The articulations are: interphalangeal articulations between phalangeal bones, and metacarpophalangeal joints connecting the phalanges to the metacarpal bones. Muscles
Each finger may flex and extend, abduct and adduct, and so  also circumduct. Flexion is by far the strongest movement. In humans, there are two large muscles that produce flexion of each finger, and additional muscles that augment the movement. The muscle bulks that move each finger may be partly blended, and the tendons may be attached to each other by a net of fibrous tissue, preventing completely free movement. Although each finger seems to move independently, moving one finger also moves the other fingers slightly which is called finger interdependence or finger enslaving.Fingers do not contain muscles (other than arrector pili). The muscles that move the finger joints are in the palm and forearm. The long tendons that deliver motion from the forearm muscles may be observed to move under the skin at the wrist and on the back of the hand. Muscles of the fingers can be subdivided into extrinsic and intrinsic muscles. The extrinsic muscles are the long flexors and extensors. They are called extrinsic because the muscle belly is located on the forearm. The fingers have two long flexors, located on the underside of the forearm. They insert by tendons to the phalanges of the fingers. The deep flexor attaches to the distal phalanx, and the superficial flexor attaches to the middle phalanx. The flexors allow for the actual bending of the fingers.
However, these subgroups do not affect how the disease is diagnosed or treated. Treatment
Prostaglandins
If the diagnosis is made prenatally, prostaglandin E1 (PGE1) is started after birth to avoid closure of the ductus arteriosus. Prostaglandin therapy is performed via a continuous infusion, due to how quickly prostaglandins are metabolized in the body. However, the diagnosis may go undetected, delaying treatment until closure of the ductus arteriosus produces symptoms. Surgery
Curative treatment consists of open heart surgery soon after birth, preferably immediately after diagnosis. Often, a synthetic patch is used to recreate the lost section of aorta. Recent research has revealed that an initial single-stage repair using direct anastomoses and repair of any existing cardiac defects is the preferred surgical technique, as opposed to a two-stage surgical repair.Awaiting surgery, prostaglandin can be administered to keep the ductus arteriosus open, thereby allowing blood flow to the lower body. After successful treatment, the patient is monitored for the rest of their life by a specialist to ensure that problems do not occur. Prognosis
Failure to treat the condition yields a mortality rate of 90% at a median age of 4 days. Death occurs due to increased blood flow from the left side of the heart (oxygenated blood) to the right side (deoxygenated blood), inducing heart failure; pulmonary edema; and eventual closing of the ductus arteriosus. For an infant with an interrupted aortic arch, a patent (open) ductus arteriosus allows for blood to bypass the "interruption," without which blood will be unable to reach the lower half of the body.