The wrist and the hand Flashcards
Which carpal bones articulate with the radius to form the wrist (radiocarpal) joint?
Distally – The proximal row of the carpal bones (except the pisiform).
Proximally – The distal end of the radius, and the articular disk (see below)
What does the proximal row of carpal bones contain?
scaphoid, lunate, triquetral and pisiform (from radial side to ulnar)
What does the distal row of carpal bones cont
The distal row is composed of the hamate, capitate, trapezoid and trapezium (from ulnar side to radial).
What is a scaphoid fracture?
Results from a fall on an outstretched hand when the hand is abducted
Scaphoid bone has a narrow ‘waist’ that is mostly likely to fracture
Common injury in young adults
Tenderness in anatomical snuffbox
The scaphoid bone is the most commonly fractured carpal bone. What can happen if this injury is missed by a clinician?
Blood supply from distal > proximal segment
Fracture > proximal segment has blood supply interrupted
If missed / not fixed > avascular necrosis of proximal segment > affects wrist joint
What is a colles’ fracture?
One of the most common fractures of the ‘wrist’, a Colles’ fracture, is actually a fracture of the distal radius.
What is a boxer’s fracture?
A boxer’s fracture is the break of the 5th metacarpal bones of the hand near the knuckle.
Symptoms include pain and a depressed knuckle.
Classically, it occurs after a person hits an object with a closed fist. The knuckle is then bent towards the palm of the hand.
What are Bouchard’s nodes?
Bouchard’s nodes. Bouchard’s nodes are hard, bony outgrowths or gelatinous cysts on the proximal interphalangeal joints. Seen in OA
What are Heberden’s nodes?
Heberden’s nodes are bony growths that develop on the distal interphalangeal joints. Heberden’s nodes only develop in people who have osteoarthritis
What joints does rheumatoid arthritis affect?
Swelling of the PIP and MCP joints of the hands
What joints does osteoarthritis affect?
DIP, PIP, CMC most commonly but can affect most joints
Where is the carpal tunnel?
The carpal tunnel is a space or ‘channel’ on the anterior aspect of the
What muscles pass through the carpal tunnel?
The tendon of flexor pollicis longus
Four tendons of flexor digitorum profundus
Four tendons of flexor digitorum superficialis
What nerve passes through the carpal tunnel?
median nerve
What forms the floor of the carpal tunnel?
carpal bones
What forms the sides of the carpal tunnel?
carpal bones
What forms the roof of the carpal tunnel?
flexor retinaculum (transverse carpal ligament) on the anterior surface of the wrist
What is the Palmar aponeurosis?
a triangular shaped thickening of deep fascia beneath the skin of the palm
What are the 5 groups of intrinsic muscles in the palm of the hand ?
The thenar eminence (3 intrinsic muscles of the thumb)
The hypothenar eminence (3 intrinsic muscles of the little finger)
Adductor pollicis
The lumbrical muscles (there are 4)
The palmar interossei (there are 3)
What are the thenar eminence muscles?
Abductor Pollicis Brevis, Opponens Pollicis and Flexor Pollicis Brevis
Which intrinsic muscles are supplied by the median nerve?
The hypothenar eminence (3 intrinsic muscles of the little finger)
Adductor pollicis
lumbrical muscles 3rd and 4th
The palmar interossei (there are 3)
Which intrinsic muscles are supplied by the ulnar nerve?
The hypothenar eminence (3 intrinsic muscles of the little finger)
Adductor pollicis
lumbrical muscles 3rd and 4th
The palmar interossei (there are 3)
What are the Muscles of the thenar eminence muscles and their actions?
Abductor Pollicis Brevis: Abducts the thumb.
Opponens Pollicis: The opponens pollicis is the largest of the thenar muscles, and lies underneath the other two.Actions: Opposes the thumb, by medially rotating and flexing the metacarpal on the trapezium.
Flexor Pollicis Brevis: Flexes the metacarpophalangeal (MCP) joint of the thumb.
What is the innervation of the thenar eminence muscles?
Innervation: Median nerve.
What are the hypothenar eminence muscles?
Abductor digiti minimi, Flexor digiti minimi, Opponens digiti minimi
What is the innervation of the hypothenar eminence muscles?
Ulnar Nerve
What is the innervation of the hypothenar eminence muscles?
Ulnar Nerve
What is the origin of the lumbrical muscles?
FDP tendons in the palm
What is the insertion of the lumbrical muscles?
The lumbricals insert onto the extensor expansions.
What is the innervation of the lumbrical muscles?
1st and 2nd lumbricals : Median N
3rd and 4th :Ulnar N
What is the innervation of the lumbrical muscles?
1st and 2nd lumbricals : Median N
3rd and 4th :Ulnar N
What is the innervation of the interossei muscles?
Ulnar Nerve
What is the innervation of the interossei muscles?
Deep branch of Ulnar Nerve
What is the insertion of the interossei muscles?
They lie between the metacarpal bones and insert on the extensor expansion.
What is the insertion of the interossei muscles?
They lie between the metacarpal bones and insert on the extensor expansion and base of proximal phalanges
Dorsal Interossi
The 4 dorsal interossei each originate from two adjacent metacarpals. Their tendons converge towards the middle finger. When they contract, they pull digits 2 and 4 away from the middle finger – this is abduction
What is the extensor expansion?
it helps anchor the long extensor tendons and Is the point of insertion for the interossei and the lumbrical muscles. Extensor expansions cover the dorsum and sides of the distal metacarpal bones and proximal phalanges and maintain the extensor tendons in the midline of the digits.
What allows flexion at the MCPJ and extension at the IPJ to occur simultaneously?
When the interossei and lumbricals act together, and because they insert on the extensor expansion, they allow flexion at the MCPJ and extension at the IPJ to occur simultaneously
What veins form the dorsal venous network?
The cephalic vein and basilic vein. The cephalic vein runs through the anatomical snuffbox and can be seen and accessed in this location.
What is the superficial arch formed from?
terminal part of the ulnar artery with input from the radial artery
What is the deep arch formed from?
terminal part of the radial artery with input from the ulnar artery
What digits are mainly supplied by the Radial A?
digit 1 and lateral 1/2 of 2nd digit
What digits are mainly supplied by the Ulnar A?
Digits 3,4 and 5 and medial half of 2nd digit
What is Allen’s Test ?
allows a clinician to assess the adequacy of the blood flow within both the ulnar and radial arteries before accessing themfor arterial blood samples or for procedures like coronary angiography.
How do you preform Allen’s Test ?
Wrap hand around your opposite wrist, such that your thumb is lying over the ulnar artery and your middle (or index) finger is lying over your radial artery
Apply pressure to occludeBF from both A’s. Maintaining that pressure, now clench and unclench your fist rapidly for about 15 seconds. This pumps the venous blood out of your hand. Now, still occluding the arteries, stop clenching your fist and open out your fingers; your hand should look pale.
Now, to assess the patency of your ulnar artery, release your thumb from over the ulnar artery (but not from over the radial) You should see the pinkness return first to the medial side of your hand before spreading across towards the middle of the hand; your hand may feel warm as the blood flows in. If you now release your finger from over the radial artery; blood will flow now into this side of your hand and return the pink colour.
Now repeat, but this time assess the patency of the radial artery by releasing your index (or middle) finger from over the radial artery.
What is Raynaud’s syndrome?
spasm of arteries cause episodes of reduced blood flow. Usually digital A’s are occluded. Spasm can be in response to cold/ emotional stress etc..
Cutaneous innervation of the ulnar N
Palm - sensory to the skin over the ulnar 1 ½ digits and the adjacent part of the palm
Dorsum - sensory to the skin over the ulnar 2 digits except the lateral half of the skin over the distal phalanx of the 4th finger. Also sensory to the adjacent part of the skin over the dorsum of the hand
Cutaneous innervation of the median N
Palm - sensory to the skin over the palmar aspect of the lateral and 3 ½ digits and the adjacent part of the palm of the hand. Dorsum - sensory to the skin over the dorsal aspect of the distal phalanges of the lateral 3 ½ digits.
Cutaneous innervation of the radial N
Sensory to the skin over the remaining part of the dorsum of the hand and over the dorsum of the lateral 2 ½ digits, but only as far as the interphalangeal joint of the thumb and the distal interphalangeal joints of the 2nd and 3rd fingers.
