FACTS & HINTS

HIGH-YIELD FACTS

Clinical Points

Subluxation of the Radial Head (Nursemaid Elbow)

Caused bysudden pulling on the upper limb with the forearm pronated

Distal attachment of the annular ligament is torn and radial head slips out, trapping the ligament between it and the capitulum Preschool children, especiallygirls, most vulnerable

Head of radius is repositioned bysupinating forearm fullyand then flexing elbow

Bursitis of the Elbow

Repeated pressure or friction on a bursa maycause it to become inflamed and tender

Subcutaneous olecranon bursitis ("student's elbow") most common, often occurring in students (from resting elbows on desk), darts players and from falls and abrasions to the elbow

Subtendinous olecranon bursitis less common, as is bicipitoradial bursitis

Epicondylitis

Activities involving repetitive movements of wrist maylead to localized elbow pain

Repeated extension of wrist causes lateral epicondylitis ("tennis elbow")-microtrauma of common extensor muscle origin, with pain felt over the lateral aspect of the elbow

Medial epicondylitis ("golfer's elbow") from repeated wrist flexion, with pain felt over the medial epicondyle, especiallyon resisted wrist flexion

Bursitis or synovitis maycoexist with epicondylitis

MNEMONICS

Memory Aids

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47 Wrist and Hand

STUDYAIMS

At the end of your study, you should be able to:

Describe the radiocarpal joint, its movements, and supporting ligaments

Know the bones of the hand and their organization

Describe the movements at the carpometacarpal, metacarpophalangeal, and interphalangeal joints

Describe the organization of the deep fascia of the hand

Understand the arrangement of the intrinsic muscles of the hand

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GUIDE

Upper Limb: Wrist and Hand

[Plate 441, Movement of Wrist]

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[Plate 442, Ligaments of Wrist]

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[Plate 443, Ligaments of Wrist (Continued)]

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[Plate 445, Wrist and Hand Radiographs]

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[Plate 455, Wrist and Hand: Superficial Radial Dissection]

Wrist (Radiocarpal) Joint

Biaxial synovial joint

Located at a line joining the styloid processes of the radius and ulna

Articulation of distal end of radius and articular disc of radioulnar joint with the proximal row of carpal bones (except the pisiform)

Fibrous capsule surrounds the wrist

From distal ends of radius and ulna to proximal row of carpal bones

Lined bya synovial membrane with numerous folds

Movements

Flexion/extension

Abduction/adduction (radial/ulnar abduction)

Circumduction

Adduction greater than abduction

Ligaments

Dorsal and palmar radiocarpal ligaments from the radius to the two rows of carpals on the palmar and dorsal sides

Ulnar collateral ligament from the ulnar styloid process to the triquetrum

Radial styloid ligament from the radial styloid process to the scaphoid

Blood supply: Branches of the dorsal and palmar carpal arches

Nerve supply

Anterior interosseous branch of median nerve

Posterior interosseous branch of radial nerve Dorsal and deep branches of ulnar nerve

Hand

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Bones (27)

Carpal bones (bones of the wrist or carpus)

Proximal row: Scaphoid, lunate, triquetrum, pisiform,

Distal row: Trapezium, trapezoid, capitate, hamate

Metacarpals (5) consist of

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Base (proximal)-articulate with distal row of carpal bones

Body

Head (distal)-articulate with proximal phalanges and form knuckles

Phalanges (14)

Each digit has three phalanges: proximal, middle, and distal, except for

Thumb (has two)

Each phalanxhas a base (proximal), body, and head (distal)

Decrease in size from proximal to distal

Major Joints of the Hand

Carpometacarpal, metacarpophalangeal, and interphalangeal are all synovial joints supplied bybranches of adjacent vessels and nerves Intercarpal joints

Joints between carpal bones of first row and joints between carpal bones of second row

Midcarpal joint between first and second rows

Supported byanterior, posterior, and interosseous ligaments

Function as a single unit

Small gliding movements between carpal bones Carpometacarpal joints

Plane type synovial joints, except for carpometacarpal of thumb (saddle type)

Medial four carpometacarpal joints in one fibrous joint capsule

Separate capsule for thumb

Joint for thumb between the trapezium and first metacarpal

Allows flexion, extension, abduction, adduction, circumduction, and opposition

Loose joint capsule allows for free movement Metacarpophalangeal joints (MCP)

Heads of metacarpals articulate with base of proximal phalanx

Deep transverse metacarpal ligaments hold heads of metacarpals 2 through 5 together

Separate joint capsule for each joint

Movements: flexion, extension, abduction, and adduction

Because the collateral ligaments tighten during flexion, abduction, and adduction are onlypossible in the extended position Interphalangeal joints

Proximal interphalangeal joint = PIP Distal interphalangeal joint = DIP Allow flexion and extension

Fascia of the Hand

Extensor and flexor retinaculum continuous with antebrachial fascia

Palmar fascia thickened centrallyas the palmar aponeurosis

Four distinct extensions to the bases of the fingers

Continuous with the fibrous tendon sheaths

Anchored tightlyto skin of palm bynumerous ligamentous bands (retinacula cutis)

Fibrous digital sheaths surround synovial sheaths that enclose superficial and deep flexor tendons

Medial fibrous septum extends from medial border of palmar aponeurosis to fifth metacarpal

Lateral fibrous septum extends from lateral border of palmar aponeurosis to third metacarpal

Septa create compartments within the palm

Muscles of the Hand

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Adductor pollicis

Thenar (lateral) compartment

Abductor pollicis brevis

Flexor pollicis brevis

Opponens pollicis

Hypothenar (medial) compartment

Abductor digiti minimi

Flexor digiti minimi brevis

Opponens digiti minimi

Short muscles of the hand

Lumbricals-unusual in that theyflexMCP joints and extend IP joints

Palmar interossei-adduct digits

Dorsal interossei-abduct digits

Palmaris brevis

Wrinkles skin of hypothenar eminence

Improves palmar grip

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