V1 angles posteriorly between longus colli medially and scalenus anterior laterally behind the common carotid artery to enter the transverse foramen of C6. Relations: 1  anteriorly: common carotid artery, vertebral vein, thoracic duct (left VA) and lymphatic duct (right VA).
9. For an easy-to-use graphical illustration of when baby should sit up, please see our baby development chart. What this information says is that at age 7 months, roughly 70% of all babies can sit alone for short periods of up to about half a minute. And 90% of all babies can do so by about 9 months old..Similarly, by about 3 months about 50% of all babies can sit when supported with cushions. Letâs say have a baby of about 7 months old who does not sit alone for short periods.nd 90% of all babies can do so by about 9 months old.. Similarly, by about 3 months about 50% of all babies can sit when supported with cushions. Letâs say have a baby of about 7 months old who does not sit alone for short periods.
In between five and six months, your baby usually starts to sit up with your help, holding his head in an upright position, keeping the back straight. He may even be able to sit for a second or so without taking any assistance from you, before toppling down after a while [1] .