Anatomy - hand and wrist Flashcards
Describe the blood supply to the scaphoid? What is the main supply?
Dorsal carpal branch of the radial artery is the main - supplies 80% Also: Superficial palmar branch of the radial artery
Which ligament is violated and must be repaired in the volar approach to the scaphoid?
Radioscaphocapitate ligament
Which ligament is the strongest ligament that resists perilunate dislocations in the wrist?
Long radiolunate ligament
What is the weakest point in the volar wrist?
Space of Poirier
What is the significance of the Space of Poirier?
It is the weakest point in the volar wrist and is where volar lunate dislocations occur most often.
Where is the Space of Poirier located?
Volar wrist at the junction of the Lunate and Trapezium/TrapezoidBordered by the Radiocapitate & Radiolunotriquetral ligaments (aka long radiolunate)
What “ligament” in the wrist is actually a neurovascular bundle?
Radioscapholunate ligament
What are the components of the radioscapholunate ligament?
Vascular branches of the anterior interosseous and radial arteriesNerve branches of the anterior interosseous nerve
Where is the radioscapholunate ligament found?
Between the long and short radiolunate ligaments, piercing the joint capsule
What are the components of the TFCC?
Triangular fibrocartilage disc (articular disc)Meniscus homolog (disc-carpal ligaments)Volar Ulnocarpal ligaments (ulnolunate & ulnotriquetral)Dorsal and volar Radioulnar ligaments (palmar & dorsal, each with a superficial & deep component)ECU subsheath
What is the ligament of Testut?
Radioscapholunate ligament. Actually a neurovascular bundle with no contribution to carpal stability
What are the contents of the anatomical snuffbox?
Radial arterySensory branch of the radial nerveWrist joint capsuleFat
What are the borders of the anatomical snuffbox?
Trianglr: Anterior: EPB, ABL Posterior: EPL (extensor compartments 1&3)Base: radial stylus processFloor: scaphoid & trapezium
What are the stabilizers of the DRUJ?
Extrinsic:ECU tendon & SubsheathPronator quadratusInterosseous membraneJoint capsuleTFCCIntrinsic:Bony contactSuperficial radioulnar ligaments - origina at ulnar styloidDeep radioulnar ligaments (ligamentum subcruentum) origin at fovea
What are the components of the scapholunate ligament?
Dorsal (strongest)PalmarProximal (thin, membranous)
What is a lesser arc injury?
Purely ligamentous perilunate injury
What is a greater arc injury?
Fracture around the lunate - scaphoid, capitate, hamate, triquetrum
What are the extrinsic ligaments of the dorsal wrist?
Dorsal radiocarpal ligamentsDorsal intercarpal ligaments
What is Kienbock’s disease?
Avascular necrosis of the lunate.
Why do perilunate dislocations usually NOT end up in AVN?
Because it has a rich blood supply including:Dorsal and volar radial branchesBranches of the dorsal and volar intercarpal arch Anterior interosseous artery
How many articulations does the scaphoid have?
5 Radius, capitate, lunate, trapezoid, trapezium
What is intersection syndrome?
Overuse condition affecting the seconddorsal compartment - ECRL and ECRB
What is DeQuervain’s tenosynovitis?
Inflammation of the tenosynovium of the abductor pollicis longus and extensor pollicis brevis tendonsAffects 1st dorsal compartmentDiagnosed with Finklestein’s test - Increase in pain when the thumb is held in palm and wrist is ulnarly deviated - Pain is over the radial side of the wrist (1st dorsal compartment)
What is Wartenberg’s Syndrome
Radial neuritis- Neuritis of the superficial branch of the radial nerve- Inflammation due to stretch, compression or direct blow- Compression occurs between the brachioradialis and ECRL
Describe Eaton’s classification of the radiographic stages of thumb CMC OA
1: Normal2: Joint spacer narrowing, osteophytes 2mm3: Joint space narrowing, osteophytes >2mm4: pantrapezial arthritis
What is the bony articulation of the distal radioulnar joint?
Sigmoid notch of the radius articulation with the ulnai.e. “lesser” sigmoid notch
What are the stabilizers of the distal radio-ulnar joint (DRUJ)?
- Bony integrity between sigmoid notch of the radius and ulna- Interosseous membrane- TFCC- Joint capsule- Pronator quadratus- Extensor carpi ulnaris
What are the muscular attachments of the proximal row of the carpal bones?
None
What carpal bones do not contribute to carpal motion?
Pisiform: it’s a sesamoid bone of the flexor carpi ulnaris
The Pisiform is a sesamoid bone for what tendon?
Flexor carpi ulnaris (FCU)
What are the contents of the carpal tunnel?
9 flexor tendons:- 4 for flexor digitorum superficialis- 4 for flexor digitorum profundus- Flexor pollicis longusMedian nerve
What are the borders of the carpal tunnel?
Radially: scaphoid & TrapeziumUlnar: Pisiform & hamateRoof: flexor retinaculum/transverse carpal ligamentFloor: proximal carpal row & radiocarpal ligaments
During carpal tunnel release, what nerve is most at risk when cutting the transverse carpal ligament? How do you avoid it?
Recurrent motor branch of the median nerveAvoid it by making your cut as ulnar as possible- Ulnar side of the 4th digit when flexed to the palm
What are the borders of Guyon’s Canal?
Roof: volar carpal ligamentFloor: Transverse carpal ligament & hypothenar usclesRadial: Hook of hamateUlnar: Pisiform, pisohamate ligament, abductor digiti minimi muscle belly
How is Guyon’s Canal divided? What is the pathology of damaging each division?
3 zones:Zone 1: proximal to the bifurcation of the ulnar nerve - Causes mixed motor and sensory symptomsZone 2: surrounds deep motor branch of the ulnar nerve - It is more radial - Causes only motor symptomsZone 3: Surrounds superficial sensory branch of the ulnar nerve - It is more ulnar - Causes only sensory symptoms
what is the major contributor to the superficial palmar arch?
Ulnar artery- Radial has minor contributions
What is the major contributor to the deep and superficial palmar arches?
Radial artery: deepulnar artery: superficial
What muscles attach to the scaphoid>?
None
How much of the scaphoid is covered in articular cartilage?
70%
name the intrinsic hand muscles of the thenar eminence and their function:
Abductor pollicis brevis- Abducts thumb at CMC & MCPFlexor pollicis brevis- Flexes thumb at CMC & MCPOpponens pollicis- Opposition of thumb
What is the innervation of flexor pollicis brevis?
Dual innervation- Superficial: median- Deep: ulnar
What are the intrinsic hand muscles of the hypothenar eminence and their actions?
Abductor digiti minimi brevis- Abducts 5th digit at MCPFlexor digiti minimi- Flexes 5th digit at MCPOpponens digiti minimi- Opposition of 5th digit
Name the intrinsic hand muscles of the hypothenar eminence and their nervous innervation
Abductor digiti minimiFlexor digiti mimini brevisOpponens digiti minimi- All innervated by ulnar nerve
Name the intrinsic muscles of the thenar eminence and their nervous innervation:
Abductor pollicis brevis- Median nerveFlexor pollicis brevis - Dual innevation- Superficial: median nerve- Deep: ulnar nerveOpponens pollicis- Median nerve
What are the muscles of the hand innervated by the median nerve?
LOAF- Lumbricals (radial 2 aka 1 & 2)- Opponens pollicis- Abductor pollicis brevis- Flexor pollicis brevis - note this has dual innervation - Superficial: median - Deep: ulnar
What is the only muscle to originate and insert onto a tendon? Which tendons does it originate and insert into?
Lumbricals- Originate from tendons of flexor digitorum profundus- Insert into extensor expansion on dorsal aspect of each digit’s radial side
What is the function of the dorsal and palmar interossei?
Dorsal: Abduct the fingers Palmar: Adduct the fingers - Remember DAB and PAD
What is the OINA of the palmar interossei?
O: They originate on the side facing the long finger1st: ulnar side of 2nd MC2nd: radial side of 4th MC3rd: radial side of 5th MCI: Extensor expansion of 2,4,5 digitsN: ulnarA: adduction of 1,2,4,5th digitsnb: adduction/abduction is named relative to long finger
What is the OINA of the dorsal interossei?
O:1st medial head: radial side of 2nd MC1st lateral head: ulnar side of 1st MC2nd, 3rd, 4th: space between the MC bonesI:1st: radial sid of 2nd proximal phalanx2nd: radial side of 3rd PP3rd: ulnar side of 3rd PP4th ulnar side of 4th PPN: ulnarA: ABduction of 2,3,5 fingers (away from midline)
What are the O, I, N, A of the lumbricals?
O: tendons of flexor digitorum profundusI: extensor expansion on dorsal aspect of each digit’s radial sideN: 1/2: median, 3/4: ulnarA: flexion of MCP of digist 2-5 - Extension of DIP & PIP of digits 2-5
What is the OINA of the palmaris brevis?
O: Flexor retinaculumI: Palmar surface of skin on ulnar side of handN: UlnarA: Wrinkles skin on ulnar side of hand
Describe the safe position of the hand. Why is it safe?
Intrinsic plus position:- Wrist extended 10 deg- MCP Flexion to 70 deg- IP extendedIt’s safe b/c with the MCPs in flexion, the collaterals are tight (at their longest)- So they will not get tight in a shortened position (short/lax in extension)
What are the components of the extensor hood?
Central tendonLateral BandsDorsal/palmar interosseiLumbricalsOblique retinacular ligamentsSagittal bandsWorks on both the MCP and IP joints