EF osteology/arthrology

humeroulnar joint arthro

sagittal plane, ML axis

concave trochlear notch on convex trochlea

flexion: anterior roll/glide

extension: posterior roll/glide

0-140

humeroradial joint arthro

1 DoF

sagittal plane, ML axis

concave radial head on convex capitulum

flexion: anterior roll/glide

extension: posterior roll/glide

0-140

proximal radioulnar joint

1 DoF

transverse plane, vertical axis

convex radial head on concave ulna (radial notch)

arthro: SPIN

pronation: 0-80, supination: 0-90

distal radioulnar joint

1 DoF

transverse plane, vertical axis

convex ulnar head on concave radius (ulnar notch)

pronation: anterior roll/glide

supination: posterior roll/glide

pronation: 0-80, supination: 0-90

MCL

anterior, posterior, transverse fiber bundles. ALL originate on medial epicondyle, insert near trochlear notch. resist VALGUS load at the elbow

• transverse not remarkable

anterior band of MCL

strongest fibers in complex

• resist VALGUS loading in full range

• taut in extension

  • assists in strengthening annular ligament

posterior band of MCL

• limit VALGUS load during FLEXION

  • taut during flexion

LCL

2 primary bands: RCL, UCL. insert on lateral epicondyle. All limit VARUS load

RCL (anterior)

inserts on the radius, reinforces annular ligament

• taut on extension

UCL (posterior)

attaches near supinator crest on ulna

• limits varus load at the elbow

• taut on flexion

joint capsule ligaments

anterior ligament, oblique anterior ligament, posterior ligament.

joint capsule further strengthened by these

humeroulnar joint type

ginglymus joint

1 DoF- flexion/extension

why is there not much glide during humeroulnar joint movement?

concave trochlear notch arc is very large. DISTRACTION is most common tx intervention at this joint

humeroradial joint type

ovoid joint

1 DoF- flexion/extension

why can humeroulnar joint be considered saddle?

lateral view: ulna is concave

anterior view: ulna is convex with trochlear ridge highest in middle, 2 concavities on either side

• bony and ligamentous stability makes it function as hinge

how is humeroradial joint flexion limited?

soft tissue opposition and anterior bony contact

how is humeroradial extension limited?

bony contact of olecranon in fossa and capsular/soft tissue restriction

passive tension in biceps may limit

elbow extension when shoulder is extended

close pack position for humeroulnar joint

full extension

close pack position for humeroradial joint

semiflexion, semipronation

loose pack position for humeroulnar joint

70-90 degrees flexion

loose pack position for humeroradial joint

70 degrees flexion, 35 degrees supination

functional elbow range

100 degrees, from 30-130 degrees of flexion

radioulnar joint type

pivot joint

1 DoF: pronation/supination

annular ligament

fibrous band that forms 4/5 of a ring and is attached to anterior/posterior radial notch of ulna. lined with articular cartilage

• limits SUPINATION

interosseous membrane

assists in transmitting forces from hand/distal radius to ulna (80% of load thru radius). anterior fibers run superior lateral-inferior medial

• UNDER TENSION in neutral

• SLACK in pronation/supination

oblique cord

runs laterally from ulna to distal to the radial tuberosity of radius.

• limits SUPINATION

quadrate ligament

extends between inferior radial notch to neck of radius. reinforces inferior superior radioulnar joint, holds radial head against notch

• limits RADIAL HEAD SPIN in pronation/supination

distal RU ligament

anterior/posterior ligaments that hold radius and ulna together

• anterior limits SUPINATION

• posterior limits PRONATION

TFCC

articular disc, UCL, palmoulnar ligament

articular disc functions

• separate distal RU joint and RC joint

• provide dual articular surface- proximally with ulnar head, distally with radiocarpal jt

• helps bind radius and ulna together

supination is limited by

annular ligament, oblique cord, anterior RU ligament, quadrate

pronation is limited by

impact of radius on the ulna and posterior RU ligament, quadrate

close pack position for RU joint

full supination or pronation

loose pack position for RU joint

70 degrees flexion, 35 degrees supination

functional forearm motion

100 degrees, 50 degrees pronation, 50 supination