Abdomen and Pelvis Muscles, Vasculature, and Nerves Charts PDF

Muscles Origin Insertion Innervation Action(s) External oblique External surfaces of 5th–12th ribs Linea alba, pubic tubercle, and anterior half of iliac crest Thoraco-abdo minal and subcostal nerves (anterior rami of T7–T12 spinal nerves) Compress and support abdominal viscera; flex and ro...

Muscles Origin Insertion Innervation Action(s) External oblique External surfaces of 5th–12th ribs Linea alba, pubic tubercle, and anterior half of iliac crest Thoraco-abdo minal and subcostal nerves (anterior rami of T7–T12 spinal nerves) Compress and support abdominal viscera; flex and rotate trunk Internal oblique Thoracolumbar fascia, anterior two thirds of iliac crest, and connective tissue deep to inguinal ligament Inferior borders of 10th–12th ribs, linea alba, and pubis via conjoint tendon Thoraco-abdo minal nerves (anterior rami of T7–T11), subcostal and first lumbar nerve Transversus abdominis Internal surfaces of 7th–12th costal cartilages, thoracolumbar fascia, iliac crest, and connective tissue deep to inguinal ligament Linea alba with aponeurosis of internal oblique, pubic crest, and pubis via conjoint tendon Rectus abdominis Pubic symphysis and pubic crest Xiphoid process and 5th–7th costal cartilages Compresses and supports abdominal viscera Thoraco-abdo minal and subcostal nerves (anterior rami of T7–T12 spinal nerves) Flexes trunk (lumbar vertebrae) and compresses abdominal visceraa; stabilizes and controls tilt of pelvis (antilordosis) Nerves of Anterolateral Abdominal Wall Nerve Origin Course Distribution Thoraco-abdomina l (T7–T11) Distal, abdominal parts of lower five intercostal nerves Run between second and third layers of abdominal muscles; muscular, lateral, and anterior cutaneous branches enter subcutaneous tissue. Muscles of anterolateral abdominal wall and overlying skin (T7–T9 superior to umbilicus; T10 around umbilicus; T11 immediately below umbilicus) Subcostal (T12) Anterior ramus of T12 spinal nerve Runs along inferior border of 12th rib, then onto subumbilical abdominal wall Muscles of anterolateral abdominal wall and overlying skin midway between level of umbilicus and iliac crest, inguinal ligament, and pubic crest inferiorly Iliohypogastric (L1) Superior terminal branch of anterior ramus of L1 spinal nerve Pierces transversus abdominis muscle; branches pierce external oblique aponeurosis of most inferior abdominal wall Skin overlying iliac crest, upper inguinal, and hypogastric regions; internal oblique and transversus abdominis Ilio-inguinal (L1) Passes between second and third layers of abdominal muscles, then traverses inguinal canal Skin of scrotum or labium majus, mons pubis, and adjacent medial aspect of thigh; most inferior internal oblique and transversus abdominis Inferior terminal branch of anterior ramus of L1 spinal nerve Vessels of Anterolateral Abdominal Wall The blood vessels of the anterolateral abdominal wall are illustrated on the right side in Figure 5.7 and listed and described in Table 5.3. TABLE 5.3. Principal Arteries of Anterolateral Abdominal Wall Nerve Origin Course Distribution Musculophrenic Internal thoracic artery Descends along costal margin Abdominal wall of hypochondriac region, anterolateral, diaphragm Descends in rectus sheath deep to rectus abdominis Superior rectus abdominis and superior part of anterolateral abdominal wall Abdominal aorta Arteries continue beyond ribs to descend in abdominal wall between internal oblique and transversus abdominis Abdominal wall, lateral region External iliac artery Runs superiorly and enters rectus sheath; runs deep to rectus abdominis Inferior rectus abdominis and medial part of anterolateral abdominal wall Runs on deep aspect of anterior abdominal wall, parallel to inguinal ligament Iliacus muscle and inferior part of anterolateral abdominal wall Superior epigastric 10th and 11th posterior intercostal Subcostal Inferior epigastric Deep circumflex iliac Superficial circumflex iliac Femoral artery Superficial epigastric Runs in superficial fascia along inguinal ligament Superficial abdominal wall of inguinal region and adjacent anterior thigh Runs in superficial fascia toward umbilicus Subcutaneous tissue and skin over pubic and inferior umbilical region Arterial Supply to Esophagus, Stomach, Duodenum, Liver, Gallbladder, Pancreas, and Spleen Arterya Origin Course Distribution Celiac trunk Abdominal aorta (T12) just distal to aortic hiatus of diaphragm After short antero-inferior course, bifurcates into splenic and common hepatic arteries Esophagus, stomach, duodenum (proximal to bile duct), liver and biliary apparatus, and pancreas Left gastric Celiac trunk Ascends retroperitoneally to esophageal hiatus, giving rise to an esophageal branch; then descending along lesser curvature to anastomose with right gastric artery Distal portion of esophagus and left portion of lesser curvature of stomach Splenic Left gastro-omental (gastro-epiploic) Splenic artery in hilum of spleen Short gastric (4 or 5 branches) Runs retroperitoneally along superior border of pancreas, then passes between layers of splenorenal ligament to hilum of spleen Body of pancreas, spleen, and greater curvature of stomach; posterior gastric branch supplies posterior wall and fundus of stomach Passes between layers of gastrosplenic ligament to greater curvature of stomach Left portion of greater curvature of stomach Pass between layers of gastrosplenic ligament to fundus of stomach Fundus of stomach Hepaticb Celiac trunk Passes retroperitoneally to reach hepatoduodenal ligament and passes between its layers to porta hepatis; divides into right and left hepatic arteries Liver, gallbladder, stomach, pancreas, duodenum, and respective lobes of liver Cystic Right hepatic artery Arises within hepatoduodenal ligament Gallbladder and cystic duct Right gastricc Hepatic artery Runs along lesser curvature of stomach Right portion of lesser curvature of stomach Gastroduodenal Right gastro-omental (gastro-epiploic)c Gastroduodenal artery Anterior and posterior superior pancreaticoduodenal Anterior and posterior inferior pancreaticoduodenal Superior mesenteric artery Descends retroperitoneally posterior to gastroduodenal junction Stomach, pancreas, first part of duodenum, and distal part of bile duct Passes between layers of greater omentum to greater curvature of stomach Right portion of greater curvature of stomach Descend on head of pancreas Proximal portion of duodenum and head of pancreas Ascend on head of pancreas Distal portion of duodenum and head of pancreas Arterial Supply to Intestines Artery Origin Course Distribution Superior mesenteric Abdominal aorta (L1) Runs in root of mesentery to ileocecal junction Part of gastrointestinal tract derived from midgut Intestinal (n = 15–18) Superior mesenteric artery Passes between two layers of mesentery Jejunum and ileum Ascends retroperitoneally and passes between layers of transverse mesocolon Transverse colon Middle colic Right colic Passes retroperitoneally to reach ascending colon Ascending colon Ileocolic Terminal branch of superior mesenteric artery Runs along root of mesentery and divides into ileal and colic branches Ileum, cecum, and ascending colon Appendicular Ileocolic artery Passes between layers of meso-appendix Appendix Inferior mesenteric Abdominal aorta (L3) Descends retroperitoneally to left of abdominal aorta Descending colon Left colic Inferior mesenteric artery Passes retroperitoneally toward left to descending colon Sigmoid (n = 3 or 4 branches) Passes retroperitoneally toward left to sigmoid colon Descending and sigmoid colon Superior rectal Terminal branch of inferior mesenteric artery Descends retroperitoneally to rectum Proximal part of rectum Middle rectal Internal iliac artery Passes retroperitoneally to rectum Midpart of rectum Inferior rectal Internal pudendal artery Crosses ischio-anal fossa to reach rectum Distal part of rectum and anal canal Autonomic Innervation of Abdominal Viscera (Splanchnic Nerves) Splanchnic Nerves Autonomi System c Fiber Typea Origin A. Cardiopulmonary (cervical and upper thoracic) Postsynap Sympathetic tic Cervical and Thoracic cavity upper (viscera superior to thoracic level of diaphragm) sympathetic trunk B. Abdominopelvic Presynapt ic Lower thoracic and abdominope lvic sympathetic trunk: Abdominopelvic cavity (prevertebral ganglia serving viscera and suprarenal glands inferior to level of diaphragm) Thoracic sympathetic trunk: Abdominal prevertebral ganglia: 1. Lower thoracic a. b. Greater c. d. Lesser Destination a. a. b. Celiac b. T5–T e. f. Least ganglia 9 or c. T10 d. Aorticorenal level ganglia c. e. d. T10– f. and T11 level e. f. T12 level 2. Lumbar Abdominal sympathetic trunk Other abdominal prevertebral ganglia (superior and inferior mesenteric, and of intermesenteric/hyp ogastric plexuses) 3. Sacral Pelvic (sacral) sympathetic trunk Pelvic prevertebral ganglia C. Pelvic aSplanchnic Parasympath Anterior etic rami of S2–S4 spinal nerves Intrinsic ganglia of descending and sigmoid colon, rectum, and pelvic viscera nerves also convey visceral afferent fibers, which are not part of the autonomic nervous system. Main Muscles of Posterior Abdominal Wall Muscle Superior Attachments Inferior Attachment(s) Innervation Actions Psoas majora Transverse processes of lumbar vertebrae; sides of bodies of T12–S1 vertebrae and intervening IV discs By a strong tendon to lesser trochanter of femur Lumbar plexus via anterior branches of nerves L2–L4 Acting inferiorly with iliacus, flexes thigh; acting superiorly, flexes vertebral column laterally to balance the trunk; when sitting, acts inferiorly with iliacus to flex trunk Iliacusa Superior two thirds of iliac fossa, ala of sacrum, and anterior sacro-iliac ligaments Lesser trochanter of femur and shaft inferior to it and to psoas major tendon Femoral Flexes thigh and nerve (L2–L4) stabilizes hip joint; acts with psoas major Quadratus lumborum Medial half of inferior border of 12th rib and tips of lumbar transverse processes Iliolumbar ligament and internal lip of iliac crest Anterior branches of T12 and L1–L4 nerves aPsoas Extends and laterally flexes vertebral column; fixes 12th rib during inspiration major and iliacus muscles are often described together as the iliopsoas muscle when flexion of the thigh is discussed (see Chapter 7). The iliopsoas is the chief flexor of the thigh; when thigh is fixed, it is a strong flexor of the trunk (e.g., during sit-ups). PELVIS Comparison of Male and Female Bony Pelves Bony Pelvis Male (♂) Female (♀) General structure Thick and heavy Thin and light Greater pelvis (pelvis major) Deep Shallow Lesser pelvis (pelvis minor) Narrow and deep Wide and shallow Pelvic inlet (superior pelvic aperture) Heart-shaped Oval or rounded Pelvic outlet (inferior pelvic aperture) Comparatively small Comparatively large Pubic arch and subpubic angle (degree) Narrow (<70 degrees) Wide (>80 degrees) Obturator foramen Round Oval Acetabulum Large Small Muscles of Pelvic Walls and Floor Muscle Proximal Attachment Distal Attachment Innervatio n Main Action Levator ani (pubococcygeus and iliococcygeus) Body of pubis, tendinous arch of levator ani, ischial spine Perineal body, coccyx, anococcygea l ligament, walls of prostate or vagina, rectum, anal canal Nerve to levator ani (branches of S4), inferior anal (rectal) nerve, coccygeal plexus Helps support pelvic viscera; resists increases in intra-abdo minal pressure Coccygeus (ischiococcygeus) Ischial spine Inferior end of sacrum and coccyx Branches of Forms S4 and S5 small part nerves of pelvic diaphragm that supports pelvic viscera; flexes coccyx Obturator internus Pelvic surface of ilium and ischium; obturator membrane Piriformis Pelvic surface of 2nd–4th sacral segments; superior margin of greater sciatic notch and sacrotuberou s ligament Greater trochanter of femur Nerve to obturator internus (L5, S1, S2) Laterally rotates hip joint; assists in holding head of femur in acetabulum Anterior rami of S1 and S2 Laterally rotates hip joint; abducts hip joint; assists in holding head of femur in acetabulum Nerves of Sacral and Coccygeal Plexuses Nervea Segmental Origin (Anterior Rami) Distribution 1 Sciatic L4, L5, S1, S2, S3 Articular branches to hip joint and muscular branches to flexors of knee (hamstring muscles) and all muscles in leg and foot 2 Superior gluteal L4, L5, S1 Gluteus medius, gluteus minimus, and tensor fasciae latae muscles 3 Inferior gluteal L5, S1, S2 Gluteus maximus muscle 4 Nerve to piriformis S1, S2 Piriformis muscle 5 Nerve to quadratus femoris and inferior gemellus L4, L5, S1 Quadratus femoris and inferior gemellus muscles 6 Nerve to obturator internus and superior gemellus L5, S1, S2 Obturator internus and superior gemellus muscles 7 Pudendal S2, S3, S4 Structures in perineum: sensory to genitalia, muscular branches to perineal muscles, sphincter urethrae, and external anal sphincter 8 Nerves to levator ani and coccygeus S3, S4 Levator ani and coccygeus muscles 9 Posterior femoral cutaneous S2, S3 Cutaneous branches to buttocks and uppermost medial and posterior surfaces of thigh 10 Perforating cutaneous S2, S3 Cutaneous branches to medial part of buttocks 11 Pelvic splanchnic S2, S3, S4 Pelvic viscera via inferior hypogastric and pelvic plexus Arteries of Lesser Pelvisa Artery Origin Course Distribution Internal iliac (2) Common iliac artery Passes over pelvic brim to reach pelvic cavity Main blood supply to pelvic organs, gluteal muscles, and perineum Anterior division of internal iliac artery Internal iliac artery Passes anteriorly and divides into visceral branches and obturator artery Pelvic viscera and muscles in medial compartment of thigh Umbilical Anterior division of internal iliac artery Short pelvic course; obliterates after origin of superior vesical artery Via superior vesical artery Runs antero-inferiorly on lateral pelvic wall Pelvic muscles, nutrient artery to ilium, and head of femur Obturator (4) Superior vesical artery Patent part of umbilical artery Passes to superior aspect of urinary bladder Superior aspect of urinary bladder; often ductus deferens in male Artery to ductus deferens Superior or inferior vesical artery Runs subperitoneally to ductus deferens Ductus deferens Inferior vesicalb Anterior division of internal iliac artery Passes subperitoneally to inferior aspect of male urinary bladder Urinary bladder and pelvic part of ureter, seminal gland, and prostate in males Descends in pelvis to rectum Seminal gland, prostate, and rectum Middle rectal (11) Internal pudendal (10) Leaves pelvis through greater sciatic foramen and enters perineum (ischio-anal fossa) by passing through lesser sciatic foramen Main artery to perineum, including muscles of anal canal and perineum; skin and urogenital triangle; erectile bodies Inferior glutealc (9) Leaves pelvis through greater sciatic foramen inferior to piriformis Piriformis, coccygeus, levator ani, and gluteal muscles Uterine Runs medially on levator ani; crosses ureter to reach base of broad ligament Pelvic part of ureter, uterus, ligament of uterus, uterine tube, and vagina Vagina and branches to inferior part of urinary bladder Vaginal Anterior division of internal iliac artery (uterine artery) At junction of body and cervix of uterus, it descends to vagina Gonadal (testicular and ovarian) Abdominal aorta Descends retroperitoneally; Testis and ovary, testicular artery passes into respectively deep inguinal ring; ovarian artery crosses brim of pelvis and runs medially in suspensory ligament to ovary. Posterior division of internal iliac artery Internal iliac artery Passes posteriorly and gives rise to parietal branches Pelvic wall and gluteal region Iliolumbar Posterior division of internal iliac artery Ascends anterior to sacro-iliac joint and posterior to common iliac vessels and psoas major Iliacus, psoas major, quadratus lumborum muscles, and cauda equina in vertebral canal Lateral sacral (7) Runs on superficial aspect of piriformis Piriformis and vertebral canal Superior gluteal (8) Leaves pelvis through greater sciatic foramen, superior to piriformis Gluteal muscles and tensor fasciae latae Lymphatic Drainage of Female Pelvis and Perineum Lymph Node Group Typically Drains Lumbar (along ovarian vessels) Gonads and associated structures, common iliac nodes (ovary, uterine tube except isthmus and intrauterine parts, fundus of uterus) Inferior mesenteric Superiormost rectum, sigmoid colon, descending colon, pararectal nodes Internal iliac Inferior pelvic structures, deep perineal structures, sacral nodes (base of bladder, inferior pelvic ureter, anal canal above pectinate line, inferior rectum, middle and upper vagina, cervix, body of uterus) External iliac Anterosuperior pelvic structures, deep inguinal nodes (superior bladder, superior pelvic ureter, upper vagina, cervix, lower body of uterus) Superficial inguinal Lower limb; superficial drainage of inferolateral quadrant of trunk, including anterior abdominal wall inferior to umbilicus, gluteal region, superficial perineal structures (superolateral uterus near attachment of round ligament, skin of perineum including vulva, ostium of vagina inferior to hymen, prepuce of clitoris, peri-anal skin, anal canal inferior to pectinate line) Deep inguinal Glans clitoris, superficial inguinal nodes Sacral Postero-inferior pelvic structures, inferior rectum, inferior vagina Pararectal Superior rectum TABLE 6.7. Lymphatic Drainage of Male Pelvis and Perineum Lymph Node Group Typically Drains Lumbar (near testicular vessels) Urethra, testis, epididymis Inferior mesenteric Superiormost rectum, sigmoid colon, descending colon, pararectal nodes Internal iliac External and internal iliac lymph nodes External iliac Inferior pelvic structures, deep perineal structures, sacral nodes (prostatic urethra, prostate, base of bladder, inferior pelvic ureter, inferior seminal glands, cavernous bodies, anal canal above pectinate line, inferior rectum) Superficial inguinal Lower limb; superficial drainage of inferolateral quadrant of trunk, including anterior abdominal wall inferior to umbilicus, gluteal region, superficial perineal structures (skin of perineum, including skin and prepuce of penis, scrotum, peri-anal skin, anal canal inferior to pectinate line) Deep inguinal Glans penis, superficial inguinal nodes, distal spongy urethra Sacral Postero-inferior pelvic structures, inferior rectum Pararectal Superior rectum Parts of Male Urethra Part Length (cm) Location/Disposition Features Intramural (preprostatic) part 0.5–1.5 Extends almost vertically through neck of bladder Surrounded by internal urethral sphincter; diameter and length vary, depending on whether bladder is filling or emptying. Prostatic urethra 3.0–4.0 Descends through anterior prostate, forming gentle, anteriorly concave curve; is bounded anteriorly by vertical, trough-like part (rhabdosphincter) of external urethral sphincter Widest and most dilatable part; features urethral crest with seminal colliculus, flanked by prostatic sinuses into which the prostatic ducts open; ejaculatory ducts open onto colliculus; hence, urinary and reproductive tracts merge in this part. Intermediate (membranous) part 1.0–1.5 Passes through deep perineal pouch, surrounded by circular fibers of external urethral sphincter; penetrates perineal membrane Narrowest and least distensible part (except for external urethral orifice) Spongy urethra ~15 Courses through corpus spongiosum; initial widening occurs in bulb of penis; widens again distally as navicular fossa (in the glans penis) Longest and most mobile part; bulbo-urethral glands open into bulbous part; distally, urethral glands open into small urethral lacunae entering lumen of this part. Muscles of Perineum Muscle Origin Course and Insertion Innervation Main Action(s) External anal sphincter Skin and fascia surrounding anus and coccyx via anococcygeal ligament Passes around lateral aspects of anal canal, inserting into perineal body Inferior anal nerve, branch of pudendal nerve (S2–S4) Constricts anal canal during peristalsis, resisting defecation; supports and fixes perineal body/pelvic floor Bulbospongiosu s ​ ​ ​ Male: ​ media surround n s lateral raphe aspects on of bulb of ventral penis and surfac most e of proximal bulb of part of penis body of and penis, perine inserting al into body perineal ​ ​ Male: Muscular (deep) branch of perineal nerve, branch of pudendal nerve (S2–S4) Supports and fixes perineal body/pelvic floor ​ ​ compres ses bulb of penis to expel last drops of urine/se men; assists erection by membran Femal e, dorsal e: aspect of perine corpora al spongios body um and compres sing outflow via deep perineal vein and cavernos by a, and pushing fascia of blood bulb of from bulb penis into body ​ ​ Female: passes on each side of Male: of penis ​ ​ Female: “sphincte lower r” of vagina, vagina; enclosing assists in bulb and erection greater of clitoris vestibular (and bulb gland; of inserts vestibule) onto ; pubic compres arch and ses fascia of greater corpora vestibular cavernos gland a of clitoris Ischiocavernosu s Internal surface of ischiopubic ramus and ischial tuberosity Embraces crus of penis or clitoris, inserting onto inferior and medial aspects of crus and to perineal membrane medial to crus Superficial transverse perineal Internal surface of ischiopubic ramus and ischial tuberosity; compressor urethrae portion only Passes along superior posterior border of perineal membrane to perineal body Maintains erection of penis or clitoris by compressing outflow veins and pushing blood from root of penis or clitoris into body Muscular (deep) branch of perineal nerve, branch of pudendal nerve (S2–S4); Support and fix perineal body (pelvic floor) to support abdominopelvic viscera and resist increased intra-abdominal pressure Deep transverse perineal Passes along superior posterior border of perineal membrane to perineal body and external anal sphincter External urethral sphincter Surrounds urethra superior to perineal membrane ​ ​ Compresses urethra to maintain urinary continence ​ Male: ​ Female: also Urethrov ascends aginal anterior sphincter aspect of portion prostate also ​ ​ dorsal nerve of penis or clitoris, terminal branch of pudendal nerve (S2–S4) compres Female: ses Some vagina. fibers also enclose vagina (urethrov aginal sphincter) . Arterial Supply of Perineum Artery Origin Course Internal pudendal Internal iliac artery Leaves pelvis through Primary artery of greater sciatic foramen; perineum and external hooks around ischial genital organs spine to enter perineum via lesser sciatic foramen; enters pudendal canal Inferior rectal Internal pudendal artery Arises at entrance to pudendal canal; crosses ischio-anal fossa to anal canal Anal canal inferior to pectinate line; anal sphincters; peri-anal skin Arises within pudendal canal; passes to superficial perineal pouch (space) on exit Supplies superficial perineal muscles and scrotum in male; vestibule in female Perineal Posterior scrotal or labial Terminal branch of perineal artery Artery of bulb of penis or vestibule Deep artery of penis or clitoris Terminal branch of internal pudendal artery Distribution Runs in subcutaneous Skin of scrotum or tissue of posterior labia majora and scrotum or labia majora minora Pierces perineal membrane to reach bulb of penis or vestibule of vagina Supplies bulb of penis and bulbo-urethral gland in male; bulb of vestibule and greater vestibular gland in female Pierces perineal membrane to run centrally within corpora cavernosa of penis or clitoris Supplies most erectile tissue of penis or clitoris via helicine arteries Dorsal artery of penis or clitoris External pudendal, superficial, and deep branches Femoral artery Pierces perineal membrane and passes through suspensory ligament of penis or clitoris to run on dorsum of penis or clitoris, flanked by deep dorsal veins Deep perineal pouch; skin of penis; connective tissues of erectile tissue of penis or clitoris; distal corpus spongiosum of penis, including spongy urethra Pass medially across thigh to reach scrotum or labia majora (anterior aspect of urogenital triangle) Anterior aspect of scrotum and skin at root of penis in male; mons pubis and anterior aspect of labia in female