Shoulder Joint
Shoulder Joint
By/
Rasha M. El-Shinety; Ph.D, MD
Ass. Prof. of Anatomy & Embryology
SHOULDER JOINT
Type of joint:
•
Synovial.
•
Polyaxial.
•
Ball and socket.
SHOULDER JOINT
•
Articular surfaces:
1.
Head of humerus.
2.
Glenoid cavity of scapula.
–
Each of the articular surfaces is covered by hyaline
cartilage.
–
The glenoid cavity is deepened by a fibro-cartilagi
nous rim;
labrum glenoidale.
SHOULDER JOINT
Capsule:
•
The capsule is attached to the margins of the glenoid c
avity outside the labrum glenoidale.
•
Laterally the capsule is attached to the anatomical neck
of the humerus, except inferiorly where it extends abo
ut 1 cm to the shaft.
•
N.B the supraglenoid tubercle is inside the capsule so t
he tendon of long head of biceps is an intra-capsular ex
tra-synovial structure.
•
Thickenings of the capsule (false ligaments of the
joint):
The capsule is thickened by 3 glenohumeral ligaments.
SHOULDER JOINT
Synovial membrane
•
It lines all the structures inside the capsule of t
he shoulder joint EXCEPT the articular cartilag
e
•
It forms a tubular sheath around the tendon o
f long head of biceps so it is an intra-capsular,
extra-synovial strucure.
SHOULDER JOINT
LIGAMENTS RELATED TO SHOULDER JOINT
1- False ligaments:
They are the thickening of the capsule of the
shoulder joint (glenohumeral ligaments).
2- True ligaments:
Coraco-humeral ligament.
Transverse humeral ligament (bridges over the b
icepetal groove).
SHOULDER JOINT
Movements of shoulder joint
•
Flexion: This movement is done by the clavicular
head of pictoralis major, anterior fibers of the del
toid and the coracobrachialis.
•
Extension: This movement is done by the posterio
r fibers of the deltoid and teres major.
•
Adduction: This movement is done by the pectora
lis major, teres major and latissimusdorsi.
•
Abduction: This movement is done by the supras
pinatus and deltoid.
SHOULDER JOINT
Movements of shoulder joint
•
Medial rotation: This movement is done by the p
ectoralis major, teres major, latissimusdorsi, subsc
apularis and anterior fibers of the deltoid.
•
Lateral rotation: This movement is done by the inf
raspinatus, teres minor and posterior fibers of the
deltoid.
•
Circumduction; a movement of abduction,
extension, adduction and flexion in succession.
SHOULDER JOINT
Nerve supply of shoulder joint:
1.
Suprascapular
2.
Axillary
3.
Musculocutaneous
SHOULDER JOINT
Factors share in stability of shoulder joint:
The stability of any joint is an action of 3 factors:
Bony factor
Ligamentous factor
Muscular factor
1- Bony factor
The shallow glenoid cavity opposite to a relatively larger head
is a negative factor in stability of this joint. However the labru
m glenoidale deepens the shallow glenoid cavity so it helps in
stability of the joint.
Coraco-acromial arch, acts as a second socket for the head of
humerus and prevents its upward dislocation.
SHOULDER JOINT
2- Ligamentous factor
•
Labrum glenoidale.
•
Coraco-acromial ligament as bridges over the bony arch.
3. Muscular factor
It is the main factor aiding to stability of the joint.
•
Rotator cuff of muscles (they are the 4 muscles that firmly a
dherent to the capsule of shoulder joint; subscapularis, sup
raspinatus, infraspinatus and teres minor.
•
Splinting effect of long heads of biceps and triceps muscles.
•
Long head of biceps prevents upwards dislocation of the joi
nt.
Understanding the shoulder joint, a synovial polyaxial ball-and-socket joint, with articular surfaces, capsule details, ligaments, and movements involved. Explore the complexities of this crucial joint in the human body.
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Presentation Transcript
Shoulder Joint By/ Rasha M. El-Shinety; Ph.D, MD Ass. Prof. of Anatomy & Embryology
SHOULDER JOINT Type of joint: Synovial. Polyaxial. Ball and socket.
SHOULDER JOINT Articular surfaces: 1. Head of humerus. 2. Glenoid cavity of scapula. Each of the articular surfaces is covered by hyaline cartilage. The glenoid cavity is deepened by a fibro-cartilagi nous rim; labrum glenoidale.
SHOULDER JOINT Capsule: The capsule is attached to the margins of the glenoid c avity outside the labrum glenoidale. Laterally the capsule is attached to the anatomical neck of the humerus, except inferiorly where it extends abo ut 1 cm to the shaft. N.B the supraglenoid tubercle is inside the capsule so t he tendon of long head of biceps is an intra-capsular ex tra-synovial structure. Thickenings of the capsule (false ligaments of the joint): The capsule is thickened by 3 glenohumeral ligaments.
SHOULDER JOINT Synovial membrane It lines all the structures inside the capsule of t he shoulder joint EXCEPT the articular cartilag e It forms a tubular sheath around the tendon o f long head of biceps so it is an intra-capsular, extra-synovial strucure.
SHOULDER JOINT LIGAMENTS RELATED TO SHOULDER JOINT 1- False ligaments: They are the thickening of the capsule of the shoulder joint (glenohumeral ligaments). 2- True ligaments: Coraco-humeral ligament. Transverse humeral ligament (bridges over the b icepetal groove).
SHOULDER JOINT Movements of shoulder joint Flexion: This movement is done by the clavicular head of pictoralis major, anterior fibers of the del toid and the coracobrachialis. Extension: This movement is done by the posterio r fibers of the deltoid and teres major. Adduction: This movement is done by the pectora lis major, teres major and latissimusdorsi. Abduction: This movement is done by the supras pinatus and deltoid.
SHOULDER JOINT Movements of shoulder joint Medial rotation: This movement is done by the p ectoralis major, teres major, latissimusdorsi, subsc apularis and anterior fibers of the deltoid. Lateral rotation: This movement is done by the inf raspinatus, teres minor and posterior fibers of the deltoid. Circumduction; a movement of abduction, extension, adduction and flexion in succession.
SHOULDER JOINT Nerve supply of shoulder joint: 1. Suprascapular 2. Axillary 3. Musculocutaneous
SHOULDER JOINT Factors share in stability of shoulder joint: The stability of any joint is an action of 3 factors: Bony factor Ligamentous factor Muscular factor 1- Bony factor The shallow glenoid cavity opposite to a relatively larger head is a negative factor in stability of this joint. However the labru m glenoidale deepens the shallow glenoid cavity so it helps in stability of the joint. Coraco-acromial arch, acts as a second socket for the head of humerus and prevents its upward dislocation.
SHOULDER JOINT 2- Ligamentous factor Labrum glenoidale. Coraco-acromial ligament as bridges over the bony arch. 3. Muscular factor It is the main factor aiding to stability of the joint. Rotator cuff of muscles (they are the 4 muscles that firmly a dherent to the capsule of shoulder joint; subscapularis, sup raspinatus, infraspinatus and teres minor. Splinting effect of long heads of biceps and triceps muscles. Long head of biceps prevents upwards dislocation of the joi nt.
