Elbow, Wrist and Hand Flashcards

1
Q

describe the makeup of the elbow’s joint capsule

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

what is the normal carrying angle of the elbow?

A

8-15 degrees

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3
Q

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

A

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

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4
Q

list the passive structures that reinforce the elbow joint

A
  1. medial (ulnar) collateral ligaments
    1. A/P Transverse
  2. Lateral (radial) collateral ligaments
    1. lateral ulnar collateral ligament
    2. annular ligament
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5
Q

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

A

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

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6
Q

what is the role of the annular ligament?

A

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

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7
Q

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

A

flexion/extension

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8
Q

describe the arthrokinematics at the humeroulnar and humeroradial joint

A

concave on convex

roll and slide in same direction

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9
Q

At the humeroulnar joint, what is the:

closed pack position

open pack position

capsular pattern

A

closed = full extension and supination

open = flexed 70 degrees, supinated 10 degrees

capsular pattern = flexion > extension

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10
Q

at the humeroradial joint, what is the following:

closed pack position

open pack position

capsular pattern

A

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

open = full extension and supination

capsular pattern = flexion > extension

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11
Q

what types of joints are the proximal and distal radioulnar?

A

synovial pivot

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12
Q

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

A

proximal = convex on concave

distal = concave on convex

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13
Q

describe the following for the proximal radioulnar joint:

closed pack position

open pack position

capsular pattern

A

closed pack = 5 degrees supination

open = 70 degrees flexion and 35 degrees supination

capsular pattern: supination = pronation

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14
Q

describe the following for the distal radioulnar joint:

closed pack position

open pack position

capsular pattern

A

closed = 5 degrees supination

open = 10 degrees supination

capsular pattern: supination = pronation

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15
Q

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

A

supinated position

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

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16
Q

what is the workhorse of the elbow?

A

brachialis

can produce equal force regardless of position

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17
Q

describe the synergy between the triceps and anterior deltoid

A

ant deltoid synergizes with triceps during elbow extension

this will counter shoulder extension potential of triceps

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18
Q

what muscle is primarily activated with low level supination?

A

supinator

19
Q

what role does the triceps play during forceful supination?

A

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

20
Q

what muscle is primarily activated during low level pronation?

A

pronator quadratus

21
Q

what role does the triceps play during forceful supination?

A

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

22
Q

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

A
  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
23
Q

what bones make up the radiocarpal joint?

A

radius with schapoid, lunate, and triquetrum

24
Q

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

A

radiocarpal joint

midcarpal joint

25
Q

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

A

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

26
Q

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

A

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

27
Q

what is beneath the extensor retinaculum?

A

6 fibro-osseus compartments

28
Q

what are the factors that contribute to carpal tunnel syndrome?

A
  1. overcrowding (9 extrinisic flexor tendons + median nerve)
  2. excessive mechanical stress
  3. fibrotic changes of CT
29
Q

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

A

flexion/extension

radial/ulnar deviation

30
Q

describe the arthrokinematics that occur at the radiocarpal and midcarpal joints

A

convex on concave = roll is opposite of slide

31
Q

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

A

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

32
Q

what is the main function of the wrist extensors?

A
  1. position and stabilize wrist in activities that require active flexion of digits (making a fist)
  2. act to counterbalance wrist flexor torque
33
Q

List the joints in the hand

A
  1. CMC
  2. MCP
  3. IP
  4. DIP
34
Q

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

A

flexion/extension

abduction/adduction

opposition/reposition

35
Q

describe the arthrokinematics at the 1st CMC joint

A

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

ADB/ADD = convex on concave

36
Q

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

A

closed pack = full opposition

open pack = midway between flx/ext and abd/add

capsular pattern = abduction

37
Q

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

A

closed = full flexion

open = midway between flx/ext

capsular pattern = not really defined

38
Q

describe the arthrokinematics at the MCP joints

A

concave on convex

roll and glide same direction

39
Q

describe the arthrokinematics at the IP joints

A

concave on convex

palmar/dorsal roll with anterior/posterior glide

(in same direction)

40
Q

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

A

closed = full flexion

open = slight flexion

capsular pattern: flexion = extension

41
Q

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

A

closed = full extension

open = slight flexion

capsular pattern: equal loss of flexion and extension

42
Q

what is the function of the flexor mechanism?

A

prevent bowstringing the tendons w/contraction of extrinsic finger flexors

(these refer to the flexor pulleys embedded within fibrous digital sheaths)

43
Q

describe the anatomy of the extensor mechanism

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