joints

Question 1

shoulder girdle/scapulothoracic motion

Answer 1

scapula moves on the posterior rib cage
joint motion occurs at sternoclavicular joint & to a much lesser amount at the acromioclavicular joint
cannot isolate out joints

Question 2

shoulder girdle/scapulothoracic movements

Answer 2

1. protraction / retraction [punching motions]
2. rotation [abduction and adduction of arm like in jumping jacks]
3. elevation / depression [shrugging shoulders]

Question 3

SC joint

classification, composition, movement type and correlating joint class

Answer 3

(multiaxial) arthrodial classification (some classify as seller)
Medial head of the Clavicle articulates with the Manubrium of the Sternum to form the S-C joint
Inter fibrocartilaginous disc divides the joint into two separate joint cavities
Elevation & Depression acts like a Hinge Joint
All other motion much like a Ball & Socket joint

Question 4

sc joint ligaments

Answer 4

interclavicular ligament
costoclavicular ligament [strongest]
anterior sc ligament
posterior sc ligament

Question 5

why is sc joint so stable

Answer 5

1. Only point of attachment of the upper extremity to the axial skeleton
2. Enhance upper extremity motion
3. Acts as a pivot point [hinge joint] for a lot of the motion at the shoulder

Question 6

Acromioclavicular (AC) joint

Answer 6

Acromion Process of Scapula articulates with the lateral head of the Clavicle
Can only perform a slight amount of gliding motion in all three planes
Not very mobile, but is crucial for normal upper extremity motion

Question 7

ac joint ligaments

Answer 7

1. Acromioclavicular ligament
2. Coracoclavicular ligament (conoid & trapezoid)
3. Coracoacromial ligament

Question 8

Scapulothoracic joint

Answer 8

Not a true synovial joint, does not have regular synovial features
Movement depends on SC & AC joints which allows the scapula to move
Supported dynamically by its muscles
No ligamentous support
Scapula sits about 30 degrees in front of the Frontal plane

Question 9

scapula at rest

Answer 9

sits about 30 degrees in front of the frontal plane