1. Bones of the Shoulder Complex
   1. Clavicle
      1. Structure
         1. Crank shaped, aligned close to transverse plane. Articular surfaces covered by thick fibrocartilage.
            1. Subtopic 1
      2. Functions
         1. Strut to hold the shoulder complex on the axioskeleton. Contributes to ROM of shoulder joint, transmits muscle force to scapula.
      3. Attachments
         1. Pectoralis major, deltoid, trapezius, subclavius. Plus costoclavicular and coracoclavicular ligaments. Articulates with sternum and acromion (of scapula).
            1. Subtopic 1
   2. Scapula
      1. Structure
         1. Flat and triangular. Landmarks--superior and inferior angle, medial, axillary, and superior border, acromion, spine, coracoid process, many fossas. Important fossa--glenoid fossa where humerus articulates. Angled about 30 or 45 degrees from frontal plane. Articular surfaces covered by thick fibrocartilage.
            1. Subtopic 1
      2. Functions
         1. Provides site for 15 muscles to attach, rotates and tilts for greater shoulder ROM
      3. Attachments
         1. Trapezius, serratus anterior, pectoralis minor, rhomboid major and minor, levator scapulae, deltoid , biceps, coracobrachialis, teres major and minor, supraspinatus, infraspinatus, sub-scapularis, triceps.
            1. Subtopic 1
   3. Humerus
      1. Structure
         1. Only proximal portion affects shoulder. Landmarks--large humeral head and neck. Greater and lesser tubercles, deltoid tuberosity. Intertubercular and spiral grooves.
            1. Subtopic 1
            2. Subtopic 1
      2. Functions
         1. Provides site for several muscles to attach.
      3. Attachments
         1. Pectoralis major, latissimus dorsi, deltoid, coracobrachialis, teres major and minor, supraspinatus and infraspinatus, subscapularis.
            1. Subtopic 1
   4. Sternum
      1. Structure
         1. Flat bone. Landmarks--manubrium, clavicular notches, sternal angle.
            1. Subtopic 1
      2. Functions
         1. Provides attachment between shoulder structures and thorax.
      3. Attachments
         1. Pectoralis major, ribs, and clavicle.
            1. Subtopic 1
   5. Thorax
      1. Important because it is foundation for shoulder complex and scapulae move upon it.
         1. bony thorax
2. Joints of the Shoulder Complex
   1. Sternoclavicular
      1. Type
         1. Triaxial. Either ball- and-socket or saddle.
      2. Supporting structures
         1. Joint capsule, anterior and posterior sternoclavicular ligaments, interclavicular ligament, costoclavicular ligament, and intra-articular disk.
            1. Subtopic 1
      3. Motions
         1. Elevation and depression, protraction and retraction, upward and downward rotation.
   2. Acromioclavicular
      1. Type
         1. Gliding joint. Has fibrocartilage instead of hyaline.
            1. Subtopic 1
      2. Supporting structures
         1. Joint capsule, superior and inferior acromioclavicular ligaments, and the coracoclavicular ligament.
      3. Motions
         1. Gliding rotation about 3 axes. Allows movement between scapula and clavicle.
   3. Scapulothoracic
      1. Type
         1. Not really a joint at all. Adds to motion and stability of glenohumeral joint.
            1. Subtopic 1
      2. Allows for
         1. Allows for: elevation and depression, abduction and adduction, upward and downward rotation, anterior and posterior scapular tilt, internal and external rotation.
   4. Glenohumeral
      1. Type
         1. Triaxial ball-and-socket joint. Unstable because it is so mobile.
            1. Subtopic 1
      2. Supporting structures
         1. Joint capsule, labrum, three glenohumeral ligaments, coracohumeral ligament, and surrounding muscles. Labrum is a ring of fibrous tissue and fibrocartilage that deepens the glenoid fossa.
      3. Motions
         1. Flexion/extension, abduction/adduction, medial/lateral rotation.
3. Palpable Bony Landmarks of the Shoulder Complex
   1. Sternal notch Sternal angle Second rib Sternal end of clavicle Sternoclavicular joint Superiorr and anterior surface of the clavicle Acromion Acromioclavicular joint Coracoid process Vertebral border of the scapula Spine of the scapula Inferior angle of the scapula Axillary border of the scapula Greater and lesser tubercle of the humerus Intertubercular groove of humerus
      1. https://www.youtube.com/watch?v=vr4kbkH82ZA
         1. https://slideplayer.com/slide/4184792/
4. Vocabulary Distinctions to Note
   1. Arm-trunk motion--motion of the shoulder complex in general, describing angle between arm and trunk.
      1. Scapular elevation-- elevation of the scapula, which does not involve moving the arm.
         1. Shoulder elevation-- elevating the arm. An arm-trunk motion, not a scapular motion.
            1. Scapulohumeral rhythm--indicates the proportion of glenohumeral and scapulothoracic joint motion in shoulder motion
5. How Joints Move During Shoulder Flexion/Abduction
   1. Scapulothoracic
      1. rotates upwardly and externally
      2. tilts posteriorly
   2. Sternoclavicular
      1. elevates approximately 40°
      2. rotates upwardly
   3. Acromioclavicular
      1. scapula shifts away from clavicle with motion
6. Effects of Loss of Motion of Various Joints
   1. Glenohumeral motion loss
      1. 50–65% loss in overall shoulder flexion and abduction, loss of all normal shoulder rotation ROM.
   2. Scapulothoracic motion loss
      1. Up to 33% loss of shoulder flexion and abduction ROM. Active shoulder flexion in particular may lose up to 90 degrees of motion due to active insufficiency of the glenohumeral muscles
   3. Sternoclavicular/ acromioclavicular motion loss
      1. Up to 60 degree loss of shoulder flexion or abduction
7. Bones of the shoulder complex from musculoskeletal key
8. Motions of the scapula
9. Clinical Relevance
   1. Scapular position in shoulder dysfunction
      1. abnormal scapular positions
      2. abnormal orientation of glenoid fossa
         1. instability of glenohumeral joint
      3. shoulder impingement syndromes during active shoulder abduction
         1. excessive anterior tilting and decreased upward rotation
      4. bottomline:
         1. careful eval of scapular positions is important for patients with shoulder dysfunction
   2. Depth of the bicipital groove
      1. varies
      2. shallow groove appears to contribute in dislocations of biceps tendons
   3. Fracture of clavicle
      1. in general: sternoclavicular joint is well stabilized
         1. clavicle fractures are more common than dislocations
         2. clavicle most commonly fractured in humans
      2. trauma
         1. occurs from F applied to UE
         2. occurred by direct blow to the shoulder (falls on the shoulder)
            1. Ground F on lateral and superior aspect of acromion & clavicle
            2. forces clavicle medially and inferiorly
            3. However, joint is firmly supported against movements, so ground F tends to deform the clavicle
            4. first costal cartilage inferior to clavicle is a barrier to deformation of clavicle, so the clavicle is likely to fracture
         3. fracture
            1. occurs middle (more frequent) or lateral 1/3 of clavicle
            2. mechanism unclear
            3. bending? direct compression?
      3. bottomline: regardless of mechanism, clavicle fractures are more common than strnoclavicular joint dislocations, partially bc of the firm stabilization provided by the disc and ligaments of the sternoclavicular joint
   4. dislocation of the acromioclavicular (AC) joint
      1. common in sports injury
         1. football or rugby
      2. mechanism
         1. similar to clavicular fractures
            1. blow to or fall on the shoulder
      3. strength of coracoclavicular ligament
         1. dislocation of AC joint often occurs w/ a fracture of the coracoid process (type III dislocation) instead of disruption of ligament itself
      4. bottomline:
         1. examining, appropriate measures should be taken to determine if there's a concomitant fracture of the clavicle and/or coracoid process
   5. osteoarthritis of the acromioclavicular joint
      1. common site of osteoarthritis, in individuals who have a history of heavy labor or athletic activities
      2. normal mobility of the joint helps explain why pain and lost mobility in it from arthritic changes can produce significant loss of shoulder mobility and function
   6. adhesive capsulitis
      1. fibrous adhesions form in glenohumeral joint capsule
      2. capsule unable to unfold to allow full flexion or abduction
         1. decreased glenohumeral joint excursion
      3. classified as idiopathic (insidious onset) or secondary
         1. related to thyroid disease, diabetes, proximal humeral fracture
      4. bottomline:
         1. either idiopathic or secondary adhesive capsulitis
         2. classic findings are
            1. severe and painful lim in joint ROM
         3. patients complain of periscapular muscle pain due to overuse of these muscles in an attempt to increase shoulder complex motion through excessive scapulothoracic mvmts
   7. examining or stetching the glenohumeral joint ligaments
      1. altering pos allows to selectively assess specific portions of glenohumeral capsuloligamentous complex
         1. ex. lateral rotation reduces amount of anterior translation of humeral head by several mm
         2. direct treatment toward a particular portion of the complex
         3. anterior glide with glenohumeral joint abducted applies a greater stretch to inferior glenohumeral ligament than to superior and middle glenohumeral ligaments
      2. if clinician assesses anterior glide of the humeral head with the joint laterally rotated and does not observe a reduction in the anterior glide excursion
         1. injury to anterior capsuloligamentous complex
      3. bottomline: understand attachment sites and orientations to assess and treat different portions of the complex
         1. use this knowledge to reduce the loads on an injured or repaired structure
   8. shoulder impingement syndrome in competitive swimmers
      1. cluster of signs and symptoms that result from chronic irritation of any or all structures in subcromial space
         1. from repeated or sustained compression resulting from an intermittent or prolonged narrowing of subacromial space
      2. symptoms
         1. pain in superior aspect of shoulder beginning in midranges of shoulder elevation and worsening with increasing excursion of flexion or abduction
      3. In swimming: repeated position of shoulder abduction with medial rotation
         1. narrows subacromial space and increases risk of impingement
      4. prevention
         1. swimmers should perform strength and endurance exercises for scapular muscles so that scapular position can enhance subacromial space even as humeral position tends to narrow it
      5. others: scapulothoracic motion during shoulder elevation
         1. either excessive scapular internal rotation or anterior tilt could narrow subcromial space and produce compression of subacromial contents
         2. repeated or prolonged compression could cause inflammatory response = pain
   9. measurement of medial rotation ROM of shoulder
      1. firm manual stabilization is necessary to prevent scapula from tilting anteriorly to substitute for medial rotation
   10. Shoulder impingement syndrome is most common source of complaints
       1. associated with abnormal scapulohumeral rhythm during shoulder flexion or abduction
       2. multiple mechanical dysfunctions
10. joints of the shoulder complex
    1. https://www.youtube.com/watch?v=qnDSVhFxasQ
11. scapulohumeral rhythm
    1. Subtopic 1