Glenohumeral Anatomy

Glenohumeral Anatomy

1. Motion

   • Abduction/Adduction
     • convex on concave
     • frontal plane
     • aB
       • with IR: 60 degrees
       • with ER: 120 degrees
         • or 180
     • aD
       • 30 degrees
   • Flexion/Extension
     • convex on concave
     • flex: 120
       • or 180
     • ext: 30
       • or 60
     • sagittal plane
   • IR/ER
     • spin in place
     • transverse plane
     • with arm abducted
       • ER: 90
       • IR: 80
   • Horizontal aB/aD
     • convex on concave
     • transverse plane
     • at 90 degrees aB
       • aB: 30-45
       • aD: 140

2. Muscles

   • Accessory N.
     • traps
       • upper: elevation & UR middle: retraction lower: depression & UR
   • Dorsal Scap
     • levator scapulae
       • elevation & DR
     • rhomboids
       • major: retraction & DR minor: retraction
   • Long thoracic
     • serratus anterior
       • protraction & UR
   • Medial Pectoral
     • pectoralis minor
       • DR, protraction, & depression
   • Subclavius
     • subclavius
       • SC joint stability
   • Axillary
     • Deltoid
       • anterior: elevation, horizontal add middle: abduction posterior: extension, horizontal abd
     • teres minor
       • ER, horizontal abd
   • Lateral Pectoral
     • pectoralis major
       • horizontal add, add, IR
   • Musculocutaneous
     • coracobrachialis
       • flexion, horizontal add
     • biceps
       • flexion
   • thoracodorsal
     • lat
       • extension, IR, add
   • Subscapular
     • teres major
       • add, extension, horizontal abd, IR
     • subscapularis
       • IR, horizontal add
   • Suprascapular
     • supraspinatus
       • abduction
     • infraspinatus
       • ER, horizontal abd
   • Radial
     • tricpes
       • extension, adduction
     • Brchioradialis

3. Ligaments

   • Superior Glenohumeral
     • blends with labrum, long head of biceps & coracoid process inserts into lesser tuberosity
     • prevent inferior translation
     • resists ER in adduction
   • Middle Glenohumeral
     • middle of anterior glenoid rim inserts onto lesser tuberosity
     • sits at 1-3 oclock on R UE
     • resist inferior translation during abd/ER
     • resist anterior tranlation
   • Inferior Glenohumeral
     • Anterior 2-4, posterior 7-9 o'clock
       • axillary pouch between
     • stabilizes against anterior and posterior translation
   • Cracohumeral
     • lateral coracoid anterior portion of humerous -blends btwn supraspinatus and infraspinatus
     • suspend arm against gravity
     • limit flexion, ER, and ext
   • Transverse Humeral
     • crosses intertubercular groove
     • controls long head of biceps position

4. Bursae

   • Subacromial
     • largest bursa in the body
     • inflammation-> decreased ROM -> decreased strength -> dysfunction
     • subdeltoid, subacromial and subcoracoid
   • Subscapularis
     • protects subscap tendon
   • Infraspinatus
     • btwn infraspinatus and joint capsule
   • Scapular
     • may cause scapular crepitis

5. Soft Tissue

   • Labrum
     • increases depth of rim -50% of depth weak and tears easily
   • Capsule
     • abduction: tight inferior; joint compression ER: tight anterior IR: tight posterior
     • thickest superior & inferior
       • inferior folds onto itself frequent site of adhesion
     • at rest: tight superior and lateral
     • maximum tightness: extreme abduction & ER