Elbow Complex Flashcards
Elbow Complex consists of:
-Elbow Joint; Humeroulnar + Humeroradial Joints
-Proximal radioulnar joint (PRUJ)
-Distal radioulnar joint (DRUJ)
Elbow Functions
-Mobility for the hand by shortening or lengthening entire UE
-Stability for forceful movements (Ex: tools)
-Links shoulder to hand
Elbow Joint
(HUJ, HRJ)
Compound, modified/loose Hinge Joint
1 DOF; Flexion and Extension
Small amounts of axial rotation ABD/ADD of ulna
Proximal/ Distal Radioulnar Joints
(DRUJ) (PRUJ)
Linked; Function as 1 joint
Uniaxial, diarthrodial Pivot joint
1 DOF; Rotation of forearm (Pronation/Supination)
Humeroulnar (HUJ) Articulation
Trochlea of humerus with Trochlea notch of ulna
HUJ Open-Packed Position
70 deg supination; 10 deg flexion
HUJ Close-Packed Position
Full extension and supination
During elbow flexion at the HUJ, there is an ________ roll and _______ glide.
anterior; anterior
During elbow extension at the HUJ, there is a _______ roll and ________glide.
posterior; posterior
Humeroradial (HRJ) Articulation
Capitulum with Radial Head
HRJ Open-Packed Position
Full extension and supination
HRJ Close-Packed Position
90 deg flexion; 5 deg supination
During elbow flexion at the HRJ, there is a ______roll and a ______glide.
Anterior; anterior
During elbow extension at the HRJ, there is a _______ roll and ________glide.
Posterior; posterior
HUJ and HRJ Structures
-Joint capsule
-Medial and Lateral Collateral Ligaments
HUJ and HRJ Joint Capsule
-Fairly large, loose, weak anteriorly/posteriorly
-Synovial folds expand for full ROM
Synovial Membrane
-Lines olecranon, coronoid, radial fossae
-Lines medial trochlea and lower part of annular ligament
-Folds in to divide the HUJ and HRJ
Fat Pads
-Between capsule and synovial membrane
-By the olecranon, coronoid, radial fossae
HUJ and HRJ Medial (Ulnar) Collateral Ligament
Anterior bundle
-Primary restraint to valgus at 20-120 deg elbow flexion
Posterior bundle (vertically oriented)
-Limits elbow extension; guides motion throughout flexion
Transverse fibers
-Limits longitudinal distractions
HUJ and HRJ Lateral Collateral Ligament Complex
Lateral (radial) Collateral Ligament
Lateral (ulnar)Collateral Ligament
Annular Ligament
-stabilizes radial head against ulna
What does the HUJ and HRJ Lateral Collateral Ligament Complex do combined?
Restraint to varus
Restraint to combined varus + supination
Reinforces HRJ; limits distraction
Maintains posterolateral stability
Secures ulna to humerus (prevents dislocation)
Prevents forearm from rotating off humerus in valgus and supination during flexion from a fully extended position
HUJ and HRJ Axis of Motion
Centered in middle of trochlea on a line that intersects the longitudinal axis of the humerus
Carrying angle: Acute angle formed by long axis of humerus and forearm
-Normal:8-15 deg
-Cubitus valgus: >15 deg
-Cubitus varus: <5 deg
T/F Oblique axis results in a change in the relationship of the forearm and humerus when flexed.
True
Normal carrying angle with _______, ulna guided so that it’s in line with the same plane of the humerus when fully flexed.
Flexion
T/F Ulna medially guided from extension to flexion to put in the same plane as the humerus when fully flexed.
True
When cubitus valgus, going from extension to flexion, where does the forearm rest?
Forearm rest more medially when fully flexed