The hand Flashcards
(22 cards)
Name the bones of the hand?
- Carpals
- Metacarpals
- Phalanges
- Fingers = distal, middle, proximal
- Thumb = distal + proximal
Describe pronation?
- Turn the thumb over across the hand.
- The movement is critical for function.
How are the MCP joints stabilised?
- 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.
Describe extrinsic muscles?
- Originate outside the hand in forearm.
- Insert inside hand via tendons.
- Muscle belly in forearm.
- Provides movement and power.
Describe intrinsic muscles?
- Originate inside the hand.
- Insert within hand.
- Provide precision movement and dexterity.
Describe the thenar eminence?
- Intrinsic.
- Muscle bulk that give shape to the hand.
- On radial side.
- Includes:
- opponens pollicis
- abductor pollicis brevis
- flexor pollicis brevis
- adductor pollicis
Describe the hypothenar eminence?
- Intrinsic.
- Ulnar side.
- Includes:
- opponens digiti minimi
- abductor digiti minimi
- flexor digiti minimi
Describe the lumbricals?
-Originate from the tendons of flexor digitorum profunds and insert into tendons of the extensor digitorum communis.
Describe the dorsal interossei?
- Originate from the metacarpal bones + insert into the proximal phalanges.
- Abduct the fingers + flex MCPs.
Describe the palmar interossei?
- Originate from the metacarpal bones + insert into the proximal phalanges.
- Adduct fingers + flex MCPs.
Describe the palmar aponerosis?
- 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.
What is the extensor mechanism?
- 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.
Explain the power grip?
- Cylinder, ball, hook.
- Fingers flexed
- Wrist stabilised
- Thumb opposed
- Hand in contact with object
Explain the hook grip?
- 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.
Explain the cylinder grip?
- 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
Describe the precision grip?
- Plate, pinch, key, pincer.
- Tip/pad of thumb and finger.
- Deep precision muscles.
- Thumb opposed.
Explain the pinch grip?
-FDP = produce a force.
-FPL = produce force with thumb.
-Adductor pollicis = works with FPB to stabilise thumb.
-
Explain the pincer grip? (TIP to TIP)
- 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.
Explain what happens when closing the hand- extrinsic?
- FPL = flexes thumb
- FDS = flexes fingers
- FDP = flexes fingers
- All pass down anterior aspect of forarm to wrist.
Explain what happens when closing the hand- intrinsic?
- 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.
Explain what happens when opening the hand- extrinsic?
- EDC = extends fingers.
- EDM = extends little finger.
- EI = extends index finger.
- APL = abducts and extends wrist.
- EPL = extends thumb.
- EPB = extends thumb.
Explain what happens when opening the hand- intrinsic?
- APB = abducts thumb
- ADM = abducts little finger.
