The lumbrical muscles do not attach to the proximal phalanx directly, but rather connect the tendons of flexor digitorum profundus (below, ie volar) to the extensor tendons (above, ie dorsal) and produce flexion by pulling on the extensor tendons as they pass over the proximal phalanx.
By the time they are 12 months old, most babies can weigh three times what they weighed at birth and gain about an inch per month in length. The average infant at one year may be between 2630 inches long. Social and Emotional Development-Infants respond when you say their name. They begin to fear strangers.
What's my baby doing when I feel her move? The first thing a baby does is big body movements, such as flexing and extending the arms and legs, Dr. Keller says. Hiccups begin around 11 weeks, as the neurological system develops, but you won't feel the rhythmic, recurring jerks that signal them until much later.