Articular capsules of proximal interphalangeal joints
Capsulae articulares articulationum interphalangearum proximalium manus
The capsules enclosing the hinge joints between the proximal and middle phalanges of the index, middle, ring and little fingers.
At a glance
- English
- Articular capsules of proximal interphalangeal joints
- Latin (TA2)
- Capsulae articulares articulationum interphalangearum proximalium manus
- System
- Joint
- Region
- Hand
- Side
- Paired, left and right
About the articular capsules of proximal interphalangeal joints
The proximal interphalangeal joint of each finger joins the two-ridged head of the proximal phalanx to the base of the middle phalanx. It is the finger joint with the widest range of bending, and its capsule, a fibrous sleeve lined with synovial membrane, is fixed close to the edges of both articular surfaces.
On the dorsum the capsule is thin and fused with the central slip of the extensor tendon, which inserts on the base of the middle phalanx, flanked by the lateral bands. At the sides it is strengthened by strong collateral ligaments, with accessory fibres fanning towards the palm. On the palmar side lies a thick palmar plate, anchored proximally by check-rein ligaments, which stops the joint bending backwards. The two slips of flexor digitorum superficialis insert on the middle phalanx in front of this plate, with the profundus tendon passing between them.
Because the joint is so mobile and exposed, its capsule is often injured. A forced straightening injury, the jammed finger, can tear the palmar plate and leave a stiff, swollen joint for months. Rupture of the central slip lets the lateral bands slide forwards, producing the boutonniere deformity with a bent middle joint and an overextended tip. The reverse pattern, with the middle joint overextended and the tip bent, is the swan-neck deformity. Osteoarthritis causes bony Bouchard nodes here, and rheumatoid arthritis commonly involves these joints.
Attachments and function
- Formed by
- Margins of the articular surfaces of the heads of the proximal phalanges of the index to little fingers.
- Joins
- Margins of the articular surfaces of the bases of the corresponding middle phalanges.
- Movements
- Enclose and stabilise the hinge joints at the middle of the fingers, allowing a wide range of 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 proximal 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.
