Joints

1. Sternoclavicular joint
2. Acromioclavicular joint
3. Scapulothoracic joint
4. Glenohumeral joint

1. Sternoclavicular joint

Articulation / orientation

Medial end of clavical connects with manubrium sterni. It is saddle shaped joint and it has 3 degrees of motion:

• Elevation and depression
• Protraction and retraction
• Rotation

Ligaments and passive components

• Fibrocartilaginous disc
• Fibrous capsule
• Anterior sternoclavicular ligament
• Posterior sternoclavicular ligament
• Interclavicular ligament
• Costoclavicular ligament

Kinematics

Elevation and depression

• Elevation (30° - 45°) and Depression occurs in frontal plane and sagittal axis
• Exact motion occurs in oblique direction: Elevation in posterosuperiorly and depression in anteroinferiorly.
• During elevation convex surface of clavical glides inferiorly and rolls superiorly. In depression, clavical glides superiorly and rolls inferiorly.
• Elevation is limited by costoclavicular ligament and depression is limited by interclavicular ligament.

Protraction and retraction

• Protraction and retraction occurs in transverse plane and vertical axis.
• Protraction is about 15° to 30° and retraction is 15° to 30°.
• Articular disc is involved in protraction and retraction. During protraction, concave aspect of clavicle glides and rolls forward. In retraction, clavical glides and rolls posteriorly.
• Protraction is limited by posterior sternoclavicular ligament and costoclavicular ligament. Anterior sternoclavicular ligament limits retraction.

Rotation

• Posterior rotation occurs during shoulder abduction above 90°. Posterior rotation of the clavicle is about 40° to 50°.
• Rotation occurs in medial to lateral axis.
• Posterior rotation is a passive motion and caused by tightening of the acromioclavicular ligaments during upward rotation of scapula.

Mobilization points

• Antero-inferior glide - Elevation
• Postero-superior glide - Depression
• Anterior glide - Protraction
• Posterior glide - Retraction
• Posterior rotational glide - to improve shoulder flexion.

2. Acromioclavicular joint

Articulation / orientation

Lateral, inferior and posterior part of clavicle binds with medial, superior and anterior part of acromion process (slight concave end). It is synovial joint with plane variety. There is no concave convex rule for this joint.

Ligaments

• Superior and inferior acromioclavicular ligaments
• Coracoclavicular ligaments
  • Conoid part
  • Trapezoid part

Kinematics

• Elevation and depression
• Protraction and retraction
• Upward and downward rotation

Mobilization points

• Clavicle end posterior glide - improves protraction and upward rotation of scapula.
• Clavicle end anterior glide - improves retraction.

3. Scapulothoracic joint

ST joint is a functional joint formed by superolateral convex surface of the thorax and the cancave surface of the scapula.

Subscapular bursae provides cohesive force for the joint surfaces. There is no ligament present in this joint.

Kinematics

Scapulothoracic motions are the sum of motions from the AC joint and SC joint.

• Elevation and depression
• Protraction and retraction
• Upward and downward rotations

Mobilization points

• Superior glide - elevation
• Inferior glide - depression
• Lateral glide - protraction
• Medial glide - retraction
• Superior and lateral glide - upward rotation

4. Glenohumeral joint

Articulation

GH joint is a synovial ball and socket joint. it has 3°s of freedom. GH joint is formed by concave glenoid fossa and convex humeral head. To maintain alignment in scapular plane, humeral head faces superiorly, medially and posteriorly.

Ligaments and other structures

• Superior glenohumeral ligament
• Middle glenohumeral ligament
• Inferior glenohumeral ligament
• Coracoacromial ligament
• Coracohumeral ligament
• Joint capsule
• Glenoid labrum

Kinematics and mobilization glides

Osteokinematics and arthrokinematics
• Flexion - posterior glide
• Extension - anterior glide
• Abduction - inferior glide
• Adduction - superior glide
• Int / Medial rotation - posterior glide
• Ext / Lateral rotation - anterior glide
• Circumduction - combined glides

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