L5: Malpresentation & Malposition (Face) Flashcards
Def of Face Presentation
- Cephalic malpresentation in which presenting part is face, denominator is mentum (chin) & head is extended.
Incidence of Face Presentation
1/300-1/400 of deliveries.
Positions of Face Presentation
Positions of Face Presentation
- Which is more common, Anterior or Posterior? why?
- MA positions (70%) are more common than MP positions (30%)
- Because face presentation is the result of extension of deflexed head in OP position (ROP extends to LMA while LOP extends to RMA).
Most Common Position in Face Presentation
LMA
Types of Face Presentation
1ry & 2ry
Def of 1ry Face Presentation
Occurs during pregnancy before onset of labor
Etiology of 1ry Face Presentation
Def of 2ry Face Presentation
- Develops during labor (common) & occurs in cases of OP positions associated e any condition which retards descent of occiput & encourages descent of sinciput
Etiology of 2ry Face Presentation
Mechanism of Labor in MA Position
Mechanism of Labor in MA Position
- Descent
Slow
Mechanism of Labor in MA Position
- Engagment
Engaging longitudinal diameter is SMB (9.5 cm)
Mechanism of Labor in MA Position
- Increased EXTENSION
Chin becomes the lower most part of head.
Mechanism of Labor in MA Position
- Internal Rotation
- Flexion
- Chin reaches pelvic floor 1st → rotates anteriorly 1/8 circle → becomes direct mentoanterior (DMA).
- Submental region impinges under symphysis pubis & head is delivered by flexion.
Mechanism of Labor in MA Position
- Restitution
Chin rotates 1/8 circle in opposite direction of internal rotation.
Mechanism of Labor in MA Position
- External Rotation
Chin rotates 1/8 circle in the same direction of restitution due to internal rotation of anterior shoulder from oblique diameter to A-P diameter.
Mechanism of Labor in MA Position
- Delivery of shoulders & Trunk & Legs
As normal Labor
Mechanism of Labor in MP Position
Mechanism of Labor in MP Position
- Descent
Slower
Mechanism of Labor in MP Position
- Engagement
Engaging longitudinal diameter is SMB (9.5 cm).
Mechanism of Labor in MP Position
- Increased Extension
Chin becomes the lower most part of head.