Shoulder Flashcards
(117 cards)
GHJ joint type
Synovial joint rotating around 3 axes
Humeral head positioning
-facing medially, posteriorly, superiously
Angle of inclination
-the head is inclined approximately 130* from long axis of shaft
Retroversion
-rotation of the humeral head in the transverse plane is 30*
Glenoid fossa position
7* laterally from scapula and oriented posteriorly with a slight 5* superior tilt relative to medial border of scapula
Labrum
- deepens the foss and supplies a negative intraarticular vacuum effect -sealing the joint
- assists with stability
GHJ capsule
along with ligaments have double the surface area of the humeral head itself
-capsule arises form glenoid neck and labrum - inserts on articular margin of anatomical neck of humeral head (except inferomedially where it extends down the humeral neck)
2 openings in GHJ capsule
1) between humeral tubercles allowing biceps tendon to exit the joint
2) connection between joint and subscapularis bursa
Inferior GHJ capsule
-very redundant to allow for greater ROM
Anterior & Posterior capsule
- posterior is thin
- extracapsular ligaments surround superior and anterior joint
Superior GH ligament
-either a robust or thin tissue that provides restraint to inferior translations of humeral head when arm is adducted
Middle GH ligament
-restraint to anterior humeral translation with the arm in mid-range of abduction up to about 45* and also limits ER with arm at side
Inferior GH ligament complex
- expansive band of tissue in the inferior capsule - thickened anterior and posterior band
- “hammock” type axillary pouch
- anterior band works in conjunction with anterior and posterior bands to limit anterior translation in either direction when the GHJ is abducted to 90*
- in ER and abduction - anterior band wraps around front of GHJ to limit anterior translation
- in IR - posterior band prevents posterior translation
Scapulothoracic joint
- not a true joint
- between anterior scapula and posterior thorax and rib cage
Scapula superior and inferior border and scapular angles
- 2nd thoracic vertebrae
- 7th thoracic vertebrae
- angled 30-40* from coronal plane to place glenoid fossa anteriorly - “scapular plane”
- upwardly rotated 10-20* from vertical and tips 10-20* anteriorly
Sternoclavicular joint
- saddle shaped joint (diarthrodial)
- inherently unstable, but one of the least dislocated joints
- allows motions of protraction/retraction, elevation/depression, and rotation
- only true skeletal articulation between the axial region and UE
SC joint disc
- helps with stability and separates joint into 2 compartments
- medial end of clavicle is concave in the AP direction and convex in the SI direction
SC joint capsule
- surrounds entire joint
- weak and supported by thickenings called AP SC ligaments
Posterior SC ligament
-causes significant increases in AP translations - greater than that of any ligament
Interclavicular ligament
- medial ends of both clavicles
- thought to provide restrains to inferior forces on medial end of clavicle
Costoclavicular ligament
-anterior and posterior bundles that run from superior surface of the first rib to the undersurface of clavicle
AC joint
- synovial planar joint with 3* of freedom
- articular disc lies between 2 surfaces - provides stability improving fit between 2 surfaces
- hyaline cartilage becomes fibrocartilage by age 17 on acromial side and by age 24 on clavicular side
AC joint capsule
-surrounds to help provide stability
Conoid and trapexoid ligaments (coracoclavicular ligaments)
-provide stability medial to the AC joint