Joints of UE Flashcards
What are the joints in the pectoral girdle?
Sternoclavicular (SC) joint
Acromioclavicular (AC) joint
Scapulothoracic (ST) joint
Glenohumeral (GH) joint
Why is the ST joint not considered a true joint?
Because the scapula has no direct bony connection to the thorax, it is a physiological joint reflecting how the scapula moves relative to the thorax
What are the movements of the scapula?
elevation/depression
retraction/protraction
upward rotation/downward rotation
What muscles elevate the scapula?
superior fibers of trapezius
levator scapulae
What muscles cause scapular depression?
inferior fibers of trapezius
pectoralis minor
What muscles retract the scapula?
middle fibers of trapezius
rhomboid minor and major
What muscles protract the scapula?
pectoralis minor
serratus anterior
What muscles perform upward rotation of the scapula?
serratus anterior
superior and inferior fibers of trapezius
What muscles perform downward rotation of the scapula?
levator scapulae
rhomboid minor and rhomboid major
For every 2 deg of glenohumeral movement there is…
1 deg of scapulothoracic movement
Sternoclavicular (SC) joint
synovial joint with an articular disc
movements: anterior/posterior
elevation/depression
sternoclavicular joint injury
dislocations uncommon due to strength of capsular ligaments, more likely that clavicle will frx.
What are the ligaments of the SC joint?
costoclavicular ligament
capsular ligament
Acromioclavicular (AC) joint
synovial joint with an articular disc
primary movement: rotation of the acromion on the clavicle
What are the ligaments of the AC joint?
acromioclavicular ligament -reinforces joint
coracoclavicular ligament - prevents medial movement of the scapula relative to the clavicle
Dislocation of the AC joint
shoulder seperation
acromioclavicular ligament can tear or rupture through a direct blow or fall on a shoulder or outstretched hand
if the coracoclavicular ligaments also tears/ruptures- the shoulder will separate from the clavicle
Glenohumeral joint
ball &socket joint with glenoid labrum
What is the glenoid labrum?
fibrocartilaginous ring that acts to deepen the glenoid cavity
What movements occur at the GHJ?
flexion/extension
abduction/adduction
medial rotation/lateral rotation
What muscles flex the GHJ?
pectoralis major
anterior deltoid
coracobrachialis
biceps brachii (weakly)
What muscles extend the GHJ?
Posterior deltoid
latissimus dorsi
long head of triceps brachii
What muscles abduct the GHJ?
supraspinatus- initial 15deg
deltoid- after 15deg
What muscles adduct the GHJ?
pectoralis major
latissimus dorsi
subscapularis
teres major
What are the ligaments of the GHJ?
capsular: coracohumeral, glenohumeral, transverse humeral
extracapsular: coracoacromial
How can rotator cuff muscles be injured?
repetitive use
tendon of supraspinatous muscle is most frequently torn
Dislocation of GHJ
ligaments and tendons do not cross the GHJ inferiorly, therefore the inferior aspect of the capsule is weakest, most dislocations occur “anteriorly”
Anterior GHJ dislocations endangers which vessels?
musculocutaneous n.
branches of axillary a.
What vessels are endangered by surgical neck fracture?
axillary n.
circumflex humeral aa.
What vessels are endangered by mid shaft humeral fracture?
radial n. and deep artery and vein of the arm
What vessels are endangered by surgical supracondylar fracture?
median n. and brachial a.
What vessels are endangered by surgical medial epicondyle fracture?
ulnar n.
Elbow joint
hinge synovial joint
fibrous capsule encloses both elbow & proximal radioulnar joints
very stable in adults, less stable in children
capitulum of the humerus articulates with…
the radial head
trochlea of the humerus articulates with…
the ulna
What movements occur at the elbow joint?
flexion/extension
What are the ligaments of the elbow joint?
ulnar (medial) collateral ligament
radial (lateral collateral ligament)
anular ligament
What muscles flex the elbow?
biceps brachii
brachialis
brachioradialis
What muscles extend the elbow?
triceps brachii
Does the ulna or radius stay stable when rotating?
the ulna
Proximal and Distal radioulnar joints
synovial joints
movements: pronation/supination
Pulled or nursemaid’s elbow
subluxation (partial dislocation) of the radial head from the anular ligament, most common in preschool children, may tear anular ligament
Wrist (Radiocarpal) joint
synovial joint between the distal radius, articular disc, scaphoid, lunate and triquetrum
What movements occur at the wrist (radiocarpal) joint?
flexion/extension
abduction/adduction
Colles fracture
distal radius fracture
mechanism: FOOSH
associated with “dinner fork deformity” : a posterior displacement of the distal fragment, causing angulation
scaphoid fracture
most frequently fractured carpal bone
mechanism: FOOSH
avascular necrosis is a potential complication of this injury
Anterior dislocation of the lunate
occurs when landing on the dorsal side of the wrist, lunate is pushed anteriorly, compressing contents of the carpal tunnel, esp. the median nerve
Mallet finger
Avulsion of the extensor expansion at the level of the DIP
digit flexed at DIP due to unopposed contraction of flexor digitorum profundus
Boutonniere deformity
avulsion of extensor expansion at the level of the PIP
extensor expansion is still attached distally at the level of the DIP
