The hand

Question 1

Name the bones of the hand?

Answer 1

• Carpals
• Metacarpals
• Phalanges
  
  • Fingers = distal, middle, proximal
  • Thumb = distal + proximal

Question 2

Describe pronation?

Answer 2

• Turn the thumb over across the hand.

- The movement is critical for function.

Question 3

How are the MCP joints stabilised?

Answer 3

• Collateral ligaments - cord and fan.
• When joint in extension cord is slack allowing side to side movement.
• When flexion, cord is tight and no side to side.
• Palmar ligament prevents hyperextension.
• Short ligaments join MCPs of fingers, form the palm.

Question 4

Describe extrinsic muscles?

Answer 4

• Originate outside the hand in forearm.
• Insert inside hand via tendons.
• Muscle belly in forearm.
• Provides movement and power.

Question 5

Describe intrinsic muscles?

Answer 5

• Originate inside the hand.
• Insert within hand.
• Provide precision movement and dexterity.

Question 6

Describe the thenar eminence?

Answer 6

• Intrinsic.
• Muscle bulk that give shape to the hand.
• On radial side.
• Includes:
• opponens pollicis
• abductor pollicis brevis
• flexor pollicis brevis
• adductor pollicis

Question 7

Describe the hypothenar eminence?

Answer 7

• Intrinsic.
• Ulnar side.
• Includes:
• opponens digiti minimi
• abductor digiti minimi
• flexor digiti minimi

Question 8

Describe the lumbricals?

Answer 8

-Originate from the tendons of flexor digitorum profunds and insert into tendons of the extensor digitorum communis.

Question 9

Describe the dorsal interossei?

Answer 9

• Originate from the metacarpal bones + insert into the proximal phalanges.
• Abduct the fingers + flex MCPs.

Question 10

Describe the palmar interossei?

Answer 10

• Originate from the metacarpal bones + insert into the proximal phalanges.
• Adduct fingers + flex MCPs.

Question 11

Describe the palmar aponerosis?

Answer 11

• Thick central section which lies in the palm between thenar and hypothenar eminence.
• Cover all other muscles.
• Divides into 4 slips.
• Attach to sheath of each finger.

-Separated from skin of hand by a layer of fat.

Question 12

What is the extensor mechanism?

Answer 12

• Extrinsic and intrinsic muscles.
• Extension of finger = intrinsic relax + extensor tendon pulls lateral band above PIP, pulling the finger up.
• Curl finger, intrinsic activate and pull lateral band under point of PIP.

Question 13

Explain the power grip?

Answer 13

• Cylinder, ball, hook.
• Fingers flexed
• Wrist stabilised
• Thumb opposed
• Hand in contact with object

Question 14

Explain the hook grip?

Answer 14

• Flexor digitorum superficials = flexion at MCP + PIP.
• Flexor digitorum profunds = flexion at MCP + PIP + DIP.
• Flexor digiti minimi = flexion of little finger at MCP.
• Opponens digiti minimi = stabilises middle of hand.

Question 15

Explain the cylinder grip?

Answer 15

• FDS = flexion of fingers.
• FDP = flexion of fingers.
• FDM = flexion of little finger
• FPL = flexion of thumb
• FPB = flexion of thumb
• Opponens pollicis = rotation of thumb
• APB = abduction of thumb
• APL = abduction of thumb

Question 16

Describe the precision grip?

Answer 16

• Plate, pinch, key, pincer.
• Tip/pad of thumb and finger.
• Deep precision muscles.
• Thumb opposed.

Question 17

Explain the pinch grip?

Answer 17

-FDP = produce a force.
-FPL = produce force with thumb.
-Adductor pollicis = works with FPB to stabilise thumb.
-

Question 18

Explain the pincer grip? (TIP to TIP)

Answer 18

• FDS + FDP + lumbricals for flexion of index fingers.
• FPL + FPB for flexion of the thumb.
• Opponens pollicis for rotation of thumb.
• Abductor pollicis brevis for abduction of thumb.

Question 19

Explain what happens when closing the hand- extrinsic?

Answer 19

• FPL = flexes thumb
• FDS = flexes fingers
• FDP = flexes fingers
• All pass down anterior aspect of forarm to wrist.

Question 20

Explain what happens when closing the hand- intrinsic?

Answer 20

• FPB = flexes thumb and pronation.
• OP = Pronates thumb
• FDP = flexes little finger
• ODM = assists FDP to pull MC forward.
• AP = adducts thumb and assists with supination.

Question 21

Explain what happens when opening the hand- extrinsic?

Answer 21

• EDC = extends fingers.
• EDM = extends little finger.
• EI = extends index finger.
• APL = abducts and extends wrist.
• EPL = extends thumb.
• EPB = extends thumb.

Question 22

Explain what happens when opening the hand- intrinsic?

Answer 22

• APB = abducts thumb

- ADM = abducts little finger.