1. Les deux coiffes de l’épaule! Olivier Gagey Hôpitaux Universitaires Paris-Sud
2. Ce n’est pas une faute d’orthographe! A coté de la coiffe des rotateurs, il nous faut examiner la muscle deltoïde dans ses rapports avec l’extrémité supérieure de l’humérus !
3. Comprendre le rôle de la coiffe L’anatomie et la fonction ligamentaire sont une clef de lecture !
4. La fonction de la coiffe se comprend à partir de celle des ligaments Au repos aucun ligament articulaire n’est tendu
7. Le labrum et le vide intra articulaire Le labrum accroît discrètement la congruence. Si le phénomène de vide est bien documenté son importance quantitative reste non élucidée
25. Le deltoïde Modèle en éléments finis, la coiffe ne « travaille pas » Pas de lien mécanique significatif entre tête et glène.
26. En résumé Le deltoïde seul est capable de stabiliser la tête et de permettre au moins 60° d’élévation de l’humérus.
27. En clinique L’immense majorité des épaules fonctionnent bien en dépit de lésions sévères de la coiffe, sous condition d’indolence ! Comment l’expliquer ?
31. Le deltoïde Le verrou contribue à diminuer la pression de la tête sous l’acromion
32. Le deltoïde Le deltoïde fait de même en raison de la pression qu’il exerce sur ce large interface
33. La bourse sous deltoïdienne Les forces créées par le deltoïde transitent par la bourse !
34. Le deltoïde (moyen et antérieur) agit sur la tête par l’intermédiaire de la bourse séreuse Bourse injectée avec du sérum
35. La bourse s’interpose entre deltoïde et humérus dans la zone de plus grande réflexion du muscle En avant et arrière de la bourse il n’y a que du conjonctif
36. La bourse s’interpose entre deltoïde et humérus dans la zone de plus grande réflexion du muscle Bursographie « Naturelle »
37.
38. L’articulation sous deltoïdienne (De Sèze) La bourse contient des terminaisons nerveuses libres (douleur) Le tendons n’ont pas d’innervation douloureuse ! En outre
To understand functional anatomy of the cuff is challenging
When the arm is at rest along the chest wall, there are no tensed ligaments
When the arm is at rest along the chest wall, there are no tensed ligaments
When the arm is at rest along the chest wall, there are no tensed ligaments
When the arm is at rest along the chest wall, there are no tensed ligaments
Tension of the glenohumeral ligaments occurs only above 60° elevation. Note in addition that ther are no landmark to differentiate middle from inferior glenohumeral ligaments.
Obviously the labrum and the vacuum phenomenon play a role in stabilizing the joint but we should assume that it of poor importance.
The biomechanical challenge is also provided by the absence of congruence between the joint surfaces how to stabilize an orange in the front of a vertical dishe?
The coracoacromial arch is in close contact of the upper end of the humerus even in anatomic specimens (ie in absence of any muscle contraction), this is due to the vacuum phenomenon.
The coracohumeral ligament is equiped with proprioception receptors (accordin Golcke) this indicates that the ligament is involved in the control of movement.
The CA arch provides additional control in a second direction.
To understand the stabilization mechanism we should consider two cuff working aroune the humeral head
The first one is a pulling cuff with four powerful muscles, the second one is the deltoideus
The anterosuperior fibrous lock is oh high importance. It includes the upper tendon of subscapularis, the anterior part of the supraspinatus tendon, thelong part of biceps brachialis the superior glenohumeral ligmanent and the coracohumeral ligament. The deltopectoral approach weakens the fibrous lock which failure leads, for instance, to the migration of the prosthetic head.
The rotator cuff includes four muscles with a complex deep fibrous structure inside that changes the mechanical properties : increased strenght and shorter course
The rotator cuff includes four muscles with a complex deep fibrous structure inside that changes the mechanical properties : increased strenght and shorter course
The cuff has two functions : on one hand to pull the head and press it agains the glenoid on the other to provide external rotation
Lateral rotation contributes a great deal to the elevation of the hand,
The deltoideus wraps itself around the upper end of the humerus this is true from the beginning of the elevation until 60°
The middle part of the deltoideus has strong fibrous bands. No such bands exist in the anterior nor in the posterior deltoideus.
Middle deltoideus is a multipennate muscle (high strenght with short course), this part of the muscle is the main elevator of the humerus The contraction of the deltoideus crates an « inflatable cuff » around the upper end of the humerus
The resultant deltoideus force allied to the upper end of the humerus pushes the head downward whereas it pulls the humeral shaft upwards. This was demonstrated by Duchenne de Boulogne at the end of the eighteen century
The resultant deltoideus force allied to the upper end of the humerus pushes the head downward whereas it pulls the humeral shaft upwards. This was demonstrated by Duchenne de Boulogne at the end of the eighteen century
The resultant deltoideus force allied to the upper end of the humerus pushes the head downward whereas it pulls the humeral shaft upwards. This was demonstrated by Duchenne de Boulogne at the end of the eighteen century
The resultant deltoideus force allied to the upper end of the humerus pushes the head downward whereas it pulls the humeral shaft upwards. This was demonstrated by Duchenne de Boulogne at the end of the eighteen century
The resultant deltoideus force allied to the upper end of the humerus pushes the head downward whereas it pulls the humeral shaft upwards. This was demonstrated by Duchenne de Boulogne at the end of the eighteen century
The resultant deltoideus force allied to the upper end of the humerus pushes the head downward whereas it pulls the humeral shaft upwards. This was demonstrated by Duchenne de Boulogne at the end of the eighteen century
The resultant deltoideus force allied to the upper end of the humerus pushes the head downward whereas it pulls the humeral shaft upwards. This was demonstrated by Duchenne de Boulogne at the end of the eighteen century
The resultant deltoideus force allied to the upper end of the humerus pushes the head downward whereas it pulls the humeral shaft upwards. This was demonstrated by Duchenne de Boulogne at the end of the eighteen century
The resultant deltoideus force allied to the upper end of the humerus pushes the head downward whereas it pulls the humeral shaft upwards. This was demonstrated by Duchenne de Boulogne at the end of the eighteen century
The resultant deltoideus force allied to the upper end of the humerus pushes the head downward whereas it pulls the humeral shaft upwards. This was demonstrated by Duchenne de Boulogne at the end of the eighteen century
The resultant deltoideus force allied to the upper end of the humerus pushes the head downward whereas it pulls the humeral shaft upwards. This was demonstrated by Duchenne de Boulogne at the end of the eighteen century
The resultant deltoideus force allied to the upper end of the humerus pushes the head downward whereas it pulls the humeral shaft upwards. This was demonstrated by Duchenne de Boulogne at the end of the eighteen century
The deltoideus acts on the humerus through the subdeltoid bursa. A painfull bursa may be responsible of inhibition of the middle deltoideus that explains mainy cases of pseudoparalytic shoulders.
The deltoideus acts on the humerus through the subdeltoid bursa. A painfull bursa may be responsible of inhibition of the middle deltoideus that explains mainy cases of pseudoparalytic shoulders.
The deltoideus acts on the humerus through the subdeltoid bursa. A painfull bursa may be responsible of inhibition of the middle deltoideus that explains mainy cases of pseudoparalytic shoulders.
Ther is a true joint organisation under the deltoideus as emphasized by De Sèze (the fifth joint of the shoulder) with full congruency, synovial tissue and mechanoreceptors.
Ther is a true joint organisation under the deltoideus as emphasized by De Sèze (the fifth joint of the shoulder) with full congruency, synovial tissue and mechanoreceptors.