Articular capsules of distal interphalangeal joints
Capsulae articulares articulationum interphalangearum distalium manus
The capsules enclosing the hinge joints between the middle and distal phalanges of the index, middle, ring and little fingers.
At a glance
- English
- Articular capsules of distal interphalangeal joints
- Latin (TA2)
- Capsulae articulares articulationum interphalangearum distalium manus
- System
- Joint
- Region
- Hand
- Side
- Paired, left and right
About the articular capsules of distal interphalangeal joints
The distal interphalangeal joints of the hand lie at the last crease of each finger, between the head of the middle phalanx and the base of the distal phalanx. The thumb has no middle phalanx and so no joint of this name. Each is a hinge joint enclosed by a capsule of fibrous tissue lined with synovial membrane, attached close to the edges of both articular surfaces.
On the back, the capsule is thin and fused with the terminal part of the extensor mechanism, which inserts on the base of the distal phalanx. At the sides it is reinforced by collateral ligaments. On the palm side it is thickened into a palmar plate, a firm fibrocartilage pad that prevents the joint bending backwards too far. The tendon of flexor digitorum profundus passes over this plate in its fibrous sheath to insert on the palmar base of the distal phalanx.
The joints allow flexion and extension of the fingertips. Several common injuries and diseases involve them. A blow that forcibly bends a straightened fingertip can tear or pull off the extensor insertion, so the tip droops: mallet finger. Forced straightening of a gripping finger can pull flexor digitorum profundus off the bone, often in the ring finger, an injury called jersey finger. In osteoarthritis bony swellings called Heberden nodes form at the joint margins, and the capsule thickens. Psoriatic arthritis also has a marked tendency to affect these joints.
Attachments and function
- Formed by
- Margins of the articular surfaces of the heads of the middle phalanges of the index to little fingers.
- Joins
- Margins of the articular surfaces of the bases of the corresponding distal phalanges.
- Movements
- Enclose and stabilise the hinge joints of the fingertips, allowing flexion and extension.
- Nerve supply
- Palmar and dorsal digital nerves from the median and ulnar nerves, with dorsal digital branches of the radial and ulnar nerves.
- Blood supply
- Palmar and dorsal digital arteries of the fingers.
Anthromica
See the articular capsules of distal interphalangeal joints 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.
