Shoulder Complex
In scapulohumeral rhythm, the GH joint goes through 120º of _______ and 60º of ________.
-abduction
-scapulothoracic upward rotation
Which joint provides the most stability?
Humeroulnar
What is the thin, fibrous ligament that lies just below the radial notch of the ulna and stabilizes the proximal radioulnar joint?
Quadrate ligament
Name the muscles that require lower level extensor torque.
Anconeous, Triceps (medial head)
What movement is limited by bone impingement at the wrist.
Radial deviation
Name the primary adductor and extensor muscles of the shoulder.
Greatest contributors: Lats, Teres major, Pec major (sternal head)
-Posterior deltoid
-Triceps (long head)
-Infraspinatus and Teres minor assist
The lateral collateral ligament complex is made up of
-Radial collateral ligament
-Lateral (ulnar) collateral ligament
What 3 things are the TFCC complex mainly composed of?
a.Articular disc – Triangular fibrocartilage
b.Capsular ligaments of the distal radioulnar joint
c.Ulnar collateral ligament
Will also accept:
-palmar ulnocarpal ligament
-fascial sheath that encloses extensor carpi ulnaris
Maximal isometric flexion at the elbow is around how many degrees?
85º to 95º
What is negative ulnar variance?
Short distal ulna compared to distal radius
What structure contributes to posterior rotation of the clavicle around its axis during shoulder abduction?
Coracoclavicular ligament
Which ligament bundle resists valgus force and is taut at extreme elbow flexion?
Posterior bundles of UCL
What movement creates a low angle-of-insertion of muscle to bone?
Elbow extension
Name the 2 requirements in order for a muscle to be considered as a supinator/pronator.
1. Must attach on both sides of the axis of rotation
2. Muscle must produce a force that acts with an internal moment arm about the axis of rotation for pronation and supination.
1. _______ ligaments lie within the synovial lining and rely on synovial fluid for nutrients
2. _______ ligaments rely on vascularized tissues for nutrients
1. Intrinsic
2. Extrinsic
Dynamic stabilization of GH joint comes from? (Name at least two)
1.Force of prime movers
2.Force of gravity
3.Force of muscular stabilizers
4.Articular surface geometry
5.Passive capsuloligamentous forces
Intracapsular pressure is determined by
Closed chain
Define the Law of Parsimony.
The selection or preference to recruit one joint muscles occurs first. It will then recruit multi-joint muscles if necessary and it involves exerting more energy.
Arthrokinematics of wrist flexion.
Convex surface of lunate rolls palmarly on radius as simultaneously slides dorsally.
At midcarpal joint, head of capitate rolls palmarly on lunate and simultaneously slides dorsally.
What muscles act as a force couple in scapular upward rotation?
What muscles act as a force couple in scapular posterior tilt?
What muscles act as a force couple in scapular retraction?
Upward rotation: Serratus anterior, Upper trapezius, Lower trapezius
Posterior tilt: Serratus anterior, Lower Trapezius
Retraction: Rhomboids, Middle trapezius, Lower trapezius
Name the components of the Terrible Triad Injury.
What 3 things happens to the joint to cause this triad?
1.Elbow joint dislocation
2.Fracture of the radial head
3.Fracture of the coronoid process
Joint: Extreme compression, Hyperextension, Valgus force
Full pronation slackens the _________ to about 70% of its original length.
Palmar capsular ligament
Maximal force output of a muscle performing _______ muscle contraction is greater than its contraction velocity is close to zero.
Concentric
Name the 2 forms of carpal instability.
a. Rotational collapse of the wrist
b. Ulnar translocation of the carpus