The wrist made up of 8 carpal bones (wrist bone) and they are arranged in 2 rows.

1) The proximal row ( from lateral to medial side ) consists :

✓ The scaphoid

✓ The lunate

✓ The triquetral

✓ The pisiform

2) The distal row consists ( in same order )

✓ The trapezium

✓ The trapezoid

✓ The capitate

✓ The hamate



1) The scaphoid

– Boat shaped

– Has a tubercle on its lateral side.

2) The lunate

– Half moon shaped or crescentic.

3) The triquetral

– Pyramidal in shape.

– Has an isolated oval facet ( on distal part of palmar surface ).

4) The pisiform

– Pea shaped.

– It has only one oval facet ( on proximal part of its dorsal surface ).

5) The trapezium

– Quadrangular in shape.

– It has a crest and groove anteriorly.

– It has a sellar articular surface distally .

6) The trapezoid

– Resembles the shoe of a baby.

7) The capitate

– Largest carpal bone with a rounded head.

8) The hamate

– Wedge shaped with hook near its base.




* General points

1) The proximal row of carpal bone (wrist bone)

– Convex proximally

– Concave distally

2) The distal row

– Convex Proximally

– Flat distally

– The palmar and dorsal suface : non articular except for triquetral and pisiform

– Lateral surface of the scaphoid and trapezium : Non Articular

– The medial surface of triquetral , pisiform and hamate : non Articular

3) The Dorsal non-articular surface is always larger than palmar non-articular surface , except for lunate , in which the palmar surface is larger than the dorsal surface .

* Specific points

1) The scaphoid

– Tubercle is directed laterally , forward and downward.


2) The lunate

– A small semilunar articular surface for the scaphoid is on the lateral side.

– A quadrilateral articular surface for triquetral on medial side.

3)The triquetral

– Oval facet for the pisiform lies on distal part of palmar surface

– Medial and dorsal surface are continuous and non-articular.

4) The pisiform

– The oval facet for triquetral lies on proximal part of dorsal surface

– the lateral surface is grooved by ulnar nerve.

5) The trapezium

– The palmar surface has a vertical groove for tendon of Flexor carpi radialis

– The groove is limited laterally by crest of trapezium

– The distal surface bears a sellar concavo-convex articular surface for base of 1 st metacarpal bone.

6) The Trapezoid

– Distal articular surface is bigger than proximal

– Palmar non-articular Surface is prolonged laterally.

7) The capitate

– Dorsomedial angle is distal-most projection from body of the capitate .

– It bears a small facet for 4 th metacarpal bone.

8) The hamate

– The hook projects from distal part of palmar surface and is directed laterally.




– There are 4 bony pillars at 4 corners of corpus.

– All the attachments are to these 4 pillars,

1) The tubercle of scaphoid

– The flexor retinaculum

– A few fibres of abductor pollicis longus.

2) The pisiform gives attachment to,

– Flexor carpi ulnaris

– Flexor retinaculum and it’s superficial slip

– Abductor digiti minimi

– Extensor retinaculum

3) The trapezium

– The crest gives origin to Abductor pollicis brevis, flexor pollicis brevis and opponens pollicis ( Thenar eminence ).

– Edge if groove give attachment to 2 layers of flexor retinaculum .

– Lateral surface gives attachment to lateral ligament of wrist joint

– Groove lodges the tendon of Flexor carpi radialis.

4) The hamate

– Tip of hook gives attachment to the flexor retinaculum.

– Medial side of hook gives attachment to flexor digiti minimi and opponens digiti minimi.




1) The scaphoid

Radius, lunate, trapezium ,trapezoid and capitate

2) The lunate

Radius , scaphoid , capitate , hamate and triquetral

3) The triquetral

– Pisiform , lunate, hamate and articular disc of inferior radioulnar joint

4) The pisiform

– Articulates with triquetral

5) The trapezium

– Scaphoid , 1 st and 2 nd metacarpal and trapezoid

6) The Trapezoid

– Scaphoid , trapezium, 2 nd metacarpal and capitate

7) The capitate

– Scaphoid , lunate, Hamate, 2 nd , 3 rd and 4 th metacarpal and trapezoid.

8) The hamate

– Lunate , triquetral , capitate and 4 th and 5 th metacarpal bones.



1) Capitate – 2 months

2) Hamate – 3 months

3) Triquetral – 3 years

4) Lunate – 4 years

5) Scaphoid – 5 years

6) Trapezium – 5 years

7) Trapezoid – 5 years

8) Pisiform – 12 years.





1) Fracture of scaphoid

– This fracture occurs through the waist at right angles to its long axis

– Fracture caused by fall on outstretched hand or on tip of the fingers

– This causes tenderness and swelling in Anatomical snuff box

– Also causes pain on longitudinal percussion of thumb and index finger

– The importance of fracture lies inits liability to nonunion and avascular necrosis of body of the bone .

– Normally , the scaphoid has 2 nutrient arteries , one entering the palmar surface of the tubercle and other the dorsal surface of the body.

– In about 13% of cases both vessels enter through the tubercle or through distal half of the bone .

– In such cases , fracture may deprive the proximal half of the bone of its blood supply leading to avascular necrosis.


2) Dislocation of lunate

– May be produced by fall on acutely Dorsiflexion of hand with elbow flexion.

– This displaces lunate anteriorly , also leading to carpal tunnel syndrome like features.






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