14 - Axilla and Shoulder Flashcards
acromioclavicular joint
- Synovial plane joint
- primarily supported (reinforced) by extrinsic ligaments: Coracoclavicular ligament (two strong ligaments between the coracoid process and clavicle -Conoid ligament and Trapezoid ligament)
sternoclavicular joint
- Synovial saddle-shaped joint
- Articular surfaces: manubrium, first costal cartilage and the sternal end of clavicle
- Only articulation between the upper limb and axial skeleton
- Strongly supported by ligaments and very rarely dislocated
which joints are required for movement of the scapula
sternoclavicular and acromioclavicular joints
anterior thoracoappendicular muscles (4)
Pectoralis major
Pectoralis minor
Subclavius
Serratus anterior
posterior thoracoappendicular muscles (5)
Trapezius Latissimus dorsi Levator scapulae Rhomboideus major Rhomboideus minor
scapulohumeral muscles (3)
Deltoid
Rotator cuff (Supraspinatus, Infraspinatus, Teres minor, Subscapularis)
Teres major
trapezius innervation and actions
INNERVATION- Spinal accessory n. (CN XI), C3, C4
ACTIONS -
Superior fibres - elevate scapula
Middle fibres - retract scapula
Inferior fibres - depress scapula
Sup. & Inf. fibres - rotate scapula glenoid-up
latissimus dorsi innervation and actions
INNERVATION- Thoracodorsal n.
ACTIONS- extend, adduct & medially rotate humerus at glenohumeral joint
- Forms posterior axillary fold along with teres major m.
levator scapulae innervation and actions
INNERVATION- Dorsal scapular n.
ACTIONS- elevate scapula, rotate scapula glenoid-down
rhomboideus minor innervation and actions
INNERVATION- dorsal scapular n.
ACTIONS - retract scapula, rotate scapula glenoid-down, hold scapula to thoracic wall
rhomboideus major innervation and actions
INNERVATION- dorsal scapular n.
ACTIONS - retract scapula, rotate scapula glenoid-down, hold scapula to thoracic wall
deltoid innervation and actions
INNERVATION - axillary nerve
ACTIONS -
Anterior fibers - flex & medially rotate arm
Middle fibers- abduct arm ((5)15 - 90°)
Posterior fibers - extend and laterally rotate arm
teres major
INNERVATION- lower subscapular nerve
ACTIONS - adduct and medially rotate arm
- Forms posterior axillary fold along with latissimus dorsi
Rotator cuff
There are four rotator cuff muscles. Three of them act to rotate the arm. All of the tendons of the muscles of the rotator cuff blend with and reinforce the fibrous joint capsule of the glenohumeral joint (i.e., they form a ‘cuff’ around the shoulder joint).
The rotator cuff muscles are the PRIMARY support of the glenohumeral joint. All are innervated by C5 & C6 ventral rami.
subscapularis O, I, A
O - subscapular fossa of scapula
I - lesser tubercle of humerus
ACTIONS - medial rotation & adduction of arm
infraspinatus O, I, A
O - infraspinous fossa of scapula
I - greater tubercle of humerus ACTIONS - lateral rotation of arm