THORAX/ABDOMEN/PELVIS EXAM REVIEW   Abdominal Muscles Muscles Origin Insertion Innervation Action(s) Other External oblique External surfaces of ribs 5-12 Lineal alba, pubic tubercle, and anterior half of iliac crest Inferior six thoracic nerves and subcostal nerve Compress and support abdominal viscera; flex and rotate trunk, maintain posture 3 flat muscles of anteriolateral abdominal wall   External fibers run inferiomedially, internal fibers run at right angles to external, and transverse fibers run horizontally     Aponeurosis of all three fibers forms rectus sheath Internal oblique Thoracolumbar fascia, anterior 2/3 of iliac crest, and lateral ½ of inguinal ligament Inferior borders of ribs 10-12, linea alba, and pubis via conjoint tendon Anterior rami of inferior 6 thoracic and 1st lumbar nerves Tranverse abdominal Internal surfaces of costal cartilage 7-12, thoracolumbar fascia, iliac crest, and lateral 1/3 of inguinal ligament Linea alba w/ aponeurosis of internal oblique, public crest, and pecten pubis via conjoint tendon Compresses and supports abdominal viscera Rectus abdominus Pubic symphysis, pubic crest Xiphoid process and costal cartilages 5-7 Anterior rami of inferior 6 thoracic nerves Flexes trunk and compresses abdominal viscera   Pyramidal Inferior rectus sheath Linea alba     Triangular muscles that lies in the rectus sheath anterior to the inferior part of the rectus abdominus       Abdominal Nerves Nerve Origin Course Distribution Other Thoracoabdominal (T7-T11) Continuation of inferior intercostals nerves Run btwn 2nd and 3rd layers of abdominal muscles Anterior abdominal muscles and overlying skin; periphery of diaphragm T7-T9 supply skin superior to umbilicus T10 supplies umbilicus Subcostal (T12) Anterior ramus of T12 Runs along inferior border of rib 12 Lowest slip of external oblique m. and skin over anterior superior iliac spine and hip   Iliohypogastric (L1) Chiefly from anterior ramus of L1 Pierces transverse abdominal m., branches pierce external oblique aponeurosis Skin of hypogastric region and over iliac crest; internal oblique and transverse abdominal   Ilioinguinal (L1) Anterior ramus of L1 Pass btwn 2nd and 3rd layer of abdominal muscles and passes through ilioinguinal canal Skin of scrotum/ labium majus, mons pubis, and adj. medial aspect of thigh; internal oblique and transverse abdominal         Abdominal Arteries Artery Origin Course Distribution Other Superior epigastric Internal thoracic a. Descends in rectus sheath deep to rectus abdominus Rectus abdominis and superior part of anterolateral abd wall   Inferior epigastric External iliac a. Runs superiorly and enters rectus sheath; runs deep to rectus abdominus Rectus abdominis and medial part of anteriolateral abdominal wall   Deep circumflex iliac Runs on deep aspect of ant abd wall, parallel to inguinal ligament Illiacus muscle and inf part of anterolateral abd wall   Superficial circumflex iliac Femoral a. Runs in superficial fascia along inguinal ligament Subcutaneous tissue and skin over inferior portion of anterolateral abd wall   Superficial epigastric Runs in superficial fascia toward umbilicus Subcutaneous tissue and skin over suprapubic region     FETAL/ADULT HOMOLOGS Fetal Structure Function Adult Homolog Umbilical vein Bring oxygen and nutrients from placenta to fetus Ligamentum teres hepatis Ductus venosus Shunts most of blood through liver (already processed by mother’s liver) Ligamentum venosum Foramen ovule Shunts blood from right atrium to left atrum, bypassing nonfunctional lungs Fossa ovalis Ductus arteriosus Shunts right ventricular blood from pulmonary trunk to aorta, bypassing nonfunctional lungs Ligamentum arteriosum Umbilical arteries Returns poorly oxygenated blood and metabolic waste to the placenta Medial umbilical ligaments (Urachus connects apex of bladder with umbilicus) Truncus arteriosus   Aorta, pulmonary trunk Bulbus cordis   Superior 1/3=truncus arteriosus (aorta, pulmonary trunk) Middle 1/3=conus arteriosus (outflow tract) Proximal 1/3=right ventricle Primitive ventricle   Left ventricle Primitive atrium   Auricles Pectinate muscle walls of L/R atria Sinus venosus   Right atrium Gubernaculum   Females: round ligament, ligament of the ovary Males: spermatic cord Processes vaginalis Bubble of peritoneum that follows the descending gubernaculum to form the inguinal canal Tunica vaginalis Medullary cords (male) Cortical cords (female) Formed from primitive sex cords Seminiferous tubules Ovarian tubes Genital tubercle   Phallus (male) Clitoris (female)                     EMBRYOLOGICAL ORIGINS Endoderm Mesoderm Bladder Ureter (mesenephros) (intermed. mesoderm) Urethra Kidney (metanephros) (intermed.) Prostate Seminal vesicles (intermed.) Trigone (bladder) Trigone (ureteric inlets to bladder)   Gonads (testes, ovaries; intermed. mesoderm)   Genital ducts (vas deferens, fallopian tubes)   External genitalia (penis, scrotum, vagina)   GENITAL DEVELOPMENT Indifferent stage organ Male fetal (adult) Female fetal (adult) Primitive sex cords *Testis/medullary cords (Þ seminiferous tubules) *Cortical cords (Þ fallopian tubes) Genital ridge *Mesenchyme of genital ridge (Þ Leydig cells) ___ Mesonephric (Wolffian) duct *Ductuli efferentes (Þ ductus deferens Þ vas deferens when acquires muscular coat) *epididymis *seminal vesicles Stimulated by testosterone (Leydig cells) Degenerate (no testosterone) Paramesonephric (Mullerian) duct Suppressed (MIS of Sertoli cells) *Uterine canal (cranial 2/3 Þ bilateral uterine tubes, caudal 1/3fusion Þ uterus) *Sinovaginal bulbs (Þvagina) Abdominal wall Processus vaginalis (Þ tunica vaginalis)   Primitive sex cells Sperm Egg Gubernaculum Spermatic cord Round ligament, ligament of the ovary Genital tubercle Phallus (penis) clitoris Genital swellings Scrotum Labia majora Urethral folds Fuse Þ urethral plate Labia minora