[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 joint capsules [Joints and ligaments](https://durgical.com/en/anatomy/system/joints-and-ligaments/) · [Upper limb](https://durgical.com/en/anatomy/region/upper-limb/) # Finger joint capsules The finger joint capsules are the sleeves that seal the knuckles and finger joints; they swell in arthritis. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=upper_limb&select=finger_capsules&side=r) Opens in the Durgical app, no sign-up needed. ## What it is Small bags of tissue around the knuckles and finger joints. ## What it does Seal the joints; they swell in arthritis. ## Key points - MCP collateral ligaments are tight in flexion and slack in extension, so the hand is splinted with the MCPs flexed and the IPs straight (safe or intrinsic-plus position) to stop them shortening - The PIP joint stiffens more than any other: its volar plate and accessory collateral ligaments contract after even minor sprains, leaving a flexion contracture - Rheumatoid arthritis swells the MCP and PIP capsules and spares the DIPs; osteoarthritis favours the DIPs (Heberden nodes) and PIPs (Bouchard nodes) ## Key facts **Attaches** Around each MCP and IP joint, from head to base of the next bone **Function** Thickened at the sides by the collateral ligaments and in front by the volar plates ## Relations **In front** Volar plate; in front of it the flexor tendons in their fibrous sheath, with the A1 pulley over the MCP and the A3 pulley over the PIP **Behind** Extensor mechanism: the sagittal bands over the MCP, the central slip on the base of the middle phalanx over the PIP, the terminal tendon over the DIP **Lateral** On both sides, proper and accessory collateral ligaments; the lateral bands and the [digital nerves](https://durgical.com/en/anatomy/palmar-digital-nerves/) and arteries run alongside ## How to find it In a fist the knuckle is the metacarpal head, so the MCP joint line lies just distal to it; the palmar crease at the base of the finger is well distal to the joint. Synovitis fills the valleys between the knuckles; an IP effusion gives a spindle-shaped finger. ## Examination - MCP squeeze test: pain on squeezing across the knuckles suggests MCP synovitis, as in early inflammatory arthritis - Collateral stress testing (MCP flexed, IP joints straight): more opening than on the other hand means a collateral ligament tear ## On imaging Ultrasound with Doppler finds synovitis and effusion in the MCP and PIP capsules before X-ray changes. X-ray shows rheumatoid erosions first at the bare areas, where the capsule attaches to bone not covered by cartilage. ## Clinical notes - Fight bite: a tooth wound over a clenched MCP often enters the capsule; with the fingers straight, the [skin](https://durgical.com/en/anatomy/skin/) wound slides away from the joint wound, and septic arthritis can follow - In rheumatoid arthritis, boutonnière and swan-neck deformities start with synovitis stretching the PIP capsule and its supports - A jammed finger with a volar plate injury at the PIP can leave a fixed flexion contracture (pseudo-boutonnière) ## Related conditions - [Farber disease (Farber lipogranulomatosis)](https://durgical.com/en/conditions/farber-disease/) - [Chikungunya](https://durgical.com/en/conditions/chikungunya/) - [Systemic lupus erythematosus](https://durgical.com/en/conditions/systemic-lupus-erythematosus/) - [Rheumatoid arthritis](https://durgical.com/en/conditions/rheumatoid-arthritis/) - [Psoriatic arthritis](https://durgical.com/en/conditions/psoriatic-arthritis/) - [Mixed connective tissue disease](https://durgical.com/en/conditions/mixed-connective-tissue-disease/) - [Rheumatoid arthritis of the hand and wrist](https://durgical.com/en/conditions/rheumatoid-arthritis-of-the-hand-and-wrist/) ## Test yourself Think of the answer, then tap the question to see it. ## In what position is the hand splinted to protect the finger joint capsules, and why? MCPs flexed and IPs straight (safe position), because the MCP collaterals are tight in flexion and would otherwise shorten. ## Which finger joint stiffens more than any other after injury? The PIP joint: its volar plate and accessory collaterals contract after even minor sprains, leaving a flexion contracture. ## Which finger joint capsules does rheumatoid arthritis swell, and which does osteoarthritis favour? Rheumatoid arthritis swells the MCP and PIP capsules and spares the DIPs; osteoarthritis favours the DIPs (Heberden) and PIPs (Bouchard). [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/anatomy/finger-joint-capsules/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** capsulae articulares articulationum metacarpophalangearum et interphalangearum manus TA2 1536 **Official Spanish (DeCS)** Cápsulas articulares metacarpofalángicas e interfalángicas de la mano **English (TA2)** Finger joint capsules ## Related - [1st metacarpal](https://durgical.com/en/anatomy/1st-metacarpal/) - [2nd metacarpal](https://durgical.com/en/anatomy/2nd-metacarpal/) - [3rd metacarpal](https://durgical.com/en/anatomy/3rd-metacarpal/) - [4th metacarpal](https://durgical.com/en/anatomy/4th-metacarpal/) - [5th metacarpal](https://durgical.com/en/anatomy/5th-metacarpal/) - [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/) Sources: Terminologia Anatomica (TA2); [Anatomy, Shoulder and Upper Limb, Metacarpophalangeal Joints](https://www.ncbi.nlm.nih.gov/books/NBK538428/). ## **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/finger-joint-capsules/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/finger-joint-capsules/