Question 66#

In hand embryology:

A. The apical ectodermal ridge governs thumb development

Question 67#

The most common form of carpal instability is:

A. Midcarpal instability

Scapholunate instability. Scapholunate instability is the most common form of carpal instability in terms of anatomical location. It was not until 1972 when Linschied et al described the clinical features that this condition became well recognised, although Destot had described the radiological features in 1926. Of the various described carpal instabilities, dorsal intercalated segment instability (DISI) is the most common followed by volar intercalated segment instability (VISI). DISI can be recognised by dorsal tilt of the lunate on a true lateral wrist radiograph associated with volar tilt of the scaphoid, producing a scapholunate angle of greater than 60°. The normal scapholunate angle is 30-60°. 

Question 68#

In arthrogryphosis: 

A. The arms should be positioned one up and one down

Question 69#

DeQuervain’s stenosing tenosynovitis is most often clinically confused with:

A. Carpal tunnel syndrome

Osteoarthritis of the CMC joint of the thumb. To provide appropriate treatment, DeQuervain’s stenosing tenosynovitis needs to be differentiated from intersection syndrome (tendon entrapment of the second extensor compartment) and arthritis of the thumb CMC joint or scaphotrapezial/trapezoid joint.

Question 70#

Regarding syndactyly:

A. Web creep is less likely to occur if the separation is performed after age two