Shoulder joint Flashcards
articulating surface of glenohumeral joint (shoulder joint)
synovial joint - synovial fluid produced
head of humerus articulates with glenoid fossa of scapula
both articulating surfaces covered with hyaline cartilage
glenoid fossa deepened by glenoid labrum
1:4 ratio of much larger head of humerus, so unstable joint
joint capsule + location
fibrous sheathe enclose joint (outer fibrous, inner synovial fluid) - innermost of the whole joint
from anatomical neck of humerus to glenoid fossa
lax joint capsule - movement
synovial membrane
inner surface of joint - secreting synovial fluid into the articulating surfaces - prevents friction
synovial bursae: what is it? function? location? which ones are in shoulder joint?
fluid filled sac to reduce friction between tendons and other stuctures
- subscapular
- subacromion
- subcoracoid
(3. infraspinatous - subdeltoid)
subacromial bursae
inferior to deltoid + acromion
superior to joint capsule
supports deltoid + supraspinatus muscles
inflammation of bursa causes shoulder problems
Glenohumeral joint
ball & socket joint
between glenoid fossa of scapula and head of humerus
connects upper limb to trunk
mobile, not stable
subscapular bursae
between subscapularis tendon + scapula (top of scapular, below tendon)
reduces wear + tear of tendon during movement of shoulder joint
name the 3 ligaments involved in the shoulder joint
- glenohumeral ligament
- coracoacromial ligament
- transverse humeral ligament
glenohumeral ligament
has 3 bands: superior, middle, inferior
stabilises anterior aspect of shoulder joint
like joint capsule, runs from glenoid fossa to anatomical neck of humerus
coracohumeral ligament
attach base of coracoid process (scapula) to greater tubercle of humerus
support superior part of joint capsule (top)
transverse humeral ligament
spans distance between 2 tubercles of humerus, holding tendon of LONG head of biceps in intertubercular groove
coracoacomial ligament
acromion to coracoid process (both scapula)
prevents SUPERIOR displacement of humeral head
forms CORACOACROMIAL ARCH
arterial supply to glenohumeral joint
anterior + posterior circumflex humeral arteries
suprascapular artery
both have branches that anastomose around the joint
nerve supply to the glenohumeral joint
axillary, suprascapular, lateral pectoral nerves
roots C5, C6 of brachial plexus
upper brachial plexus injury (Erb’s palsy) affect should joint function
factors contributing to stability of shoulder joint
- type of joint - ball + socket
- bony surfaces - shallow glenoid cavity + large humeral head (1:4)
- laxity of joint capsule
factors that contribute to stability
- rotator cuff muscles - fusing joint capsule with tubercles of humerus, resting tone ‘pull’ humeral head into glenoid cavity
- glenoid labrum - fibrocartilaginous ridge surrounding glenoid cavity - making it deeper
- ligaments - reinforce joint capsule, forms coracoacromial arch
dislocation of should joint
humeral head in relation to infraglenoid tubercle
what is dislocation of the shoulder joint described in relation to?
head of humerus to infraglenoid tubercle (glenoid fossa ?)
which dislocation is the most common dislocation?
why doesn’t superior dislocation happen often?
anterior dislocation
superior movement of the humeral head prevented by coraco-acromial arch
what is anterior dislocation usually caused by?
what happens to the humeral head
excessive extension + lateral rotation of humerus
humeral head forced anteriorly + inferiorly - to weakest part of joint capsule
long term consequences of dislocation?
recurrent dislocation as tear of joint capsule leads to increased risk of future dislocation
which nerve can be damaged during dislocation of shoulder and what does it lead to?
axillary nerve - close to head of humerus
paralysing deltoid + loss of sensation over regimental badge area
radial nerve can be stretch as bound tightly to radial groove
rotator cuff tendonitis
rotator cuff muscles stabilise glenohumeral joint
tendonitis - inflammation of muscle tendons (from overuse)
can cause degenerative change in subacromial bursa (bursa under acromion) + supraspinatus tendon
cause friction
characteristic sign of rotator cuff tendonitis
painful arc
pain in middle of ABduction
affected area comes in contact with the acromion
