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 age do babies start sitting up. Most babies begin learning to sit up when they are four to seven months of age as their motor skills start developing gradually.In the third and fourth months, the head and neck muscles start gathering strength, helping the baby to raise his head and hold it in that position during tummy time [1] .ost babies begin learning to sit up when they are four to seven months of age as their motor skills start developing gradually. In the third and fourth months, the head and neck muscles start gathering strength, helping the baby to raise his head and hold it in that position during tummy time [1] .