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.
Thatâs when they start to lose the âtongue-thrust reflexâ or extrusion reflex, which is important for sucking the breast or bottle when they are younger, but interferes with feeding. Babies at this point can also lift their heads up independently and hold their necks high. If your baby is around this age, can sit up well with support, and shows interest in the foods he sees you eating, itâs probably a good time to venture into feeding your baby solid food. If your baby is exclusively breastfed, it is recommended that you wait until he is 6 months to start solids.