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Scapulothoracic (ST) joint - Coggle Diagram
Scapulothoracic (ST) joint
Articulation
is between the scapula and thorax
is not a true anatomic joint
cos it's not a union of bony segments
by fibrous, catilagenous,or synovial tissues
Junction created by the anterior aspect of the scapula on the posterior thorax
Depends on the integrity of AC and SC joints
Functional ST joint is part of a true closed chain with AC, SC and thorax
Resting Position of the Scapula
Rest on posterior thorax, 5cm from the midline and between the 2nd through 7th rib
Internally rotated 35-45 degrees from the coronal plane
10-15 degrees anteriorly tilted from vertical plane
5-10 degrees upwards rotated from a vertical when compared to the longitudinal axis
Motions of the Scapula
3 rotations same as the AC joint
Primary scapular motion
Upward and downward rotation
Secondary scapular motion
Internal/external rotation
Anterior and posterior tilting
2 Translatory motions
Elevation/depression
Protraction and Retraction
Scapulothoracic Stability
Provided by the structures that maintain integrity of the linked AC and SC joint
Muscles that attach both to the scapula and thorax maintain the contact between these 2 surfaces while producing movements
Muscles that attach both to the scapula and thorax maintain the contact between these 2 surfaces while producing movements
Stabilization is provided by the scapulothoracic musculature, which pulls or compresses the scapula to the thorax
Scapular motions keep the humeral head in glenoid fossa and provides optimal contact for the maneuvering arm
Add ranges to the elevation and provide a stable base for the controlled motions between the ball and socket
Scapula with associated muscles functions as an example of dynamic stabilization in the human body