Hand

Question 1

Longitudinal Arch

Answer 1

follows general shape of the second and third rays, provide an important element of longitudinal stability to the hand, distal end is very mobile.

Question 2

Proximal Transverse

Answer 2

formed by distal row of carpal bones, this is a static, rigid arch that forms the carpal tunnel. Capitate is keystone

Question 3

Distal Transverse

Answer 3

sides of distal arch of mobile, keystone of the distal transverse arch is formed by the MCP joints of these central metacarpals

Question 4

Thumb degrees of freedom

Answer 4

3, flexion/extension, abduction/adduction, opposition/reposition

Question 5

Anterior (palmer) oblique ligament

Answer 5

thin and weak ligament; slack in opposition, flexion, and abduction; taut in full extension (“hitch hiker” position)

Question 6

Ulnar Collateral Ligament

Answer 6

taut in abduction and extension

Question 7

Intercarpal Ligament

Answer 7

taut in opposition, flexion, and abduction

Question 8

Radial Collateral ligament

Answer 8

relatively thick and strong ligament; densely populated with sensory fibers; taut in opposition, flexion, and abduction; prime stabilizer of the opposed CMC joint

Question 9

Posterior Oblique

Answer 9

relatively thick and strong ligament; densely populated with sensory fibers; taut in opposition, flexion, and abduction; prime stabilizer of the opposed CMC joint

Question 10

Mechanics of Opposition

Answer 10

Phase 1 (Metacarpal abduction)
Phase 2 (metacarpal flexion and medial rotation)
Full opposition = close-packed position

Question 11

Palmer plates function

Answer 11

strengthen the structure of the MCP joints and limit the extremes of extension

Question 12

Cord part of the collateral ligament

Answer 12

thick and strong

Question 13

Accessory part of the collateral ligament

Answer 13

thinner, fan-shaped fibers

Question 14

Deep transverse metacarpal ligaments

Answer 14

three ligaments that merge into a wide, flat structure that interconnects and loosely binds the second through the fifth metacarpals. Attach between each palmer plate.

Question 15

Check-rein Ligaments

Answer 15

These tissues reinforce the proximal attachments of the palmer plate, as well as assist in limiting hyperextension of the joint.

Question 16

Positions of function (wrist, thumb CMC, MCPs, PIPs, DIPs)

Answer 16

Wrist: 20 to 30 degrees of extension with slight ulnar deviation
Thumb CMC: 35 to 45 degrees of CMC joint abduction
MCPs: 35 to 45 degrees of MCP joint flexion
PIPs: 15 to 30 degrees of flexion
DIPs: 15 to 30 degrees of flexion

Question 17

Major Pulleys

Answer 17

A2 and A4 attach to the shafts of the proximal and middle phalanges.

Question 18

Minor Pulleys

Answer 18

A1, A3, A5 attach directly to the palmer plate at each of the three joints within a finger.

Question 19

Cruciate pulleys

Answer 19

C1, C2, C3, made of thin, flexible fibers that crisscross over the tendons at regions where the digital sheaths bend during flexion.

Question 20

Central Band

Answer 20

serves as the “backbone” of the extensor mechanism, transmits extensor force from the extensor digitorum across the PIP joint

Question 21

Lateral Band

Answer 21

Transmit extensor force from the extensor digitorum, lumbricals, and interossei across the PIP and DIP joints

Question 22

Dorsal Hood

Answer 22

two different fibers, transverse fibers stabilize the extensor digitorum tendon, and assists the extensor digitorum in extending the MCP joint. Oblique fibers transfer force from lumbricals and interossei to the lateral bands of the extensor mechanism, thereby assisting with extension of the PIP and DIP joints

Question 23

Oblique Retinacular Ligaments

Answer 23

Helps coordinate movement between the PIP and DIP joints of the fingers