Maternal Anatomy

Chapter 2 ReviewWilliams Obstetrics

Felicia Katz8/10/11

Anterior Abdominal Wall

Blood Supply

• Femoral artery branches– Superficial epigastric– External pudendal– Supply skin and subcutaneous tissue over lower

abdominal wall and mons• External Iliac branches– Inferior epigastric vessels– Supply muscles and fascia of lower abdominal wall

Innervation

• T7-12 • Ilioinguinal (L1)– Skin of lower abdominal wall, upper portion of

labia majora, and inner thigh• Iliohypogastric (L1)– Skin over suprapubic area

• Course between layers of rectus sheath lateral to rectus muscle

External Genitalia

Vagina

•Non-keratinized squamous epithelium, smooth muscle layer•Upper 1/3 mullerian derived•Lower 2/3 urogenital sinus derived•Lubricated by transudate across subepithelial capillary plexus

Vascular Supply

• Proximal portion supplied by cervical branch of uterine artery

• Remainder by vaginal artery (variable origin)

• Lower third and vulva lymphatics drain to inguinal nodes; remainder iliac nodes

Anterior and Posterior Triangles

Anus

• IAS: constant resting tone for fecal continence; may be torn with 4th deg lacs

• Anal cushions: venous plexus; cause of hemorrhoids• Dentate line: external hemorrhoids painful 2/2 innervated

stratefied squamous epithelium

Uterus

• Posterior aspect covered by visceral peritoneum (serosa)• Lower portion of anterior wall adjacent to bladder

(dissected during c/s)• Nulliparous 6-8cm; multiparous 9-10cm• Majority of muscle fibers located at fundus, and at

anterior and posterior walls as compared to lateral walls• Innervation

– T11/T12 transmit pain sensation from contractions– Pudendal nerve transmits pain from lower vagina and skin

Cervix

• Squamous epithelium on ectocervix• Columnar epithelium on endocervix

Endometrium

Ligaments

Blood Supply

Blood Supply

• Uterine artery– Branch of internal iliac– Courses along base of broad ligament toward cervix

then branches in two and runs along uterine wall– Crosses over ureter 2cm from cervix

• Ovarian artery– Direct branch from aorta– Enters broad ligament through IP ligament– Anastamoses with branch of uterine artery

Pelvic Bony Anatomy

Pelvic Inlet

• Posterior boundary = sacral promontory• Anterior boundary = pubic symphysis• Lateral boundary = linea terminalis

Measure adequacy of inlet via the obsetrical conjugate (subtract 1.5-2cm from diagonal conjugate)

Pelvic inlet

Mid-Pelvis

• Ischial spines (10cm)

Outlet

• Posterior boundary = coccyx

• Anterior boundary = pubic arch

Pelvis Types

Pelvic Floor