Chapter 23 - Anatomy of the Hand and Wrist

Question 1

Anatomy of the nail bed

Answer 1

• the periosteum of the distal phalanx lies immediately palmar to the sterile and germinal matrices
• distance from the extensor tendon insertion to the proximal germinal matrix is 1.2-1.4mm

Question 2

what acts as the palmar stabilizer of the MCPJs?

Answer 2

palmar plate -> connected to the deep transverse metacarpal ligament

Question 3

The digital fascia is composed of:

Answer 3

• spiral bands: originate on the pretendinous band, passes DORSAL to the neurovascular bundle to insert on the lateral digital sheet
• natatory ligament: occupies interdigital web spaces
• grayson’s ligament: originate form the palmar flexor sheath. pass palmar to the NV bundles to insert to the skin. these fibers are PREPENDICULAR to the digital axis
• Cleland’s ligament: originate at the phalanx, pass dorsal to the NV bundle to insert on skin. FOUR on each side of the finger: two adjacent to the PIPJ, two adjacent to the DIPJ

Question 4

compartments of the forearm (3)

Answer 4

1. palmar
   - can be divided into deep and superficial
   - deep: PQ, FDP, FPL (ulnar n/a, median n, radial a)
   - superifical: FDS, FCR, FCU, palmaris longus, pronator teres
2. dorsal: APL, EPB, EIP, EPL, EDC, ECU, EDM, supinator, radial n
3. mobile wad: BR, ECRL, ECRB

Question 5

Compartments of the Hand

Answer 5

1. thenar: opponens policis, abductor policis brevis, flexor policis brevis
2. adductor policis
3. hypothenar compartment: abductor digiti minimi, oponens digiti minimi, flexor digiti minimi brevis
4. four dorsal interossei
5. three palmar interossei
6. carpal tunnel

Question 6

Collateral ligaments of the MCP joints are _______ in flexion, and ________ in extension

Answer 6

tight in flexion, loose in extension
therefore - the MCPJs are stable in flexion, and unstable in extension

Question 7

MCP joint of the fingers are ______________ joints (type)

Answer 7

tri-axial condyloid

Question 8

IP joints of the fingers are ______________ joints (type)

Answer 8

hinge=

Question 9

IPjoint colateral ligament anatomy

Answer 9

Two slips: BOT originate at the pit on the head of the proximal phalanx
1. proper slip: inserts onto the lateral tubercle at the base of the middle phalanx
2. accessory slip: inserts onto the volar plate

Question 10

Extensor tendon anatomy

Answer 10

extrinsic extensor tendon trifurcates at the base of P1 - the central portion becomes the central slip and inserts onto the dorsal base of P2
- lateral slips are joined by contributions of the extensor hood to form the lateral bands. lateral bands converge over the middle phalanx to form the terminal tendon, inserting at the base of P3

Question 11

Anatomy of the flexor tendons at the finger

Answer 11

At the level of the A1 pulley - the FDS flattens and bifurcates to allow FDP to come from deep to superficial in order to insert onto the base of P3
- each slip of the DFS that has bifurcated then splits again into medial and lateral slips
- the medial slips of both FDS slip meet back together at Camper’s chiasm over the distal P1, joining the volar plate
- the lateral slips of both FDS slips continue on to insert at the base of P2

Question 12

Flexor tendon vascular supply

Answer 12

Direct vascular supply (transverse digital arteries arising form the digital arteries to supply the vincular system, and direct arterial supply from intraosseous vessels at the tendinous insertions)
Synovial diffusion (avascular zones of FDS and FDP within the flexor tendon sheath rely on intratendinous canaliculi for synovial diffusion)

Question 13

the EIP and EDM are commonly located _________ to the EDC tendon in the dorsum of the hand

Answer 13

ulnar

Question 14

intrinsic mm of the hand - interosseous mm

Answer 14

Interosseous: originate from the metacarpal diaphyses, pass dorsal to the deep transverse intermetacarpal ligament, ulnar nerve innervation (first may be innervated by median)
Dorsal interossei (4) - BI-pennate. two mm bellies - one superficial and one deep. Superficial (passes under the sagittal hood to become the lateral tendon) acts to abduct the digit, deep (passes over sagittal hood to become lateral tendon) acts to flex the MCPj

Question 15

intrinsic mm of the hand - lumbricals

Answer 15

originate on the FDP tendon. Pass palmar to the deep intertransverse metacarpal ligament - on the RADIAL SIDE of each digit
insert onto the radial lateral band of the extensor apparatus
extend the PIP and the DIP
1/2 - are unipennate, and median innervation
3/4 - are bipennate and ulnar innervation

Question 16

primary blood supply to the scaphoid

Answer 16

branch of the radial artery at the doral ridge

secondary supply - group of smaller vessels entering the palmar tubercle supplies the distal 30%

Question 17

Capitate articulations

Answer 17

three facets separated by two ridges - articulates with index, long, and ring metacarpals

Question 18

Pisiform anatomic location

Answer 18

within the FCU tendon, serves as the origin for the abductor digiti minimi

Question 19

Dorsal Extrinsic wrist ligaments

Answer 19

dorsal intercarpal ligament
dorsal radiocarpal ligament

Question 20

Intrinsic wrist ligaments

Answer 20

Scapholunate interosseous ligament (dorsal third is the thickest/strongest portion of the ligament)
Lunotriquetral interosseous ligament (volar portion is the thickest)

Question 21

TCC

Answer 21

composed of the central meniscus homolog, the dorsal and palmar radioulnar ligaments, the floor of the ECU tendon sheath, volar ulnocarpal ligaments
originates from the radial boredr to the dital radius, and inserts onto the base of the ulnar styloid and distal ulna thru the ligamentum subcruentum

Question 22

Primary stabilizers of the distal radioulnar joint

Answer 22

dorsal and volar radioulnar ligaments

Question 23

Carpal kinematics - ulnar deviation

Answer 23

with ulnar deviation - the proximal row EXTENDS relative to the forearm and the distal row

Question 24

carpal kinematics - radial deviation

Answer 24

with radial deviation - the proximal row FLEXES relative to the forearm an the distal row