Each PIP joint has proper and accessory collateral ligaments: the proper collateral ligament (PCL) is the primary valgus-varus restraint running from the lateral condyle of the proximal phalanx to the lateral base of the middle phalanx; the accessory collateral ligament (ACL) arises just dorsal to the PCL and inserts on the volar plate rather than the phalanx. The accessory collateral ligaments check extension by supporting the volar plate, creating the dorsal extension block of the PIP joint.
Supports the volar plate at the PIP joint preventing hyperextension; contributes to the soft tissue box surrounding the PIP joint; the PIP accessory collateral ligaments are the 'check reins' that limit PIP extension beyond the neutral position.
The accessory collateral check reins are released in PIP joint contracture correction: extension contractures from intrinsic tightness (positive intrinsic tightness test) require accessory collateral and volar plate release. Flexion contractures after dorsal PIP injury or boutonniere repair require lateral band and accessory collateral release to restore extension. The accessory collaterals are the primary structure of the extension block splint mechanism — dorsal splinting at 20-30 degrees flexion relaxes the check reins and allows the volar plate to heal after volar plate injuries.
Extension contracture of the PIP joint from chronic intrinsic tightness or post-traumatic scarring tightens the accessory collateral check reins preventing full extension; surgical release of the accessory collateral check reins (check resinectomy) combined with volar plate release restores PIP extension range in established fixed flexion contractures.
This website uses cookies to enhance your experience. Some are essential for site functionality, while others help us analyze and improve your usage experience. Please review your options and make your choice.
If you are under 16 years old, please ensure that you have received consent from your parent or guardian for any non-essential cookies.
Your privacy is important to us. You can adjust your cookie settings at any time. For more information about how we use data, please read our privacy policy. You may change your preferences at any time by clicking on the settings button below.
Note that if you choose to disable some types of cookies, it may impact your experience of the site and the services we are able to offer.
Some required resources have been blocked, which can affect third-party services and may cause the site to not function properly.
This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.
