Atlas of Human Anatomy by Netter

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 phalanx has 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 by branches 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 by anterior, 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 only possible 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 centrally as the palmar aponeurosis

Four distinct extensions to the bases of the fingers

Continuous with the fibrous tendon sheaths

Anchored tightly to skin of palm by numerous 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 they flex MCP joints and extend IP joints

Palmar interossei-adduct digits

Dorsal interossei-abduct digits

Palmaris brevis

Wrinkles skin of hypothenar eminence

Improves palmar grip

Muscle Origin Insertion Innervation Action Blood

Supply

Abductor

pollicis

brevis

Flexor retinaculum, tubercles of scaphoid

and trapezium

Lateral side of base

of proximal phalanx

of thumb (1st digit)

Recurrent

branch of

median

nerve (C8-

T1)

Abducts and assists in

opposition of thumb

Superficial

palmar

branch of

radial artery