Shoulder Joint Complex GH JOINT Flashcards
Shoulder complex comprises of:
humerus scapula clavicle sternum 1st rib
how many joints?
3 physiologic
1 functional
3 physiologic joints
Glenohumeral Joint (GH)
Sternoclavicular (SC)
Arcrominoclavicular (AC)
1 Functional joint
Scapulothroacic joint (no bony connections between the scapula and thorax)
the complex is designed to
facilitate upper extremity mobility
NOT designed for stability
Osteology of the shoulder complex
humerus scapula clavicle sternum 1st rib
The most common sight of humeral fracture
surgical neck
inferior to greater and lesser tubercles
Glenohumeral Joint is
a synovial ball and socket joint
between the head of the humerus and the glenoid cavity of the scapula
Maintains ____ degrees of freedom
3! degress of freedom
physiologic motions
flexion/extension
ABduction/ ADduction
internal (medial)/ external (lateral) rotation
Circumduction- (combo of motions NOT a degree of freedom)
a wide range of movements provided at the cost of
skeletal stability
joint stability is provided by:
the rotator cuff muscles, long head of the biceps, related bony processes, and extra scapular ligaments
articular surfaces ar:
glenoid fossa of the scapula
sperical humeral head
Glenoid fossa is:
long longitudinally
narrow transversely
shallow
covers only 1/3rd of the articular surface of the humeral head
humeral head
large in size and spherical
longitudinal diameter is 2x greater than the fossa
the glenoid cavity is deepened and expanded peripherally by:
a fibrocartilagenous collar: glenoid labrum that attaches to the margin of the fossa
associated GH structures superficial to deep
- Coracohumeral ligament
- Joint Capsule (outer fibrous capsule, inner synovial membrane)
- glenohumeral ligaments
- tendon of the long head of the biceps
- glenoid labrum
- glenoid cavity
5th rotator cuff muscle
long head of the biceps brachii
the joint capsule is:
tigher superiorly
looser inferiorly
A looser inferior joint capsule:
accomadates ABduction of the arm
Bursae are:
where the synovial membrane protrudes through apertures in the fibrous membrane
they lie between the tendons of surrounding muscles and the fibrous membranes
most consistant bursae
subtendinous bursa of subscapularis
synovial structures do what?
reduce friction between the tendons and adjacent joint capsule and bone
Associated GH structures
- Coracohumeral ligament
- Joint Capsule (outer fibrous capsule, inner synovial membrane)
- glenohumeral ligaments
- tendon of the long head of the biceps
- glenoid labrum
- glenoid cavity
I. Coracohumeral joint
thickening of the fibrous joint capsule
attaching from the coracoid process to the greater tubercle
maintaining the position of humeral head in fossa and limits superior translation of the humeral head
IIa. outer fibrous joint capsule
attaches to the margin of the glenoid cavity and anatomical neck of the humerus
taught superiorly
loose-fitting inferiourly
static restraint that limits motion and stabilizes the joint
IIb. inner synovial membrane
secretes synovial fluid and serves to reduce frictional forces
portion of the synovial membrane forms the synovial sheath that encloses the tendon of the long head of the biceps
(axillary pouch)
inferior redundant fold of the fibrous capsule and synovium
facilitates humeral elevation without stretching/tearing of the capsule
III. 3 glenohumeral ligaments
run from the glenoid rim to the anatomical neck of humerus
- Superior GH
- Middle GH
- Inferior GH
- Superior GH
provide stability anterosuperiorly
- Middle GH
provides stability anteriorly but is often poorly developed or absent
- Inferior GH
strongest and most important
anterior & posterior bands plus the capsular pouch (inferior glenohumeral complex)
provide stability anteriorly and inferiorly
Inferior glenohumeral complex works:
acts like a hammock to provide anterior & superior stability
ALWAYS taut in humeral abduction
the anterior band is the:
primary static restraint to anterior translation of the humeral head
IV. Tendon of the long head of the biceps
attaches to the supraglenoid tubercle of the glenoid fossa
travels through the joint capsule
through the intertubercular groove
to meet with the short head of the biceps
held in place by the transverse humeral ligament
and by the tendon of the pec MAJOR
V. glenoid labrum
ring of fibrocartilage attaches to rim of fossa
extends, deepeneds fossa
improving stability
VI. Glenoid cavity
most deep structure
Coracromial Arch formed by:
osseoligamentous structure formed by:
coracoid process
acromion process
coracromial ligament
Forms a:
bony-ligamentous roof-over the subacromial bursa and the tendon insertions of the supraspinatus & LH biceps
what does it do good/bad?
good: protects the subacromial structures from direct trauma from above
bad: GH instability can lead to impingement of structures in the subacromial space
subacromial/subdeltoid bursa:
-between acromion process and deltoid &
the humeral head and supraspinatus tendon
-tendon insertions of supra and infra spinouts
-tendon of LH of biceps
innervation to the GH
sensory innveration: supraspacular and axillary nerves
GH artthrokinematics
abduction/ adduction
External/ internal rotation
flexion/ extension
Shoulder ADduction
convex humeral head rolls superiorly and glides inferiorly on the concave glenoid fossa
Shoulder ABduction
convex humeral head rolls inferiorly and glides superiorly on glenoid fossa
External rotation
covex humeral head rolls posteriorly and glides anteriorly on the fossa
Internal rotation
convex humeral head rolls anteriorly and glides posteriorly on the fossa
Flexion and extension
sagittal plane involves the spin of the coves humeral head on the concave glenoid fossa
