Hand and Brachial Plexus

Question 1

Bones of the hand

Answer 1

From proximal to distal: carpal, metacarpal and phalanges

Question 2

Which bones bones compose the proximal row of carpals?

Answer 2

Scaphoid, lunate, triquetrum, and pisiform

Question 3

Which carpal bone is the most commonly fractured and where is it found?

Answer 3

The scaphoid, which lies beneath the anatomical snuffbox.

Question 4

Where do the proximal row of carpal bones articulate?

Answer 4

Distal radius

Question 5

Which bones compose the distal row of carpals?

Answer 5

Trapezium, trapezoid, capitate (round bone), and hamate (hook bone)

Question 6

With what structures does the distal row of carpals articulate with?

Answer 6

Proximal row of carpal + Metacarpals

Question 7

Metacarpal characteristics

Answer 7

Numbered 1 to 5 (thumb to little finger)

Posses a base, shaft, and head

Associated with head of first metacarpal

Question 8

Which metacarpal bone is most commonly fractured?

Answer 8

5th metacarpal

Question 9

Phalanges characteristics

Answer 9

Posses a base, shaft, and head

Termed proximal, distal, and proximal

Question 10

Which phalange is most commonly fractured?

Answer 10

Distal phalange of middle finger

Question 11

What movements does the carpal joint provide?

Answer 11

Provide gliding movements and significant wrist extension and flexion.

Question 12

What are the 4 carpal joints of the hand?

Answer 12

1. Carpometacarpal
2. Metacarpophalangeal
3. Proximal interphalangeal (the first phalange [the thumb] only posses this one)
4. Distal phalangeal

Question 13

Carpometacarpal and thumb joint ligaments and characteristics

Answer 13

1. Palmar and dorsal (dorsal is strongest)
2. Interosseous

Allow flexion, extension, ABduction, ADduction, and circumduction

Run from carpals to metacarpals of digits 2-5

Question 14

Metacarpophalangeal joint ligaments characteristics

Answer 14

1. Radial and ulnar collateral- tight in flexion and loose in extension
2. Palmar (volar) plate- if broken digit, cast in flexion or it will shorten

Question 15

Interphalangeal joint ligaments characteristics

Answer 15

1. Two collaterals- oriented obliquely

2. Palmar (volar) plate- prevents hyperextension

Question 16

Where do intrinsic hand muscles originate and what do they do?

Answer 16

They originate and insert in the hand and carry out fine, precise movement.

Question 17

Which muscles are more important in powerful hand movements?

Answer 17

Forearm muscles

Question 18

Intrinsic hand muscles

Answer 18

1. Thenar eminence (thumb)
2. Hypothenar eminence (little finger)
3. Interosseous
4. Lumbrical

Question 19

Which muscles create the thenar eminence and which nerve supplies them?

Answer 19

1. Flexor pollicis brevis
2. Abductor pollicis brevis
3. Opponens pollicis

Median Nerve

Question 20

Which muscles make up the Hypothenar eminence and what nerve supplies them?

Answer 20

1. Flexor digiti minimi brevis
2. Abductor digiti minimi
3. Opponens digiti minimi

Innervated by ulnar nerve

Question 21

Abductor pollicis brevis: attachment and function

Answer 21

Origin: flexor retinaculum and tubercle of scaphoid and trapezium
Insertion: lateral side of base of proximal phalanx of thumb
Function: ABducts thumb

Question 22

Flexor pollicis brevis: attachment and function

Answer 22

Origin: flexor retinaculum and tubercle of trapezium
Insertion: lateral side of base of proximal phalanx of thumb
Function: flexes proximal phalanx of thumb

Question 23

Opponens pollicis: attachment and function

Answer 23

Origin: flexor retinaculum and tubercle of trapezium
Insertion: lateral side of first metacarpal bone
Function: opposes thumb towards center of palm and rotates it medially

Question 24

ADductor pollicis: attachment and function

Answer 24

Origin

• Oblique head: bases of 2nd and 3rd metacarpals and capitate
• Transverse head: anterior surface of body of 3rd metacarpal

Insertion: medial side of base of proximal phalanx of thumb

Function: ADduct thumb towards middle digit

Question 25

ABductor digiti minimi: attachment and function

Answer 25

Origin: pisiform and tendon of flexor carpi ulnaris Insertion: medial side of base of proximal phalanx of 5th digit Function: ABducts 5th digit

Question 26

Flexor digiti minimi brevis: attachment and function

Answer 26

Origin: hook of hamate and flexor retinaculum Insertion: medial side of base of proximal phalanx of 5th digit Function: flexes proximal phalanx of 5th digit

Question 27

Opponens digiti minimi: attachment and function

Answer 27

Origin: hook of hamate and flexor retinaculum Insertion: medial side of base of proximal phalanx of 5th metacarpal Function: draws the 5th metacarpal anteriorly and rotates it, bringing 5th digit into opposition with thumb

Question 28

Lumbricals 1 and 2: attachment and function

Answer 28

Origin: lateral two tendons of flexor digitorum profundus Insertion: lateral side of extensors expansions of 2nd and 3rd digits Function: flex digit at MCP joints and extend to IP joint

Question 29

Lumbricals 3 and 4: attachment and function

Answer 29

Origin: medial three tendons of flexor digitorum profundus Insertion: lateral side of extensors expansion of 4th and 5th digits Function: flex digit at MCP joints and extend to IP joint

Question 30

Dorsal interossei: attachment and function

Answer 30

Origin: adjacent sides of two metacarpals Insertion: extensor expansions and bases of proximal phalanges of 2nd to 4th digits Function: ABducts digits; flexes digits at MCP joints and extend to IP joints

Question 31

Palmar interossei: attachment and function

Answer 31

Origin: sides of 2nd, 4th, and 5th metacarpal bones Insertion: extensor expansions and bases of proximal phalanges of 2nd, 4th, and 5th digits Function: ABducts digits; flexes digits at MCP joints and extend to IP joints

Question 32

What surrounds the long tendons as they pass through the hand towards the fingers and what binds them to the phalanges?

Answer 32

Synovial Sheath | Fibrous digital sheath

Question 33

What is the anatomical snuff box created by the extensor tendons of the thumb on the dorsum of the hand composed of?

Answer 33

- Medially, the tendon of the extensor pollicis longus | - Laterally, the tendons of the abductor pollicis longus and extensor pollicis brevis

Question 34

How is the brachial plexus divided?

Answer 34

Five roots (ventral rami) Three trunks Six divisions (three anterior, three posterior) Three cords (named for their relationship to the axillary artery) Five large terminal branches

Question 35

From where does the brachial plexus arises?

Answer 35

Ventral rami of spinal nerves C5-T1

Question 36

Where is C4 found?

Answer 36

From the cervical plexus over the shoulder.

Question 37

What nerve root spans from the lateral arm, over deltoid and triceps?

Answer 37

C5

Question 38

What area does nerve root C7 supply?

Answer 38

Skin of the hand, primarily second through third or fourth digits

Question 39

Whic areas are supplied by C8 and T1?

Answer 39

C8: medial two digits (fourth and fifth digits), hypothenar eminence, and medial forearm T1: medial arm