Finger function

Question 1

Extrinsic finger flexors

Answer 1

Flexor Digitorium Superficialis and Profundus

Question 2

FDS

Answer 2

Flexes the PIP - each tendon is controlled independently

Question 3

FDP

Answer 3

Flexes the DIP - assists with PIP

The tendon to the index finger can act independently

Question 4

Campers Chiasm

Answer 4

FDP emerges thru split in FDS tendon so FDS can attach to the base of mid phalanx

Question 5

Flexor Pulleys

Answer 5

Fibrous osseus tunnels at metacarpal and mid phalanges to:

Aid in lubrication and nutrition
Prevent “bowstringing”

Question 6

Extrinsic Extensors

Answer 6

Brachioradialis
Extensor carpi radialis longus and brevis
Extensor digitorum
Extensor digit minimi
Extensor carpi ulnaris
Anconeus

Question 7

Extrinsic Extensors

Answer 7

Pass under extensor retinaculum in individual tendon sheaths to improve excursion efficiency

Question 8

Extensor Mechanism

Answer 8

Distal attachment for ED and intrinsic finger muscles

Question 9

ED at the proximal phalanx flattens into

Answer 9

A central band and then attaches to the middle phalanx

Question 10

Where do the lateral bands rejoin?

Answer 10

as the terminal tendon to distal phalanx. This allows extensor force to be transferred throughout the whole finger

Question 11

Intrinsic Minus (Claw) Hand

Answer 11

Imbalance of strong extrinsic overpowering weak intrinsics resulting in MCP hyperextension and IP flexion

Question 12

External thumb Extensors/ Abductors

Answer 12

Forms the anatomical snuffbox:

Extensor pollicis longus (ulnar side)
Extensor pollicis brevis (radial side)
Abductor pollicis longus (radial side)

Question 13

Intrinsic Muscles

Answer 13

Thenar Eminence Muscles:

Opponens Pollicis
abductor pollicis brevis
Flexor pollicis brevis

Question 14

What is the function of the intrinsic muscles

Answer 14

To position thumb during opposition

Injury to median nerve decreases the ability to oppose (which decreases grip)

Question 15

Hypothenar Muscles - Intrinsic

Answer 15

Function to cup ulnar border and deepen transverse arch

Function compromised by injury to ulnar nerve

Question 16

Lumbricales

Answer 16

Flex MCPJ and extend IP joints (tabletop position)

Question 17

Lumbricales are innervated by

Answer 17

1st and 2nd innervated by median nerve 3rd and 4th by ulnar nerve

Question 18

Interossei

Answer 18

Ab/Adduction at MCPJs
Flexes MCP and extends IP joints

Question 19

Power

Answer 19

Forceful motor activities

Question 20

Precision

Answer 20

Variety of fine motor, precision activities

Question 21

Hook

Answer 21

Not using thumb