The Hand

Question 1

What structures contribute to hand function?

Answer 1

Forearm muscles, long tendons, and the lumbricals.

Question 2

What are the three groups of small muscles in the hand?

Answer 2

Thenar, hypothenar eminences, and intrinsic palm muscles.

Question 3

How is finger abduction defined?

Answer 3

Movement away from the middle finger.

Question 4

How is finger adduction defined?

Answer 4

Movement towards the middle finger.

Question 5

What movement is achieved through combined muscle action in the thumb?

Answer 5

Opposition.

Question 6

Where do the lumbrical muscles originate and insert?

Answer 6

From radial sides of FDP tendons and insert into the extensor apparatus.

Question 7

Which nerve innervates the lateral 2 lumbricals?

Answer 7

Median nerve.

Question 8

Which nerve innervates the medial 2 lumbricals?

Answer 8

Ulnar nerve.

Question 9

What are the functions of the lumbricals?

Answer 9

Flexion at MCP joints and extension at IP joints.

Question 10

What are the muscles of the thenar eminence?

Answer 10

Opponens pollicis, abductor pollicis brevis, flexor pollicis brevis.

Question 11

What nerve innervates the thenar muscles?

Answer 11

Median nerve.

Question 12

What is the function of adductor pollicis and its innervation?

Answer 12

Adduction of the thumb; innervated by the ulnar nerve.

Question 13

What are the functions of the interosseous muscles?

Answer 13

Abduction (dorsal interossei), adduction (palmar interossei), flex MCP joints, extend IP joints.

Question 14

Which arteries supply the hand?

Answer 14

Radial and ulnar arteries.

Question 15

What do the radial and ulnar arteries form in the hand?

Answer 15

Superficial and deep palmar arches.

Question 16

What is the function of the superficial palmar arch?

Answer 16

Gives rise to digital branches to the fingers.

Question 17

Where is the deep palmar arch located?

Answer 17

Deeper than the superficial arch, contributing to deep hand structures.

Question 18

How many digital nerves supply each digit?

Answer 18

Four digital nerves per digit.

Question 19

What should be considered in a ring block of a digit?

Answer 19

All four digital nerves must be anesthetized.

Question 20

What typically accompanies digital arteries?

Answer 20

Digital nerves.

Question 21

What can a laceration of a digital artery also damage?

Answer 21

The accompanying digital nerve.

Question 22

Which muscles of the hand does the median nerve supply?

Answer 22

Thenar muscles and lateral 2 lumbricals.

Question 23

What kind of loss occurs with median nerve damage?

Answer 23

Motor loss (especially opposition and abduction of thumb) and sensory loss on lateral palm and digits.

Question 24

What is the main motor supply of the ulnar nerve in the hand?

Answer 24

Most small hand muscles, including interossei and medial 2 lumbricals.

Question 25

What type of motor loss occurs with ulnar nerve injury?

Answer 25

Loss of adduction and fine motor control.

Question 26

What does the radial nerve control in the hand?

Answer 26

Wrist and finger extension (weak if injured), no motor to intrinsic hand muscles.

Question 27

Which area does the radial nerve supply sensory innervation to?

Answer 27

Dorsal thumb, index, middle fingers (not tips), part of hand.

Question 28

What is the result of radial nerve damage at the wrist?

Answer 28

Weak wrist extension (wrist drop).

Question 29

What fingers are innervated by the ulnar nerve?

Answer 29

The little finger and half of the ring finger.

Question 31

How many bones are there in the hand and wrist combined?

Answer 31

27 bones.

Question 32

Name the 3 groups of hand bones.

Answer 32

Carpal bones (8), metacarpals (5), phalanges (14).

Question 33

How many phalanges does the thumb have?

Answer 33

Two (proximal and distal).

Question 34

Which carpal bone is most commonly fractured?

Answer 34

Scaphoid.

Question 35

Which carpal bone is prone to dislocation?

Answer 35

Lunate.

Question 36

Which carpal bone has a hook that can be damaged?

Answer 36

Hamate.

Question 37

What forms the anterior wall of the carpal tunnel?

Answer 37

Flexor retinaculum.

Question 38

What forms the roof and sides of the carpal tunnel?

Answer 38

The arch of the carpal bones.

Question 39

What tendon inserts into the base of the distal phalanx?

Answer 39

Flexor digitorum profundus (FDP).

Question 40

What is the function of the lumbricals?

Answer 40

Flexion of MCP joints, extension of IP joints, fine control (e.g., writing).

Question 41

: How many lumbricals are there, and where do they originate?

Answer 41

4, originating from the radial sides of FDP tendons.

Question 42

Which nerves supply the lumbricals?

Answer 42

Radial 2 by median nerve, ulnar 2 by ulnar nerve.

Question 43

What muscles make up the thenar eminence?

Answer 43

Opponens pollicis, abductor pollicis brevis, flexor pollicis brevis.

Question 44

What nerve supplies most thenar muscles?

Answer 44

Median nerve.

Question 45

What is the innervation of adductor pollicis?

Answer 45

Ulnar nerve.

Question 46

What muscles make up the hypothenar eminence?

Answer 46

Abductor digiti minimi, flexor digiti minimi, opponens digiti minimi.

Question 47

How many palmar interossei are there, and what is their function?

Answer 47

3; they adduct the digits (PAD).

Question 48

How many dorsal interossei are there, and what is their function?

Answer 48

4; they abduct the digits (DAB).

Question 50

What nerve innervates all interosseous muscles?

Answer 50

Ulnar nerve.

Question 51

What complex action is enabled by the small muscles of the hand?

Answer 51

Opposition, fine motor skills (e.g., piano playing).

Question 52

What causes the “hand of benediction”?

Answer 52

Median nerve injury – seen when attempting to make a fist.

Question 53

What causes the “ulnar claw”?

Answer 53

Ulnar nerve injury – results in permanent flexion of 4th and 5th digits.

Question 54

What is the ulnar paradox?

Answer 54

The more proximal the ulnar injury, the less severe the claw (closer to the paw, worse the claw).

Question 55

What is wrist drop a sign of?

Answer 55

Radial nerve injury – weak wrist and finger extension.

Question 56

What two arteries form the arterial supply of the hand?

Answer 56

Ulnar and radial arteries.

Question 57

What arches are formed by these arteries?

Answer 57

Superficial and deep palmar arches.

Question 58

What do digital arteries branch from?

Answer 58

Common palmar digital arteries → proper digital arteries.

Question 59

How many digital nerves supply each finger?

Answer 59

Four per digit.