15.6 Anatomy: Joints of Upper Limb 3

Question 1

How many phalanges does each digit have?

Answer 1

3 except for thumb (2)

Question 2

What are the bones of the wrist in order from proximal to distal, lateral to medial?

Answer 2

Scaphoid, lunate, triquetrum, pisiform

Trapezium, Trapezeoid, capitate, hamate

Question 3

When do carpal bones commence ossification?

What is the significance of this?

Where are their ossification centres?

Answer 3

Only after birth

Can age skeleton

Ossifcation centre at one end (others normally central)

Question 4

What is the first and last bone of the wrist to ossify?

Answer 4

First: capitate (largest)
Last: Pisiform

Question 5

What comprises the floor of the anatomical snuffbox?

Answer 5

Scaphoid

Question 6

What type of bone is the pisiform? Why is it in this position?

Answer 6

Sesamoid bone, sits up (increased leverage for wrist flexion)

Question 7

What do the proximal and distal wrist creases signify?

Answer 7

Proximal: wrist joint (head of ulna, styloid of radius)
Distal: proximal attachment of flexor retinaculum

Question 8

What type of joints are the radiocarpal and intercarpal?

Answer 8

Radiocarpal: ellipsoid
Intercarpal: condylar

Question 9

What bones are articular at the wrist?

Answer 9

Scaphoid and lunate (distal radius, NOT ulna)

Question 10

What are the movements at the radiocarpal joint? Which is greater?

Answer 10

UD/RD, F/E

ulnar deviation greater, flexion greater-radial styloid blocks movement

Question 11

What can happen if the RU disc is damaged?

Answer 11

Poor repair, no blood supply

Question 12

What are the movements at the intercarpal joints?

What type of joint is it?

Answer 12

Opposite to the wrist

Functional (rather than anatomic) joint

Question 13

What prevents the carpal bones from sliding medially?

Answer 13

Capsular ligaments (holds lunate and scaphoid in position)

Question 14

What is significant about the radiocarpal ligaments?

Answer 14

They all transmit vessels to carpal bones (also stabilisers)

Question 15

Do tendons attach to bones of the carpal region?

Answer 15

NO (except FCU pisiform)

Question 16

Where do flexor/extensor tendons of the writ attach?

Answer 16

Distal to joint (proximal aspects on metacarpals), direct compression force proximally

Question 17

What is the most commonly fractured bone in the upper limb?

Answer 17

Distal radius (Colles fracture)- dinner fork

Question 18

What is the most commonly fractured and subluxed of the carpal bones?

Answer 18

Fractured: scaphoid
Subluxed: lunate

Question 19

What is a Bennett’s and a boxer’s fracture?

Answer 19

Base of 1st metacarpal: Bennett’s

Neck of 5th metacarpal (boxer’s)

Question 20

What is the danger of a scaphoid fracture?

Answer 20

Proximal pole can die from avascular necrosis (swelling in snuffbox may be hiding fracture), important to immobilise or pin it

(avascular necrosis of lunate too)

Question 21

What type of joint movement do we get at each phalanges?

Answer 21

1st: saddle (thumb)-opposition
2nd/3rd: immobile
4th/5th: F/E elements
5th: most F, E and abduction

Question 22

What are metacarpals II-V linked by?

Answer 22

Deep transverse metacarpal ligament

all synovial joints

Question 23

What position do we want to immobilise the hand in if injured regarding ligaments?

Answer 23

Want to immobilise in flexion to prevent tightening of collateral ligaments

(lax in extension to allow abduction)

Question 24

What type of joints are the metacarpophalangeal joints?

Answer 24

Coyndyloid

Volar plate expands articular surface area

Question 25

What is a swan neck and a boutonniere deformity?

Answer 25

Swan neck: Palmar IP joint injury (compensatory flexion)

Boutonniere: Dorsal IP injury (compensatory hyperextension)