuff?
external/internal rotation, abduction
what actions do rotator muscles help with?
dynamic stabilizer to pull humeral head into socket when raising the arm
what is the main function of the rotator cuff muscles?
pectoralis major, deltoid, coracobrachialis, biceps brachii
what are the anterior muscles that move the humeus?
latissimus dorsi, teres major, triceps brachii
what are the posterior muscles that move the humerus?
pectoralis major, coracobrachialis, latissimus dorsi, teres major
what muscles are involved in adduction?
supraspinatus, deltoid
what muscles are involved in abduction?
subscapularis, pectoralis major, latissimus dorsi, teres major
what muscles are involved in internal rotation
infraspinatus, deltoid
what muscles are involved in external rotation?
supraspinatus-deltoid force couple
Supraspinatus initiates abduction by elevating the humeral head and pulling it snugly into the glenoid fossa (with other rotator cuff muscles)
Deltoid has a mechanical advantage to abduct humerus once humeral head is stabilized in glenoid
upper trapezius-serratus anterior force couple
Upper trapezius contracts to upwardly rotate the scapula
Serratus anterior contracts to pull the scapula away from the midline of the body
Resultant vector causes the scapula to protract around the circumference of the rib cage
flexion/extension
what motions occur at the elbow?
olecranon process
where on the elbow does motion occur?
supination/pronation
what motions occur at the forearm?
radioulnar joint
where do motions at forearm occur?
humerus, ulna, radius
what bones make up the elbow and forearm?
radius
what bone moves during pronation and supination?
capitulum
part on humerus that articulates with radius
trochlea
part on humerus that articulates with ulna
radial fossa
part of the humerus that fits the radial head during flexion
coronoid fossa
part of the humerus that fits coronoid process during flexion
olecranon fossa
part of the humerus that fits olecranon process during extension
right behind medial epicondyle of humerus
where does ulnar nerve run?
trochlear notch
articulates with trochlea of humerus
olecranon process
proximal end of ulna and lip of trochlear notch
coronoid process
distal lip of trochlear notch
radial notch of ulna
articulates with radial head, proximal
ulnar head
articulates with ulnar notch of radius, distal
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