Extensor Region of Forearm and Dorsum of Hand: Learning Objectives and Review Questions

True/False

True/False - Part 1

1. The extensor carpi radialis inserts on the base of the proximal phalanx of the second digit.
2. Making a fist entails tightly flexing the finger joints with assistance from the extensors of the hand.
3. The extensor carpi radialis brevis is an adductor of the wrist.
4. The extensor carpi radialis longus is a more potent adductor of the wrist than is the extensor carpi radialis brevis.
5. The extensor carpi ulnaris receives the only muscular branch of the ulnar nerve in the forearm.
6. The supinator muscle, on the space shuttle, may weakly extends the elbow.
7. The supinator muscle extends the elbow.
8. The supinator is an agonist to the biceps at the proximal radio ulnar joint and an antagonist at the elbow joint.
9. The abductor pollicis longus muscle is innervated by the posterior interosseous nerve.
10. The extensor pollicis longus forms the anterior border of the anatomical snuff box.
11. The muscles having tendons bordering the anatomical snuff box are innervated by the posterior interosseous nerve.
12. The extensor pollicis brevis forms the anterior border of the anatomical snuff box.
13. The abductor pollicis longus shares a compartment with the extensor pollicis brevis but is not consider a boundary of the anatomical snuff box.
14. The extensor indices is not tethered by the intertendinous connections the limit independence of the extensor digitorum tendons.
15. The posterior interosseous nerve enters the posterior compartment of the forearm by passing the superior free edge of the interosseous membrane.
16. The posterior interosseous artery enters the posterior compartment of the forearm by passing the superior free edge of the interosseous membrane.
17. The anterior interosseous artery enters the posterior compartment of the forearm by passing through the interosseous membrane at the level of the extensor retinaculum.
18. Gray's Figures 49.16 and 49.17 would be entirely political correct as identifications on your upper limb examination.
19. The deep radial nerve is within a neurovascular bundle with the radial artery.
20. The interosseous recurrent artery ascents toward the posterior surface of the lateral elbow deep to the anconeus muscle.
21. Brachioradialis flexes the elbow and extends the wrist.
22. Extensor carpi radialis longus inserts at the base of the second metacarpal.
23. The abductor pollicis longus intervenes between the posterior interosseous membrane and the posterior interosseous nerve.
24. The anterior interosseous nerve is directly applied to the interosseous membrane.
25. The superficial branch of the radial nerve can be palpated as it crosses the medial (posterior) boundary of the anatomical snuff box.
26. The tendon of flexor carpi radialis longus crosses the anatomical snuff box proximal to the crossing of the radial artery.
27. The dorsal carpal arch receives arterial branches from the radial artery, anterior posterior interosseous arter, posterior interosseous artery, and the dorsal branch of the ulmar artery.
28. The dorsal metacarpal arteries lie on the posterior surface of the dorsal interosseous muscles.
29. The extensor hood moves distally during extension.
30. Extensions of the lateral bands extend beyond the distal attachment of the central band.
31. The central slip together with the lateral band is similar to a trident with a short center prong.
32. Despite that the interossei are posterior to the deep transverse metacarpal ligament, there are anterior to the axis of the metacarpophalangeal joint.

True/False Part 2

1. The tendons of extensor digitorum, like the long extensor of the foot, is joined by the tendons of the extensor digitorum brevis to the form the extensor hood.
2. The supinator, innervated by the deep radial nerve, is synergistic with the biceps, innervated by the musculocutaneous nerve.
3. Abductor pollicis longus commonly shares a tendon sheath with extensor pollicis brevis.
4. The extensor indicis acts independently of extensor digitorum at the distal interphalangeal joint of the index finger.
5. The posterior interosseus nerve innervates the muscles that define the antomical snuff box plus two additional muscles.
6. The brachioradialis, innervated by the radial nerve, is synergistic with the brachialis, innervated by the musculocutaneous nerve.
7. The brachioradialis flexes the elbow and extends the wrist.
8. A dorsal digital expansion that has a lumbrical approach from the right (dorsal view) is of the left hand.

True/False - Part 3

1. The fiber direction of the interosseous membrane is from distal ulnar to proximal radial.
2. The nerve that circles the radius deep to the supinator muscle is the deep radial nerve.
3. The radial nerve divides within the cubital fossa into a superficial radial nerve and a deep radial nerve (this is true).
4. The innervation to the muscles of the "outcropping" and the extensor indicis is provided by the posterior interosseus nerve.
5. Despite that abductor pollicis longus does not cross the MB joint is is still agonistic to thumb extension.
6. Extensor indicis extends the index finger independent of extensor digitorum.
7. The anatomical snuff box has the extensor pollicis longus as the anterolateral border.
8. Anterior to the radial artery, within the anatomical snuffbox, is the scaphoid bone.
9. The dorsal carpal arch (rete) receives blood from the anterior interosseous artery.
10. Dorsal metacarpal arteries pass the posterior surfaces of the dorsal interosseous muscles.
11. Palmar metacarpal arteries pass the anterior surfaces of the palmar interosseous muscles.
12. A branch of the superficial radial nerve can be palpated as it crosses the tendon of extensor pollicis longus as this tendon provides a border for the antomical snuffbox.
13. The muscles taking orgin from the common extensor tendon (lateral humeral epicondyle) extend at the elbow.
14. The extensor carpi radialis longus and brevis muscles are inneravated by the deep radial nerve.
15. The extensor carpi ulnaris muscle is innervated by the posterior interosseus nerve.
16. The supinator muscle is innervated by the posterior interosseous nerve.
17. The extensor pollicis longus muscle is innervated by the deep radial nerve).
18. The extensor carpi radialis longus is considered primaritly a wrist extensor while the extensor carpi radialis brevis is a radial devator (abductor).
19. The princips pollicis artery is a content of the anatomical snuff box.
20. The anterior interosseous artery is located on the posterior surface of the distal interosseous membrane.
21. The anterior interosseous artery contributes to the dorsal rete.
22. There is a superior free edge of the interosseous membrane and superior to that is the oblique cord.
23. The posterior interosseous artery travels with the deep radial nerve to arrive in the posterior compartment of the forearem.
24. The interosseous recurrent artery passes through the heads of origin of the flexor carpi ulnaris.
25. The tendon(s) of abductor pollicis longus are immediately anterior to the tendons of extensor pollicis brevis when at the level of the anatomical snuff box.
26. The finger that has a dorsal interosseous on the radial (lateral) side and a palmar interosseous on the ulnar (medial) side is the ring finger.
27. The finger that nearly always has five tendons attaching to the extensor hood is the middle finger.
28. The fiber direction of the interosseous membrane resists proxmal movement of the radius.
29. The anconeus muscle crosses the elbow joint.
30. A lesion of the radial nerve at the spiral (radial) groove would paralyze the anconeus muscle.
31. The interosseous recurrent artery is deep to the anconeus muscle.
32. The posterior recurrent ulnar artery passes through the heads of origin of the extensor carpi radialis longus muscle.
33. The posterior interosseous artery and the posterior interosseous nerve are usually separated from each other by the extensor indicis and the muscles of the outcropping.
34. The extensors of the forearm are, in a sense, agonistic to the flexors of the forearm in mediating a firm grip.
35. A lesion of the deep radial nerve as it spirals around the radius deep to supinator would cause the resting wrist position to be flexed and abducted.
36. A lesion of the superficial radial nerve would cause anesthesia of the nail beds of the radial 2.5 fingers.
37. The radial collateral ligament of the elbow contributes support to the anular ligament.
38. The radial notch of the ulna resists proximal and distal dislocation of the radius.
39. A total lesion of the posterior interosseous nerve (think snuff box and outcropping) would cause uncompensated loss of extension of the thumb.
40. A total lesion of the posterior interosseous nerve (think snuff box and outcropping) would cause uncompensated loss of abduction of the thumb.
41. The tendons of extensor digitorum are secured to the metacarpal bones by vincula long and brevia.
42. Tendon sheaths for the long extensors/adbuctor of the forearm pass deep to the extensor retinaculum.

Short Answer and Definitions

1. Interosseus membrane

Essay

1. Discuss the extensor region of the forearm. Include contents, compartments, relationships, boundaries, fascial specializations, vascularization, innervation, lymphatics, muscles and movements, and compensation in the case of nerve injury.