Elbow, Wrist and Hand

Question 1

describe the makeup of the elbow’s joint capsule

Answer 1

1. large loose and weak (A/P)
2. reinforced laterally by collateral ligaments

Question 2

what is the normal carrying angle of the elbow?

Answer 2

8-15 degrees

Question 3

what is the purpose of the carrying angle at the elbow?

Answer 3

allows for a person to carry an object away from side of the thigh

Question 4

list the passive structures that reinforce the elbow joint

Answer 4

1. medial (ulnar) collateral ligaments
   
   1. A/P Transverse
2. Lateral (radial) collateral ligaments
   
   1. lateral ulnar collateral ligament
   2. annular ligament

Question 5

what does the A/P transverse ligament do at the elbow?

Answer 5

stabilizes against valgus torque at the elbow and limits elbow extension at end ROM

Question 6

what is the role of the annular ligament?

Answer 6

stabilizes against varus torque at the elbow and combined varus and supination torques

Question 7

what osteokinematic motions are available at the humeroulnar and humeroradial joint?

Answer 7

flexion/extension

Question 8

describe the arthrokinematics at the humeroulnar and humeroradial joint

Answer 8

concave on convex

roll and slide in same direction

Question 9

At the humeroulnar joint, what is the:

closed pack position

open pack position

capsular pattern

Answer 9

closed = full extension and supination

open = flexed 70 degrees, supinated 10 degrees

capsular pattern = flexion > extension

Question 10

at the humeroradial joint, what is the following:

closed pack position

open pack position

capsular pattern

Answer 10

closed = 90 degrees of elbow flexion and 5 degrees of supination

open = full extension and supination

capsular pattern = flexion > extension

Question 11

what types of joints are the proximal and distal radioulnar?

Answer 11

synovial pivot

Question 12

how is the arthrokinematics different at the proximal and distal radioulnar?

Answer 12

proximal = convex on concave

distal = concave on convex

Question 13

describe the following for the proximal radioulnar joint:

closed pack position

open pack position

capsular pattern

Answer 13

closed pack = 5 degrees supination

open = 70 degrees flexion and 35 degrees supination

capsular pattern: supination = pronation

Question 14

describe the following for the distal radioulnar joint:

closed pack position

open pack position

capsular pattern

Answer 14

closed = 5 degrees supination

open = 10 degrees supination

capsular pattern: supination = pronation

Question 15

how do we produce the most torque for elbow flexion at the elbow?

Answer 15

supinated position

increased flexor moment arm of biceps and brachioradialis when forearm is supinated

Question 16

what is the workhorse of the elbow?

Answer 16

brachialis

can produce equal force regardless of position

Question 17

describe the synergy between the triceps and anterior deltoid

Answer 17

ant deltoid synergizes with triceps during elbow extension

this will counter shoulder extension potential of triceps

Question 18

what muscle is primarily activated with low level supination?

Answer 18

supinator

Question 19

what role does the triceps play during forceful supination?

Answer 19

must co-contract to prevent the biceps from actually flexing the elbow and shoulder during supination effort

Question 20

what muscle is primarily activated during low level pronation?

Answer 20

pronator quadratus

Question 21

what role does the triceps play during forceful supination?

Answer 21

acts as a synergist to counter tendency of biceps brachii to flex elbow

Question 22

what are 2 points of consensus with regards to the wrist complex?

Answer 22

1. structure and biomechanics of wrist and hand vary tremondously from person to person
2. even subtle variations can produce differences in the way a given function occurs

Question 23

what bones make up the radiocarpal joint?

Answer 23

radius with schapoid, lunate, and triquetrum

Question 24

what makes up the 2-joint system in the wrist?

Answer 24

radiocarpal joint

midcarpal joint

Question 25

what is the benefit of the 2 joint system in the wrist?

Answer 25

permits large ROM w/less exposed articular surface and tighter joint capsules less tendency for structural pinch at extremes of motion allows for flatter multi-joint surfaces that are more capable of withstanding imposed pressures

Question 26

what is the function of the TFCC (triangular fibrocartilage complex)?

Answer 26

binds distal ends of ulna and radius while allowing radius to rotate around fixed ulna

Question 27

what is beneath the extensor retinaculum?

Answer 27

6 fibro-osseus compartments

Question 28

what are the factors that contribute to carpal tunnel syndrome?

Answer 28

1. overcrowding (9 extrinisic flexor tendons + median nerve) 2. excessive mechanical stress 3. fibrotic changes of CT

Question 29

what osteokinematic motions are available at the radiocarpal and midcarpal joints?

Answer 29

flexion/extension radial/ulnar deviation

Question 30

describe the arthrokinematics that occur at the radiocarpal and midcarpal joints

Answer 30

convex on concave = roll is opposite of slide

Question 31

what is the closed/open pack position and capsular pattern for the radiocarpal joint?

Answer 31

closed pack = full extension w/radial deviation open pack = neutral flexion/extension w/slight ulnar deviation capsular pattern: flexion = extension , slight radial and ulnar deviation

Question 32

what is the main function of the wrist extensors?

Answer 32

1. position and stabilize wrist in activities that require active flexion of digits (making a fist) 2. act to counterbalance wrist flexor torque

Question 33

List the joints in the hand

Answer 33

1. CMC 2. MCP 3. IP 4. DIP

Question 34

what osteokinematic motions are available at the 1st CMC joint?

Answer 34

flexion/extension abduction/adduction opposition/reposition

Question 35

describe the arthrokinematics at the 1st CMC joint

Answer 35

flexion/extension = concave on convex (M/L roll with glide) ADB/ADD = convex on concave

Question 36

what is the open/closed pack position and capsular pattern for the 1st CMC joint?

Answer 36

closed pack = full opposition open pack = midway between flx/ext and abd/add capsular pattern = abduction

Question 37

what is the open/closed pack position and capsular pattern for 2-5 CMC joints?

Answer 37

closed = full flexion open = midway between flx/ext capsular pattern = not really defined

Question 38

describe the arthrokinematics at the MCP joints

Answer 38

concave on convex roll and glide same direction

Question 39

describe the arthrokinematics at the IP joints

Answer 39

concave on convex palmar/dorsal roll with anterior/posterior glide (in same direction)

Question 40

what is the open/closed pack position and capsular pattern for the MCP joints?

Answer 40

closed = full flexion open = slight flexion capsular pattern: flexion = extension

Question 41

what is the open/closed pack position and capsular pattern for IP joints?

Answer 41

closed = full extension open = slight flexion capsular pattern: equal loss of flexion and extension

Question 42

what is the function of the flexor mechanism?

Answer 42

prevent bowstringing the tendons w/contraction of extrinsic finger flexors (these refer to the flexor pulleys embedded within fibrous digital sheaths)

Question 43

describe the anatomy of the extensor mechanism

Answer 43

* Distal to wrist they lack digital sheath or pulley system. Tendons become integrated into fibrous extensor expansion