The Pronators and Supinators
Donald Sammut
Hand Surgeon
KCH Upper Limb Anatomy
plus lecture notes
Pronation(and(supination(of(the(hand(occurs(by(movement(at(two(articulations((
between(radius(and(ulna((Beyond(the(elbow).((
This(involves(the(radius(spiralling(around(the(ulna(
(
This(is(not(to(be(confused(with(the(rotation(that(is(possible(when(the(elbow(is(extended((
and(there(is(contribution(by(humerus(and(scapula,(as(well(as(radio?ulnar(movement.(
(
With(humero?scapular(contribution,(the(hand(can(be(rotated(through(nearly(360°(
Pronation(and((
Supination(of(the((
forearm(
Plus(Humeral(rotation(
and(
Scapular(movement(
Range:(
(
Elbow(flexed:(
140°(to(150(°(
(
With(elbow(extended(and(adding((
Humeral(rotation(and(scapular(movement:((
350°(
(
(
Power(
(
Supination(>(Pronation(
Antigravity(
Pronation(is(often(aided(by(gravity((the(hand(readily(falls(into(pronation)(
(
Supination(is(often(anti?gravity(
(
Both(are(indispensable(contributors(to(the(versatility(of(the(upper(limb((
in(orientating(the(hand(in(space(
(
Supination(is(the(more(powerful,(a(fact(that(is(made(use(of(in(the(design(of((
screw(and(bolt(thread.(Screwing(into(wood(is(usually(harder(than((undoing(a(screw,((
Thread(tightens(clockwise,(which(would(be(achieved(by(supination((
of(a(hand(holding(a(screwdriver.((
(
(
The(typical(action(of(pronation(and(supination(is(the(turning(of(a(key(in(a(lock(
The(hand(clamps(on(to(the(key(
The(forearm(rotates.(
(
Supination(
Pronation(
Supination(
(
Avge(75°(
Pronation(
(
Avge(64°(
In(pronation(and(supination,(the(ulna(is(static.(
The(Radius(spirals(around(the(ulna(
(
Actually(the(ulna(abducts(and(adducts(slightly(during(supination(and(pronation,((
so(the(radius(does(not(describe(a(symmetrical(spiral.(This(is(of(no/minimal(clinical(relevance.
(
(
ULNA(
RADIUS(
RADIUS(
ULNA(
Static((
Ulna(
Interosseous((
Membrane(
The(Proximal(Radio?Ulnar(Joint(
(
Uni?axial(pivot(joint(
(Radial(head(with(radial(notch(of(Ulna((
(and(Capitulum(of(Humerus(
The(Distal(Radio?Ulnar(Joint(
(
Uni?axial(pivot(joint(
The(proximal(radio?ulnar(joint(
The(Radius(articulates(with(the(ulnar(radial(notch(proximally(and(also,((
by(a(shallow(facet,(with(the(capitulum(of(the(Humerus(
The(anular(ligament(is(a(strong(transmitter(of(force(from(the(hand,((
via(the(radius(and(on(into(the(ulna(and(humerus.(
(
It(also(ensures(that(the(radial(head(remains(congruous(with(the(radial(notch(
(in(the(proximal(Ulna(
Humerus
Radial Fossa
Lateral
epicondyle
Capitulum
Coronoid fossa
Medial
epicondyle
Trochlea
Radial head
Coronoid
Process
Radial Neck
Radial Tuberosity
Ulnar Tuberosity
CAPITULUM
TROCHLEA
Anular
Ligament
The(distal(radio?ulnar(joint(
The(distal(radio?ulnar(joint(
(
The(radius(glides(around(the(convex(head(of(the(ulna(which(articulates((
with(the(ulnar(notch(in(the(distal(radius.(
(
The(radius(is(held(in(this(accurate(arc(around(the(ulnar(head(by(the(triangular(fibrocartilage.
This(triangle(is(strongest(and(thickest(dorsal(and(volar.((
These(two(parts(act(like(spokes(of(a(wheel,(ensuring(that(the(radius((
and(ulna(remain(congruous.(
(
The(central(part(is(not(crucial(to(structure(and(stability(and(is(
(frequently(perforated(or(deficient(in(later(life(without(compromise(of(function.(
TFCC(
Triangular(
Fibro?Cartilaginous(
Complex(
Rupture(of(the(Triangular(Fibrocartilage(results(in(loss(on(congruity((
and(instability(of(the(distal(radio?ulnar(joint((DRIUJ)(
The(interosseous(membrane(connects(radius(to(ulna(
(
It(also(spirals(as(the(radius(spirals(around(the(ulna.(
(
It(is(relatively(slack(in(full(pronation(and(in(full(supination.(
It(is(tight(in(neutral((Mid(pronation/Mid(supination)(
(
The(hand(hangs(from(the(radius(and(the(ulna(does(not(participate(in(wrist(articulation.((
Weight(is(transmitted(via(the(radius(and(then,(partly(directly(into(the(humerus(and((
partly(through(the(ulna(which(hangs(from(the(humerus(via(the(very(strong((
bony(articulation(of(the(Olecranon.(
(
The(interosseous(membrane(probably(does(not(participate(significantly(in((
load(transmission.(
Transmission((
of((force(
Collateral(
Ligament(
Anular((
Ligament(
Interosseous(
Membrane(
(tense(in(neutral)(
SUPINATION(
Biceps(Brachii(
Supinator(
Two(powerful(muscles(produce(supination(
(
Biceps(Brachii(inserts(into(the(radial(tuberosity.(The(tendon(winds(round(the(radius((
in(full(pronation(and(unwinds(forcefully(when(powerful,(fast(supination(is(required.(
It(also(has(attachment(into(the(deep(fascia(of(the(forearm(via(the(bicipital(aponeurosis,((
which(gives(it(purchase(on(the(forearm(with(a(better(moment(arm(
(
Supinator(has(two(heads,((
One(transverse(connecting(ulna(to(radius(
One(oblique(connecting(humerus(to(radius.(
Both(produce(powerful(supination(of(the(radius(on(the(ulna(
BICEPS(BRACHII(
Biceps(Brachii(
Bicipital(Aponeurosis(
Biceps(Tendon(
Insertion((
Biceps(Brachii(
(
(
(
(
(
Radial(Tuberosity(
(
+(
(
via(Bicipital(Aponeurosis(
into(
Deep(fascia(of(forearm(
The(bicipital(aponeurosis(crosses(the(path(of(the(median(nerve(and(brachial(artery(
in(the(cubital(fossa.((
It(can(be(a(cause(of(proximal(compression(of(the(median(nerve(
Biceps:(Puts(in(the(Corkscrew…(
Biceps:(Puts(in(the(Corkscrew…and(pulls(out(the(cork.(
Supinator(
Superficial(layer(
(Humeral(Head)(
(
Anterior(view(
(
(
(
•  Lateral(Epicondyle(
•  Radial(Collateral(
((((((Ligament(
•  Anular(Ligament(
(
(
(
(
(
Lateral(aspect(of(
Proximal(1/3rd((
Radius(
Supinator(
Superficial(layer(
(Humeral(Head)(
(
Posterior(view(
(
(
(
Supinator(
Deep(layer(
(Ulnar(head)(
(
Anterior(view(
(
(
(
(
(
Supinator(Crest(
Of((Ulna(
(
(
(
(
Lateral(aspect(of(
Proximal(1/3rd(
Radius(
(
Supinator(
Deep(layer(
(Ulnar(head)(
(
Posterior(view(
(
(
(
(
(
(
Supinator(
Deep(and(superficial(
Layers(
(
Anterior(
Posterior(
Pronation(
Supination(
Pronation(
Supination(
The(posterior(interosseous(nerve((nerve(of(the(extensor(compartment(of(the(forearm)(
leaves(the(main(radial(nerve(as(a(terminal(branch(beneath(Brachioradialis(
and(travels(between(the(two(heads(of(Supinator(to(reach(the(back(of(the((
interosseous(membrane(
The Arcade
of Frohse
also
The Supinator arch
Fritz(Frohse:(Anatomist(1871(?(1916(
Hypertrophy(of(the(supinator(can(cause(compression(of(the(posterior(interosseous(nerve(
(Under(the(Arcade(of(Frohse,(or(the(‘Supinator(Tunnel’)(
(
This(presents(clinically(as(weakness(of(thumb(extension(and(extension(of(the(digits.(
When(invited(to(extend(the(wrist,(the(patient(will(extend(and(deviate(to(the(radial(side((
because(the(Mobile(wad((with(ECRL(and(ECRB(are(unaffected)(
PRONATION(
Pronator(Teres(
Pronator(Quadratus(
Pronation(is(produced(by(two(Muscles(
(
Pronator(Teres(lies(proximal(in(the(forearm.(It(consists(of(two(heads,(
(between(which(the(median(nerve(enters(the(forearm.(
It(forms(the(medial(border(of(the(cubital(fossa.(
(
(
Pronator(Quadratus(is(quadrangular(and(lies(in(the(distal(quarter(of(the(forearm,((
between(radius(and(ulna(and(deep(on(the(interosseous(membrane.(
(
Pronator((
Teres(
(
(
Humeral(Head:((
•  Common(Flexor(Origin(
•  Medial(Intermuscular((
(Septum(
Ulnar(Head:(
Medial(Side(Coronoid(
(
(
(
(
Lateral(edge(Midway(
Radius(
(
Pronator((
Quadratus(
Distal(ulna(
(
(
(
(
Distal(radius(
(
FDP(
FPL(
PQ(
One(can(test(separately((for(Pronator(Teres(and(Pronator(Quadratus.(
(
Since(Pronator(Teres(crosses(the(elbow,(flexing(the(elbow(will(slacken(it(and(render(it(weak.(
(Pronation(with(elbow(flexed(tests(mainly(Pronator(Quadratus.(
(
To(test(Pronator(Teres,(the(elbow(is(held(extended(and(one(ensures(that(there(is(no((
pronation(occurring(by(internal(and(external(rotation(of(the(humerus.(
(
(
Summary(
(
Supination:(
(
Biceps(Brachii:((
Into(Radial(tuberosity(via(strong(tendon(which(strongly(rotates(the(radius(into(supination(
and(via(Bicipital(aponeurosis(into(deep(fascia(
(
Supinator:(Superficial(and(Deep(Heads(
(
(Humero/Ulnar(to(Radius,(upper(third(
(
(Ulnar(to(Radius(upper(third.((
(
(
(
(
Pronation:(
(
Pronator(Teres:(2(heads:(Humero/Ulnar(to(Radius(midway(down(lateral(border(
(
Pronator(Quadratus:(Distal(Ulna(to(distal(Radius.(
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