In the vertex<unk>  the head is flexed and the occiput leads the way. This is the most common configuration and seen at term in 95% of singletons. If the head is extended, the face becomes the leading part. Face<unk> s account for less than 1% of<unk> s at term. In the sinicipital<unk>  the large fontanelle is the presenting part; with further labor the head will either flex or extend more so that in the end this<unk>  leads to a vertex or face<unk> . In the brow<unk>  the head is slightly extended, but less than in the face<unk> . The chin<unk>  is a variant of the face<unk>  with maximum extension of the head. Non-cephalic<unk> s are the breech<unk>  (3.5%) and the shoulder<unk>  (0.5%). Vertex<unk>  The vertex is the area of the vault bounded anteriorly by the anterior fontanelle and the coronal suture, posteriorly by the posterior fontanelle and the lambdoid suture and laterally by 2 lines passing through the parietal eminences. In the vertex<unk>  the occiput typically is anterior and thus in an optimal position to negotiate the pelvic curve by extending the head. In an occiput posterior position, labor becomes prolonged, and more operative interventions are deemed necessary. The prevalence of the persistent occiput posterior is given as 4.7%. The vertex<unk> s are further classified according to the position of the occiput, both right, left, or transverse and anterior or posterior: *Left Occipito-Anterior (LOA), Left Occipito-Posterior (LOP), Left Occipito-Transverse (LOT) *Right Occipito-Anterior (ROA), Right Occipito-Posterior (ROP), Right Occipito-Transverse (ROT) Right occipito-anterior Straight occipito-anterior Left occipito-anterior Right occipito-transverse 140px Left occipito-transverse Right occipito-posterior Straight occipito-posterior Left occipito-posterior The Occipito-Anterior position is ideal for birth; it means that the baby is lined up so as to fit through the pelvis as easily as possible. The baby is head down, facing the spine, with its back anterior. In this position, the baby's chin is tucked onto its chest, so that the smallest part of its head will be applied to the cervix first. The position is usually "Left Occiput Anterior", or LOA. Occasionally, the baby may be "Right Occiput Anterior", or ROA. Face<unk>  William Smellie, 1792 Factors that predispose to face<unk>  are prematurity, macrosomia, anencephaly and other malformations, cephalopelvic disproportion, and polyhydramnios. In an uncomplicated face<unk>  duration of labor is not altered. Perinatal losses with face<unk>  occur with traumatic version and extraction and midforceps procedures Duff indicates that the prevalence of face<unk> s is about 1/500–600., while Benedetti et al. found it to be 1/1,250 term deliveries. Face<unk> s are classified according to the position of the chin (mentum): *Left Mento-Anterior (LMA), Left Mento-Posterior (LMP), Left Mento-Transverse (LMT) *Right Mento-Anterior (RMA), Right Mento-Posterior (RMP), Right Mento-Transverse (RMT) Brow<unk>  While some consider the brow<unk>  as an intermediate stage towards the face<unk> , others disagree. Thus Bhal et al. indicated that both conditions are about equally common (1/994 face and 1/755 brow positions), and that prematurity was more common with face while postmaturity was more common with brow positions. Oskie<unk>  The Oskie<unk>  is similar to the Occipito-Anterior position, where the baby is head down, facing the spine, with back on the ventral side of the uterus; however, in this position, while the torso is aligned with the mother's longitudinal axis, the legs of the fetus are extended straight along the frontal axis of the mother, as if the baby is creating a right angle with its body. For the Oskie position to occur the baby's head must be far down the pelvis in order to allow room for leg extension, typically the arms are bent, tucked against the baby's body. There are no known complications for labor and delivery. This<unk>  is rare and is not well researched.
Cephalic presentation
Non-lifting sign
Shoulder presentation
Dysmorphic feature
Thrifty phenotype
Multiple abnormalities
Vertical auto profile
Triangular face