Deformity in which the fingertip is curled in and cannot straighten itself
Due to injury to extensor digitorium tendons at DIPJ
Forced flexion of the finger when finger is extended:
. Sport Injury: Finger struck by volleyball, basketball or baseball when it is in extension
. Other common mechanisms of injury include forcefully tucking in a bedspread or slipcover or pushing off a sock with extended fingers.
Trigger finger is the popular name of stenosing tenosynovitis, a painful condition in which a finger or thumb locks when it is bent (flexed) or straightened (extended).
Due to narrowing of the sheath that surrounds the tendon in the affected finger, or a nodule forms on the tendon.
Trigger finger is often an overuse injury because of repetitive or frequent movement of the fingers (ex. hobbies as playing a musical instrument or crocheting)
Trigger finger may also result from trauma or accident
It is called trigger finger because when the finger unlocks, it pops back suddenly, as if releasing a trigger on a gun.
Hyperflexion at the PIP joint with hyperextension at the DIP
Passive extension of the PIP joint is easy.
Flexion deformity of the PIP joint, due to interruption of the central slip of the extensor tendon:
The lateral bands separate
The head of the proximal phalanx pops through the gap like a finger through a button hole
The DIP joint is drawn into hyperextension.
The 3 main etiologies:
RA and other inflammatory arthritides (most often)
Burns and infections
Swan – Neck deformity
the PIP joint is hyper extended . DIP joint is flexed.
Due to injury or inflammation (RA)
Swelling and pain due to inflammation from injury or disease (RA)
Pathologic condition of the hand in which the fascia of the palm are shortened and thickened