Upper limb

Metacarpals and phalanges of the hand

Ossa metacarpi et phalanges manus

Origin

5 metacarpal bones (I–V) and 14 phalanges (proximal, middle, distal for digits II–V, proximal/distal for thumb)

Insertion

Insertion site for interossei, lumbricals, thenar/hypothenar muscles, and flexor/extensor digitorum tendons

Function

Provides skeletal scaffold for palm and digits, enabling precision grip, power grip, and thumb opposition

Innervation

Median nerve (radial 3.5 digits) and ulnar nerve (ulnar 1.5 digits and deep intrinsics)

Movement & chain

Flexion, extension, abduction, adduction, and circumduction at MCP, PIP, and DIP joints; saddle opposition of thumb

Palpation

Easily palpated on dorsal aspect of hand and throughout each digit

Clinical

Boxer's fracture (5th metacarpal neck fracture); Bennett fracture-dislocation of thumb; mallet finger; trigger finger

Segmental innervation

C6–T1

In clinical practice

Core assessment in hand surgery, splinting, and occupational hand rehabilitation

Region in the model

Upper limb