ELBOW JOINT

ELBOW COMPLEXINCLUDES: -elbow joint -proximal & distal radio ulnarjoint

ELBOW JOINTCONSIST OF - Humeroulnar - humeroradialARTICULATING SURFACES ON HUMERUS - Trochlea - capitulumARTICULATING SURFACES ON ULNA& RADIUS - trochlear notch trochlear groove - head of radius capitulotrochlear groove

ELBOW JOINT

ELBOW JOINTCONGRUENT- HUMEROULNARINCONGRUENT-HUMERORADIALNORMAL VALGUS ANGULATION

TYPE-MODIFIED/LOOSE HINGE JOINT(?) 1DEGREE OF FREADM CONTACT DURING FLE.-EXT.

JOINT CAPSULEAttachment:-Anteriorly-just above coronoid & radial fossa & distally on the Coronoid process of ulna Medially & Laterally-it is blends with the fiber of the M.C.L & L.C.LPosteriorly-on the olecranon fossa It is weak anteriorly & posteriorly

JOINT CAPSULESynovial fold attaches to the proximal RU joint near the junction of annular ligament & joint capsule.Practical application-hypertrophied synovial fold is a source of pain in case of lateral epicondylalgiaResting position(CAPSULE RELAXED) HU JT-70* FLEXION,10* SUPINATION HR JT- NEAR EXT. SOME SUP.Closed position- HU JT-EXTENSION & SUPINATION HR JT-90*FLEXION,5* SUPINATION

JOINT CAPSULE

LIGAMENTSMEDIAL COLLATERAL LIGAMENT-ANTERIOR MCL-PRIMARY RESTRAINT OF VALGUS STRESS FROM 20*-120* OF FLEXTIONPOSTERIOR MCL-LESS SIGNIFICANT ROLE IN PROVIDING VALGUS STABILITYOBLIQUE MCL-ASSIST IN PROVIDING VALGUS STABILITY AND KEEP THE JOINT SURFACES IN APPROXIMATION

LATERAL COLLATERAL LIGAMENT COMPLEXLCL-PROVIDES REINFORCEMENT FOR THE HR ARTICULATION AND PROTECTION AGAINST VARUS STRESS IN SOME POSITION LCL as a key structure that is always disrupted in elbow position.LUCL-IS A SECONDARY RESTRAINT TO THE VARUS STRESSLUCL provides posterolateral stability by securing the ulna to the humerusPractical application..

MUSCLESTHREE MAIN FLEXORS- -biceps -brachialis -brachioradialisTWO MAIN EXTENSOR -triceps -anconeusCommon extensorPractical application

AXIS OF MOTIONPasses through the center of the trochlea and capitulum.Axis is not fixedInstantaneous axis during flexion- extensionValgus-varus laxity Max.(0*-40*)

LONG AXIS OF HUMERUS AND FOREARMLateral deviation of ulna in relation to the humerus (valgus angulation)Cubitus valgus (normal) angle-15*in full extCubitus varus(abnomal)

RANGE OF MOTIONFLEXION RANGE-0*-135*/145*SHOULDER AND FOREARM POSITION AFFECT AHE R.O.M

MUSCLE ACTIONFLEXORSBRACHIALIS -Is a mobility muscle (insertion close to jt) -M.A is greatest at >100*of flexion -Not affected by position -active in all type of contra- ction.

MUSCLE ACTIONBICEPS -Is also mobility muscle -M.A is largest in 80*-100* -small in extension -It is active during unresisted elbow flexion & supinated forearmBRACHIORADIALIS -Inserted distally hence its provide stability -largest component muscle force goes towards compression

-M.A is largest in 100*-120*-inactive in eccentric flexor activity-B.R shows no activity in slow,Unresisted Concentric elbow flexion-It shows higher level of activity in rapid alternating supination-pronation

MUSCLE ACTIONEXTESORS -Largest M.A.at 90* -elbow extension is done by -lateral &medial head of triceps70- 90 persent -anconeus-15 persent -triceps contribute less C.N.S SELECTIVELY RECRUITS UNIARTICULAR MUSCLE

SUPERIOR RADIOULNAR JOINTARTICULATING SURFACE: -ulnar radial notch -head of radius -annular ligament -capitulamUNIAXIAL PIVOT TYPE

INFERIOR RADIOULNAR JOINTARTICULATING SURFACES: -ulnar notch of radius -articular disk -head of ulna

ARTICULAR DISKAlso referred as a triangular fibrocartilageBASE:attached to the distal edge of the ulnar notch of radiusAPEX:atteched to the ulnar styloid process & ulnar headMEDIALLY: continues with UCL

ARTICULAR DISKThe margin is formed by dorsal and palmar radioulnar ligamentAVASCULAR: -80 percent of central portionA.D has a free nerve ending in periphery, disk may be a source of pain

RADIO-ULNAR ARTICULATIONMechanically linkedPronation of the forearm occurs as a result of the radiuss crossing over the ulna at S.R.U JOINTAt D.R.U JOINT the ulnar notch of the radius slides around the ulnar head & the disk follows the radius

LIGAMENTSTHREE MAIN LIGAMENTS:ANNULAR LIGAMENT- is a strong band that forms 4/5th of a ring that encircles the radial headQUADRATE LIGAMENT- it reinforces the inferior aspect of the joint capsule & maintain the radial head in apposition.Also limits spin of the radial head in supination &pronationOBLIQUE CORD- is a flat band on ventral forearm.its fiber is right angle to Introsseus membrane.it may assist in preventing separation of the radius & ulna

LIGAMENTS continueDORSAL AND PALMAR RADIOULNAR LIGAMENT-originate from the ulnar notch of the radius to insert on the ulnar fovea &base of the ulnar styloid process.Both reinforce the D.R.U JT.INTEROSSEUS MEMBRANE- -central portion -membranous portion -dorsal oblique cord

LIGAMENTS cont.CENTRAL BAND-strong,thick,ligamentous structure that consist of high collagen content surrounded by elastin.it is taut throughout the forearm rotationMEMBRANOUS PORTION- soft & thin structure.that max. taut in supinationDORSAL OBLIQUE CORD-extend from the proximal quarter of ulna to middle of radius.that max. taut in pronation

IOM maintain the space between radius ulna Force in the IOM that depends on: - elbow flexion angle & forearm rotation -maximum 43N at 30*flexion & forearm supinatedThe IOM transfers load from the wrist to the forearm via oblique fiber

MUSCLESPRIMARY MUSCLES- -pronator teres -pronator quadratus -biceps -supinatorOTHER MUSCLES THAT ACTIVE DURING SUPINATION AND PRONATION, ESPECIALLY WHEN GRIPPING IS INVOLVED -FCU & ECU -ECRB -anconeus -brachioradialis

AXIS OF MOTIONEXTENDING FROM CENTER OF RAIUS HEAD TO THE CENTER OF ULNAR HEAD.In pronation...There is a little motion of ulnaUlnar head moves distally & dorsally in pronationMotion of the proximal ulna is negligible

RANGE OF MOTIONTOTAL ROM IS 150* AT RADIOULNAR JOINTASSESSED WITH ELBOW IN 90* FLEXIONSUPINATION IS LIMITED BY PASSIVE TENSION IN THE PALMAR RADIO-ULNAR LIGAMENT AND THE OBLIQUE CORD

MUSCLE ACTIONPronator teres produce pronation & stabilize the RU JT.Pronator quadratus is active in resisted & unresisted pronation & in slow/fast pronation.The deep head is active in both resisted supination & pronation ACT AS A DYNAMIC STABILIZERSupinator act during unresisted slow supination in all position.Biceps act during supination perform against resistance and during fast supination

Elbow in varus position,force was transmittedFrom distal radius through the IOM to the proximal ulna

Elbow in valgus position,The force is transmitted Through the radius

EFFECT OF AGE AND INJURYINJURY-COMPRESSION INJURY-falling on hand with elbow in closed pack.DISTRACTION INJURY-tensile force may pulled radius inferiorly out of the annular ligament.lifting a child(nursemaids elbow)

INJURYVALGUS/VARUS INJURY-in valgus stress MCL is subjected to undergoing repetitive stress,ligament may become lax & lead to medial instability increase carrying angle.

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