Thumb Biomechanics & Innervation
This nerve branch innervates the first dorsal interosseous muscle, assisting thumb adduction.
What is the ulnar nerve?
Origin of the abductor pollicis longus includes the posterior surface of which two bones?
What are the ulna and radius?
Tenderness in the anatomical snuff box after a fall indicates likely fracture of which carpal bone?
What is the scaphoid?
Which carpal bone is most commonly fractured due to FOOSH injuries?
What is the scaphoid?
The dorsal radiocarpal ligament primarily resists which wrist movement?
What is wrist flexion?
The carpometacarpal (CMC) joint of the thumb is a saddle joint allowing which two primary movements?
What are flexion/extension and abduction/adduction?
The opponens pollicis inserts on which part of the first metacarpal?
What is the lateral shaft?
Damage to the radial artery within the snuff box can result in what rare but serious complication?
What is a pseudoaneurysm?
The lunate receives blood supply from this artery, making it vulnerable to avascular necrosis.
What is the dorsal intercarpal artery?
This ligament forms the primary stabilizing structure of the distal radioulnar joint.
What is the triangular fibrocartilage complex (TFCC)?
This movement occurs at the metacarpophalangeal joint of the thumb but not at the interphalangeal joint.
What is rotation?
Which muscle inserts on the base of the distal phalanx of the thumb and assists in IP joint extension?
What is extensor pollicis longus?
De Quervain’s tenosynovitis affects which two tendons forming the lateral border of the snuff box?
What are abductor pollicis longus and extensor pollicis brevis?
The pisiform acts as a sesamoid bone embedded in which tendon?
What is flexor carpi ulnaris?
The scapholunate ligament is critical in preventing this specific wrist deformity.
What is dorsal intercalated segment instability (DISI)?
The recurrent branch of this nerve innervates the thenar muscles except the adductor pollicis.
What is the median nerve?
This muscle originates on the flexor retinaculum and trapezium and is key in thumb opposition.
What is opponens pollicis?
The sensory branch of the radial nerve provides sensation to the dorsal hand but is often spared in this nerve compression syndrome.
What is carpal tunnel syndrome?
Kienböck’s disease is avascular necrosis of which carpal bone?
What is the lunate?
The volar plate of the MCP joint prevents this movement.
What is hyperextension?
The flexor pollicis longus is innervated by this nerve branch, which can be selectively tested by flexion of the distal phalanx of the thumb.
What is the anterior interosseous nerve?
The adductor pollicis has two heads—transverse and oblique. The oblique head originates from which carpal bone?
What is the capitate?
The arterial supply to the scaphoid is predominantly from branches entering which part of the bone?
What is the distal pole?
The triquetrum articulates with which carpal bone to its lateral side?
What is the hamate?
Injury to the lunotriquetral ligament leads to which specific carpal instability pattern?
What is volar intercalated segment instability (VISI)?