Pathomechanics of elbow)

Dr .Manal Radwan SalimLecturer of Physical Therapy

BiomeIIFall 2013-2014

Tuesday 3-12-2014

Elbow/ Forearm AnatomyArthrology and Movements

Humeroulnar Humeroradial Proximal & Distal Radioulnar

Ligaments and Capsule:Joint CapsuleUlnar Collateral (UCL)

3 bundlesLateral Ulnar Collateral (LUCL)Radial Collateral (RCL)Annular Interosseus Membrane

Common elbow abnormalities

the normal value of carrying angle is

10-5 degrees valgum

a) Cubitum Varum: abnormal decrease in carrying angle.

b) Cubitum Valgum: abnormal

increase in the angle.

1- Changes in Carrying Angle

2- Changes in bony alignment following fractures:Fracture of distal humerus or proximal ulna can alter the normal orientation of the articular surfaces of humeroulnar articulation.

a)From frontal view: Any change in the relative

alignment olecranon between the two humeral epicondyles affects both flexion and extension ranges

2- Cubitum Recurvatum: hyperextension of elbow joint.

ii. a hypothetical increase in the superior orientation of the trochlear notch increases extension ROM and decreases flexion ROM.

3-Humeroulnar Disolcation

a) Posterior dislocation:b) As there is little bony limitation

to the trochlear notch being pushed off trochlea.

b) Posterolateral dislocation:More frequent, occur in a combination of lateral and posterior movement of the forearm resulting from a force directed laterally on the distal forearm.

4- Superior radioulnar dislocation “pulled elbow injuries”

Occur at preschool children due to weakness of the annular ligament that allow the radial head to slip away from its ring by the tensile force applied to fore arm

5-Joint swelling and elbow flexion

Position of comfort in case of swelling is significant elbow flexi which is due to minimized tension on joint capsule at 80 degree flexion thus reducing stress on ligaments and minimize pain. But if condition persists this leads to flexion contractures.

6-BursitisSuperficial location

makes it extremely

susceptible to injury (acute or

chronic) --

direct blow

7-Musculature/Tendinitisa) Medial Epicondylitis –

chronic “Pitcher’s, Golfer Elbow” :

Caused by repeated flexion (common flexor tendon), valgus stresses, faulty biomechanics

b) Lateral Epicondylitis – chronic “Tennis Elbow”Caused by -overuse of extensor /supinator muscles, faulty biomechanics (common extensor tendon).-faulty backhand, too much topspin, too small or large grip.

9- PATHOMECHANICS OF MUSCLES AROUND ELBOW

a) Flexor groups:

Biceps Brachii

Brachioradialis

Pronator Teres

Brachialis

i. Biceps brachii Effect of weakness:Loss of flexion and radioulnar

supination strength that is compensated by other muscles.

Also may cause slight weakness in shoulder flexion

Supinated pronated

Effect of tightness:Limited extension range in elbow and

shoulder with tightness degree changes by alteration in other joint positions

if Shoulder in extension position lead to limit extension range at elbow and vice versa

- Forearm pronation lead to limit extension range at elbow and vice vera

ii. Brachiallis Effect of weakness:

Decreased elbow flexion in all forearm ranges.

Effect of tightness: Limited extension range regardless of shoulder and forearm position.

Brachialis

n.b. differentiate between brachialis tightness and anterior capsular tightnessTight muscular tissue feel rubbery or springy at end range. Capsular tightness end feel is harder and less spring

iii. brachioradialis Effect of

weakness:Decreased elbow flexion

strength in addition to decreased resisted pronation and supination as forearm moves toward neutral position

Effect of tightness:Limited extension range

in elbow and supination and pronation range

During rapid elbow flexion it acts as stabilizing to elbow joint against radial aaceleration

iv. Supinator Effect of weakness:Decreased forearm forceful

supination strength in case of intact biceps.

No supination with elbow extended.

Effect of tightness:A two joint muscle thus max

tightness appear when performing elbow extension and pronation

i. Pronator teris Effect of weakness:Decreased elbow flexion and forearm pronation strength In loading situations as loosening a screw

Effect of tightness:Limited extension range in elbow and

supination. A two joint muscle thus max tightness appear when performing elbow extension and supination

Pronator Teres

ii.Triceps brachii Effect of weakness:A profound decrease in elbow extension.In tetraplegia with zero triceps push up could

be done with elbow mechanically locked in hyperextension.

Effect of tightness:Limited flexion range in elbow and may

contribute to diminished shoulder elevation ROM that could interferes with functional daily activities as most daily activities can be performed with a total elbow flexion excursion of about 100°. Ex personal care activities as feeding and hygeine.

Other j positions

Effect of tightness (range)

Effect of weakness (strength)

Muscle

-Shoulder radioulnar

Elbow ext. range pron. Range

- Elbow flex. strength- flex. strength at shoulder - Sup. strength

Biceps brachii

Non elbow ext

elbow flex. strength in all forearm positions

brachialis

Non elbow ext

elbow flex strength resisted pron. and sup. force output as forearm moves toward neutral position

brachioradialis

Non pron forceful sup and pron with extended elbow

supinator

Radioulnar

elbow ext sup

resisted elbow flex resisted in pron

Pronator teres

elbow flex elbow flexion strngth Triceps brachii