ANATOMY Anatomy of the Forearm, Wrist and Hand 2 Flashcards
Thesuperficial layerof the posterior forearm contains seven muscles. What are these?
-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
Describe brachioradialis
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.
Describe anconeus
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.
Label this
Label and describe the deep posterior forearm compartment
Abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus - all three act on the thumb
Describe the nervous supply of this part
Label this and describe the blood supply of the forearm
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
Describe the 5 different parts of the hand
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
Label the hand compartments
Intrinsic muscles of the hand are called the interossei. Describe these
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
Label this, and explain why there is no palmar for middle finger
No palmar for middle finger bc it is the midline so you cnanot adduct towards itself v much
What are the lumbricals in the fingers?
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
Label this and use it to explain the arterial supply of the hand
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
What is Allen’s test?
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
Label
Describe what the median and deep branch nerve supplies in the hand
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
