week1 SEM 2 Joints of the Shoulder Region

Question 1

shoulder joint complex consists of 4 different joints

Answer 1

• Glenohumeral joint
• Acromioclavicular joint
• Sternoclavicular joint
• Scapulothoracic joint

Question 2

Glenohumeral (shoulder) joint classification and movements

Answer 2

*Classification
synovial, multiaxial, ball and socket
*Movements
* flexion - extension
* abduction – adduction
* internal (medial) -external (lateral)

Question 3

what makes the glenohumeral joint

Answer 3

humeral head ~1/2 sphere
glenoid fossa - very shallow
only 25 - 30% contact between articular surfaces

Question 4

what is the attachment of the glenohumeral joint

Answer 4

• medially to margin of glenoid fossa and glenoid labrum
• laterally to margin of anatomical neck of humerus
• reflected inferiorly onto medial shaft of humerus

Question 5

the glenohumeral joint is reinforced by

Answer 5

• rotator cuff tendons
• long head of triceps tendon
• glenohumeral and coracohumeral ligaments (capsular ligaments)

Question 6

Glenoid labrum
function and what it is

Answer 6

• fibrocartilaginous structure
  around glenoid fossa
• functions to:
• facilitate mobility
• increase glenoid concavity- up to
  50%
• provide attachment for joint
  capsule, ligaments, muscles

Question 7

what is the orientation of the glenoid fossa

Answer 7

When the arm is hanging the glenoid fossa faces:
* laterally
* slightly anteriorly
* slightly superiorly

Question 8

glenohumeral ligament superior middle and inferior ( prevent and limit)

Answer 8

• from anterior glenoid rim to humerus
  -superior
• prevents lateral and therefore, inferior
  dislocation of the humerus
• limits external rotation
• middle
• limits external rotation
• inferior
• prevents anterior dislocation of humerus
  when fully flexed/abducted

Question 9

Transverse humeral ligament

Answer 9

• passes between the humeral
  tubercles
• holds long head of biceps brachii
  in the bicipital groove

Question 10

Coracoacromial

Answer 10

• from coracoid to acromion
• prevents superior dislocation of
  humerus

Question 11

Acromioclavicular joint classification

Answer 11

synovial, multiaxial, plane

Question 12

Acromioclavicular joint articular surface and capsule

Answer 12

-Articular surfaces
* acromial end of clavicle
* anterior, medial acromion
-Articular capsule
* loose
* reinforced by capsular ligaments
* intra-articular disc
* partial disc which functions as a shock absorber

Question 13

Coracoclavicular (from coracoid to
clavicle) ligament

Answer 13

• conoid part (attaches to conoid tubercle)
• vertical
• limits protraction of scapula
• produces axial rotation of clavicle
• trapezoid part (attaches to trapezoid line)
• oblique
• limits retraction of scapula
• prevents medial dislocation of scapula

Question 14

Sternoclavicular joint classification

Answer 14

synovial, multiaxial, plane

Question 14

Sternoclavicular joint articular surface and capsule

Answer 14

-Articular surfaces
* sternal end of clavicle (male)
* clavicular notch of sternum (female)
* costal cartilage of rib 1
-Articular capsule
* strong
* reinforced by capsular ligaments

Question 15

Sternoclavicular joint intra-articular disc

Answer 15

• vertical disc dividing joint cavity into medial and lateral
  compartments
• functions:
• shock absorber
• prevents superior dislocation of clavicle
• thrusting forces
• weight in hand

Question 16

Sternoclavicular joint- Costoclavicular ligament (from rib 1 to clavicle)

Answer 16

• bilaminar (two layers), running at 90 degrees to one another
• limits elevation of clavicle
• limits protraction and retraction
• acts as a fulcrum or pivot about which movements occur

Question 17

Sternoclavicular joint- Anterior sternoclavicular (from sternum to clavicle)

Answer 17

• limits retraction

Question 18

Sternoclavicular joint- posterior sternoclavicular (from sternum to clavicle)

Answer 18

• limits protraction

Question 19

Sternoclavicular joint- Interclavicular

Answer 19

between clavicles

Question 20

Scapulothoracic joint function

Answer 20

• allows scapular motion against the rib cage

Question 21

what are rorator cuff muscles

Answer 21

they provide dynamic stability at sgoulder joint by:
take up slack in shoiulder joint capsule during movment
provide medial force to the humeral head
provide medial force

Question 22

scapulohumeral rhythem

Answer 22

increases range of motion - head rolls and glides on a moving glenoid fossa which moves by moving the scapula
maintains muscles at optimal length for effective contraction (deltoid and rotator cuff muscles)