Session 4-Functional Anatomy Of The Hand Flashcards
Describe how the Allen Test is carried out
Patient squeezes hand tightly and examiner places thumb and index finger over radial and ulnar arteries, compressing them. Patient opens hand while pressure is maintained, one artery tested by releasing pressure over that artery to see if hand flushes, same done to other artery and comparison is made
Why is the Allen test carried out?
50% of people don’t have an ulnar artery so this test is done to check before a blood gas is done because if a patient only has radial artery, blood gas could jeopardise circulation
Why is arterial blood gas used?
To sample arterial blood to measure O2 concentration, CO2 concentration, pH etc - can be life saving if breathing and circulation is compromised
What are the functions of palmar skin? (3)
Grasping
Feeling
Moving underlying joints
What does the nail arise from and what happens if this is damaged?
From germinal matrix (small semi-circle at base of nail)
If damaged, no nail will grow
True or false: thick skin has many densely compacted layers and the epidermis indents into the dermis, allowing the skin to move
TRUE
Which digits does the median nerve supply?
Radial 3 1/2 digits: thumb, index and middle fingers and half of the ring finger
True or false: median nerve is deep to the flexor tendons
FALSE - superficial
True or false: the median nerve enters the hand through the carpal tunnel
TRUE
Which four carpal bones form the borders of the carpal tunnel?
Trapezium
Scaphoid
Pisiform
Hamate
Which three muscles make up the thenar eminence?
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
Which mnemonic is used to remember which four muscles of the hand are supplied by the median nerve?
LOAF
Which four muscles of the hand are supplied by the median nerve?
Lateral two lumbricals
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
Which canal does the ulnar nerve pass through?
Guyon’s canal
Which digits does the ulnar nerve supply?
Little finger and half of ring finger
True or false: the ulnar nerve is superficial to the long flexor tendons
FALSE - deep
Which muscles does the ulnar nerve supply?
Interossei
True or false: the radial nerve doesn’t supply any muscles in the palm of the hand
TRUE - supplies forearm and back of hand
How many flexor tendons does each digit have?
Two flexor tendons per finger and one long flexor tendon for the thumb
Where does flexor digitorum profundus attach?
To distal phalanx
Where does flexor digitorum superficialis attach?
To middle phalanx
True or false: no blood supply runs along the tendons, the blood supply runs on the underlying bone instead
TRUE
True or false: dorsiflexion of wrist increases finger grip strength
TRUE
What are the extensor tendons of the fingers called?
Extensor digitorum communis
What is the long tendon in the thumb called?
Extensor pollicis longus
What are the lumbricals?
Muscles arising from flexor tendons that allow MCP joint to flex and extends the IP joints
True or false: the index and little fingers have an extra tendon with extra muscle so they can be lifted independently
TRUE
What is the flexor retinaculum?
Fibrous band on palmar side of hand near the wrist, arches over carpal bones of the hand and forms the carpal tunnel
What are the bony attachments of the flexor retinaculum?
Pisiform
Hamate
Scaphoid
Trapezium
Which structures pass through the carpal tunnel?
Median nerve
Nine tendons: flexor pollicis longus, four flexor digitorum superficialis and four flexor digitorum profundus
