Muscles And Bones Of The Hand

Question 1

What carpal bones are in contact with the radius?

Answer 1

Scaphoid and lunnate bone.

Question 2

What are the types of hand muscles?

Answer 2

Extrinsic hand muscles which originate in the forearm.
Intrinsic hand muscles which are containing within the carpal bone region.

Question 3

What are the muscles of the thenar eminence?

Answer 3

OAF=
Oppones pollucis.
ABductor pollucis brevis
Flexor pollucis brevis

->Innervated by the median nerve

Question 4

What is the hypothenar eminence?

Answer 4

AFO=
ABductor digiti minimi
Flexor digiti minimi
Oppones digit minimi

Question 5

What are the lumbricles?

Answer 5

“Worms” which originate from the tendon of the flexor digitorum profundus. First 2 lumbricles are unipennate, and the remaining are bipennate. They attach to the extensor hood of the finger with common insertion with the extensor digitorum.
Role is to flex the MCP joint and extend ICP joint.

Question 6

What is the flexor retinaculum?

Answer 6

Flat sheet of fibrous connective tissue which forms the roof of the carpal tunnel. The muscles which originate from here are the thenar and hypothenar eminence.

Question 7

What is the palmar aponeurosis?

Answer 7

Fascia of the palm that is continuous with the flexor retinaculum. Has attachments for the palmaris longus and palmaris quadrate.

Question 8

What is the abductor pollucis brevis?

Answer 8

Originates from the flexor retinaculum which attaches to the proximal phalanges, innervated by median nerve.

Question 9

What is the flexor pollucis brevis?

Answer 9

Superficialis head: flexor retinaculum
Deep head: Trapezius and caphate bone
The superficial and deep head join at the sesamoid bone which attaches to the proximal phalange.

Innervated by the median nerve

Question 10

What are the oppones pollucis?

Answer 10

Deepest muscle of the thenar muscle from the flexor retinaculum and the trapezium crest to lateral metacarpal bone of thumb.

Innervated by the median nerve.

Question 11

What is the flexor pollucis longus?

Answer 11

Deep anterior forearm muscle that runs between the superficial and deep head of the abductor pollucis brevis.

Question 12

What is the abductor digiti minimi?

Answer 12

From pisiform bone to the proximal phalanges 5.

Question 13

What is the flexor digiti minimi brevis?

Answer 13

Originates from the hannate bone to the base of metacarpal 5.

Question 14

What is the oppones digiti minimi?

Answer 14

From flexor retinaculum and hannate bone to the midshaft of metacarpal 5.

Question 15

What is the palmaris brevis?

Answer 15

Square shaped muscle from flexor retinaculum and palmar aponeurosis to ulnar side of skin.

Question 16

What is palmar interosseus muscle?

Answer 16

From the metacarpals to proximal phalanges for adduction towards midline of digits 2, 4 and 5, innervated by the ulnar nerve. There are 3 in total.

Thumb has a separate adductor muscle for adductor pollucis brevis and adductor pollucis longus.

Question 17

What is the distal interosseus muscle?

Answer 17

Originates from the 2 metacarpals of the proximal phalange. It is important for abduction of digit 2,3 and 4.

Digit 1 and digit 5 have abductors in the thenar and hypothenar eminences.

Question 18

What is the innervation to the muscles of the hand?

Answer 18

Mainly supplied by the ulnar nerve.

Question 19

What is the alternative innervation to the hand?

Answer 19

Median nerve supplies:
Thenar eminence (opponus pollucis, abductor pollucis brevis and flexor pollucis brevis)
Superficial head of flexor pollucis brevis
Radial side of flexor digitorum profundus
Radial Lumbricles of digit 1 and 2

Question 20

What are the features of the radial lumbricles?

Answer 20

Insert into the extensor hood and is innervated from the medial nerve for MCP flexion and ICP extension.

Question 21

What is the function of the lumbricles?

Answer 21

Flexion of metacarpoppharyngeal joints and keeps extension of interpharyngeal joint.
Fine precision movements

Question 22

Which intrinsic muscle of the thumb is innervated by the ulnar nerve?

Answer 22

Adductor pollucis

Question 23

Which nerve innervated abduction?

Answer 23

Median nerve

Question 24

Which nerve innervated adduction?

Answer 24

Ulnar nerve

Question 25

Which nerve innervates the movement of flexion and extension?

Answer 25

Mixed nerve

Question 26

What is the effect of median nerve lesion?

Answer 26

Sensory loss to the majority of the palm excluding half of digit 4 and digit 5 Dorsum of tips of fingers 2 and 3 Finger of Benediction where thumb, digit 2 and 3 remain extended.

Question 27

What is the effect of ulnar nerve lesion?

Answer 27

Loss of sensation to digit 4 and 5 Loss of motor to majority of hand muscles, resulting in claw hand.

Question 28

What is the effect of a radial nerve lesion?

Answer 28

Weak wrist extension so there is wrist drop Sensory loss of web between thumb and index

Question 29

What is the carpal tunnel?

Answer 29

Space beteeen carpal tunnel and flexor retinaculum. Allows the median nerve and the tendons of **flexor digitorum superficialis** and **flexor digitorum profundus** and **flexor pollucis longus** to pass through.

Question 30

What is the anatomical snuff box?

Answer 30

Region in the dorsal aspect of the hand bordered by the TENDONS of the ABductor pollucis longus, extensor pollucis longus and extensor pollucis brevis. It contains the trapezoid and scaphoid bone, radial artery and superficial radial nerve.

Question 31

Which muscle is responsible for extension of MCP joint?

Answer 31

Extensor digitorum.

Question 32

Which muscle is responsible for flexion of MCP joint?

Answer 32

Flexor digitorum and lumbricles

Question 33

Which muscle is responsible for extension of IP joint?

Answer 33

Lumbricles.

Question 34

How does the ulnar nerve enter the hand?

Answer 34

Guyon’s canal, a connective tissue sheath on the pisiform bone.

Question 35

What is the adductor pollucis?

Answer 35

Has a: ->transverse head which arises from the base of metacarpals 2 and 3 ->oblique head which arises from the 3rd metacarpal to attach to the proximal phalange of thumb. **Important for thumb adduction innervated by median nerve.**

Question 36

Which lumbricles are innervated by ulnar nerve?

Answer 36

Digits 3 and 4.

Question 37

What is the blood supply of the deep palmar branch?

Answer 37

Formed by the radial artery to supply blood to the thumb and index finger.

Question 38

What is the blood supply of the superficial palmar branch?

Answer 38

Formed by the ulnar artery to splurge blood to the deeper structures of the hand. Gives rise to the common digital arteries and proper digital arteries