[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Upper limb](https://durgical.com/en/anatomy/region/upper-limb/) › Finger collateral ligaments [Joints and ligaments](https://durgical.com/en/anatomy/system/joints-and-ligaments/) · [Upper limb](https://durgical.com/en/anatomy/region/upper-limb/) # Finger collateral ligaments The finger collateral ligaments sit on each side of the middle and end finger joints; they keep each joint working as a straight hinge. Official name: Collateral ligaments of the finger joints [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=upper_limb&select=ip_collateral_ligs&side=r) Opens in the Durgical app, no sign-up needed. ## What it is Small bands on each side of the finger joints; a sideways bend sprains or tears them (a 'jammed' finger). ## What it does Keep the finger joints working as straight hinges. ## Key points - The PIP joint is the finger joint most often sprained; its collaterals have proper and accessory parts, like those of the knuckle - Gross instability usually needs the collateral and at least part of the volar plate to tear together - Fusiform swelling and stiffness of the PIP joint can last for months after a sprain ## Key facts **Attaches** Heads of the proximal/middle phalanges to the bases of the next phalanges **Function** Side-to-side stability of PIP and DIP joints **Tight in** Throughout (accessory parts in extension) ## Relations **In front** Volar plate, which receives the accessory fibres; flexor tendons in their sheath, with the A3 pulley at the PIP level **Behind** Lateral bands and central slip of the extensor mechanism **Superficial** Transverse retinacular and Cleland ligaments, then the [digital nerves](https://durgical.com/en/anatomy/palmar-digital-nerves/) and [digital arteries](https://durgical.com/en/anatomy/palmar-digital-arteries/) running along each side of the finger ## How to find it The IP joints are marked by the palmar finger creases and by the [skin](https://durgical.com/en/anatomy/skin/) wrinkles on the back of the fingers. Each collateral is pressed on the side of the joint, in the middle of the side face; tenderness on one side with spindle-shaped swelling points to a sprain of that ligament. ## Examination - Collateral stress test of the PIP with the joint straight and at about 30° of flexion, compared with the neighbouring finger: wide opening (often quoted as more than 20°) suggests a complete tear - Active range of motion after a digital block: a joint that stays congruent through active flexion and extension is considered stable ## On imaging A true lateral X-ray of the single finger is needed to see a subtle subluxation or fracture; PA and oblique views show avulsion fragments from the base of the middle phalanx, or condylar fractures that mimic a sprain. ## Clinical notes - Unicondylar fractures of the proximal phalanx head can look like a collateral sprain but are unstable - Chronic laxity of the radial collateral of the index PIP weakens pinch, since it takes the thumb's pressure - Scarring of the accessory collaterals and volar plate contributes to fixed PIP flexion contractures after injury ## Test yourself Think of the answer, then tap the question to see it. ## Which finger joint is most often sprained, injuring its collateral ligaments? The PIP joint; its collaterals have proper and accessory parts, like those of the knuckle. ## What usually has to tear for gross instability of a finger joint? The collateral ligament and at least part of the volar plate together. ## Which fracture can mimic a finger collateral ligament sprain but is unstable? A unicondylar fracture of the proximal phalanx head. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/anatomy/collateral-ligaments-of-the-finger-joints/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** ligamenta interphalangea collateralia manus TA2 1843 **Official Spanish (DeCS)** Ligamentos colaterales interfalángicos de la mano **English (TA2)** Collateral ligaments of the finger joints ## Related - [Volar plates (fingers)](https://durgical.com/en/anatomy/volar-plates-of-the-interphalangeal-joints/) - [Distal phalanx, thumb](https://durgical.com/en/anatomy/distal-phalanx-of-the-thumb/) - [Distal phalanx, index finger](https://durgical.com/en/anatomy/distal-phalanx-of-the-index-finger/) - [Distal phalanx, middle finger](https://durgical.com/en/anatomy/distal-phalanx-of-the-middle-finger/) - [Distal phalanx, ring finger](https://durgical.com/en/anatomy/distal-phalanx-of-the-ring-finger/) - [Distal phalanx, little finger](https://durgical.com/en/anatomy/distal-phalanx-of-the-little-finger/) - [Middle phalanx, index finger](https://durgical.com/en/anatomy/middle-phalanx-of-the-index-finger/) - [Middle phalanx, middle finger](https://durgical.com/en/anatomy/middle-phalanx-of-the-middle-finger/) Sources: Terminologia Anatomica (TA2); [Anatomy, Shoulder and Upper Limb, Metacarpophalangeal Joints](https://www.ncbi.nlm.nih.gov/books/NBK538428/); Anatomy of the Human Body (20th ed.): Surface Anatomy of the Upper Extremity (Lea & Febiger (Gray's Anatomy, 1918), 1918) · adapted, Public domain. ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/collateral-ligaments-of-the-finger-joints/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/collateral-ligaments-of-the-finger-joints/