Elbow and Forearm Outline

Elbow Forearm Complex (EFC) includes ___ (3)

• 3 bones

• 4 synovial joints

• motions of complex

3 bones in EFC

• humerus

• radius

• ulna

4 synovial joints of EFC

• same capsule

  • humeroulnar

  • humeroradial

  • proximal radioulnar

• proximal to wrist

  • distal radioulnar

motions of EFC (3)

• flexion/extension

• pronation/supination

• general function

flexion/extension articulations (3)

• cubital

• humeroulnar between trochlea of humerus and trochlear notch of ulna

• humeroradial between capitulum of humerus and fossa on radial head

pronation/supination articulations (3)

• forearm

• proximal radioulnar between radial notch of ulna and head of radius

• distal radioulnar between head of ulna and ulnar notch of radius

general functions of EFC (2)

• adjust functional length of UE

• interaction between elbow and forearms increases range of effective hand placement

humeroulnar/radial joints is considered a ___

modified hinge joint

humeroulnar/radial joints has minimal movement in ___

planes besides sagittal

flexion/extension occurs in ____

sagittal plane about a frontal axis

humeroulnar, humeroradial, superior radioulnar joints are ___

within one joint capsule

articulating surface on humerus (2)

• trochlea

  • hour glass (sellar) shaped, convex

  • trochlear groove

  • medial portion more distal than lateral

• capitulum, convex

ulnar articulating surface

trochlear notch, concave

radial articulating surface

fossa on head of radius, concave

humeroulnar/radial joint primary accessory motion in open chain

gliding/sliding, some roll possibly at end of range

humeroulnar joint is ___

the load bearing side of joint

ligaments help bone congruency in joint, providing ___

stability

ulnar collateral ligament

• 3 bands (anterior, posterior, oblique)

• bands work together to resist valgus

anterior band

• strongest

• taut throughout elbow ROM

• primary soft tissue stabilizer against valgus from 20-120° of flexion

• assists anterior capsule in controlling hyperextension

anterior/posterior band is more taut in ___

extension/flexion

posterior band

• taut in full flexion

• resists some valgus in flexion

• weaker than anterior

oblique band

• valgus stability

• joint approximation (WAM)

radial collateral ligament

• resists varus stress

• 2 parts

radial collateral ligament path

lateral epicondyle to radius, blending with annular ligament

lateral ulnar collateral ligament

• lateral epicondyle to supinator crest of ulna

• works with ucl as guy wires in frontal plane, stability to humeroulnar articulation

• transverse plane stability - distal attachment forms sling resisting excessive supination

elbow most stable in ___

full extension (closed pack position)

carrying angle of humeroulnar/radial joints

• males 5-10°

• females 10-15°

• disappears in pronation

cubital valgus

greater than normal carrying angle

cubital varus (gunstock deformity)

less than normal carrying angle

active flexion/extension with forearm supinated

• 0°, elbow in anatomical position

• 0-145° of flexion, flexors cant shorten any more

• 0-5° of extension, stopped by olecranon (bony end feel)

passive flexion/extension with forearm supinated

• 0-160° flexion, stopped by soft tissue approximation or coronoid process and rim of radial head

• 0-5° extension, stopped by olecranon

normal adl of flexion

30-130° of flexion, lack of ROM does not typically have large negative impact

elbow flexion muscles (2)

• brachialis

• biceps brachii

brachialis

• active elbow flexor under all condition/positions

• largest physiological cross sectional area (strongest elbow flexor

• greatest force @ 100° or just above

biceps brachii

• most active when forearm supinated

• generally no activity with unresisted pronated elbow flexion

• active regardless during heavy resistance

• greatest force 80-100°

• very small force in full extension

• post delt synergist when pulling toward trunk

brachioradialis

• relatively small physiological cross sectional area

• active generally during flexion against resistance or high speed

• more active in pronation or mid-position

maximum isometric toque is found at ___

90° flexion

triceps brachii

stabilizer against elbow flexion during resisted supination (synergistic)

medial head of triceps brachii

active for extension under all condition where extensors are activated

lateral and long heads of triceps brachii

• active with resisted extension (long head last to be recruited)

• long head loses optimal length-tension depending on shoulder position

• long head largest physiologic cross section and greatest volume

anterior deltoid

synergist for long head of triceps during pushing activities

anconeus

• active in all condition of extension

• very weak extension

• more so a joint stabilizer

proximal and distal radioulnar joint

uniaxial, axis of motion runs from center of radial head to center of ulnar head

pronation/supination

• very little to no ulnar motion, radius moves on fixed ulna

• radius functionally lengthens during pronation

pronation/supination proximal articulation

• rim of radial head, convex

• ulnar radial notch, concave

• arthro is a spin

pronation/supination distal articulation

• radius ulnar notch, concave

• ulnar head, convex

• arthro is slide of ulnar notch of radius on head of ulna

connective tissue support for proximal and distal radioulnar joint (4)

• annular ligament (proximal)

• anterior/posterior radioulnar ligaments (distal)

• interosseous membrane

• triangular fibrocartilage complex

annular ligament (proximal joint)

• holds radius to ulna

• upper part line with fibrocartilage

anterior/posterior radioulnar ligaments (distal joint)

• reinforce anterior/posterior capsule

• anterior taut in full supination

• posterior taut in full pronation

interosseous membrane

• stabilizes both superior and inferior joints

• acts as attachment for forearm muscles

• assists in transmission of forces from radius to ulna

compression and tensile loads

transferred from hand to radius across wrist

as load travels along radius, they ___

transfers to ulna through interosseous membrane

triangular fibrocartilage complex (TFCC)

• general stability of inferior radioulnar joint especially for longitudinal stabilization (load from wrist to forearm)

• separates joint cavities of inferior radioulnar and radiocarpal

• reason why ulna does not participate in wrist joint

pronation

• 0-90°

• limited primarily by boney approximation

• lengthens dorsal capsular ligaments of wrist

supination

• 0-90°

• limited by passive tension in palmar ligaments of wrist, interosseous membrane, anterior radioulnar ligament, LUCL, and quadrate ligament

normal adl of pronation/supination

• 50°/55°

• less than this is debilitating, hard to substitute for loss

ROM measured with shoulder in add and elbow flexed to 90°, otherwise ___

they can substitute with shoulder internal/external rotation

pronation muscles (2)

• pronator teres

• pronator quadratus

pronator teres

• active during both rapid or resisted pronation

• can be influenced to limited extent by elbow position

• triceps synergist during pronation, no flexion from teres

pronator quadratus

• active during any pronation condition

• important dynamic stabilizer for distal radioulnar joint

supination muscles (2)

• supinator

• biceps brachii

supinator

always active during supination

biceps bracii

• active during rapid or resisted supination

• ability to create supination force most effective at 90° flexion

• triceps synergist during supination activities requiring biceps, cancels unwanted flexion from obiceps

radial head fracture

excessive compression transmitted up radius with elbow in extension

coronoid/olecranon fractures

excessive compression transmitted up ulna with elbow in extension

pulled elbow syndrome (nursemaids elbow)

radial head pulled distal to annular ligament

tennis elbow (lateral epicondylosis)

• primarily ECRB

• associated with eccentric contractions

medial epicondylitis

• usually pronator teres or FCR but can involved FCU

• associated with eccentric contractions

cubital tunnel syndrome

compression of ulnar nerve by FCU