Week 10 Wrist and flexors (anterior compartment of the forearm)

Question 1

distal carpal bones from lateral to medial

Answer 1

tripezium: most irregular bone in the carpus, four sided, tubercle
tripezoid: wedge shaped
capitate: largest bone in the carpus
hamate: wedge shaped, hook of hamate

Question 2

flexor retinaculum

laterally, medially

Answer 2

laterally: scaphoid tubercle, tubercle of trapezium
medially: pisiform, hook of hamate

Flexor retinaculum is a strong fibrous band which bridges the anterior concavity of the carpal bones thus converts it into a tunnel, the carpal tunnel.

Question 3

joint classification of proximal row and distal row of carpal bones

Answer 3

synovial plane joint

Question 4

bone and articular surfaces of proximal row and distal row of carpal bones (individual joints between)

Answer 4

scaphoid, lunate, triquetrum, pisiform
tripezium, tripezoid, capitate, hamate

Question 5

ligaments and movements of proximal row and distal row of carpal bones

Answer 5

ligaments:
- interosseous intercarpal
–> proximal row: scapholunate ligament, lunotriquetral ligament
- palmar intercarpal
- dorsal intercarpal

movements:
minimal

Question 6

joint classification of mid carpal joint

Answer 6

• synovial plane joint
• acts as functional unit
• slightly convex (laterally), slightly concave (medially)
• anatomically separate from the wrist (radiocarpal) joint

Question 7

bones and articular surfaces, fibrous capsule of midcarpal joint

Answer 7

bones and articular surfaces:
proximally: scaphoid, lunate, triquetrum
distally: trapezium, trapezoid, capitate, hamate

fibrous capsule: continuous synovial lining

Question 8

ligaments of midcarpal joint

Answer 8

palmar intercarpal
dorsal intercarpal
interosseous intercarpal
radial collateral
ulnar collateral

Question 9

movements of midcarpal joint

Answer 9

flexion/ extension
abduction/ adduction (radial/ ulnar deviation)

Question 10

proximal and distal attachment of pronator teres (PT)

ulnar and humeral head

Answer 10

proximal:
ulnar head: coronoid process
humeral head: medial epicondyle of humerus (common flexor origin)

distal:
middle of convexity of lateral surface of radius

Question 11

innervation of PT

Answer 11

median nerve (C6, C7)

Question 12

main action of PT

Answer 12

pronates and flexes forearm (at elbow)

Question 13

proximal and distal attachment of flexor carpal radialis (FCR)

Answer 13

proximal:
medial epicondyle of humerus (common flexor origin)

distal:
base of 2nd metacarpal

Question 14

innervation of FCR

Answer 14

median nerve (C6, C7)

Question 15

main action of FCR

Answer 15

flexes and abducts hand (at wrist)

Question 16

proximal and distal attachment of palmaris longus (PL)

Answer 16

proximal:
medial epicondyle of humerus (common flexor origin)

distal:
distal half of flexor retinaculum and apex of palmar aponeurosis

Question 17

innervation of PL

Answer 17

median nerve (C7, C8)

Question 18

main action of PL

Answer 18

flexes hand (at wrist) and tenses 拉緊 palmar aponeurosis

Question 19

proximal and distal attachment of flexor carpi ulnaris (FCU)

Answer 19

proximal:
ulnar head: olecranon and posterior border of ulna (via aponeurosis)
humeral head: medial epicondyle of humerus (common flexors origin)

distal:
pisiform, hook of hamate, 5th metacarpal

Question 20

innervation of FCU

Answer 20

ulnar nerve (C7, C8)

Question 21

main action of FCU

Answer 21

flexes and adducts hand (at wrist)

Question 22

proximal and distal attachment of flexor digitorum superficialis (FDS)

Answer 22

proximal:
humero-ulnar head: medial epicondyle (common flexor origin and coronoid process)

radial head:
superior half of anterior border

distal: shafts of middle phalanges of medial 4 digits

Question 23

innervation of FDS

Answer 23

medial nerve (C7, C8, T1)

Question 24

main action of FDS

Answer 24

• flexes middle phalanges at proximal IP joint of middle four digits
• acting more strongly
• flexes proximal phalanges at MCP joints

Question 25

proximal and distal attachment of flexor digitorum profundus (FDP)

Answer 25

proximal: proximal 3/4 of medial and anterior surfaces of ulna and interosseous membrane distal: medial part: bases of distal phalanges of **4th and 5th digits** lateral part: bases of distal phalanges of **2nd and 3rd digits**

Question 26

innervation of FDP

Answer 26

medial part: ulnar nerve (C8, T1) lateral part: anterior interosseous nerve, from median nerve (C8, T1)

Question 27

main action of FDP

Answer 27

medial part: **flexes distal phalanges 4 and 5 at distal IP joints** lateral part: flexes distal phalanges **2 and 3** at distal IP joints

Question 28

proximal and distal attachment of flexor pollicis longus (FPL)

Answer 28

proximal: anterior surface of radius and adjacent interosseous membrane distal: **base of distal phalanx of thumb**

Question 29

innervation of FPL

Answer 29

anterior interosseous nerve, from median nerve (C8, T1)

Question 30

main action of FPL

Answer 30

flexes phalanges of 1st digit (thumb)

Question 31

proximal and distal attachment of pronator quadratus (PQ)

Answer 31

proximal: distal 1/4 of anterior surface of **ulna** distal: distal 1/4 of anterior surface of **radius**

Question 32

innervation of PQ

Answer 32

anterior interosseous nerve, from median nerve (C8, T1)

Question 33

main action of PQ

Answer 33

- pronates forearm - deep fibers bind radius and ulna together

Question 34

which muscles attach to medial epicondyle of humerus (common flexor origin)

Answer 34

PT (humeral head), FCR PL FCU (humeral head) FDS (humero-ulnar head)

Question 35

muscles in 1st-4th layer (from lateral to medial) (from superficial to deep)

Answer 35

1st layer: PT, FCR, PL, RCU 2nd layer: FDS 3rd layer: FPL, FDP 4th layer: PQ

Question 36

which muscles are in ulnar nerve in anterior compartment of forearm

Answer 36

FCU FDP (medial part)

Question 37

courses and branches of the median nerve in the flexor compartment of the forearm

Answer 37

- **medial to brachial artery** (cubital fossa) - leaves cubital fossa through pronator teres - passes deep to FDS - **at wrist -- becomes superficial** - **gives off anterior interosseous in distal part of cubital fossa**

Question 38

courses and branches of ulnar nerve in the flexor compartment of the forearm

Answer 38

- enters forearm through FCU - continues between FCU and FDP - **runs on medial side of ulnar artery** - **at wrist -- becomes superficial** - **enters the hand via Guyon's canal** (between pisiform and hook of hamate)

Question 39

course and extent of the radial and ulnar arteries, anterior interosseous artery

Answer 39

radial artery: - over to pronator teres - runs deep to brachioradialis - superficial near the wrist - **passes through the anatomical snuffbox** ulnar artery - **deep to pronator teres** - deep to arch of FDS - branches: common interosseous, recurrent and muscular anterior interosseous artery - **from common interosseous artery**

Question 40

**borders, roof, floor, contents of carpal tunnel**

Answer 40

borders: **scaphoid, trapezium, hook of hamate, pisiform** roof: **flexor retinaculum** floor: **carpal bones, anterior ligament of wrist** contents: - **median nerve** - 9 tendons and their synovial sheaths: **tendon of FDS x4, FDP x4, FPL x1** - **tendon of FCR (separate in the roof)** ## Footnote synovial sheaths: highly vascularized, easy to swelling