Upper Extremity: Ligaments Flashcards
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Quadrate Ligament
Description:
- thickened band
- thin, square-shaped
- short but pliable to allow for pronation/supination
- cover synovial membrane below annular ligament
Attachments:
- extends from the inferior border of the annular ligament
- runs from the radial notch of the ulna to the neck of the radius
Functions:
-helps to stabilize the proximal radioulnar joint
Annular Ligament
Description:
- strong ligament that encircles the head of the radius
- retains contact of the radial head with the radial notch of the ulna
- deep surface is lines with the synovial membrane
Attachments:
- ulna (anterior and posterior to the radial notch)
- surrounds articulating surfaces and forms a collar around the head of the radius
Functions:
-anchors and stabilizes the proximal radioulnar joint
Relevant Structures:
- RCL of the elbow blends in
- upper border blends with anterior and posterior joint capsules
- superficial fibres of the anterior capsule (come from medial epicondyle of the humerus)
- inferior anterior joint capsule (with coronoid process)
- inferior aspect of the posterior joint capsule
RCL of the Elbow
Description:
- short and narrow fibrous band (less distinct than ulnar)
- fan-shaped
Attachments:
- extends from the lateral epicondyle of the humerus
- blends distally with the lateral aspect of the annular ligament
- also blends with the tendon of the supinator
Functions:
- stabilizes the lateral side of the elbow
- prevents lateral translation
- stabilizes the elbow during flexing
- limits varus stress
Relevant Structures:
-deep (transverse) fibres of the anterior joint capsule (run from UCL)
UCL of the Elbow
Description:
- thick and triangular shaped; strong
- has 3 bands (anterior,posterior and transverse)
Attachments:
Anterior Band:
-cord-like and strongest
-attached superiorly by its apex on the anterior surface of the medial epicondyle
-attached inferiority by the medial margin of the anterior surface of the coronoid process
Posterior Band:
- fan-shaped and weakest
- apex attaches superior to the inferior posterior aspect of the medial epicondyle
- attached inferiority to the medial margin of the olecranon process
Transverse Band:
-forms a bridge between the olecranon process and coronoid process
Functions:
- stabilizes the medial side of the elbow joint
- prevents values stress
- limits medial translation
- stabilizes elbow during flexion
Relevant Structures:
-deep (transverse) fibres of the anterior joint capsule (run from RCL)
Oblique Cord
Description:
- syndesmotic ligamentous band
- fibers run inferior and lateral
Attachments:
- lateral surface of the base of the coronoid process
- proximal shaft of the anterior radius, just distal to the tuberosity
Functions:
- limits movement of the radius by stabilizing the head of the radius during pronation/supination
- limits shearing of the ulna and radius
Volar Radioulnar Ligament
Description:
- narrow band
- fibre direction: oblique and medial
Attachments:
- anterior aspect of the ulnar notch
- anterior aspect of the head of the ulna
Functions:
-limits anterior shear if the radius (allows slight pivot/rotation)
Dorsal Radioulnar Ligament
Description:
- narrow band
- Fibre direction: oblique and medial
Attachments:
- posterior aspect of the ulnar notch
- posterior aspect of the head of the ulna
Functions:
-limits posterior shear if the radius on the ulna (allows slight pivot/rotation)
Arcuate Ligament
Description:
Continuous with interosseous membrane
Attachments:
- articular margins if the ulna (anterior surface)
- extends laterally and inserts on the distal aspect just superior to the ulnar notch on the radius
Functions:
- supports the joint superiorly
- stabilizes radius in pronation/supination
Palmar Radiocarpal Ligament
Description:
- broad, membranous band
- 3 bands: radioscapholunate, radiocapitate, radiotriquetral
- thickening of joint capsule
Attachments:
- anterior margin of distal radius to its styloid process to the anterior aspect of the distal ulna
- fibers descend inferiorly and medially to attach to the anterior surfaces of the scaphoid, lunate, capitate and triquetral
Functions:
-limits extension of the radiocarpal joint
Palmar Ulnocarpal Ligament
Description:
Attachments:
- anterior margin if the TFCC and the base if the styloid process of the ulna
- inserts on the anterior surfaces if the triquetrum and lunate
Functions:
-limits extension of the radiocarpal joint
Posterior Radiocarpal Ligament
Description:
- broad, ligamentous sheet
- some fibers blend with disc
- no band differentiation
Attachments:
- distal end of the radius, fibers run inferiomedially
- insert onto the scaphoid, lunate and triquetrum
Function:
-limits flexion of the radiocarpal joint
UCL of the Wrist
Description:
- short, ligamentous band
- superficial
- vertical fibre direction
Attachments:
-styloid process of the ulna toward triquetrum and pisiform
Functions:
- stabilizes medial aspect of the radiocarpal joint
- limits radial deviation
RCL of the Wrist
Description:
- weak, thin ligament
- vertical fibre direction
Attachments:
- tip of the radial styloid process
- lateral aspect of the scaphoid and trapezium
Functions:
- stabilizes the lateral aspect of the radiocarpal joint
- limits ulnar deviation
Proximal Interosseous Intercarpal Ligament
Description:
-2 bands between carpals in the proximal row
Attachments:
- scaphoid to lunate
- lunate to triquetrum
Functions:
-limits anterior and posterior shearing
Distal Intercarpal Interosseous Ligament
Description:
- between the carpals of the distal row
- dorsal aspect
Attachments:
- trapeziotrapezoid
- trapeziocapitate
- capitohamate
- triquetrohamate
Functions:
-limits posterior shearing on one another
