Wrist and Hand Flashcards
Label the features of the radius and ulna on the diagram
What attaches to the radial tuberosity?
Biceps brachii tendon
Name the bones of the hand
- Scaphoid (S)
- Lunate (L)
- Triquetrum (T)
- Pisiform (P)
- Hamate (H)
- Capitate (C)
- Trapezoid (Td)
- Trapezium (Tm)
What type of bone is the pisiform?
Where is it?
Sesamoid
Situated on the tendon of flexor carpi ulnaris
What is number 3 in the image?
What is marked by the red cross?
What sits medial to it?
3= Dorsal radial tubercle
3rd extensor wrist compartment sits medial to it.
Red cross= injection/aspiration point for the wrist
What bones form the wrist joint?
What type of joint is it?
What movements does it permit?
What separates the distal ulna from the joint?
- Distal radius
- Scaphoid
- Lunate
- Triquetrum
Synovial condyloid joint
Capable of flexion, extension, abduction and adduction (+circumduction)
Distal ulna separated by cartilagenous disc (articular disc)
Which ligaments support the wrist joint?
What are their roles?
Lateral collateral ligament
- Radial styloid → scaphoid
Medial collateral ligament
- Ulnar styloid → triquetrum
Which bone of the hand is often fractured by a fall onto outstretched hand?
What are the possible complications of this fracture?
What symptoms would the patient have?
Scaphoid fracture
Can cause avascular necrosis as the bone is supplied by distal → proximal unidirectional blood supply. Fracture can tear the arteries causing avascular necrosis of the proximal part of the scaphoid.
Patient would have tenderness in the anatomical snuffbox
What is a Bennett’s fracture?
Fracture of proximal metacarpal 1
What is a Smith’s fracture?
Ventral displacement of the radius following distal radius fracture
What is a Colle’s fracture?
Dorsal displacement of the radius following distal radius fracture
What marks the borders of the anatomical snuffbox?
What runs through it?
What can be palpated through it
Borders:
- Extensor pollicis longus
- Extensor pollicis brevis and abductor pollicis longus
Palpation:
- Radial pulse
- Scaphoid bone
Contents:
- Radial artery
- Superficial branch of radial nerve
- Cephalic vein
What is the palmar aponeurosis?
Tough fibrous layer limiting the movement of palmar skin
Attaches to palmaris longus if it is present (absent in approx 20% of the population)
Name some disorders that can change the resting position of the hand
Dupuytrens contracture
- Aponeurotic thickening causing passive flexion of medial digits
Ulnar claw hand
- Lesion to the ulnar nerve
Stenosing tenosynovitis
- Inflammation of tendons and synovial sheath causing a narrowing of pulley systems so swollen tendons get stuck.
Name the intrinsic muscles of the hand
What movements are they responsible for?
What is their innervation?
Thenar eminence (all median nerve):
- Opponens pollicis: thumb opposition by medial rotation and flexion of metacarpal on trapezium.
- Abductor pollicis brevis: thumb abduction
- Flexor pollicis brevis: thumb flexion at MCP joint
Hypothenar eminence (all ulnar nerve):
- Opponens digiti minimi: opposition of digit 5 by lateral rotation of metacarpal
- Abductor digiti minimi: abduction of 5th digit
- Flexor digiti minimi brevis: flexion of 5th digit at MCP joint
What is the golden rule for nerve supply to the hand?
Everything is C8-T1 supplied
Everything is ulnar nerve supplied except:
- Thenar muscles (median nerve)
- Lateral 2 lumbricals (to digits 2 & 3) (median nerve)
What is the role of the lumbricals?
What is their nerve supply?
- Flexion at MCP joints
- Extension at DIP joints (as they insert onto the extensor expansion)
Medial 2 lumbricals (ulnar): ulnar nerve
Lateral 2 lumbricals (radial): median nerve
What is the role of the palmar interossei?
What is their innervation?
Where is the axis of abduction and adduction on the hands?
Palmar interossei: adduction of digits (PAD)
Dorsal interossei: abduction of digits (DAB)
All supplied by ulnar nerve
Axis= middle digit
What muscle is responsible for adduction of the thumb?
What could damage/deinnervation of this muscle cause?
Adductor pollicis
Damage (e.g. in ulnar lesion) = positive Froment’ sign:
- Excess thumb flexion whilst pinching (thumb usually adducted)
Label the synovial sheaths on the diagram
What is the significance of the common synovial sheath?
Common synovial sheath extends up the 5th digit: infection from 5th digit wounds can spread to the palm, carpal tunnel and proximal forearm.
Label the palmar spaces on the diagram
Where do they sit?
Sit between the deep flexor tendons and the metacarpals/interossei in the palm
What is the carpal tunnel?
Where is it?
What is it made up of?
Located on the anterior (volar) side of the hand, 2cm distal to the distal wrist crease.
Acts as a passageway for tendons of the digit flexor muscles passing into the hand from the forearm.
Formed from the carpal bones of the hand and the flexor retinaculum. 4 points marked by:
- Hook of hamate
- Pisiform
- Scaphoid tubercle
- Trapezium tubercle
What does the carpal tunnel contain?
Which nerve travels superficial to it?
Ulnar nerve travels superficial to it in Guyon’s canal
Carpal tunnel contains:
- Median nerve
- x4 tendons of flexor digitorum superficialis
- x4 tendons of flexor digitorum profundus
- Flexor pollicis longus
What is carpal tunnel syndrome?
What are the symptoms?
What can cause it?
Involves compression of the median nerve in the carpal tunnel
Symptoms:
- Weakness of flexion of digits 1-3 at PIP and DIP joints
- Prolonged CT syndrome can cause wasting of thenar eminence
- Paraesthesias in median nerve distribution:
- Often in digital distribution
- Palm often unaffected as it is also supplied by a branch of the median nerve that runs superiorly to the carpal tunnel therefore is not compressed.
Causes:
- Ganglion cyst
- Giant cell tumour
- Neuroma
- Lipoma
- Soft tissue thickening
- Fluid retention
