ANATOMY Anatomy of the Forearm, Wrist and Hand 2

Question 1

Thesuperficial layerof the posterior forearm contains seven muscles. What are these?

Answer 1

-brachioradialis
-anconeus
-extensor carpi ulnaris
-extensor carpi radialis longus and brevis
-extensor digiti minimi (extend the little finger alone, contributes to extension at wrist
digitorium( extensor digitorum (extension of digits at interphalangeal and metacarpophalangeal joints)

note- the extensor carpi muscles all extend and abduct the wrist

Question 2

Describe brachioradialis

Answer 2

This muscle is from the back of the humerus, goes to the front of the forearm, then wraps around the back of the radius
Helps flex the forearm when in a neutral position (halfway between pronated and supinated)
Innervated by the radial nerve.

Question 3

Describe anconeus

Answer 3

Anconeus
Attachments: Originates from the lateral epicondyle, and attaches to the posterior and lateral part of the olecranon.
Actions: Extends and stabilises the elbow joint. Abducts the ulna during pronation of the forearm.
Innervation: Radial nerve.

Question 4

Label this

Answer 4

Question 5

Label and describe the deep posterior forearm compartment

Answer 5

Abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus - all three act on the thumb

Question 6

Describe the nervous supply of this part

Answer 6

Question 7

Label this and describe the blood supply of the forearm

Answer 7

brachial splits into ulnar and radial artery
radial goes to palm of hand
ulnar branches into anteirior and posteiror interosseous nerves, supplying most of the deep muscle structures

Question 8

Describe the 5 different parts of the hand

Answer 8

Interosseous muscles (between metacarpal bones - mostly adduction and abduction)
Thenar eminence - muscles acting on the thumb
Hypothenar eminence - muscles acting on little finger
Central space → long tendons going to hand run here (flexor digitorium tendons from muscles)
**Adductor pollicis muscle **- adducts the thumb

The thenar and midpalmar space allow the muscles to move over each other and separate them out
They can become infection sites

Question 9

Label the hand compartments

Answer 9

Question 10

Answer 10

Question 11

Answer 11

Question 12

Answer 12

Question 13

Answer 13

Question 14

Answer 14

Question 15

Intrinsic muscles of the hand are called the interossei. Describe these

Answer 15

Dorsal interossei: most superficial of all dorsal muscles. Hay 4 dorsal interossei muscles. ABDUCTS digits
Palmar interossei: Located anteriorly. ADDUCTS digits
Both also help flexion at the mcp joints and extension at the ip joints.
Innervation:Ulnar nerve

Question 16

Label this, and explain why there is no palmar for middle finger

Answer 16

No palmar for middle finger bc it is the midline so you cnanot adduct towards itself v much

Question 17

What are the lumbricals in the fingers?

Answer 17

There are four lumbricals in the hand, each associated with a finger.
Actions: Flexion at the MCP joint and extension at the IP joints of each digit.
Innervation: The lateral two lumbricals (of the index and middle fingers) are innervated by themedian nerve. The medial two lumbricals (of the little and ring fingers) are innervated by theulnar nerve

Question 18

Label this and use it to explain the arterial supply of the hand

Answer 18

ulnar and radial artery - form 2 arches - form anastomoses:
Superficial palmar arch– gives rise to the digital arteries, which supply the four fingers.
Deep palmar arch– located deep to the flexor tendons of the hand. It contributes to the blood supply to the digits and to wrist joint.
The adductor compartment separates them

Question 19

What is Allen’s test?

Answer 19

Allen’s test → check both arteries are doing a okay; used for surgeries or cannualas if they are blocking one artery, squeeze hand and compress one artery and release → see if hand is well perfused
If cannula is in ulnar, then you need to ensure radial can supply both arches by itself

Question 20

Label

Answer 20

Question 21

Describe what the median and deep branch nerve supplies in the hand

Answer 21

Deep branch supplies all the interosseous muscles and lumbricals, whereas the recurrent branch of the median nerve supplies the thenar muscles and branches to lumbricals 1 and 2

Radial nerve is purely cutaneous

Question 22

Answer 22