Flashcards in The Hand Deck (36):
Explain how you would test the function of the radial nerve.
Place your hand behind the back of the other person's hand and ask them to push against it. This tests extension at the wrist.
What does an inability to flex the thumb and make the OK sign indicate?
Median nerve injury
How would you test for ulnar nerve function?
Ask the patient to make a fist and place ruler under their thumb. If they are unable to sit their thumb out straight on the ruler then this indicates inability to extend the thumb - ulnar nerve injury
What is the hand of benediction?
This is seen in patients with median nerve injury when they try to make a fist. They are unable to flex their first two digits.
When does ulnar claw present?
This occurs when a patient has their hand in a fist and tries to open it. They are unable to extend the two smallest digits causing ulnar claw.
What nerve is affected in carpal tunnel syndrome?
The median nerve
What condition leads to inability to oppose the thumb, and emaciation of the thenar muscles?
Carpal tunnel syndrome
How can carpal tunnel syndrome be treated surgically?
Release of the flexor retinaculum.
What is the thenar eminence?
This is a group of muscles found on the lateral surface of the palm, responsible for opposition of the thumb.
Name the muscles found within the thenar eminence.
Abductor pollicis brevis, opponens pollicis, flexor pollicis brevis and adductor pollicis brevis
Where does abductor pollicis brevis attach and insert?
This muscle starts at the tubercles of scaphoid and trapezium and also attaches to the flexor retinaculum. It attaches to the lateral side of the base of the proximal phalanx.
Where does flexor pollicis brevis attach?
It attaches to the distal phalanx, and originates at the flexor retinaculum and tubercles of scaphoid and trapezium.
Describe the difference in function of the superficial and deep heads of flexor pollicis brevis.
The superficial head is responsible for flexion of the thumb and is innervated by the median but the deep head is innervated by the ulnar and is responsible for Adduction of the thumb.
Where on the thumb does adductor pollicis attach?
It attaches to the medial side of the base of the proximal phalanx.
Name the two heads of adductor pollicis.
Transverse head which attaches to the anterior surface of the third metacarpal and the oblique head which attaches to the base of metacarpals 2/3, capitate and the adjacent carpals.
Where is opponens pollicis found?
It is found under abductor pollicis brevis and also attaches to scaphoid, trapezium and the flexor retinaculum. Distally it attaches to the lateral side of the first metacarpal.
What functions does palmaris brevis have?
This hollows the palm of the hand aiding grip and also protects the ulnar nerve and artery.
Name the muscles of the hypothenar eminence
Opponens digiti minimi, abductor digiti minimi, flexor digiti minimi.
Where does abductor digiti minimi attach?
It attaches to pisiform and then the medial side of the base of the proximal phalange.
Name two muscles which originate from the hook of hamate and the flexor retinaculum.
Opponens pollicis and flexor digiti minimi brevis
Where does opponens pollicis attach?
The medial border of the 5th metacarpal.
Where does flexor digiti minimi attach?
It attaches to the medial side of the proximal phalange
What nerve supplies the muscles of the hand?
The ulnar nerve supplies all the muscles of the hand except the first two lubricants, opponens pollicis, adductor pollicis brevis and flexor pollicis brevis (superficial head)
What is the allens test? When is it used clinically?
This is used to test perfusion to the hand. Both the radial and ulnar arteries are compressed at the hand and then released one at a time and the hand should become red again as it reperfuses. This is done to check that blood supply from the ulnar artery is sufficient before an ABG is taken from the radial artery.
How does the ulnar artery divide in the hand?
It splits into the superficial palmar arch and the deep palmar branch.
What structures form the deep palmar arch in the hand?
The deep branch of the ulnar artery and anastomoses from the radial artery.
What functions do the Lumbricals perform?
These perform flexion of the metacarpophalangeal joints and extension of the interphalangeal joints.
Where do the Lumbricals attach?
They all attach to the lateral side of extensor expansions on digits 2-5. They also attach to the tendons of flexor digitorum profoundus.
What differences are observed between Lumbricals 1&2 and 3&4?
1&2 are both uni pennate muscles innervated by the median nerve whilst 3&4 are bipennate muscles innervated by the ulnar nerve.
What action do palmar interossei perform?
These muscles are responsible for Adduction of the digits and also assist the Lumbricals.
Where do the palmar interossei attach?
Attach to the palmar surface of the 2,4,5 metacarpals and then the base of the proximal phalanges and the extensor expansions of digits 2,4,5.
What muscles are responsible for abduction of the digits of the hand?
Where do the dorsal interossei attach?
They attach to the base of the proximal phalange and extensor expansion of digits 2,4,5 and then the adjacent metacarpal.
How many dorsal interossei muscles are there?
What is the palmar aponeurosis?
This is a thick fascia which is found between the thenar and hypothenar regions in the centre of the hand and protects the underlying structures such as the long tendons, palmar arch etc. etc.