Question 6#

In a fixed flexion contracture of the proximal interphalangeal (PIP) joint, the structure that is contributing most to the rigid flexion is:

A. The collateral ligament

The contracted proximal part of the volar plate. When the PIP joint flexes, the flexible proximal part of the volar plate (the check reins) folds back on itself to permit flexion. Left in this position, the folded portions adhere to each other and contract. This is the articular element that contracts and rigidly prevents extension.,

Question 7#

Of the extensor tendon compartments on the dorsum of the wrist:

A. The extensor pollicis longus (EPL) alters direction around the ulnar styloid

The extensor indicis proprius (EIP) shares a compartment with extensor digitorum communis (EDC). The first compartment contains APL and EPB. The second compartment contains ECRL and ECRB. The third compartment contains EPL altering direction around the tubercle of Lister. The fourth compartment contains EDC, EIP and the posterior interosseous nerve. The fifth compartment contains EDM. The sixth compartment contains ECU.

Question 8#

Of the bones in the carpus:

A. The scaphoid is the largest bone

Scapholunate dissociation is followed by flexion of the scaphoid. The capitate is the largest of the carpal bones. 80% of the scaphoid blood supply enters at the waist (hence the predilection to non-union of a proximal pole fracture) and 80% of the scaphoid surface is covered in articular cartilage. The kinetic forces of the carpus produce a tendency for the scaphoid to flex. The scaphoid moves into flexion if it is released from the lunate by laxity or rupture of the scapholunate ligament.

Question 9#

The palmar aponeurosis:

A. Covers the palm, including the central palm, thenar and hypothenar muscles

s inserted mainly into the bases of the proximal phalanges and the flexor sheaths. The palmar aponeurosis is phylogenetically the degenerated, flattened, distal part of the tendon of palmaris longus, a weak flexor of the long digits, by virtue of its insertion into the bases of the proximal phalanges and the fibrous flexor sheaths. (It also inserts into the deep transverse metacarpal ligament and some fibres extend distally along the digit). The aponeurosis is immediately superficial to the neurovascular structures in the central palm, anchoring the skin, and does not extend over the thenar or hypothenar muscles, which are freer to alter shape.

Question 10#

A contraindication to centralisation or radialisation of radial dysplasia is:

A. Single extremity involvement

Stiff elbow. A stiff elbow is a contraindication for centralisation or radialisation of the radial club hand as the centralised hand will not be able to reach the mouth or the perineum when the elbow does not have flexion passing 90°.

References:

1. Dobyns JH, Wood VE, Bayne LG. Congenital hand deformities. In: Operative hand surgery, Vol 1, 3rd ed. Green DP, Ed. New York, USA: Churchill Livingstone; 1993: 288-303.
2. Bayne LG. Radial deficiencies. In: Reconstruction of the child’s hand. Carter PR, Ed. New York, USA: Lea and Febiger; 1991: 187-97.