Hand Anatomy

Anatomy of the Hand KHALID AYOUB 03/03/03

TOPICS • • • • • • •

Osteology Arthrology Extensor tendon Flexor tendon Nerve supply Blood supply Common pathological conditions

Osteology Carpus: • Mostly articular • No tendon insertion

P

• Intrinsic Ligaments • Shape

R

Osteology Carpus: • • • • •

Mostly articular No tendon insertion Intrinsic Ligaments Shape Ossification

1 6 2

PP

6

<1 4

6

5

5 1 R

ARTHROLOGY A). Radiocarpal joint; Radius TFC

Scaphoid Lunate Triquetrum

ARTHROLOGY Extrinsic Ligaments 1. Radio-scapho-lunate (Lig. Of Testut) 2. Radial collateral 3. Palmar radiocarpal; - Radio-scapho-capitate - Radio- lunate 4. Radio-luno-triquetral

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ARTHROLOGY 5. Palmar Ulnocarpal : Ulno-lunate Ulno-triquetral 6. Ulnar collateral 7. Dorsal radiocarpal = Dorsal radiotriquetral 8. . Tranverse carpal Lig

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ARTHROLOGY B) Distal radio-ulnar joint •

Stabilised by TFCC:

1. Articular disc 2. Meniscal homologue 3. UCL 4. Palmar Ulnocarpal Lig 5. Dorsal & Ulnar RU Lig 6. Extensor carpi ulnaris sheath.

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ARTHROLOGY C). Intercarpal Joints Supported by Intrinsic Ligaments & Shape >>

D) Pisiform articulation E) Midcarpal Joint; Between the proximal and distal carpal rows

ARTHROLOGY

Distal Row Proximal Row

ARTHROLOGY

PH

F) Metacarpo-Phalangeal Joint • Ellipsoid joints • Volar plate • Collateral lig • Deep transvers MC Lig

MC

ARTHROLOGY G). Interphalangeal joint • Hinge joint • Volar plate • Collateral Lig • Accessary Lig

EXTENSOR APPARATUS A. Wrist • Extensor Retinaculum • 6 compartments

EXTENSOR APPARATUS B. Hand • EDC • EDM • EI

EXTENSOR APPARATUS C. MP Joints • Interosseous M. • Common Extensor Tendon • Sagital band • Lateral Band/Tendon • Transversr/Oblique I. L. • Lumbrical M.

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EXTENSOR APPARATUS D. Finger IP Joint • Central slip • Lateral slip • Transverse Retinacular Lig • Oblique Retinacular Lig

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Swan neck deformity Causes 1. Long extensor overactivity • Mallet deformity (1o) • Exterinsic spasticity • Intrinsic tightness 2. Failure of the volar stabilisation PIP J (Mallet deformity 2o) • Volar plate insufficiency • FDS insufficincy • Joint laxity

Boutonniere deformity 1. Rupture of the central slip 2. Volar dislocation of the lateral band 3. More efficient pull of the lateral band on the DIP J

Carpal Tunnel • From distal radius to MC bases • Radial wall; Scaphoid, trapezium • Ulnar wall; triquetrum, pisiform, hamate • Floor: Lunate, capitate, proximal MC • Roof: Flexor Retinaculum

Carpal Tunnel Componants of the roof: 1. Deep forearm fascia 2. Transverse carpal lig: - Scaphoid tubercle - Trapezium ridge - Pisiform - Hamate hook 3. Conjoined aponeurosis between thenar & hypothen.

Carpal Tunnel • Over:- Ulnar nerve and artery(Guyon) - Palmar cutaneous br. of Median N. - Palmar cutaneous br. of Ulnar N. • Contents: -Tendon X 9 - Median Nerve (on the radiopalmar aspect of the tunnel and dorsal or dorsoradial to PL

PALM • Palmar aponeurosis

PALM Palmar Spaces

PALM • Deep Palmar abscess

PALM • Synovial Sheath & Bursa

FINGERS • Superficial layer • Ligaments

FINGERS Cross-section

FINGER FLEXOR • Fibrous flexor sheath • FDS pulley system • FDP - Annulus • Synovial flexor sheath - Cruciate

FINGER FLEXOR

NAIL • Nail plate: - Body - Root • Nail bed: - Sterile matrix - Germinal matrix • Eponychiam • Labia ungues

MUSCLES ACTION Muscle

Function

Nerve supply

ED

Finger extension (MP Post. Inteross. N joint)

Dorsal Inteross

Finger Abduction Flex MP+ext IP

Palmar Inteross

Finger adduction FlexUlnar MP+ext IP

Lumbricals

Flex MP+ext IP

Ulnar

Median + Ulnar

Palmaris longus Flexion wrist/finger/ Median

Thumb Opposition Complex motion made by; • Thumb Abd … APB • Thumb pronation ….APB • Flexion CMC & MP

Mov>>>

Ulnar nerve • C7,8,T1 • Forearm: FCU & Ulnar half FDP Palmar & Dorsal Cut branches • Wrist: In Guyon canal (on Flexor Retin.) • Hand: Superficial Br Deep Br: - Hypothenar - Inteross - Add. P - Two ulnar lumbrical

Ulnar Nerve Dysfunction • Low lesion: (Below elbow) Loss innervation to the hand small muscles only

+ Preserve forearm

innervation (Ulnar FDP)

= Sever ulnar Claw Hand

deformity

Ulnar Nerve Dysfunction • High lesion (At elbow or above) Loss innervation below elbow (including FDP)

= less sever ulnar claw hand deformity

⇒ Ulnar paradox

Median Nerve • Roots: C6,7,8,T1 • Elbow: - PT, FCR,PL, FDS • Forearm: Anterion interosseous branch; [FDP (radial), FPL, PQ] • Wrist: Palmer cutaneous branch (5 cm proximal to wrist crease between PL & FCR) • Hand: -3 Thenar m. (APB, FPB,OP) - 2 radial lumbricals - 3 ½ radial fingers

Median Nerve Dysfunction Level of injury of main trunk 1. Below wrist >>>> APB (Simian Hand) 2. Mid-forearm>> palm sensation 3. Upper forearm >> Pinch test> Anterion interosseous palsy 4. Elbow and above >> Check FDS

Redial Nerve • • •

•

Roots: C5,6,7,8,T1 Above elbow: Muscular = Br., BR, ECRL Elbow: 1. Superficial terminal br. = sensory to hand 2. Deep terminal br. (Post. Inteross) >> ECRB, Supinator Forearm: - Deep terminal (Post. Inteross) br. >>> ED, EDM, ECU, APL, EPB, EPL, EI

Redial Nerve Dysfunction • Wrist >> Check sensation • Forarm: Check for post. Inteross nerve palsy >>>>> EPL, EI, ED (no sensory loss) • Elbow and above: Wrist extension

SENSORY DISTRIBUTION 1. Ulnar N. 2. Median N 3. Radial N.

Blood Supply 1. Ulnar A. •

Radial to FCU

•

Forms the superficial palmar arch ?with superficial palmar br. of radial artery

•

Gives 4 common palmar digital art.

•

Fingers: dorsal to the nerve

Blood Supply 2. Radial A. • Radial to FCR • Beneath APL …. Floor of ASB • Forms the Deep palmar arch with deep br. of ulnar ar. 1 cm proximal to Superficial arch

Scaphoid • Dorsal carpal br. supply the scaphoid dorsoditally • Two thirds …. Throughout the length • 20% ….. Only in the waist • 13% …. Only in distal 1/3

Scaphoid • Pedicled vascularised bone graft • Arterial supply of dorsal distal radius • 1,2 intercompartmental supraretinacular artery

Basic Function 1. Precision pinch

Basic Function 2. Pulp pinch: Pinch Dynamometer (25 kg)

Basic Function 3. Key pinch: Pinch Dynamometer (6-10 kg)

Basic Function 4. Chuck grip:

Basic Function 5. Hook grip

Basic Function 6. Span grasp:

Basic Function 7. Power grip

Basic Function 8. Flat hand:

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