2. • DEFINITION; The glenohumeral joint is a balland-socket type of synovial joint that permits
a wide range of movement; however the
mobility makes the joint relatively unstable.
• Joint stability is provided, instead, by the
rotator cuff muscles, the long head of the
biceps brachii muscle, related bony processes,
and extra-capsular ligaments.
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3. • ARTICULATION; The articular surfaces of the
glenohumeral joint are the large spherical head
of the humerus and the small glenoid cavity of
the scapula.
• Each of the surfaces is covered by hyaline
cartilage.
• The glenoid cavity is deepened and expanded
peripherally by a fibro-cartilaginous collar (the
glenoid labrum), which attaches to the margin of
the fossa.
• Superiorly, this labrum is continuous with the
tendon of the long head of the biceps brachii
muscle, which attaches to the supraglenoid
tubercle and passes through the articular cavity
superior to the head of the humerus.
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5. • CAPSULE; a loose fibrous capsule surrounds
the glenohumeral joint and is attached;
• Medially to the margin of the glenoid cavity.
• Laterally to the anatomical neck of the
humerus.
• Superiorly, the capsule encroaches on the
root of the coracoid process so that the
fibrous capsule encloses the proximal
attachment of the long head of biceps brachiisupraglenoid tubercle of scapula.
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7. • LIGAMENTS; the fibrous membrane of the
joint capsule is thickened and strengthened by
ligaments.
a. The glenohumeral ligaments are three
fibrous bands.
Anterosuperiorly found in three locations to
form superior, middle, and inferior
glenohumeral ligaments, which pass between
the superomedial margin of the glenoid cavity
to the lesser tubercle and inferiorly related
anatomical neck of the humerus.
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8. b. The coracohumeral ligament; found superiorly
between the base of the coracoid process and the greater
tubercle of the humerus.
c. The transverse humeral ligament; a broad fibrous
band that runs more or less obliquely from the greater to
the lesser tubercle of the humerus, bridging over the
intertubercular groove.
The ligament converts the groove into a canal that
holds the synovial sheath and tendon of the biceps
brachii in place during movements of the glenohumeral
joint.
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9.
10. INNERVATION
•
•
•
•
•
The Glenohumeral Joint is innervated by;
The suprascapular,
Axillary,
Lateral pectoral and
Branches from the posterior cord of brachial
plexus.
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11. MOVEMENTS OF THE GLENOHUMERAL JOINT
• The glenohumeral joint has more freedom of
movement than any other joint in the body.
• The glenohumeral joint allows movements
around three axes and permits:
• Flexion-extension
• Abduction-adduction
• Rotation (medial and lateral) of the humerus
• Circumduction
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12. MUSCLES INVOLED IN THE MOVEMENTS
• Flexion; clavicular part of the pectorialis
major.
• Anterior fibre of deltoid muscle.
• Coracobrachialis.
• Biceps brachii.
Both are synergist.
• Extenson; posterior part of the deltoid muscle
assisted by the teres major muscle.
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13. • Abduction; the central part of the deltoid
muscle,
• Synergized by the supraspinatus muscle.
• Adduction; pectorialis major and latissimus
dorsi,
• Assisted by the subscapularis, infraspinatus
and teres minor muscles.
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14. • Medial rotation; subscapularis,
• Assisted by pectorialis major, anterior fibre of
deltoid and latissimus dorsi.
• Lateral rotation; infraspinatus muscle,
• Synergized by posterior fibre of deltoid and
the teres minor muscle.
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15. Note;
• Joint stability is provided by surrounding
muscle tendons and a skeletal arch formed
superiorly by the coracoid process, acromion
and the coraco-acromial ligament.
• Tendons of the rotator cuff muscles (the
supraspinatus, infraspinatus, teres minor, and
subscapularis muscles) blend with the joint
capsule and form a musculotendinous collar
that surrounds the posterior, superior, and
anterior aspects of the glenohumeral joint .
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16. • This cuff of muscles stabilizes and holds the
head of the humerus in the glenoid cavity of
the scapula without compromising the arm's
flexibility and range of motion.
• The tendon of the long head of the biceps
brachii muscle passes superiorly through the
joint and restricts upward movement of the
humeral head on the glenoid cavity.
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18. BURSAE AROUND THE GLENOHUMERAL JOINT
• Several bursae containing capillary films of synovial
fluid are found within the vicinity of the glenohumeral
joint.
• Bursae are located where tendons rub against
bone, ligaments, or other tendons and where skin
moves over a bony prominence.
• Subscapular Bursa; is located between the tendon of
the subscapularis and the neck of the scapula.
• The bursa protects the tendon where it passes inferior
to the root of the coracoid process and over the neck
of the scapula.
• It usually communicates with the cavity of the shoulder
joint through an opening in the fibrous capsule; thus, it
is really an extension of the glenohumeral joint cavity.
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19. • Subacromial Bursa; Sometimes referred to as
the subdeltoid bursa.
• Lies between the deltoid, the supraspinatus
tendon, and the fibrous capsule of the
glenohumeral joint.
• Its size varies, but it does not normally
communicate with the cavity of the shoulder
joint.
• The bursa is located inferior to the acromion
and coracoacromial ligament, between them
and the supraspinatus.
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20. BLOOD SUPPLY
• Vascular supply to the glenohumeral joint is
predominantly through branches of the
anterior and posterior circumflex humeral
and suprascapular arteries through the
scapula anastomosis.
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21. APPLIED ANATOMY
• The relatively small bony glenoid cavity,
supplemented by the less robust
fibrocartilaginous glenoid labrum and the
ligamentous support, make it susceptible to
dislocation.
• Dislocation of the glenohumeral joint are
classified as anterior and rarely posterior
indicating whether the head of the humerus
had descended anteriorly or posteriorly to the
infraglenoid tubercle.
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22. • Anterior dislocation occurs most frequently
and is usually associated with an isolated
traumatic incident (all anterior dislocations
are anteroinferior).
• In some cases, the anterior inferior glenoid
labrum is torn with or without a small bony
fragment.
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23. • Once the joint capsule and cartilage are
disrupted, the joint is susceptible to further
(recurrent) dislocations.
• When an anteroinferior dislocation occurs, the
axillary nerve may be injured by direct
compression of the humeral head on the
nerve inferiorly as it passes through the
quadrangular space.
• Axillary nerve injury is indicated by paralysis of
the deltoid and loss of sensation in a small
area of skin covering the central part of the
deltoid.
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26. • The anastomosis around the scapula is an
arterial anastomosis around both surfaces
of scapula bone.
• Between the branches of subclavian and
axillary arteries.
• Arteries taking part in this anastomosis
include;
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27. 1. The suprascapular artery from the
thyrocervical trunk of the first part of the
subclavian artery.
The artery reaches the upper border of the
scapula and passes above suprascapular
ligament to reach the supraspinatus fossa,
then it curves around the spinoglenoid notch
to reach infraspinatus fossa.
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28. 2. The deep branch of transverse cervical artery
which is also a branch of the thyrocervical trunk.
The artery descends along medial border of
scapula deep to the levator scapulae and
rhomboids (sometimes the artery may arise
from the third part of the subclavian artery
and is known as dorsal scapular artery.
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29. 3. The subscapular artery from third part of
axillary artery.
Its circumflex scapular branches passes between
the two origins of teres minor muscle, enters
infraspinous fossa.
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32. • FUNCTIONAL IMPORTANCE
a. the anastomosis provides sufficient amount of
blood to the scapula muscles and upper
extremity during movement of the shoulder
joint from lateral border of scapula on its
dorsal surface.
b. In the case of blockage of main arterial trunk
distal to the origin of the thyrocervical trunk
and proximal to the origin of subscapular
artery, this anastomoses provides alternative
route for the supply of blood to the upper
extremity.
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