Flexor Region of the Forearm: Learning Objectives and Review Questions

True/False

True/False - Part 1

1. The posterior relationships of the medial humeral epicondyle include the ulnar nerve, inferior ulnar collateral artery, and the humeral head of origin of the flexor carpi ulnaris.
2. The proximal margin of the trochlear notch is contributed by the coronoid process.
3. The interosseous membrane had fiber directions that resist proximal displacement of the radius.
4. The interosseous membrane limits forces transmitted to the capitilum.
5. The styloid process of the ulna has an articular disk mediatiing articulations between the radius and the scaphoid bone.
6. The hook of the hamate provides attatchment for the medial side of the transverse carpal ligament.
7. The medial epicondyle of the humerus provides a site of attachment for the common flexor tendon.
8. Pronator teres has two heads of origin and, by one head, is a flexor of the elbow.
9. A complete lesion of the musculocutaneous nerve entirely eliminates flexion of the forearm.
10. A complete lesion of the musculocutaneous and radial nerves entirely eliminates flexion of the forearm.
11. A complete lesion of the musculocutaneous, radial, and ulnar nerves entirely eliminates flexion of the forearm.
12. A complete lesion of the musculocutaneous, radial, median, and ulnar nerves entirely eliminates flexion of the forearm.
13. A complete lesion of the radial nerve weakens flexion at the elbow.
14. A complete lesion of the ulnar nerve is expected to cause the resting position of the wrist to be extended and radially deviated wrist.
15. A complete lesion of the radial nerve is expected to cause the resting position of the wrist to be adducted and flexed.
16. A complete lesion of the medial nerve is expected to cause the resting position of the wrist to be adducted and extended.
17. A complete lesion of the musculocutaneous leaves the resting position of the wrist to be neutral.
18. A complete lesion of the ulnar nerve is expected to cause the resting position radial two fingers to be hyperextended at the metacarpophalangeal joint.
19. A complete lesion of the ulnar nerve is expected to cause the resting position radial two fingers to be flexed at the interphalangeal joints.
20. A complete lesion of the ulnar nerve is expected to cause the resting position ulnar two fingers to be hyperextended at the metacarpophalangeal joint.
21. A complete lesion of the ulnar nerve is expected to cause the resting position ulnar two fingers to be flexed at the interphalangeal joints.
22. The anterior interosseous nerve, but not the brachial artery, passes posterior to the humeral head of the pronator teres.
23. The radial two heads of the flexor digitorum profundus muscle are innervated by the superficial branch of the radial nerve.
24. Flexion of the distal interphalangeal joints is provided for by one muscle only whereas intrinsic mucles and long extensors act together to extend the distal interphalangeal joints.
25. The pronator quadratus receives the most distal motor innervation from the posterior interosseous nerve.
26. The antebrachial fascia has medial and lateral intermuscular septae.
27. Immediately posterior to the small gap between flexor carpi radialis and palmaris longus at the wrist is the median nerve.
28. At the mid-forearm level the ulnar artery and nerve are lateral to the flexor carpi ulnaris, medial to flexor digitorum superficialis, and anterior to the flexor digitorum profundus.
29. The pisiform bone and the tubercle of the scaphoid bone provide proximal attachments for the flexor retinaculum.
30. The ulnar nerve lies lateral to the ulnar artery within Guyen's tunnel.
31. The tendon of flexor carpi radialis is at risk for compression ischemia if carpal tunnel syndrome is in effect.
32. Compression of the median nerve within the carpal tunnel may lead to a supinated resting position for the thumb (ape hand).

True/False - Part 2

1. The posterior interosseous artery, together with the posterior interosseous nerve passes from the anterior compartment of the forearm to the posterior compartment on the forearm through an interval superior to the interosseous membrane and inferior to the oblique cord.
2. The predominate fiber direction of the interosseous membrane is from proximal superior and lateral to distal inferior and medial.
3. The anterior boundary of the carpal tunnel is the flexor retinaculum.
4. The pronator teres has two heads of origin; one head is biarticulate and one head is monoarticulate.
5. At the level of the hook of the hamate the ulnar nerve lies medial to the ulnar artery.
6. Entrapment of the ulnar nerve in Guyan's canal is expected to cause a "claw hand" syndrome.
7. Entrapment of the ulnar nerve at the medial epicondyle of the humerus may cause the relaxed wrist to be abducted and extended.
8. The posterior interosseous artery, together with the posterior interosseous nerve passes from the anterior compartment of the forearm to the posterior compartment on the forearm through an interval superior to the interosseous membrane and inferior to the oblique cord.
9. The predominate fiber direction of the interosseous membrane is from proximal superior and lateral to distal inferior and medial.
10. The anterior boundary of the carpal tunnel is the flexor retinaculum.
11. The pronator teres has two heads of origin; one head is biarticulate and one head is monoarticulate.

True/False - Part 3

1. Flexor carpi ulnaris shares an attachment with the abductor digiti minimi.
2. Passing between the two heads of origin of the flexor carpi ulnaris is the inferior ulnar collateral artery.
3. Passing between the heads of origin of the pronator teres is the median nerve and the brachial artery.
4. Passing posterior to the free edge of the flexor digitorum superficialis is the anterior interosseous nerve.
5. Tethering of the flexor digitorum superficialis tendons to the flexor digitorum profundus tendons permit superficialis to flex the distal interphalangeal joint.
6. The medial two heads of the flexor digitorum profundus are innervated by the median nerve whereas the lateral two heads are innervated by the radial nerve.
7. A lesion of the median and ulnar nerves within the axilla causes uncompensated loss of flexion at the elbow.
8. Lesions of the median, ulnar, and musculocutaneous nerves within the axilla result in uncompensated loss of flexion at the elbow.
9. A complete lesion of the ulnar nerve at the ulnar groove results in an abducted and extended position of the wrist.
10. Passing lateral to the pisiform bone and then medial to the hook of the hamate are the ulnar nerve and artery.
11. Compression of structures within the carpal tunnel are expected to weaken the hypothenar muscles.
12. Medial attachments of the flexor retinaculum include the pisiform bone and the hook of the hamate.
13. Lateral attachments of the flexor retinaculum include the scaphoid tubercle and the trapezoid bone.
14. The most distal skeletomotor distribution of the posterior interosseous nerve is the pronator quadratus.
15. The median nerve is separated from the anterior interosseous nerve by the muscle belly of the flexor digitorum superficialis.
16. Flexor Carpi Ulnaris orginates from the lateral epicondyle of the humerus and courses posterior to the flexor retinaculum.
17. Pronator teres is considered to be a deep flexor of the forearm
18. Palmaris Longus helps to tense the palmar aponeurosis, flexes the hand, and extends the forearm.
19. Flexor Carpi Radialis is included in the carpal tunnel.
20. The ulnar nerve enters the forearm between the two heads of flexor carpi ulnaris then courses deep to flexor carpi ulnaris and flexor digitorum profundus.
21. The superficial branch of the radial nerve is anterior to pronator teres and deep to flexor carpi radialis and brachioradialis.
22. Entrapment of the median nerve between the two heads of pronator teres with cause an inability to pronate the forearm.
23. As the median nerve courses distally in the forearm it is located anterior to flexor digitorum superficialis.
24. Flexor digitorum superficialis inserts on the sides of the distal phalanges of fingers 2-5.
25. All of the muscles in the flexor region of the forearm are innervated by the median nerve or anterior interosseus nerve.
26. The anterior interosseus artery courses anterior to pronator quadratus.
27. The anterior ulnar recurrent artery courses between brachialis and pronator teres to anastomose with inferior ulnar collateral artery.
28. The radial recurrent artery is located within the cubital fossa.
29. A complete lesion of the ulnar nerve at the ulnar groove will cause the wrist to be partially extended and partially abducted (radially deviated).
30. The pronator teres has a humeral head of origin and a radial head of origin.
31. The interosseus recurrent artery will course through supinator and lie deep to anconeus.
32. The ulnar nerve is located in the carpal tunnel.
33. The flexor pollicus longus flexes the thumb as well as assisting in abduction of the hand at the wrist.
34. The pronator quadratus' primary action is pronation, however is can "switch" origin and insertion and act as a supinator with the forearm and hand are fully pronated.
35. The flexor digitorum profundus can flex the DIP, PIP, and MP joints as well as assisting in flexion of the hand at the wrist.

Essay

1. Discuss the flexor 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.

Short Answer and Definitions

1. Interosseus membrane