osteology

radius

Plan

· cylindrical head

· narrow neck

· shaft which thickens and curves

· large lower end for carpal articulation

Head

· cylindrical

· covered with articular cartilage

· articulates with

· radial notch of ulna

· annular ligament

· spherical upper surface

· for capitellum

· narrow neck distally

Shaft

· radial tuberosity

· oval prominence proximally

· for biceps tendon

· ridge

· ulnar surface below radial tuberosity

· for IOM

· anterior oblique line

· on flexor surface

· ridge from radial tuberosity

· below line attaches FDS, FPL and PQ

· posterior oblique line

· on extensor surface

· ridge from radial tuberosity

· below line attaches APL and EPB

· lines converge at pronator pit on radial surface

· radial surface

· cylindrical surface

· between oblique lines

· attachment of supinator proximally

· attachment of PT distally (2 cm pit)

Distal end

Ulnar surface

· triangular area enclosed by anterior and posterior ridges

· IOM and deep fibres of PQ attach to anterior ridge

· distal ulnar notch

· for head of ulna

Distal surface

· articular surface for wrist joint

· lateral triangular facet for scaphoid

· ulnar square facet for lunate

· ulnar border sharp

· attaches TFC

· radial border triangular

· articulates with scaphoid

Lateral surface

· triangular

· apex is radial styloid

· radial collateral ligament of wrist attaches to tip

· BR attaches to base

· groove volar to styloid

· for tendons of APL and EPB

· lie in 1st compartment

Volar surface

· pronator hollow proximally

· extensor retinaculum attaches to lateral edge of hollow

· anterior radiocarpal ligament attaches distal to hollow

Dorsal surface

· prominent dorsal tubercle (of Lister)

· grooves for ECRL and ECRB on radial side in 2nd compartment

· groove for EPL on ulnar side in 3rd compartment

· flat surface ulnar to this for EDC and EDM in 4th compartment

ulna

Plan

· large proximal end for humeral articulation

· tapering shaft

· small distal end

Proximal end

· two projections with intervening articular notch

Olecranon

· proximal extension of shaft

· lodges in olecranon fossa of humerus in extension

· upper surface

· receives tendon of triceps

· smooth square surface

· anterior edge

· undulating articular margin

· posterior surface

· triangular surface

· covered by olecranon bursa

· apex of triangle continues as subcutaneous surface

· medial surface

· facet for ulnar collateral ligament of elbow

Coronoid process

· projects forward from anterior shaft

· lodges in coronoid fossa of humerus in flexion

· anterior lip

· articular margin

· sublime tubercle

· smooth elevation on medial lip

· attaches FDS and ulnar collateral ligament of elbow

· contacts ulnar nerve

· anterior surface

· attaches brachialis

· rough lower part called ulnar tuberosity

· medial border gives origin to deep head of PT

· lateral surface

· radial notch

· concave cylindrical facet lined with articular cartilage

· margins attach annular ligament

· shaft distal attaches quadrate ligament

· shaft more distal attaches oblique cord

Trochlear notch

· articular surface between projections

· fits trochlea of humerus

Shaft

· angled laterally from trochlear notch

· forms carrying angle

· medial ridge in middle of bone

· interosseous border

· attaches IOM

Supinator

· becomes prominent proximally at posterior lip of radial notch

· called supinator crest

· fossa anteriorly between medial coronoid and interosseous border

· called supinator fossa

· ulnar fibres of supinator originate from crest and fossa

Subcutaneous border

· runs down

· from triangular subcutaneous surface of olecranon

· along dorsal shaft

· to styloid

· attaches

· aponeurosis of FCU in upper 3/4

· deep fascia of arm

· divides shaft into extensor and flexor surfaces

Extensor surface

· narrow flat surface

· anconeus attached to upper part

· below this is vertical ridge

· 3 muscles attached between ridge and interosseous border

· APL, EPL and EI

Flexor surface

· broad convex surface

· attaches 2 muscles

· FDP attaches from upper 3/4 of shaft

· PQ attaches to lateral ridge from anterior styloid

Lower part

· expands into head

· distal and radial surfaces form DRUJ

· extended into styloid process

· base attaches TFC

· tip attaches ulnar collateral ligament of wrist

· groove on extensor surface

· lodges ECU

· in 6th extensor compartment