Shoulder joint Flashcards
six scapulohumeral muscles
- subscapularis
- supraspinatus
- infraspinatus
- teres major
- teres minor
- deltoid
rotator cuff SITS muscles
- supraspinatus
- infraspinatus
- teres minor
- subscapularis
function of SITS muscles
to hold the humeral head in the glenoid cavity of the scapula
supraspinatus origin
supraspinous fossa of scapula
supraspinatus insertion
superior facet of greater tubercle of humerus
goes through capsule of shoulder joint
supraspinatus innervation
suprascapular nerve
supraspinatus action
- aids deltoid in abduction of arm
- stabilises shoulder joint
- acts with rotator cuff muscles
infraspinatus origin
infraspinous fossa of scapula
infraspinatus insertion
- middle facet of greater tubercle of humerus
- through capsule of shoulder joint
infraspinatus innervation
suprascapular nerve
infraspinatus action
- lateral rotation of humerus
- stabilises shoulder joint
- acts with rotator cuff muscles
teres minor origin
middle part of lateral border of scapula
teres minor insertion
- inferior facet of greater tubercle of humerus
- through capsule of shoulder joint
teres minor innervation
axillary nerve
teres minor action
- lateral rotation of humerus
- stabilises shoulder joint
- acts with rotator cuff muscle
subscapularis origin
subscapular fossa
subscapularis insertion
- lesser tubercle of humerus
- fuses with capsule of shoulder joint
subscapularis innervation
subscapular nerve
subscapularis action
- medial rotation of humerus
- acts with rotator cuff muscles
- helps hold head of humerus in glenoid cavity
SITS movement
- all except supraspinatus are rotators of humerus
- supraspinatus initiates and assists deltoid in arm abduction
teres major origin
- posterior surface of inferior angle of scapula
- inferior 1/3 of lateral border of scapula
teres major insertion
medial lip of bicipital groove of humerus
teres major innervation
lower subscapular nerve
teres major action
- medial rotation of arm
- adduction of arm
deltoid
divided into 3 parts
- anterior (clavicular)
- posterior (spinal)
- middle (acromial part)
forms rounded contour of shoulder
deltoid origin
- lateral 1/3 of clavicle
- acromion
- spine of scapula
deltoid insertion
deltoid tuberosity of humerus
deltoid innervation
axillary nerve
deltoid action
- clavicular/anterior: flexion, medial rotation
- acromial/middle: abduction
- spinal/posterior: extension and lateral rotation of arm
articulations of the glenohumeral joint
head of humerus with glenoid cavity of scapula
what type of joint is the glenohumeral joint?
Synovial, ball-and-socket
what is the glenoid labrum
fibrocartilaginous tissue within the glenoid cavity of shoulder joint
attaches to edges of glenoid cavity
function of glenoid labrum
- deepen glenoid cavity
- provide stability and shock absorption to shoulder
- protects shoulder against dislocation
anterior support tendon of GH joint
subscapularis tendons
posterior support tendon of GH joint
teres minor and infraspinatus tendons
superior support tendon of GH joint
supraspinatus tendon
ligaments of GH joint
- coracohumeral ligament
- transverse humeral ligament
- superior glenohumeral ligament
- middle glenohumeral ligament
- inferior glenohumeral ligament
coracohumeral ligament
- Coracoid process to greater tubercle
- Stabilises joint superiorly
Transverse humeral ligament
- Bridges the intertubercular groove
- Holds tension of long head of biceps brachii in bicipital groove
glenohumeral ligament
- 3 ligaments representing thickenings of the anterior portion of the articular capsule
- Stabilise joint anteriorly
- Superior, middle, inferior
- Pass from superomedial margin of glenoid cavity to the lesser tubercle and anatomical neck of humerus
coracoacromial arch
- acromion
- coracoid process
- coracoacromial ligament
Tendon that restricts upper movement of the humeral head on glenoid cavity
Tendon of the long head of biceps brachii
Subacromial/subdeltoid bursa
- Between acromion or deltoid and supraspinatus tendon
- Inflammation of this bursa can cause sever shoulder problems
Blood supply to GH joint
- Circumflex humeral arteries
- Branches of axillary and suprascapular arteries
Innervation of GH joint
Small branches of:
- axillary nerves
- Subscapular nerves
- Musculocutaneous nerves
- Pectoral nerves
- Suprascapular nerves
Shoulder dislocation
- displacement of humeral head from glenoid cavity
- rotator cuff stabilises shoulder joint
- weakest inferiorly and anteriorly
- humeral head break through joint capsule below glenoid cavity
