Scaphotrapeziotrapezoidal ligament
Ligamentum scaphotrapeziotrapezoideum
The ligament joining the distal pole of the scaphoid to the trapezium and trapezoid on the radial side of the wrist.
At a glance
- English
- Scaphotrapeziotrapezoidal ligament
- Latin (TA2)
- Ligamentum scaphotrapeziotrapezoideum
- System
- Ligament
- Region
- Hand
- Side
- Paired, left and right
About the scaphotrapeziotrapezoidal ligament
The scaphotrapeziotrapezoidal ligament, often shortened to the STT ligament, holds the distal pole of the scaphoid against the trapezium and trapezoid. These three bones meet at the scaphotrapeziotrapezoidal joint, a small synovial joint that forms the radial end of the midcarpal joint. The ligament arises from the palmar and radial aspects of the distal scaphoid, around the scaphoid tubercle, and fans out distally to the neighbouring surfaces of the trapezium and the trapezoid.
It lies close to the tendon of flexor carpi radialis, which crosses this region in a groove on the trapezium on its way to the base of the second metacarpal. With the scaphocapitate ligament on the ulnar side of the distal scaphoid, it forms the main distal anchor of the scaphoid to the distal carpal row. The flexor retinaculum attaches nearby, to the scaphoid tubercle and the tubercle of the trapezium.
Its main role is to resist flexion and palmar displacement of the distal scaphoid, acting as a distal restraint for the bone that bridges the two carpal rows. It also helps pass load from the radial side of the hand, including the thumb and index ray, onto the scaphoid. The STT joint is a common site of osteoarthritis and often shows changes alongside arthritis at the base of the thumb. This causes pain at the base of the thenar eminence and may irritate the neighbouring flexor carpi radialis tendon.
Attachments and function
- Attaches from
- Palmar and radial surfaces of the distal pole of the scaphoid, around the scaphoid tubercle.
- Attaches to
- Adjoining surfaces of the trapezium and trapezoid.
- Function
- Holds the distal scaphoid to the trapezium and trapezoid and resists flexion and palmar shift of the distal scaphoid.
- Nerve supply
- Articular twigs from the anterior interosseous nerve and the deep branch of the ulnar nerve, which supply the palmar side of the carpus.
- Blood supply
- Small branches of the palmar carpal arch, reinforced by recurrent branches from the deep palmar arch.
Anthromica
See the scaphotrapeziotrapezoidal ligament where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
