6.4 Hand

Question 1

What bones make up the hand?

Answer 1

Carpals, metacarpals, and phalanges.

Question 2

How many phalanges does each finger have?

Answer 2

Three (proximal, middle, distal), except the thumb which has two (proximal and distal).

Question 3

What are the joints between the carpals and metacarpals called?

Answer 3

Carpometacarpal (CMC) joints.

Question 4

Which carpometacarpal joint provides the greatest mobility?

Answer 4

The first CMC joint of the thumb.

Question 5

What are the joints between the metacarpals and phalanges called?

Answer 5

Metacarpophalangeal (MCP) joints.

Question 6

What are the joints between the phalanges called?

Answer 6

Proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints.

Question 7

How many interphalangeal joints does the thumb have?

Answer 7

One interphalangeal (IP) joint.

Question 8

At the MCP and IP joints, what is the arthrokinematic relationship?

Answer 8

Concave proximal bone surface moving on a convex distal bone surface.

Question 9

What is the orientation of the thumb compared to the other fingers?

Answer 9

It is rotated 90° medially, allowing it to oppose and flex across the palm.

Question 10

What are the three arches of the hand?

Answer 10

Proximal transverse arch, distal transverse arch, and longitudinal arch.

Question 11

What is the keystone (center) of the proximal transverse arch?

Answer 11

The capitate.

Question 12

Where is the distal transverse arch located?

Answer 12

At the metacarpophalangeal (MCP) joints.

Question 13

What functional purpose do the arches of the hand serve?

Answer 13

They allow cupping and grasping motions for better object manipulation.

Question 14

What motions occur at the MCP joints of the fingers?

Answer 14

Flexion, extension, abduction, and adduction.

Question 15

What motions occur at the IP joints?

Answer 15

Flexion and extension only (one degree of freedom).

Question 16

What defines finger abduction and adduction?

Answer 16

Movements away from or toward the third (middle) finger.

Question 17

What type of joint are the MCP joints?

Answer 17

Condyloid joints.

Question 18

During MCP flexion, what are the arthrokinematics?

Answer 18

Concave proximal phalanx rolls and glides anteriorly on convex metacarpal head.

Question 19

During MCP extension, what are the arthrokinematics?

Answer 19

Concave proximal phalanx rolls and glides posteriorly on convex metacarpal head.

Question 20

During finger abduction, what is the arthrokinematic direction of movement?

Answer 20

Roll and glide occur radially.

Question 21

During finger adduction, what is the arthrokinematic direction of movement?

Answer 21

Roll and glide occur ulnarly.

Question 22

How many degrees of freedom does the thumb MCP joint have?

Answer 22

Primarily one — flexion and extension (ab/adduction are accessory motions only).

Question 23

What type of joint is the thumb CMC joint?

Answer 23

A saddle joint between the trapezium and the first metacarpal.

Question 24

Describe the articular surfaces of the trapezium at the first CMC joint.

Answer 24

Concave palmar–dorsal and convex medial–lateral, resembling a saddle.

Question 25

During thumb CMC flexion, what are the arthrokinematics?

Answer 25

Concave metacarpal moves on convex trapezium; roll and glide in the same direction (ulnarly/medially).

Question 26

During thumb CMC extension, what are the arthrokinematics?

Answer 26

Concave metacarpal moves on convex trapezium; roll and glide in the same direction (radially/laterally).

Question 27

During thumb CMC abduction, what are the arthrokinematics?

Answer 27

Convex metacarpal moves on concave trapezium; roll anteriorly, glide posteriorly.

Question 28

During thumb CMC adduction, what are the arthrokinematics?

Answer 28

Convex metacarpal moves on concave trapezium; roll posteriorly, glide anteriorly.

Question 29

What combined motions make up thumb opposition?

Answer 29

Abduction, flexion, and medial rotation of the first metacarpal.

Question 30

What is the closed-packed position of the first CMC joint?

Answer 30

Full opposition.

Question 31

Which metacarpals have increased mobility to enhance grip function?

Answer 31

The fourth and fifth metacarpals.

Question 32

Why are the fourth and fifth CMC joints more mobile?

Answer 32

To improve effectiveness of grasp by allowing the palm to conform around objects.

Question 33

What is the arthrokinematic rule for the IP joints of the fingers and thumb?

Answer 33

Concave on convex — roll and glide occur in the same direction.

Question 34

During flexion at the IP joints, what is the roll and glide direction?

Answer 34

Both roll and glide anteriorly.

Question 35

During extension at the IP joints, what is the roll and glide direction?

Answer 35

Both roll and glide posteriorly.