Shoulder region Flashcards
which bones make up the shoulder region (pectoral girdle)?
Clavicle, scapula and proximal humerus (also sternum, rubs and thoracic vertebral column need to be considered)
what are the joints of the shoulder region?
sternoclavicular, acromioclavicular! glenouhumeral joints
What is the scapular plane?
30 degrees internally rotated from frontal plane, normal position of scapula in anatomical position
What type of joint is the SCJ?
a stable, biaxial joint
synovial saddle joint
what bone is the SCJ between?
between the clavicle and the sternum & 1st costal cartilage
what are the movements of the clavicle?
elevation, depression
protraction + retraction
conjunct rotation
what cause conjunct rotation of the clavicle?
conoid ligament (coracoid process to inferior+posterior point of the lateral convex curve of clavicle)
tightening of ligament results in conjunct rotation
what are the bones that articulate the acromioclavicular joint?
distal end of clavicle and medial aspect of acromion process
what type of joint is ACJ?
synovial plane joint (no bony stability)
what are the coracoclavicular ligaments and what are their functions?
conoid ligament and trapezoid ligament
Conoid ligament suspends scapula and resists superior glide of lateral clavicle
trapezoid ligament resists medial glide of the scapula relative to the clavicle
what type of joint is the GHJ?
ball and socket multiaxial diarthrosis
what are the axioclavicular/axioscapular muscles?
- upper fibres of trapezius
- subclavius
- pec minor
- serrated anterior
what are the actions of serrated anterior?
scapular protraction (primary muscle), scapular upward rotation
holds media, border of scapula against thorax
what is the paradoxical scapular position during movement?
downward rotation, anterior tilt and internal rotation
what are the posterior axioclavicular/axioscapular muscles?
- upper traps
- middle traps
- lower traps
- levator scapulae
- rhomboid minor
- rhomboid major
describe the movements of the trapezius muscles
All 3 muscles contribute to scapular retraction
All 3 muscles contribute to scapular upward rotation (to a lesser degree)
upper traps contributes to scapular elevation (due to upward direction of fibres)
lower traps contribute to scapular depression (due to downward rotation of fibres)
what are the actions of levator scapulae, and the rhomboid muscles?
all 3 muscles produce scapular retraction (levator scapulae is weak contributor to this action)
all 3 muscles produce downward rotation (opposite to traps)
all produce scapular elevation due to superior line of action
what is the normal scapular movement during scapular plane abduction?
upward rotation, posterior tilt, external rotation
how is scapular posterior tilt produced?
the synergy between serratus anterior and lower traps
how is scapular external rotation achieved
serratus anterior and middle traps force couple (synergy)
what effects does subacrimial impingement syndrome have on muscle movements?
less scapular upward rotation and external rotation
more clavicular elevation and retraction
scapular muscle activity ratios were altered
What is the muscle synergy of downward rotation?
protraction from pec minor and
retraction from levitation scapulae and rhomboids cancel each other
Describe movement of the different parts of deltoid
anterior deltoid contribute to flexion, abduction, horizontal flexion and medial rotation
middle deltoid is a prime abductor
posterior deltoid contributes to extension, abduction, horizontal extension and lateral rotation
What do rotator cuff muscles have in common?
All rotator cuff muscles have a medial line of action which produces compression of the GH joint
