WRIST COMPLEXWRIST COMPLEX

Bones and Joints of the Bones and Joints of the WristWrist

Proximal Row of Carpal BonesProximal Row of Carpal BonesReview- testableReview- testableScaphoid:Scaphoid:

Most lateral.Most lateral.Forms floor of anatomical snuff box.Forms floor of anatomical snuff box.Most commonly fractured wrist bone.Most commonly fractured wrist bone.Fractures may compromise radial artery in Fractures may compromise radial artery in snuff box.snuff box.Articulates with radius.Articulates with radius.

Proximal Row of Carpal BonesProximal Row of Carpal BonesLunate:Lunate:

Articulates with radiusArticulates with radiusTriquetral:Triquetral:

Articulates with ulna (via articular (ulnar) Articulates with ulna (via articular (ulnar) disc) during extreme ulnar deviation.disc) during extreme ulnar deviation.

Pisiform:Pisiform:Sesamoid boneSesamoid boneForms in tendon of the flexor carpi ulnarisForms in tendon of the flexor carpi ulnaris

Distal Row of Carpal Bones:Distal Row of Carpal Bones:Trapezium:Trapezium:

Most lateralMost lateralTrapezoidTrapezoidCapitate Capitate Hamate Hamate

Distal Row of Carpal Bones:Distal Row of Carpal Bones:Entire complex enclosed in a common Entire complex enclosed in a common

synovial membrane.synovial membrane.Articulations are plane joints that perform Articulations are plane joints that perform

gliding motions.gliding motions.

Radiocarpal JointRadiocarpal Joint Condyloid (ellipsoidal) synovial joint.Condyloid (ellipsoidal) synovial joint. Two degrees of freedom.Two degrees of freedom. Articular surfaces:Articular surfaces:

Scaphoid (convex)Scaphoid (convex)Lunate (convex)Lunate (convex)Distal radius:Distal radius:

Two concave fossae (lateral and medial)Two concave fossae (lateral and medial)Triquetral (convex)Triquetral (convex)

Only during extreme ulnar deviationOnly during extreme ulnar deviation

Radiocarpal Joint LigamentsRadiocarpal Joint Ligaments Lateral (radial) collateral ligament.Lateral (radial) collateral ligament. Medial (ulnar) collateral ligament.Medial (ulnar) collateral ligament. Dorsal radiocarpal ligament.Dorsal radiocarpal ligament. Palmar radiocarpal ligament.Palmar radiocarpal ligament.

Strengthen capsuleStrengthen capsule

Radiocarpal Joint FunctionsRadiocarpal Joint FunctionsSome flexion and extensionSome flexion and extensionUlnar deviationUlnar deviation

Radiocarpal Joint ArteriesRadiocarpal Joint ArteriesArticular arteriesArticular arteriesArise from dorsal and palmar carpal Arise from dorsal and palmar carpal

arches.arches.

Radiocarpal Joint NervesRadiocarpal Joint NervesAnterior interosseous branch of median Anterior interosseous branch of median

nerve.nerve.Posterior interosseous branch of radial Posterior interosseous branch of radial

nerve.nerve.Dorsal and deep branches of the ulnar Dorsal and deep branches of the ulnar

nerve.nerve.

Radiocarpal Joint InjuriesRadiocarpal Joint InjuriesColle’s fractureColle’s fractureScaphoid fractureScaphoid fracture

Usually at “waist”Usually at “waist”Compromises radial artery in snuffboxCompromises radial artery in snuffbox

Midcarpal JointMidcarpal JointMade up of intercarpal joints:Made up of intercarpal joints:

Between proximal and distal rows of Between proximal and distal rows of carpals carpals and between carpals.and between carpals.

Movements:Movements:Some flexion and extension.Some flexion and extension.Radial deviation (abduction).Radial deviation (abduction).Especially due to movement of head of Especially due to movement of head of

capitate in its socket.capitate in its socket.Enclosed within synovial capsule.Enclosed within synovial capsule.

Midcarpal JointMidcarpal JointLigaments:Ligaments:

Dorsal ligaments.Dorsal ligaments.Palmar ligaments.Palmar ligaments.Interosseous ligaments.Interosseous ligaments.

Nerves and arteries:Nerves and arteries:Same as for radiocarpal.Same as for radiocarpal.

Palmar Structure SequencePalmar Structure Sequence(radial to ulnar)(radial to ulnar)

RadiusRadiusRadial arteryRadial arteryFlexor carpi radialis tendonFlexor carpi radialis tendonMedian nerve:Median nerve:

Under palmaris longus tendonUnder palmaris longus tendon

Palmar Structure SequencePalmar Structure Sequence(radial to ulnar)(radial to ulnar)

Flexor digitorum superficialis tendonsFlexor digitorum superficialis tendonsUlnar arteryUlnar arteryUlnar nerveUlnar nerveFlexor carpi ulnaris tendonFlexor carpi ulnaris tendon

HANDHAND

Carpometacarpal JointsCarpometacarpal JointsPlane synovial joints:Plane synovial joints:Motion:Motion:

None for digits 2-3None for digits 2-3Limited for 4Limited for 4More mobile for 5More mobile for 5

Carpometacarpal JointsCarpometacarpal JointsSaddle (sellaris) joint between metacarpus Saddle (sellaris) joint between metacarpus

and trapezium:and trapezium:Movements:Movements:

Abduction/adductionAbduction/adductionFlexion/extensionFlexion/extensionCircumductionCircumductionOppositionOpposition

Metacarpophalangeal JointsMetacarpophalangeal JointsCondyloid synovial jointsCondyloid synovial jointsMovements:Movements:

Flexion/extensionFlexion/extensionAbduction/adductionAbduction/adductionSome opposition at MCP 5Some opposition at MCP 5

Capsular ligaments:Capsular ligaments:Palmar ligaments (pads)Palmar ligaments (pads)Collaterals Collaterals

Interphalangeal JointsInterphalangeal JointsSynovial hinge jointsSynovial hinge jointsOnly flexion/extension allowedOnly flexion/extension allowedLigaments:Ligaments:

Strong collateralsStrong collateralsProximal interphalangeal joints (PIPs)Proximal interphalangeal joints (PIPs)Distal interphalangeal joints (DIPs)Distal interphalangeal joints (DIPs)

Dorsal Venous DrainageDorsal Venous DrainageDorsal venous arch drains hand dorsum.Dorsal venous arch drains hand dorsum.Medially drains into basilic.Medially drains into basilic.Laterally drains into cephalic.Laterally drains into cephalic.

Lymphatic DrainageLymphatic DrainageMedial via lymph vessels accompanying Medial via lymph vessels accompanying

basilic vein to:basilic vein to:Supratrochlear nodes to:Supratrochlear nodes to:Lateral axillary nodes.Lateral axillary nodes.

Lateral via lymph vessels accompanying Lateral via lymph vessels accompanying cephalic vein to:cephalic vein to:

Infraclavicular nodes to:Infraclavicular nodes to:Lateral axillary nodes.Lateral axillary nodes.

Arterial Supply to DorsumArterial Supply to DorsumVia dorsal arterial arch from:Via dorsal arterial arch from:

Radial and ulnar arteries.Radial and ulnar arteries.Dorsal metacarpals.Dorsal metacarpals.Dorsal digitals.Dorsal digitals.

Muscles of Dorsum of HandMuscles of Dorsum of HandLong extensor tendons.Long extensor tendons.Dorsal interosseous muscles (4):Dorsal interosseous muscles (4):

Attachments:Attachments:DAB:DAB:

AbductorsAbductorsMiddle finger is referenceMiddle finger is referenceMiddle finger has twoMiddle finger has twoFirst and fifth digits have none.First and fifth digits have none.

Long Extensors

Superficial PalmSuperficial PalmPalmar aponeurosisPalmar aponeurosisFlexor retinaculumFlexor retinaculumPalmaris brevisPalmaris brevis

Palmar AponeurosisPalmar AponeurosisTriangular layer of deep fascia located Triangular layer of deep fascia located

between two eminences.between two eminences.Provides protection for superficial vessels, Provides protection for superficial vessels,

nerves, and tendons.nerves, and tendons.Anchored to skin and flexor retinaculum.Anchored to skin and flexor retinaculum.Splits into four slips that blend with fibrous Splits into four slips that blend with fibrous

flexor sheaths of four medial digits (II – V).flexor sheaths of four medial digits (II – V).

Flexor RetinaculumFlexor Retinaculum= Transverse carpal ligament.= Transverse carpal ligament.Laterally attaches to tubercles of scaphoid Laterally attaches to tubercles of scaphoid

and trapezium.and trapezium.Medially attaches to hook of hamate and Medially attaches to hook of hamate and

pisiform.pisiform.

Palmaris Brevis MusclePalmaris Brevis MuscleO:O: Flexor retinaculum and palmar Flexor retinaculum and palmar

aponeurosis.aponeurosis. I:I: Skin on medial side of palm.Skin on medial side of palm.A:A: Tenses skin on palm.Tenses skin on palm.

Carpal Tunnel ContentsCarpal Tunnel ContentsLong flexor tendons of:Long flexor tendons of:

Flexor digitorum superficialisFlexor digitorum superficialisFlexor digitorum profundusFlexor digitorum profundusFlexor pollicis longusFlexor pollicis longus

Median nerveMedian nerve

Note: ulnar nerve and artery pass through Note: ulnar nerve and artery pass through Guyon’s canal.Guyon’s canal.

Long Flexors

Intrinsic Muscles of the ThumbIntrinsic Muscles of the ThumbThenar eminence:Thenar eminence:Adductor pollicis:Adductor pollicis:

Innervation:Innervation:Deep branch of ulnar nerve (C8, T1).Deep branch of ulnar nerve (C8, T1).

Thenar Eminence MusclesThenar Eminence MusclesAbductor pollicis brevisAbductor pollicis brevisFlexor pollicis brevisFlexor pollicis brevisOpponens pollicisOpponens pollicis

Innervation:Innervation:Recurrent branch of median nerve (C8, Recurrent branch of median nerve (C8,

T1).T1).

Thenar Muscles

Hypothenar EminenceHypothenar Eminence Intrinsic muscles for digit V.Intrinsic muscles for digit V.

Abductor digiti minimiAbductor digiti minimiFlexor digiti minimi brevisFlexor digiti minimi brevisOpponens digiti minimiOpponens digiti minimi

Innervation:Innervation:Ulnar nerveUlnar nerve

Hypothenar Muscles

Long Digital FlexorsLong Digital FlexorsFlexor digitorum superficialisFlexor digitorum superficialisFlexor digitorum profundusFlexor digitorum profundus

Flexor Digitorum SuperficialisFlexor Digitorum SuperficialisFlexes PIP (and MCP and wrist).Flexes PIP (and MCP and wrist).Each tendon passes through fibrous flexor Each tendon passes through fibrous flexor

sheath.sheath.Each tendon bifurcates opposite proximal Each tendon bifurcates opposite proximal

phalanx.phalanx.Each tendon inserts on middle phalanx.Each tendon inserts on middle phalanx.

Flexor Digitorum ProfundusFlexor Digitorum ProfundusFlexes DIP (and PIP and MCP).Flexes DIP (and PIP and MCP).More active than superficialis.More active than superficialis.Each tendon inserts on distal phalanx.Each tendon inserts on distal phalanx.

VinculaeVinculaeSmall vascular bundles connecting palmar Small vascular bundles connecting palmar

surface of phalanges with long flexor surface of phalanges with long flexor tendons.tendons.

Long and shortLong and short

Long Flexors

Dorsal InterosseiDorsal InterosseiFour bipennate muscles.Four bipennate muscles.Each arises via two heads from adjacent Each arises via two heads from adjacent

sides of two metacapals.sides of two metacapals.

Dorsal InterosseiDorsal Interossei Insertion:Insertion:

Onto extensor expansions and:Onto extensor expansions and:Radial sides of proximal phalanges 2 and Radial sides of proximal phalanges 2 and

3;3;Ulnar sides of proximal phalanges 3 and 4.Ulnar sides of proximal phalanges 3 and 4.Note: digit has two dorsal interossei.Note: digit has two dorsal interossei.

Abducts MP joints of digits 2-4:Abducts MP joints of digits 2-4:Reference is line through middle finger.Reference is line through middle finger.

Interossei Muscles

Palmar InterosseiPalmar InterosseiFour unipennate muscles:Four unipennate muscles:

First is sometimes considered part of flexor First is sometimes considered part of flexor pollicis brevis.pollicis brevis.Supply each digit except third:Supply each digit except third:

Reference is middle finger.Reference is middle finger. Innervation for all interossei (incl. dorsal):Innervation for all interossei (incl. dorsal):

Ulnar nerveUlnar nerve

Interossei Muscles

LumbricalsLumbricals Four small, narrow, elongated muscles.Four small, narrow, elongated muscles. Each arises from the radial side of a flexor Each arises from the radial side of a flexor

digitorum profundus tendon.digitorum profundus tendon. Innervation:Innervation:

Two on radial side:Two on radial side:Median nerveMedian nerve

Two on ulnar side:Two on ulnar side:Ulnar nerveUlnar nerve

Flex MCP joints and extend IP joints.Flex MCP joints and extend IP joints.

Arterial Supply to HandArterial Supply to HandSuperficial palmar arch:Superficial palmar arch:

Continuation of ulnar artery.Continuation of ulnar artery.Deep palmar arch:Deep palmar arch:

Continuation of radial artery.Continuation of radial artery.

Route of Radial ArteryRoute of Radial ArterySmallest terminal branch of brachial artery.Smallest terminal branch of brachial artery.Passes proximally deep to brachioradialis Passes proximally deep to brachioradialis

muscle.muscle.Distally the artery lies against the radius Distally the artery lies against the radius

lateral to the tendon of the flexor carpi lateral to the tendon of the flexor carpi radialis, where it can be felt (radial pulse).radialis, where it can be felt (radial pulse).

Passes across scaphoid in anatomical Passes across scaphoid in anatomical snuff box.snuff box.

Route of Radial ArteryRoute of Radial ArteryWraps around the dorsum of first Wraps around the dorsum of first

metacarpus:metacarpus:Gives off arteries to the thumb and index Gives off arteries to the thumb and index finger.finger.

Pierces the first dorsal interosseous Pierces the first dorsal interosseous muscle and reappears in the palm of the muscle and reappears in the palm of the hand.hand.

Gives rise to the deep palmar arch.Gives rise to the deep palmar arch.

Deep Palmar Arch

Boundaries of the Boundaries of the Anatomical Snuff BoxAnatomical Snuff Box

Lateral (anterior):Lateral (anterior):Tendons of the:Tendons of the:

Abductor pollicis longus.Abductor pollicis longus.Extensor pollicis brevis.Extensor pollicis brevis.

Medial (posterior):Medial (posterior):Tendon of the:Tendon of the:

Extensor pollicis longus.Extensor pollicis longus.

Ulnar Nerve in the HandUlnar Nerve in the HandEnters hand superficial to flexor Enters hand superficial to flexor

retinaculum.retinaculum.Superficial branch:Superficial branch:

Muscular branch to palmaris brevisMuscular branch to palmaris brevis

Cutaneous to palmar aspect of ulnar side Cutaneous to palmar aspect of ulnar side of of little finger and adjacent sides of little and little finger and adjacent sides of little and

ring fingers, including tips and dorsum.ring fingers, including tips and dorsum.

Ulnar Nerve in the HandUlnar Nerve in the HandDeep branch:Deep branch:

Supplies hypothenar muscles, all Supplies hypothenar muscles, all interossei, interossei, two ulnar side lumbricals, and two ulnar side lumbricals, and adductor adductor pollicis.pollicis.

Nerve Supply to Hand

Median Nerve in the HandMedian Nerve in the HandEnters palm deep to flexor retinaculum.Enters palm deep to flexor retinaculum.Divides into lateral and medial branches:Divides into lateral and medial branches:

Lateral branch:Lateral branch:To thenar muscles and first lumbrical.To thenar muscles and first lumbrical.Cutaneous to anterior surface of thumb Cutaneous to anterior surface of thumb

and and radial side of index finger.radial side of index finger.Medial branch:Medial branch:

To second lumbrical.To second lumbrical.Cutaneous to adjacent sides of digits 2-4, Cutaneous to adjacent sides of digits 2-4, including nail-bed and finger tips.including nail-bed and finger tips.

Spaces in the HandSpaces in the HandThenar space:Thenar space:

Located between the palmar side of the Located between the palmar side of the adductor pollicis muscle and the long flexor adductor pollicis muscle and the long flexor tendons to the index finger and the thumb.tendons to the index finger and the thumb.

Midpalmar space:Midpalmar space:Located between metacarpals 4-5 and the Located between metacarpals 4-5 and the long flexor tendons to digits 4-5.long flexor tendons to digits 4-5.

Clinical NotesClinical Notes Mallet finger:Mallet finger:

Avulsion by long flexor tendon.Avulsion by long flexor tendon.Results in hyperflexion of DIP.Results in hyperflexion of DIP.

Dupuytren’s contracture:Dupuytren’s contracture:Progressive fibrosis of palmar aponeurosis.Progressive fibrosis of palmar aponeurosis.Results in marked flexion of fingers at MP Results in marked flexion of fingers at MP joints.joints.

Colle’s fracture.Colle’s fracture. Fracture of scaphoid.Fracture of scaphoid.

Clinical NotesClinical NotesMedian nerve injury:Median nerve injury:

Loss of thumb opposition.Loss of thumb opposition.Atrophy of thenar muscles.Atrophy of thenar muscles.Ape hand.Ape hand.

Ulnar nerve injury:Ulnar nerve injury:Paralysis and atrophy of interossei.Paralysis and atrophy of interossei.

GutteringGutteringLoss of thumb adduction.Loss of thumb adduction.Clawhand.Clawhand.

EXTENSOR MECHANISMEXTENSOR MECHANISM

ComponentsComponentsHoodHoodLateral bands:Lateral bands:

To bases of distal phalanges.To bases of distal phalanges.Central band:Central band:

To base of middle phalanx.To base of middle phalanx.Function:Function:

Flexion at MCP joint.Flexion at MCP joint.Extension at PIP, DIP joints.Extension at PIP, DIP joints.

Functional NotesFunctional NotesExtension of the PIP is always Extension of the PIP is always

accompanied by the simultaneous accompanied by the simultaneous extension of the DIP.extension of the DIP.

When the PIP is flexed, the DIP may be When the PIP is flexed, the DIP may be extended or flexedextended or flexed

Clinical NotesClinical Notes If lateral bands detach:If lateral bands detach:

Lateral bands will flex the PIP and Lateral bands will flex the PIP and hyperextend the DIP.hyperextend the DIP.