Bones

Question 1

State bony markings of distal radius and ulna

Answer 1

Radial and Ulna styloid process
Dorsal Tubercle of radius (Lister’s Tubercle)
Head of Ulna
Triangular fibrocartilage complex (TFCC)

Question 2

State the bones of the hand

Answer 2

27 bones split into Three groups of in the hand:

8 carpal bones - bones of the wrist (carpus); arranged in two rows, a proximal and a distal row, each consisting of four bones:
Proximal row (lateral to medial) - scaphoid, lunate, triquetral, pisiform
Distal row (lateral to medial) - trapezium, trapezoid, capitate, hamate

5 metacarpals ( I to V ) - bones of the metacarpus

14 phalanges - bones of the digits
Thumb has a proximal and distal phalanges
Digits 2-5 have proximal, middle and distal phalanges

Question 3

Describe structure of scaphoid

Answer 3

Boat shaped bone

prominent tubercle (palpable) on its lateral palmar surface that is directed anteriorly
 Tubercle is 	responsible for blood supply; avascular necrosis is a common problem post fracture

Question 4

Describe structure of lunate

Answer 4

Crescent shape bone

Articulates with the scaphoid (laterally) and triquetral (medially)

Question 5

Describe structure of triquetral

Answer 5

Three sides bone

Sits below pisiform articulating with its dorsal surface

Question 6

Describe structure of pisiform

Answer 6

Pea shaped bone
medial aspect of proximal carpal row (palpable on palmar surface)

sesamoid bone in the tendon of the flexor carpi ulnaris
articulates with the palmar surface of the triquetrum

Question 7

Describe structure of trapezium

Answer 7

Irregular four sided bone

articulates with the base of the metacarpal bone of the thumb; forms 1st CMC joint

distinct tubercle on its palmar surface that projects anteriorly (palpable)

Important for mobility of the thumb

Question 8

Describe structure of trapezoid

Answer 8

Four sided bone

Articulates with base of index finger metacarpal; forms 5th CMC joint

Question 9

Describe structure of capitate

Answer 9

Largest carpus bone
Contains a head
Articulates with the base of metacarpal III; forms 3rd CMC joint

Question 10

Describe structure of hamate

Answer 10

lateral and distal to the pisiform

Hook of hamate - palpable on palmar surface in the muscles on the medial side of the proximal palm (the hypothenar eminence)

Articulates distally with the bases of MCs 4-5 (Ring and Little fingers); forms CMC joints 4-5

Question 11

Describe structure of metacarpals

Answer 11

Each metacarpal consists of:

Proximal base - articulate with the corresponding distal row carpal bones
base of MC 4-5 articulate with hamate
base of MC 2-5 articulate with each other

Elongated shaft (body)

Distal head - Articulate with the proximal phalanges of the corresponding digits
distal heads Form the knuckles on the dorsal surface of the hand

Metacarpal of the thumb functions independently and has increased flexibility at the carpometacarpal joint to provide opposition of the thumb to the fingers

Carpal bones and metacarpals of the index, middle, ring, and little fingers (metacarpals II to V) tend to function as a unit and form much of the bony framework of the palm

Question 12

Describe structure of phalanges

Answer 12

Each phalanx has a:

Proximal base - Base of each proximal phalanx articulates with the head of the related metacarpal bone

Elongate shaft (body)

Distal head - Head of each distal phalanx is non-articular and flattened into a crescent-shaped palmar tuberosity, which lies under the palmar pad at the end of the digit