What’s the hand? Definitions of hand: verb:   place into the hands or custody of noun:   ability noun:   a card player in a game of bridge noun:   a hired laborer on a farm or ranch noun:   a member of the crew of a ship noun:   a position given by its location to the side of an object noun:   a rotating pointer on the face of a timepiece noun:   a round of applause to signify approval noun:   a unit of length equal to 4 inches; used in measuring

horses noun:   one of two sides of an issue noun:   physical assistance noun:   something written by hand noun:   terminal part of the forelimb in certain vertebrates (e.g.

apes or kangaroos): "the kangaroo's forearms seem undeveloped but the powerful five-fingered hands are skilled at feinting and clouting"- Springfield (Mass.) Union 

noun:   the cards held in a card game by a given player at any given time

noun:   the (prehensile) extremity of the superior limb

¼ of the motor cortex is devoted to the hand

Motions of the Wrist and Hand• Forearm

– Flexion– Extension– Supination– Pronation

• Wrist– Flexion– Extension– Ulnar deviation– Radial deviation– Circumduction

• Hand– Flexion– Extension– Adduction– Abduction– Opposition– Circumduction

*Palmar and Dorsal Side

Bony Anatomy of the Forearm • Two Bones that articulate with the elbow (proximal) and the wrist (distal)

• Ulna– Larger and longer bone of the two (extension of the humerus). It distally articulates with the triquetrium and lunate via the TFCC.

– Ulnar styloid process• Radius

– Distal end makes up majority of the wrist articulation

– Two articulations -one with the carpal bones and the other with the ulna

– Articulates with the scaphoid and lunate– Radial styloid process

Hand and Wrist Anatomy14 phalanges

2 sesamoid bones (thumb)5 metacarpals8 carpal bonesDistal Radius

Forms small ulnar notch to accept the ulnar head

Radial styloid processDistal Ulna

Ulnar styloid process arises from medial surface

Ulnar head

Carpals(flat bones aligned in 2 rows)Proximal

Scaphoid-most commonly fractures Lunate-most commonly dislocated Triquetrum Pisiform-acts as sesmoid bone

Distal Trapezium(aligns with 1st metacarpal) Trapezoid(2nd metacarpal) Capitate(3rd metacarpal) Hamate(4th and 5th metacarpal)

Anatomy of the Carpal BonesWrist is made up of 8 carpal bonesScaphoid- name is derived from the Greek word skaphe, meaning boat. Most commonly fractured carpal bone

Lunate- Poor blood supply. Triquetrum- Three sided bonePisiform- Sesamoid bone, floating in the flexor carpi ulnaris muscle

Trapezium-Lays between the scaphoid and the thumb’s metacarpal

Trapezoid- Lays at the base of the second metacarpal (index or pointer finger)

Capitate-Largest of the carpal bonesHamate- Latin word means “hook”. “She Looks Too Pretty; Try To Catch Her”

Anatomy of the Phalanges5 MetacarpalsNumbered 1-5 starting at the thumbOr named thumb, index, middle, ring and little finger

Thumb = pollicusPinky = digiti minimiIndex = IndicusJoints

Carpometacarpal (CMC) = carpals to metacarpals Metacarpophalangeal (MCP) = metacarpals to phalanges

Proximal interphalangeal (PIP) = proximal phalanges to middlephalanges

Distal Interphalangeal (DIP) = middle phalanges to distal phalanges

Collateral ligaments of the IP joints

ArticulationsDistal Radioulnar

Formed by ulnar head and ulnar notchAllows 1 degree freedom of movement

Pronation/supinationRadius glides around the ulna

Radiocarpal jointReinforced by ligamentous thickeningFormed by distal radius articulating with scaphoid, lunate and triangular fibrocartilage disk(TFCC)

Ellipsoid joint (2 degrees freedom) Flexion/extension Radial/ulnar deviation

Intercarpal JointsPalmar/dorsal/interosseous ligaments between each carpal

Very little gliding

Midcarpal JointsProximal/distal carpal row separated by a single joint cavity with small fibrous projections connecting the rows

Limited mobility in flex/ext, radial/ulnar deviation

Carpometacarpal Joint (CMC)MC1/trapeziumMC2/trapezoidMC3/capitateMC4and 5/hamate (forms 1 articulation)

1st CMC (thumb)Saddle joint

2 degrees of freedom(3)Flexion/extensionAbduction/adduction

Accessory rotationAllows for opposition

2-4 CMCPlane/synovial joint1 degree freedom

Flexion/extension

5th CMC2 degree freedom

Flexion/extension Abduction/adduction

Metacarpophalangeal Joint (MCP)Two degrees freedom of movement

Flexion/extension Abduction/adduction

Thumb can abduct at any point/fingers only when extended

Collateral ligaments Varus/valgus force

When fingers are in flexion they tighten and limit abduction/adduction

Interphalangeal JointOne degree freedom of movement

Flexion/extensionCollateral ligaments

Muscular AnatomyWrist Extensors (innervated by radial n.)Superficial

Extensor carpi radialis brevis/longusExtensor carpi ulnarisExtensor digitoriumAbductor pollicus longusExtensor Digiti Minimibrachioradialis

Deep compartmentExtensor pollicus longus/brevisExtensor indicessupinator

Secured by extensor retinaculum

Wrist flexors (median n.)Superficial

Flexor carpi radialis Flexor carpi ulnaris Palmaris longus Pronator teres

- Intermediate Flexor digitorium superficialis

Deep Flexor digitorium profundus Flexor pollicis longus Pronator quadratus

Palmar (intrinsic)Thenar

Abductor pollicis brevis Flexor pollicis brevis Opponens Pollicis Tendon FPL Adductor pollicis

HypothenarAbductor digiti minimiOpponens digiti minimiFlexor digiti minimi brevis

Muscles of the ForearmAnterior MusclesWrist and Finger Flexors and Wrist PronatorsFlexors of the wrist

Flexor Carpi Radialis = near carpals on radial side

Flexor Carpi Ulnaris = near carpals on ulnar side

Palmaris Longus (absent in about 25% of population)(thumb and little finger opposition)

Muscles of the ForearmAnterior Muscles

Pronators Pronator Teres Pronator Quadratus

Muscles of the ForearmAnterior Muscles

Digit Flexors Flexor Digitorum Superficialis (share a muscle belly with FDP, why all fingers will move)

Flexor Digitorum Profundus (lumbrical muscles of fingers arise from the distal tendons)

Flexor Pollicis Longus (10% of population the tip of the index and the thumb move together)

Muscles of the ForearmPosterior MusclesWrist and Finger Extensors and Wrist SupinatorsWrist Extensors

extensor carpi radialis brevis = posterior & radial side, short

extensor carpi radialis longus = posterior & radial side, long extensor carpi ulnaris = posterior & ulnar side

Finger Extensors (attach at the common extensor tendon on the lateral epicondyle) extensor digitorum = extends digits extensor indicis = extends pointer finger extensor digiti minimi = extends pinky

Thumb Extensors abductor pollicis longus (Lay hand flat on table and abduct thumb)

extensor pollicis brevis/longus (Lay hand flat on table and extend only the thumb)

Nerve Distribution of the Hand

Ligaments of the Forearm• Interosseus Membrane- A fibrous sheath that connects the radius and the ulna.

• Radiocarpal ligaments-– Volar Radiocarpal ligament– Dorsal Radiocarpal ligament

• Ulnar collateral ligaments• Radial collateral ligaments

Dorsal Wrist ligaments Volar Wrist Ligaments

CentralTendons FDS/FDP

Superficialis (PIP) Profundus (DIP)

LumbricalesRadial side profundus tendon(extensor hood) Flex MP/ext PIP/DIP

Palmar aponeurosisInterossei

4 palmar/4 dorsal

Carpal TunnelFibro-osseous structure

Floor is proximal carpal bonesRoof is transverse carpal ligament

Tunnel contains 10 structuresMedian n., flexor pollicis longus tendon, 4 slips of flexor digitorium superficialis, flexor digitorium profundus

Compression results in paresthesia 2-4 fingers and decrease grip