Diagnostic Ultrasound-Musculoskeletal (Arrastrado)

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TERMINOLOGYDefinitions Articulation complex comprising distal radioulnar,

radiocarpal, ulnocarpal, pisotriquetral, midcarpal, andcarpometacarpal joints

IMAGING ANATOMYOsseous Structures Distal radius: Lister tubercle on dorsal surface Distal ulna: Ulnar variance refers to length of ulnar

head relative to distal radius: Ulnar minus or ulnar plus Proximal carpal row: Scaphoid, lunate, triquetrum,

pisiform Scaphoid: Proximal and distal pole separated by waist

Tuberosity = volar prominence of distal pole Lunate: Half-moon-shaped Triquetrum: Triangular-shaped Pisiform: Pea-shaped sesamoid-type bone to which

flexor carpi ulnaris attaches and continues distally aspisohamate and pisometacarpal ligaments

Distal carpal row: Trapezium, trapezoid, capitate,hamate Trapezium: Saddle-shaped bone linking carpus and

thumb Trapezoid: Wedge-shaped bone Capitate: Head (proximal), neck (midportion), and

body (bulky distal portion) Hamate: Hook (hamulus) arises from palmar surface

Ligaments Extrinsic (on palmar or volar aspects of wrist) or

intrinsic (between carpal bones) Major wrist stabilizers: Volar ligaments Extrinsic ligaments

Palmar: Radioscaphocapitate, radiolunotriquetral,radioscapholunate, ulnotriquetral, ulnolunate,scaphotriquetral

Dorsal: Scaphotriquetral, radiotriquetral,ulnotriquetral, radial collateral

Intrinsic ligaments Proximal interosseous: Scapholunate, lunotriquetral Distal interosseous: Trapeziotrapezoid,

trapeziocapitate, capitohamate

Muscles and Tendons Flexors, deep

Flexor digitorum profundus: Originated from ulna;inserted to index, middle, ring, and little finger distalphalangeal bases

Flexor pollicis longus: Originated from radius,interosseous membrane and coronoid process ofulna; inserted to distal phalangeal base of thumb

Flexors, superficial Flexor carpi radialis: Originated from medial

epicondyle; inserted to 2nd metacarpal base Palmaris longus: Originated from medial epicondyle;

inserted to palmar aponeurosis Flexor carpi ulnaris: Originated from medial

epicondyle and medial olecranon/proximal ulna;inserted to pisiform

Flexor digitorum superficialis: Originated frommedial epicondyle and coronoid process of ulna andanterior radius; inserted to middle phalangeal basesof digits 2-5

Extensors, deep Abductor pollicis longus: Originated from ulna;

inserted to radial aspect 1st metacarpal base Extensor pollicis brevis: Originated from radius;

inserted to proximal phalangeal base of thumb Extensor pollicis longus: Originated from midulna;

inserted to distal phalangeal base of thumb Extensor indicis: Originated from midulna; joins

ulnar side of extensor digitorum tendon insertinginto 2nd digit extensor hood

Extensors, superficial Extensor carpi radialis longus: Originated from lateral

supracondylar ridge of humerus; inserted to dorsalradial 2nd metacarpal base

Extensor carpi radialis brevis: Originated from lateralhumeral epicondyle; inserted to dorsal radial 3rdmetacarpal base

Extensor digitorum: Originated from lateral humeralepicondyle; inserted to distal phalangeal bases ofdigits of 2-5

Extensor digiti minimi: Originated from lateralhumeral epicondyle; inserted to extensor hood oflittle finger

Extensor carpi ulnaris: Originated from lateralhumeral epicondyle; inserted to 5th metacarpal base

Retinacula Flexor retinaculum

Also called transverse carpal ligament: Attachedto pisiform and hook of hamate, scaphoid, andtrapezium

Extensor retinaculum Attaches to ulnar styloid process, triquetrum, and

pisiform medially; crosses obliquely to attach to Listertubercle and radial styloid process laterally Sends septa to radius, creating 6 compartments for

extensor tendons Compartment contents

1st: Abductor pollicis longus (APL) and extensorpollicis brevis (EPB)

2nd: Extensor carpi radialis, longus (ECRL) andbrevis (ECRB)

3rd: Extensor pollicis longus (EPL) 4th: Extensor digitorum (ED) and extensor indicis

(EI) 5th: Extensor digiti minimi (EDM) 6th: Extensor carpi ulnaris (ECU)

Anatomic Spaces Carpal tunnel

Margins: Carpal bones (dorsal margin); flexorretinaculum (volar margin); pisiform and hook ofhamate (ulnar margin); scaphoid and trapezium(radial margin); radiocarpal joint (proximal margin);and metacarpal base (distal margin) Contents: Flexor digitorum superficialis, flexor

digitorum profundus, flexor pollicis longus,median nerve

Guyon canal Margins: Fascial extension from flexor retinaculum,

volar carpal ligament (volar margin), pisiformand flexor carpi ulnaris (ulnar margin), flexorretinaculum (radial and dorsal margins) Contents: Ulnar artery and vein, ulnar nerve

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GRAPHICS, CARPAL BONES AND WRIST COMPARTMENTS

Capitate

Hamate

Pisiform

Lunate

Triquetrum

Ulna

Distal radioulnar joint

1st metacarpal

1st carpometacarpal joint

Trapezium

Scaphoid

Radial styloid process

Trapezoid

Common carpometacarpalcompartment

Pisotriquetral compartment

Distal radioulnarcompartment

Radiocarpal compartment

Midcarpal compartment

1st carpometacarpalcompartment

(Top) Graphic shows the bones of the wrist joint. (Bottom) Graphic shows the 5 different wrist compartments: Distal radioulnar compartmentis separated from the radiocarpal compartment by the triangular fibrocartilage complex (TFCC). Pisotriquetral compartment is separated fromthe radiocarpal compartment in 20%. Midcarpal compartment is separated from the radiocarpal compartment by the scapholunate andlunotriquetral ligaments and typically communicates with the carpometacarpal joints. First carpometacarpal compartment is separated from thecommon carpometacarpal compartment by the trapeziometacarpal ligament.

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GRAPHICS, DORSAL TENDONS AND TENDON SHEATHS

Abductor pollicis longustendon

Extensor pollicis longustendon

Extensor pollicis brevistendon

Extensor carpi radialis brevistendon

Extensor carpi radialislongus tendon

Extensor carpi ulnaristendonExtensor digiti minimitendon

Extensor retinaculum

Extensor digitorum tendon

Extensor indicis tendon

Compartment 1: APL, EPB

Compartment 2: ECRL,ECRB

Compartment 3: EPL

Compartment 6: ECU

Compartment 5: EDM

Compartment 4: ED, EI

(Top) Dorsal extensor tendons pass deep to the extensor retinaculum, separated into 6 compartments by fibrous attachments of the retinaculumto underlying bone. Compartment contents include abductor pollicis longus (APL) and extensor pollicis brevis (EPB), extensor carpi radialislongus (ECRL) and brevis (ECRB), extensor pollicis longus (EPL), extensor digitorum (ED) and extensor indicis (EI), extensor digiti minimi (EDM),and extensor carpi ulnaris (ECU). (Bottom) Separate tendon sheaths enclose dorsal extensor tendons in compartments 1-6 individually.

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GRAPHICS, TENDONS: RELATIONS TO DORSAL & VOLAR WRIST

Flexor carpi ulnaris

Flexor digitorumsuperficialis tendon

Flexor digitorum profundustendon

Extensor carpi ulnaristendon

Extensor digiti minimitendon


Extensor digitorum tendonslips

Ulnar nerve

Palmaris longus tendon

Flexor carpi radialis tendon

Flexor pollicis longustendon



Extensor carpi radialislongus tendon

Extensor carpi radialis brevistendon

Median nerve


Extensor digitorum tendonslips


Extensor digiti minimitendon

Extensor carpi ulnaristendon

Flexor digitorum tendon

Volar carpal ligament

Abductor digiti minimitendon

Ulnar nerve

Flexor retinaculum



Extensor carpi radialis brevis& longus tendon



Median nerve


(Top) Graphic representation shows tendons in the proximal wrist. Extensor tendons are deep to the extensor retinaculum, whereas flexortendons are proximal to the flexor retinaculum at this level in the wrist. (Bottom) Midcarpal tunnel is shown. Median nerve is slightly flattenedas it passes deep to the flexor retinaculum and remains superficial to the flexor pollicis longus. Ulnar nerve, artery, and veins lie lateral to thepisiform and may divide near the pisiform into deep and superficial branches.

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TRANSVERSE US, RADIAL ASPECT

2nd compartment tendons

Distal end of radius

Cephalic vein

1st compartment tendons

Extensor pollicis brevis tendon

Abductor pollicis tendon

Radius

Scaphoid

Cephalic vein

Extensor pollicis brevis tendon

Radial veins

Radial artery, superficial and deepbranch

Abductor pollicis longus tendon

(Top) Transverse grayscale US shows the 1st extensor compartment proximal to the distal radius. The 1st compartment contains the extensorpollicis brevis (EPB) and the larger abductor pollicis longus (APL) tendons. The 1st compartment tendons run obliquely over 2nd compartmenttendons a few centimeters proximal to the wrist. Pain may occur at this intersection (intersection syndrome). (Middle) Transverse grayscale USshows the 1st extensor compartment at the distal radius. EPB extends to the base of the proximal phalanx of the thumb, whereas APL insertsonto the base of the 1st metacarpal bone. They form the radial aspect of the anatomical snuff box. These tendons are swollen in patients with deQuervain disease. (Bottom) Transverse grayscale US shows the 1st extensor compartment at the level of the scaphoid. Dorsal branch of the radialartery passes deep to the tendons of the 1st extensor compartment to enter the dorsum of the hand.

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TRANSVERSE US, DORSAL WRIST

Extensor pollicis longus tendon

Extensor carpi radialis brevis tendon

Lister tubercle Extensor carpi radialis longus tendon

Cephalic vein

Radius



Radius


Extensor carpi radialis longus tendon

Scaphoid Extensor pollicis longus tendon

(Top) Transverse grayscale US shows the 2nd & 3rd extensor compartments at the distal radius level. The 2nd extensor compartment comprisesthe extensor carpi radialis longus (ECRL) and extensor carpi radialis brevis (ECRB). ECRL inserts into the base of the index finger metacarpal,whereas ECRB inserts into the middle finger metacarpal. The 2nd compartment is separated from the 3rd compartment, containing the extensorpollicis longus (EPL), by the Lister tubercle. (Middle) Transverse grayscale US shows the 2nd and 3rd extensor compartments at the distal radiuslevel. The 2nd compartment forms the dorsal aspect of the anatomical snuff box. (Bottom) Transverse grayscale US shows the 2nd extensorcompartment at the scaphoid level. The EPL tendon hooks around the Lister tubercle and crosses superficial to the 1st compartment tendons asit runs toward its insertion on the base of the distal phalanx of the thumb. It is prone to rupture in inflammatory arthropathies and distal radialfractures.

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TRANSVERSE US, EXTENSOR DIGITORUM

Extensor digiti minimi tendon

Ulna


Lister tubercle



Radius

Lunate




Scaphoid

Lunate

Extensor digitorum tendonsScapholunate ligament (dorsalcomponent)

Scaphoid


(Top) Transverse grayscale ultrasound shows the 4th extensor compartment at the distal radius. The 4th extensor compartment contains the 4extensor digitorum tendons and the extensor indicis tendon, which lies radial to the extensor digitorum tendons. The extensor digiti minimi hasa separate compartment. (Middle) Transverse grayscale ultrasound shows the 4th extensor compartment at the level of the proximal carpal row.The extensor retinaculum is a thickened continuation of the antebrachial fascia. It is attached to the anterior aspect of the distal radius, styloidprocess of the ulna, and the triquetral and pisiform bones. (Bottom) Transverse grayscale ultrasound shows the 4th extensor compartment atthe level of the proximal carpal row. The extensor retinaculum holds the extensor tendons in place. Because it is closely applied to the extensortendons, with anisotropy, it may appear hypoechoic and be confused with tenosynovitis.

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TRANSVERSE US, EXTENSOR CARPI ULNARIS

Extensor carpi ulnaris tendon

Ulna Extensor digiti minimi tendon

Radius


Articular disc

Radius



Hamate

Capitate

(Top) Transverse grayscale ultrasound shows the 5th and 6th extensor compartments. The 5th compartment contains the extensor digiti minimi(EDM) tendon. This tendon is joined by the extensor digitorum (ED) tendon to the little finger just proximal to the metacarpophalangeal (MCP)joint. The 6th compartment contains the extensor carpi ulnaris (ECU) tendon, which runs in a groove in the distal ulna. Its position in the groovewill change with pronation and supination. (Middle) Transverse grayscale ultrasound shows the 5th and 6th extensor compartments. The ECUtendon often has a midline irregular hypoechoic line within its substance close to the insertion. This should not be mistaken for a longitudinaltear. (Bottom) Transverse grayscale ultrasound at insertion of the ECU tendon is shown. The ECU tendon widens as it passes the lunate bone onits way to insert into the base of the 5th metacarpal.

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GRAPHICS, VOLAR WRIST

Hypothenar eminence

Flexor retinaculum

Flexor digitorum profundustendons

Flexor digitorumsuperificialis tendons

Flexor carpi ulnaris tendon

Pronator quadratus muscleFlexor pollicis longusmuscle and tendon




Thenar eminence

Opponens digiti minimimuscle

Flexor digiti minimi brevismuscle

Abductor digiti minimimuscle

Flexor digitorumsuperficialis tendons

Pronator quadratus muscle

Flexor carpi ulnaris tendon

Flexor digitorum profundustendons




Flexor retinaculum

Abductor pollicis brevismuscle

Flexor pollicis brevis muscle



(Top) Graphic shows tendons and retinaculum of the volar wrist. The flexor retinaculum spans the palmar arch, attaching to the to the tubercleof the scaphoid, the pisiform, the hook of hamate, and the ridge of the trapezium. The thenar eminence musculature includes abductor pollicisbrevis, opponens pollicis, flexor pollicis brevis, and adductor pollicis. The hypothenar eminence musculature includes palmaris brevis, adductordigiti minimi, flexor digiti minimi brevis, and opponens digiti minimi. (Bottom) Volar muscles and tendons are displayed with their relation tothe flexor retinaculum. Note the muscles of thenar and hypothenar eminences arise from the retinaculum itself. The flexor digitorum and flexorpollicis longus tendons pass deep to the retinaculum. On the radial side, the retinaculum splits to accommodate the flexor carpi radialis tendon.

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TRANSVERSE US, VOLAR WRIST

Radial artery

Palmaris longus tendon

Median nerve

Flexor digitorum superficialis muscle

Radius


Flexor pollicis longus tendon Flexor digitorum profundus muscle

Pronator quadratus muscle

Anterior interosseous artery, vein, &nerve

Interosseous membrane

Ulna


Median nerve

ScaphoidFlexor tendons

Lunate

Triquetrum

ScaphoidFlexor tendons

Capitate


Flexor retinaculum

Extrinsic carpal ligamentUlnar artery, vein, & nerve

Median nerve

Pisiform

(Top) Transverse grayscale ultrasound shows the volar aspect of the distal forearm just proximal to the wrist. In addition to the tendons thatpass through the carpal tunnel, the flexor carpi ulnaris, flexor carpi radialis, and palmaris longus tendons also traverse the wrist joint. (Middle)Transverse grayscale ultrasound shows the volar aspect of the wrist just proximal to the carpal tunnel. The 4 tendons of flexor digitorumsuperficialis (FDS), 4 tendons of flexor digitorum profundus (FDP), and flexor pollicis longus (FPL) tendons pass through the carpal tunnel.The median nerve dips deeply as it enters the carpal tunnel. (Bottom) Transverse grayscale ultrasound shows the volar aspect of the wrist atthe tunnel inlet. The inlet (and outlet) of the carpal tunnel can be best recognized by identifying the proximal and distal margins of the flexorretinaculum. In evaluating carpal tunnel syndrome, the caliber of the nerve should be measured proximal to the tunnel, at the tunnel inlet, and atthe tunnel outlet.

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US, VOLAR WRIST

Abductor pollicis brevis muscle

Trapezium

Flexor tendons

Median nerve

Ulnar artery

Opponens pollicis muscle

Capitate

Ulnar nerve & vein

Flexor retinaculum

Base of 3rd metacarpal

Trapezium

Opponens pollicis muscle

Hook of hamate

Flexor tendons

Capitate


Flexor retinaculum

Median nerve

Flexor pollicis longus tendon

Metacarpal of index finger

Flexor pollicis brevis muscle

Opponens pollicis muscle Metacarpal of ring finger

Flexor tendons

Adductor pollicis muscle


Metacarpal of 3rd finger

Ulnar artery

Branch of median nerve

(Top) Transverse grayscale ultrasound shows the volar aspect at midcarpal tunnel. The median nerve lies in the carpal tunnel just deep to theretinaculum. You may need to use anisotropy to clearly identify the margins of the median nerve separate from the adjacent flexor tendons.(Middle) Transverse grayscale ultrasound shows the volar aspect of the wrist at the tunnel outlet. The tunnel outlet is considered to be thenarrowest part of the carpal tunnel. (Bottom) Transverse grayscale ultrasound shows the volar aspect of the wrist just beyond the tunnel outlet.The median nerve divides into its terminal branches just beyond the tunnel outlet.

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US, SCAPHOID

Distal part of scaphoid

Waist of scaphoid


Joint

Proximal part of scaphoid

Radius

Trapezium

Radial artery

Articular cartilage

Scaphoid

Radius

Trapezium

Scaphoid

Articular cartilage

Radial artery

(Top) Grayscale ultrasound longitudinal to palmar aspect of the scaphoid bone is shown. Ultrasound is a useful means of diagnosing a scaphoidfracture. Angulation of the transducer along the long axis of the scaphoid allows the palmar cortical outline to be appreciated. (Middle)Grayscale ultrasound longitudinal to dorsal aspect of the scaphoid bone is shown. There is often mild cortical irregularity of the scaphoid surface,particularly on the dorsal side. The absence of surrounding edema, hematoma, periosteal thickening, and cortical discontinuity allows one todifferentiate this normal appearance from a fracture. (Bottom) Grayscale ultrasound transverse to dorsal aspect of the scaphoid bone is shown.

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GRAPHICS AND US, TRIANGULAR FIBROCARTILAGE

Ulnar collateral ligament

Extensor carpi ulnaris

Ulnar styloid process

Ulnocarpal ligament

Dorsal radioulnar ligament

Volar radioulnar ligament

Extensor carpi ulnaris tendonDorsal radioulnar ligament

Articular disc


Triquetrum

Articular cartilage

Articular disc (fibrocartilage)

Ulnar head

(Top) Graphic shows supporting structures of triangular fibrocartilage (TFCC). The ulnocarpal ligaments and the volar radioulnar ligament are onthe volar side. At the ulnar border, there is the ulnar collateral ligament. On the dorsal surface, there is the extensor carpi ulnaris (ECU) tendonand its subsheath as well as the dorsal radioulnar ligament. (Middle) Graphic depicts the axial view of the articular disc of TFCC. The articulardisc is inseparable from supporting dorsal and volar radioulnar ligaments. The disc is widest at its radial attachment. Central tears are morecommon, while peripheral tears, being better vascularized, have the capacity to heal. (Bottom) Longitudinal grayscale ultrasound shows the ulnaraspect of TFCC. The fibrocartilaginous articular disc is of different echotexture to hypoechoic hyaline cartilage. US is not as sensitive at depictingTFCC tears as MRI. The ECU tendon provides an acoustic window though which to see the articular disc of the TFCC.

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GRAPHICS, VOLAR AND DORSAL LIGAMENTS

Carpometacarpal ligaments

Capitohamate ligament

Triquetrocapitate ligament

Ulnotriquetral ligament

Lunotriquetral ligament,volar portion

Ulnocapitate ligament

Ulnolunate ligament

Volar radioulnar ligament

Trapeziocapitate ligament

Scaphotrapezium-trapezoidligament

Interligamentous sulcus

Radial collateral ligament

RadioscaphocapitateligamentLong radiolunate ligament

RadioscapholunateligamentShort radiolunate ligament

Dorsal scaphotriquetralligament

Dorsal intercarpal ligament

Trapeziotrapezoid ligament

Dorsal radioulnar ligament

Dorsal radiocarpal ligament

Carpometacarpal ligaments

Capitohamate ligament

Triquetrohamate ligament

(Top) Graphic shows volar intrinsic and extrinsic ligaments. The extrinsic ligaments connect the bones of the forearm (radius and ulna) and thoseof the carpus. The intrinsic ligaments connect carpal bones to carpal bones. (Bottom) Dorsal ligaments stabilize and restrict motion but are lesscritical to the stability of the wrist structures than the volar ligaments. On the volar aspect of the wrist, there is a triangular area of weakness(called the space of Poirier) between the lunate and capitate, which is not covered by any ligaments.

Documents

Diagnostic Ultrasound-Musculoskeletal (Arrastrado)