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155 Cards in this Set
- Front
- Back
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Oral cavity posterior border = Superior border = |
post = Palatoglossal arch Sup = palate (hard and soft) |
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Muscles around mouth: - Lip sphincter - muscle that Positions of food boluses and innervation |
Around lips - Orbicularis oris muscle that Positions of food boluses - Buccinator Both innervated by CN Vll (facial n) |
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Mastication muscles (4 of them)
and innervation |
Temporalis - elevation and retraction Masseter - elevation and protraction Lateral pterygoid (superior one) - protraction Medial pterygoid - protraction and elevation (the R pterygoids abduct jaw to the left) All innervated by CN V3 (mandicular division of trigeminal) |
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What type of joint in the temporomandibular joint, and what movements |
Bilateral synovial joint. elevation/depression, protrusion/retraction, ab/adduction of mandible. |
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Permanent teeth, how many quadratns and whats in each quadrant? |
4 quadrants, each containing 2 incisors, 1 canine(cuspid), 2 premolars/bicuspids, 3 molars Total = 32 teeth |
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Primary teeth, quadrants, teeth types |
4 quadrants each containing 2 incisors, 1 canine/cuspid, 2 molars Total = 20 |
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Innervation of teeth |
Maxillary teeth - superior alveolar nn ( maxilary division of trigeminal, CN V2) Mindibular teeth - inferior alveolar n (manibular division of trigeminal n, CN V3) |
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Tongue muscles names (4) and general classes (2) and actions and innervattion |
Intrinsic muscles within tongue - longitudinal, transverse, and vertial ones Extrinsic - bone to tongue - Genioglossus for protrusion and depression - hyoglossus for retraction and depression - styloglossus for elevation and retraction - palatoglossus for elevation and retraction All innervated by CN Xll (hyperglossal) except palatoglossus which is innervated by CN X (vagus) |
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Taste and general sensation/pain of tongue |
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Salivary glands - name - preganglionic nucleus (PN) - Cranial nerve (CN) - gnanglion (G) |
Parotid (100% serous) - medulla (PN), lX (CN), otic (G) submandibular (80% serous, 20% mucous) and sublingual (20% serous, 80% mucous) - Pons (PN), Vll (CN), submandibular (G) |
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sensory innveration of pharynx |
Mostly CN lX (glossopharyngeal) and some of CN X (Vagus) |
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Muscles (5) of pharynx and Innervation |
Sup, mid and Inf pharyngeal contstrictors (Incl. cricopharyngeus)
Palatopharyngeus
All innervated by CN X (vagus)
Stylopharyngeus innvervated by CN lX (glossopharyngeal)
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Soft palate muscles (4) and innervation |
Levator Veli Palatini Tensor veli palatini Palatoglossus Palatopharyngeus
All Inn: CN X (vagus) except tensor veli palatini (CN V3) |
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Oesophagus - Innervation - position in abdominal cavity |
Innervated by CN X travels posterior to left 1/3 of liver. |
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What type of joint are the teeth joints |
Gomphosis |
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Anatomical and physiological Regions of the stomach - names |
Anatomical Cardiac, fundus, Body, Pyloric Physiological Orad, caudad |
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What are the parts of the SI and how big are they? |
Duodenum - first 20-25cm Jejunum - proximal 2/5 of SI Ileum - distal 3/5 of SI |
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Where does the ligament of treitz (aka suspensory muscle) |
Attaches where the duodenum at the duedenojejunal flexure |
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What are the 4 parts of the duodenum? Where are the ducts and papilla located and what are their names. |
parts = superior, descending, horizontal, ascending The descending part has bile duct and pancreatic duct feeding into major duodenal papilla. there is also a minor duodenal papilla that receives a pancreatic branch. |
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What is located between the ileum and the caecum? And what structure is inferior to it? The structure is located at the intersection of ______? |
The ileocaecal sphincter is the junction between ileum and caecum. 2cm inferior is the root of the appendix located at the intersection of the taeniae coli. Note: the appendic position is variable. |
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What are the surface anatomy quadrants and regions? |
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What are the names of the mesentaries of the peritoneum (5) |
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What are the cut offs for the foregut, midgut, and hindgut? What are the neurvascular bundles called there contents? |
Foregut - coeliac neurovascualar bundle (NB) Midgut - NB Hindgut - NB All contain aa, vv, ganglion, LNs |
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What are the arteries of the stomach? |
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Arteries of the Small intestine |
Proximal duodenum - Sup. pancreaticoduodenal - Coeliac aa - supraduodenal (from gastroduodenal) Rest of SI - from SMA - inferior pancreatic duodenal aa - 15-20 jejunal and ileal branches, iliocolic with the arcades and vasa recta (straight bits off arcades that go directly to tissue) |
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LI arteries |
Proximal half Branches of the sup. mes. artery - ileocolic a - R colic a - middle colic a Distal half Branches of the inferior mesenteric artery. - L colic a ascending and descending branches - Sigmoid - superior rectal a |
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Veins of GI |
In general they drain to the hepatic portal vein. They acompany stomach aa. Stomach veins drain to splenic, superior mesenteric, or directly to hepatic portal vein. SI` and LI veins have same names as arteries. Sup and Inf mesenteric whcih drein t portal veins. |
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Lymphatics of GIT |
LNs located along major B vessels. Coeliac nodes (of foregut) and superiorly mesenteric nodes (of midgut) drain to -> intestinal lymph trunk Inferior mesenteric nodes (of hindgut) drain to lumber lymph trunks These lymph trunks then drain into the cyterna chyli (aka chyle cistern) which drains into thoracic duct which drains into the left subclavian vein. |
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What is the PSNS of the foregut and Midgut? |
The craniosacral div of the ANS. Preganglionic PSNS Neuron cell bodies are located in the Medulla -> Impulses travels via the L & R vagus nerves to the oesophageal plexus -> this then splits off into the anterior and posterior vagal trunks -> Gastric branches of the vagal trunks innervate the stomach OR they go through the superior mesenteric ganglia to synapse in the intramural ganglia which innervated smooth muscle, glands and the ENS. |
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What is the PSNS innervation of the Hindgut? |
Preganglionic PSNS neuron cell bodies are located in the lateral horn of the spinal cord S2-S4 -> impulses leave via the ventral root -> spinal nerve -> ventral rami -> pelvic splanchnics -> pelvic plexus (aka inferior hypogastric plexus) -> inferior mesenteric branches to synapse in the intramural ganglia which innervates the smooth muscle, glands and ENS. |
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What is the SNS of the GIT? |
Preganglionic SNS neuron cell bodies in the lateral horn of spinal segments: foregut FG (T6-T9) Midgut MG (T9-T11) Hindgut HG (T12-L2) send impulses out the ventral root -> spinal nerve -> ventral rami -> White rami communicans -> passes through the sympathetic chain ganglia without synapsing -> Then depending of destination go via the: Greater splanchnic (FG, MG) Lesser splanchnic (MG) Least splanchnic (HG) Lumbar splanchnic (HG) The depending on their destination that synapse with: Coeliac ganglia (FG) Superior mesenteric ganglia (MG) Inferior mesenteric ganglia (HG) Then postganglionic axons follow blood vessels nearby to innervate the smooth muscle, gland and ENS. |
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What is the course of the afferent innervation of the GIT (Pain and sensation) |
- Some afferents travel with L&R vagus nerves - vasovagal reflexes travel with S2-S4 PSNS fibres. - some (for instance pain) travel with sympathetics, except through dorsal root, primary sensory cell bodies in dorsal root ganglia, synapse in dorsal horn of same spinal cord segment - FG T6-T9 - MG T9-T11 - HG T12 -L2
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What dermatomes do the GIT regions refer their pain sensations to? |
Foregut: T6-T9 - epigastric region Midgut: T9-T11- umbilical region Hindgut: T12-L2 - hypogastric region |
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Boundaries of the abdominopelvic cavity. additional divisions |
superior: diaphragm inferior: pelvic diaphragm. additional divisions: abdominal cavity proper and pelvic cavity at the level of the pelvic aperture (pelvic brim). |
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Layers of the anterolateral wall of abdomen |
Skin and superficial fascia -> external abdominal oblique -> internal abdominal oblique -> transversus abdominis -> transversalis (endoabdominal) fascia -> extraperitoneal fat -> parietal peritoneum |
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Muscles of anterolateral wall abdomen |
External abdominal oblique and internal abdominal oblique action: compress and support abdominal viscera and flex and laterally rotate the trunk. Transversus abdominis action: compresses abdominal viscera, controls the tilt of the pelvis. Innervation of all these muscles: T6-T12, L1 ventral rami of spinal nerves. |
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The Rectus sheath. what does it aponeurose? What are its contents? Where are the linea alba and semilunaris? What are the differences between the superior 3/4 and the inferior 1/4 of the sheath. |
Aponeuroses of EO, IO, TA. The function of the sheath is to reinforce the abdominal wall. Its contents: rectus abdominis, super and inferior epigastric aa and vv, some lymphatics, distal portions of thoracoabdominal nerves, abdominal portions of anterior rami of spinal nerve T7-T12. Linea alba - between the 2 rectus muscles linae semilaris - between rect and oblique muscles). There are also tendinous intersections within the rectus abdominis which anchor muscle to sheath. superior 3/4 - the anterior sheath is from aponeurosis of external oblique and half of internal oblique. Posteriorly sheath is from aponeurosis of transverse abdominis and half of internal oblique. Inferior 1/4 (below umbilicus) - sheath of from aponeurosis of external oblique, internal oblique and transverse abdominis. There is a level at which the post part of sheath stops, this is called the arcuate line. |
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Internal surface of anterolateral wall |
MediaN umbilical ligament (fold) is the fibrous remnant of the urachus that embryologically joined the bladder and umbilical cord. The MediaL umbilical ligaments are formed from the remnants of the umbilical arteries. The lateral umbilical is fold from inferior epigastric vessels Ligamentum teres hepatis is from the remnant of umbilical vein and a fold of peritoneum called the Falciform ligament. |
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Nerves of anterolateral abdominal wall |
the neurovascular plane is between int. Oblique and TA or post. to rectus abdominis Thoracoabdominal nn are the distal parts of T7-11 intercostal nn. Skin sensation above umbilicus - T7-9 around umbilicus - T10 below umbilicus - subcostal nerve (T12) and iliohypogastric nn (L1) and ilioinguinal nn (L1) |
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Arteries of anterolateral abdo wall |
superior epigastric ( from internal thoracic a), Inferior epigastric ( from external iliac a), both these aa run post to RA. Also musculophrenic branches, Deep circumflex iliac (from ext iliac), Lumbar intercostal, Sup. circimflex iliac and superficial epigastric (from femoral a) anastomose between arch of aorta and abdominal aorta. |
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Veins of anterolateal abdo wall |
Superficial veins and subcutaneous venous plexus drain into either: - internal thoracic v superomedially - lateral thoracic v superolaterally - superficial and inferior epigastric vv inferiorly. - there are also anastomoses in with the paraumbilical vv These veins provide collateral pathways should the SVC or IVC be blocked (e.g. portal hypertension) There are Deep veins - which run with the arteries. |
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Lymphatics of abdomen |
Superficial Lymphatics - above umbilicus - ant. axillary LNs or parasternal LNs - below umbilicus - superficial inguinal LNs Deep lymphatics - drain to external iliac LNs, parasternal LNs and/or lumbar LNs |
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The Inguinal canal |
The inguinal canal is a space through the ant. abdo wall from deep inguinal ring to superficial inguinal ring. It connects the extraperitoneal space of abdomen with the scrotum or Labia majora. It is where developed testes (in foetus) can travel through to the scrotum where the temp is cooler. If born not descended can be malignant. In adults it transmits spermatic cords in males and the round ligament of uterus in females. The inguinal ligament - just superior to inguinal canal, which runs from ASIS to pubic tubercle. - It is formed from the thickened free edge of the external oblique aponeurosis and forms the floor of the inguinal canal. - The external oblique aponeurosis also contributes to the anterior wall of inguinal canal and gap in aponeurosis, this forms the superficial inguinal ring. The EO aponeurosis also forms ext. spermatic fascia. - the ant. wall, roof of the inguinal canal is formed by internal oblique aponeurosis. - The Roof is also contributed by transversus abdominis, also the posterior wall medially (via conjoint tendon) _ Posteior wall - Transversalis fascia ( incagination of this later forms the deep inguinal ring. Summary Ant wall - ext. oblique aponeurosis and int. oblique laterally Post wall - transversalis fascia, parietal peritoneum and conjoint tendon medially Floor - inguinal liagment and lacunar ligament medially Roof - internal oblique and transverse abdominis |
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Developement of the inguinal canal (5) |
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Layers of abdominal wall, spermatic cord and testes |
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Spermatic cord |
The spermatic cord contains the ductus (vas) deferens, testicular artery and pampiniform plexus of vv (testicular vv), genital branch of genitofemoral n, lymphatics, autonomic nn and other vessels. The fascia layers: external spermatic, cremasteric, internal spermatic and the Inguinal branch of ilioinguinal n. |
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Female specific contents of the inguinal canal |
round ligament of uterus, genital branch of genitofemoral n and vessels, fascia layers and inguinal branch of ilioinguinal n. |
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Posterior to the inguinal canal |
deep to the deep ring is the testicular vessels and the ductus (vas) deferens separate and travel different directions. |
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Inguinal (Hesselbach's) triangle - internal view |
Boundaries - abdominis, inferior epigastrics, inguinal ligament The femoral ring is just below the inguinal ligament and the location of the deep inguinal ring is lateral to the inferior epigastrics |
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Inguinal hernia |
Indirect hernias - originate lateral to inferior epigastric vesses and pass through the deep inguinal ring into the inguinal canal to exit via the superficial ring. Risk factor: congenitally patent processus vaginalis Direct hernias - originate medial to the inferior epigastric vessels and pass directly through the anterior abdominal wall ( inguinal triangle region) |
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Liver: Lobes, surfaces, structures that make the H appearance, divisions and segments |
Lobes: R, L, quadrate (inf), caudate (sup) Surfaces: Diaphragmatic and visceral H shape: - ligamentum venosum (remnant of Ductus venosus) - Ligamentum teres hepatis (aka round lig of L, remnant of umbilical v) - IVC - gallbladder - Porta hepatis structures Divisions and segments: portal triage structures divide like the trachea in a pattern (see a diagram) 1˚. L, R divs 2˚. Medial and Lat. divs 3˚. Sup, Inf divs. - Hepatic segments can be removed surgically. - the hepatic veins are located between divisions |
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Porta hepatis of Liver |
The contents: - Hepatic portal v and a (both bringing blood to liver) - Common hepatic duct, cystic duct, and common bile duct ( bile from liver, to/from gallbladder, to duodenum) - nerves and lymphatics It is surrounded by the hepatoduodenal ligament of lesser omentum. |
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Peritoneum of liver |
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Iiver ligaments |
Falciform, coronary and triangular ligaments |
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Hepatoduodenal lig and hepatograstric lig at the sup. part of the lesser omentum |
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Gallbladder |
Bile released via cystic duct -> common bile duct (which runs post. to and through the head of pancreas) -> ampulla of Vater (aka hepatopancreatic ampulla) -> duodenum. G has a body, fundus, and neck |
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Pancreas parts |
head, neck, body, tail and uncinate process |
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pancreatic ducts |
main pancreatic duct -> join bile duct to form -> hepatopancreati ampulla (aka ampulla of Vater) which is surrounded by Hepatopancreatic sphincter (of Oddi) -> opens out of major duodenal papilla -> into descending part of duodenum. If gallstone back up and block this exit. the accessory pancreatic duct opens at the minor duodenal papilla |
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Spleen |
diaphragmatic surface, visceral surface with hilum. There are gastric, colic and renal impressions. |
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Arterial blood supply to spleen, pancreas and duodenum |
coeliac a branches. - splenic a with its pancreatic branches - supraduodenal a (from gastroduodenal a) to duodenum - sup. pancreaticoduodenal aa (also from gastroduodenal a) to duodenum - inferior pancreaticoduodenal a (from sup. mesentaric a) to duodenum |
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Arterial supply to liver (basic), gallbladder and ducts |
coeliac branches: - common hepatic a -> hepatic proper -> R & L hepatic aa - Cystic a (from R hepatic a within cystohepatic triangle) |
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Liver portal venous system |
Hepatic portal vein (bring nutritious, O2 poor) brings blood from GIT, pancreas, and spleen from Sup mesenteric v, Inf mesenteric v and splenic v. Hepatic a brings O2 dense blood to liver. These 2 vessels mix blood in liver sinusoids -> Liver sinusoids drain to central veins -> hepatic veins (R, intermediate, L) -> IVC |
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Portal caval (portal-systemic) anastomosis |
Oesophageal - Left gastric with azygos v (portal hyperTN leads to oesophageal varices) Rectal - Inf mesenteric v with internal iliac v (portal HyperTN leads to haemorrhoids, note there are other causes) Paraumbilical - veins around ligamentum teres (paraumbilical vv) with superficial gastric vv (portal hyperTN may leads to 'caput medusae' ie prominent superficial thoracic and abdo vv) |
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Lymphatics of pancreas and duodenum |
lymph from stomach and duodenum -> pancreatic nodes -> coeliac and superior mesenteric nodes -> preaortic nodes -> cysterna chyli -> thoracic duct -> left subclavian vein junction with L internal jugular |
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Lymphatics of liver |
MAIN deep lymphatic accompany portal triad branches -> ant. sup. liver -> along porta hepatis structures -> coeliac nodes -> etc Others: Post/Sup. superficial liver -> post. mediastinal nodes Central diaphragmatic superficial liver -> parasternal nodes |
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Innervation of pancreas |
- PSNS and SNS same as stomach - pain afferents to T6-T9 - direct irritation of somatic nerves in Post abdo wall at vertebral lvls L1-2 |
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Innervation of gallbladder and liver |
PSNS and SNS same as stomach foregut Pain afferents to T6-T9 Somatic pain: irritation felt on adjacent side of diaphragm and anterior abdominal wall from intercostal nn. Somatic/referred pain: irritation of adjacent central diaphragm due to phrenic n (from C3-C5) and referred to shoulder region (C3-C5 dermatomes) |
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The Kidneys location |
Location - retroperitoneal, in the upperquadrants of abdominal cavity at vertebrallevels T11/ T12 to L3 with the hilum nearthe transpyloric plane (L1). The right kidney is slightly lower thanleft kidney due to the liver displacing theright kidney inferiorly. |
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Kidneys stucture |
Fascia layers surrounding the kidney - the kidney is encased by a fibrous capsule; external tothe capsule is perirenal (perinephric) fat – surrounds the kidney and is continuous with fat in renal sinus. The kidney, adrenal gland andperirenal fat are surrounded by renal fasciawhich extends to the diaphragm superiorly,blends with the renal vessels medially andloosely follows the ureters inferiorly(periureteric fascia). The renal fascia is alsocontinuous with transversalis fascia. External tothe renal fascia is pararenal (paranephric) fat. The fat and fascia act to protect and support thekidney. |
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Relationships of kidney-posterior |
Superior kidney: diaphragm,costodiaphragmatic recess ofpleural cavity, 11th, 12th ribs Inferior kidney: psoas major,quadratus lumborum, transversusabdominis |
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Relationships of the kidney-anterolateral |
Right kidney: adrenal (suprarenal)gland, liver, descending duodenum,(IVC), right colic flexure, smallintestine Left kidney: adrenal gland,stomach, spleen, left colic flexure,tail of pancreas, small intestine |
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The internal structure of the kidneys |
- the outer part of the kidney is thecortex with the inner component themedulla. The medulla contains therenal columns, pyramids and renalpapilla. Blood is filtered and thefiltrate is modified in the cortex andmedulla. The filtrate exits the renalpapilla as urine. Urine flows fromminor calyces to major calyces to renalpelvis to ureter then bladder. Hilum = entrance/exit of aa,vv,nn,ll,ureter Sinus = space that contains hilar vessels, calyces, renal pelvis and fat. |
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Blood supply of kidneys |
paired renal arteries arise from the aorta at L1, accessory renalvessels common (of clinical interest in kidney transplantation or surgery). Note that the rightrenal artery runs posterior to the IVC. Approximately 20% of cardiac output goes to the renalveins. Renal artery → 5 segmental arteries→ interlobar arteries→ arcuate arteries →interlobulararteries. Segmental arteries are end arteries – no significant anastomoses between renalsegments. The renal veins drain to the IVC at L1, the left renal vein also receives left gonadal andadrenal veins. Note the left renal vein travels between the aorta & superior mesenteric artery. |
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Innervation of the Kidneys |
nerves to the kidney come from the renal plexus surroundingthe renal artery and contains both P-S and sympathetic fibres. Sympathetics originate in the lateral horn of spinal cord T10-L1 (some texts T9-L2) andtravel via the least splanchnic and first lumbar splanchnic (and maybe lesser splanchnic)nerves through the aorticorenal, and renal ganglia to the renal plexus. Afferents fibres travelto spinal cord segments T10 to L1 P-S from vagus, probably supplies the smooth muscle of the renal pelvis and calyces. Travelsfrom posterior vagal trunk and then with the sympathetic fibres. |
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The Ureters |
form as the renal pelvis narrows; they descend retroperitoneally from the hilumof the kidney to the bladder (25-30cm length). They are located anterior to the psoas majormuscle and the bifurcation of the common iliac arteries. Gonadal and colic vessels crossanterior to ureters. Normal constrictions in the ureter occur at the junction of the renal pelvisand the ureter, at the level of the pelvic brim and as the ureter traverses the bladder wall – renal calculi can get stuck here. Blood supply to the ureters- small branchesarise from the renal aa, gonadal aa,abdominal aorta and common iliac aa. Innervation –the ureteric plexus(sympathetic and P-S) comes from therenal, aortic, superior and inferiorhypogastric plexuses. Autonomic nervesappear to be mainly sensory in function.Visceral afferents mainly travel to T10- L2;pain (eg passing a kidney stone) is oftendescribed as loin to groin pain as the stonepasses down the ureter (intensely painful). |
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Adrenal (suprarenal) Glands |
Endocrine gland – glucocorticoids, mineralocorticoids, sex hormones; adrenalin, noradrenalin The glands have a capsule, cortex, medulla. Theyare located adjacent to superior pole of kidneyhowever their primary attachment is to thediaphragm (it is easy to detach the kidney from theadrenal in kidney transplantation). The right suprarenal gland is pyramidal in shapeand the left is semilunar. Adrenal arteries: superior (from inferior phrenic),middle (from aorta), inferior (from renal). Adrenalveins – left drains to left renal v, right drains directto IVC Suprarenal innervation -sympathetics in lateral horn of spinal cord (text books vary T5-L1)travel via greater, lesser and least splanchnics and through the coeliac gangion withoutsynapsing. The adrenal medulla receives preganglionic sympathetic fibres. Afferents to spinalcord segments T5 to L1 (no P-S innervation). |
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The Posterior Abdominal Wall |
Muscles - Psoas major, minor, Quadratus lumborum, Iliacus. Actions: flexion at hip joint (P, I), lateral flexion of trunk (P, QL). Innervation: branches of ventral rami L1-L3, femoral n Additional muscles - Latissimus dorsi, and intrinsic muscles of spine (mainly erector spinaeand multifidus) |
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Thoracolumbar fascia |
Several layers: Posterior lamellae -superficial to erector spinae, Middle lamellae – posterior to quadratus lumborum Anterior lamellae – anterior to quadratus lumborum The fascia blends with the origin of latissimus dorsi,serratus posterior inferior, internal oblique andtransversus abdominis |
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The Diaphragm |
Musculotendinous sheet that separates thethoracic and abdominal cavities, major muscle ofrespiration. Attachments: Ribs 7-12, Lumbar vertebrae (viacrura), Xiphoid process. Crura (right and leftcrus). Arcuate ligaments: median(overaorta), medial (psoas major mm), lateral (quadratus lumborum mm) Innervation: Motor: phrenic n (C3-C5), Sensory:phrenic n centrally, intercostal nn peripherally Blood supply: inferior phrenic and musculophrenic aa Structures passing through the diaphragm - IVC at T8vertebral level, Oesophagus and vagal trunks at T10 Structures passing posterior to the diaphragm - Aorta andthoracic duct at T12 |
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The Lumbar Plexus |
- Anterior rami of L1-5 - Iliohypogastric, ilioinguinal nn (L1) - Genitofemoral n (L1, L2) - Lateral femoral cutaneous n (L2, L3) - Femoral n (L2-L4) - Obturator n (L2-L4) - Lumbosacral trunk (L4-L5) joins sacral plexus - Note subcostal n (T12) is not part of the lumbar plexus Revision ilioinguinal nn (L1) Ilio-inguinal nerve not inside spermatic cord, but runs along the outsideGenitofemoral n (L1, L2) genital portion travels inside spermatic cord. |
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Autonomic Nerves –Posterior Abdominal wall |
Sympathetic trunk (paravertebral ganglia) Prevertebral ganglia (aortic plexus): coeliac,superior mesenteric, inferior mesenteric,(intermesenteric), renal, superior hypogastric (in pelvic cavity: hypogastric nn, inferiorhypogastric plexus) |
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The Abdominal Aorta – (T12-L4) |
Unpaired branches: Coeliac, SMA,IMA, Median sacral Paired branches: Inferior phrenic,Middle adrenal, Renal, Gonadal(testicular/ovarian) Multiple paired branches: Lumbar Termination: divides into R & LCommon Iliac aa |
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Inferior vena Cava – (L5-T8) |
Origin: Common Iliac vv Unpaired tributaries: Right Adrenal, R.Gonadal, Hepatic Paired tributaries: Renal, Inferior Phrenic,Lumbar (3,4) |
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Lymphatics of posterior abdominal wall |
Two generl paths to cisterna chyli. 1. follows the aorta 2. follows the branchs of mid gut and internal and external iliac nodes drain tocommon iliac nodes which drain to lumbar nodes (lateral aortic nodes) also draining into thelumbar nodes are posterior abdominal wall, kidney, adrenal, ureters, gonads, uterus andinferior mesenteric. The lumbar nodes then drain to the lumbar trunks. Coeliac and superior mesenteric (and inferior mesenteric) nodes drain to the intestinal trunks.Lumbar & intestinal trunks drain to the cisterna chyli then to the thoracic duct which exitsabdomen via aortic hiatus terminating at the junction of the left subclavian and internaljugular veins (left venous angle). Note there is some variation between texts on where the inferior mesenteric nodes drain - all tolumbar trunks or all to intestinal trunks or to both trunks. |
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paths from salivsry duct to oral cavity. |
parotid - via parotid duct that enters between the cheek and the gums
submandibular - big close either side of the frenulum of the tongue. sublingual - on either side of the frenulum in a line |
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oesophageal relationships |
starts at C6 posterior to cricoid cartilage then enters through diaphragm at T10, enters stomach at T11 |
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The superior pelvic aperture (pelvic brim, inlet) |
A line formed by the sacralpromontory, arcuate line of the ilium and pectin pubis of the pubic bone, it divides thepelvis into the greater pelvis (pelvis major, false pelvis) above and the lesser pelvis(pelvis minor, true pelvis) below. The true pelvis contains the pelvic contents. |
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The pelvic viscera |
Male main contents; Bladder, prostate, genital ducts - ductus deferens, seminal glands, rectum. Female main contents; Bladder, vagina, uterus, uterine tubes, ovaries, rectum. |
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The Peritoneum of pelvis and its associated pouches |
The peritoneum covers the upper parts of rectum (anterolaterally), the superior surfaceof bladder, most of uterus, uterine tube and ovary.The reflection of the peritoneum over the bladder, uterus and rectum creates a number ofpouches or recesses. Males have one pouch; rectovesical. Females have two pouches;vesicouterine and rectouterine (of Douglas) Note: fluid can accumilate in the puches first. Esp the retrovesicle or rectouterine. Additional 'space' the pararectal fossa, sits laterally in both males and females that allows rectum to expand with faeces. |
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Blood supple of pelvis |
Internal iliac a (from com. iliac) - supplies pelvic viscera, pelvicwall, perineum and gluteal region. Superior rectal (from inf. Mesenteric a) Ovarian a (from aorta) Median sacral (from bifurcation of aorta) |
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Rectum - appearance, Origin, end, layers, function, perineal flexure. |
starts at rectosigmoid junciton (at S3), ends at rectoanal junction (at lvl of pelvic diaphragm). Has no haustra or teniae coli (instead full layer of longitudinal m). Have transverse rectal folds, act like valves. Rectum functions to store faeces before defecation. The perineal flexure (anorectal) splits the rectum and anal canal. Created by puborectalis muscle (a pelvic floor m), which is important in continence. |
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Rectum relationships |
Anterior relations of the rectum Male; small intestine, sigmoid colon, rectovesicalpouch, genital ducts, prostate, bladder Female; sigmoid colon, small intestine, rectouterine pouch, uterus, rectovaginal septum,posterior wall of vagina |
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blood supply rectum |
Arteries Mostly by superior rectal a. from theinferior mesenteric a.Middle rectal a. from internal iliac a.Inferior rectal a. supplies the anal canal,from internal pudendal a. (from internaliliac a) Veins - mostly by superior rectal vein (drains -> IMV to splenicv or SMV to hepatic portal v). - Middle rectal v (-> int iliac v) - Inferior rectal v drains anal canal (-> internal pudendal v -> int iliac) |
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Innervation of rectum |
SNS; T12-L2 mostly via lumbarsplanchnics to pelvic plexus PSNS; S2-4 pelvic splanchnics to pelvic plexus. Pain travelsvia P-S nerves |
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Lymphatic of rectum |
Follows the arteries; along superiorrectal and inferior mesenteric aa. to inferior mesentericnodes. Along middle rectal a. to internal iliac nodes orfrom anal canal to internal iliac nodes and superficialinguinal nodes. |
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Urinary Bladder |
The bladder consists of the detrusor muscle in the wall. The bladder is lined by transitional epithelium. The posterior surface contains the triangle formed by the two uretersentering the bladder superiorly and one urethra exiting inferiorly. The trigone is lessexpansible than the rest of the bladder so as not to damage these structures. The Apex is anterior and is attached to median umbilical ligament. The neck is inferior and leads tothe urethra. It also has a superior surface and two inferolateral surfaces (like a boat keel). |
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Innervation of Urinary bladder |
SNS; T12-L2/3 mostly via lumbar splanchnics to pelvic plexus. P-S; S2-4 pelvic splanchnics to pelvic plexus. Pain from inferior bladder travels via P-S nerves,superior bladder via symp. |
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Relations of bladder |
Superior: peritoneal cavity, vesicouterine pouch and uterus, smallintestine, sigmoid colon Inferior: prostate / pelvic and urogenital diaphragms. Posterior:rectovesical pouch, genital ducts, rectum / cervix of uterus, vagina. Anterior: pubicbones, rectus abdominis, Lateral: hip bone, pelvic wall |
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Ureters |
The Ureters are retroperitoneal and descend into the pelvis near bifurcation of common iliacvessels, the ureters travel though the bladder wall obliquely therefore the detrusor muscleacts like a sphincter preventing backflow up the ureter.In the male the ureter enters the base of bladder posterolaterally between ductus deferensand seminal vesicle. In the female the ureter travels 1-2 cm lateral to cervix of uterusbefore entering the superolateral aspect of the bladder, note the uterine vessels (ligatedduring a hysterectomy) cross superior to ureter. |
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Urethra |
Urethra commences at the internal urethral orifice (part of the bladder trigone) and ends at the external urethral orifice. The female urethra is located anterior to the vagina, 4 cmlong (short). It contains an external (skeletal) urethral sphincter in the pelvicdiaphragm/urogenital triangle but no real internal sphincter. The smooth muscle aroundthe neck of the bladder is distinct from the detrusor muscle as the fibres have an obliquearrangement running into the wall of the ureter, this helps maintain continence but is nota true sphincter. The male urethra is much longer than the female urethra and has 4 parts 1. Intramural (preprostatic), 2. Prostatic, 3. Membranous, 4. Spongy It has an internal urethral sphincter (smooth muscle) at the neck of the bladder and anexternal (voluntary) sphincter in the membranous urethra. The internal sphincter has a rich sympathetic supply and it constricts during ejaculation to prevent backflow of semeninto the bladder, it is not known if this sphincter is also involved in the control ofmicturition. In both sexes the external sphincter allows control of micturition. |
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Prostate |
The Prostate is a walnut sized gland below the bladder, it has a fibrous capsule closelyadherent to the prostatic nervous plexus and venous plexus. The apex is located inferiorlyand the base superiorly.Is divided into lobes (however there is considerable variation between texts also differentclinical subdivisions). A simple subdivision has an anterior lobe (isthmus) which is thefibromuscular section of the gland. The glandular portion is divided into two laterallobes, which can be further subdivided. Directly posterior to the urethra is the middlelobe (prone to benign prostatic hypertrophy). The posterior and lateral portions of thegland are most prone to cancer- note value of digital rectal exam of prostate. The lumen of the posterior wall of urethra contains an elevation (urethral crest) which isenlarged in the prostatic urethra (seminal colliculus). Either side of the seminal colliculusis a groove (prostatic sinus). A small central depression in the seminal colliculus is calledthe utricle (a remnant of the embryonic uterovaginal canal). Multiple ducts from prostatedrain into prostatic sinus. Ejaculatory ducts drain into the seminal colliculus just belowthe utricle. |
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blood vessels and lymphatics of bladder and prostate |
Superior and inferior vesicalarteries from internal iliac artery in males and the superior vesicle and vaginal arteries infemales. Vesical venous plexus drains to the internal iliac veins but also anastomoseswith veins of bony pelvis and to internal vertebral plexuses. Bladder and prostatic lymphatics drain to the external and internal iliac nodes. Prostaticcancer often spreads via venous system (lumbar vertebrae) as well as lymphatics. |
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Innervation of the postate |
SNS; T12-L2/3 mostly via lumbar splanchnics to pelvic plexus P-S; S2-3 pelvic splanchnics to pelvic plexus. Pain via P-S and symp (probably). |
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Male genital ducts |
Ductus deferens: extraperitoneal course through pelvis from deepinguinal ring to posterior prostate. The terminal part of the ductus deferens is dilated =ampulla (1). The ductus deferens joins with the seminal glands (2) to form the ejaculatoryduct (3), which travels almost vertically through the prostate and enters prostatic urethra(4) then into the membranous urethra (5). |
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Female Uterus |
The inferior part of the uterus is the cervix, above the cervix is the body of theuterus (the fundus is the most superior part of the body). The opening from the vaginainto the cervix is the external uterine os (opening) between the superior cervix and bodyof uterus is the internal uterine os. The wall of the uterus has several layers;endometrium (inner layer- mostly shedduring menstruation), myometrium(muscle), perimetrium (a serosa formedfrom the peritoneum) The mesentery of uterus (mesometrium)consists of part of the broad lig (notincluding the ovarian lig and mesosalpinx). |
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Orientation of the uterus |
Anteflexion - body of uterus bent slightly forward relative tocervix. Anteversion - cervix bent forward relative to vagina Position is vairable depending on bladder fullness Abnormal positions: retroversion and retroflexion |
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Cervix |
The cervix a firm cylindrical relatively narrow structure 2.5cm in length, palpable on rectalexamination. It can be divided into the supravaginal part above the vagina and the vaginalpart which protrudes into the top of the vagina creating a narrow slit like recess betweenthe cervix and the superior vagina – the fornix. External os, internal os (openings) |
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Innervation of uterus |
SNS; T12-L2 mainly lumbar splanchnics to pelvic plexus touterovaginal plexus. P-S; S2-4 pelvic splanchnics to pelvic plexus to uterovaginal plexusto cervix only (probably). Pain from cervix travels via P-S nerves, fundus and body viasymp. |
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Vagina |
Anterior wall related to bladder and urethra, posterior wall related to rectum andrectouterine pouch. Anterior, posterior, lateral fornices of vagina partially encircle thecervix. Note the peritoneal cavity can be accessed via the vagina via the thin wall of theposterior fornix into the rectouterine pouch. |
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Ovaries |
Ovaries are paired, almond shaped and sized, (in the elderly – smaller and with a pittedsurface from multiple ovulations). |
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Ligaments of the female reproductive organs |
Suspensory ligament of ovary - containsovarian aa, vv, nn, ll. Ovarian ligamentproper - attaches ovary to uterus. The Broadligament is a double layer of peritoneumthat extends from the uterus to lateral wallof pelvis; parts include the Mesometrium(mesentery of the uterus), Mesovarium(mesentery of the ovary) and Mesosalpinx(mesentery of the uterine tube). The roundligament of uterus is located in the broadligament and travels to the deep inguinalring, through inguinal canal to labia majora) |
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Innervation of vagina |
SNS; T11-L1 mostly via lumbar splanchnics to pelvic plexus to ovarianplexus. P-S; S-4 pelvic splanchnics to pelvic plexus to ovarian plexus. Pain via symp |
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Uterine (Fallopian) tube |
4 parts: intramural, isthmus, ampulla, infundibulum withfimbriae. Note females have a communication of peritoneal cavity with outside world viauterine tube, uterus, vagina. |
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Blood supply of uterus, uterine tube, vagina, ovary |
Uterine and vaginal arteries frominternal iliac artery. Venous plexus to uterine veins to internal iliac vein. Ovarian arteryfrom abdominal aorta (L2). Ovarian veins to IVC, left renal vein |
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Lymphatics of Uterus, cervix, vagina, uterine tubes, ovaries |
(Various routes); Body of uterus, cervix, vagina to internal and external iliacnodes, part of fundus along round ligament through inguinal canal, to superficial inguinalnodes, superolateral uterus, uterine tube, ovary along suspensory ligament of ovary tolumbar nodes, lower vagina to superficial inguinal nodes (ie Uterine carcinoma canspread via lymphatics via a number of possible lymphatic channels). |
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pelvic inlet |
The pelvic inlet is formed by the sacralpromontory, arcuate line of the iliumand pectin pubis of the pubic bone |
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Inferior pelvic aperture |
The inferior pelvic aperture (pelvic outlet) runsfrom the inferior part of the pubic symphysis →ischiopubic ramus → sacrotuberous ligament → tipof coccyx. |
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Joints of pelvis |
Pubic symphysis – secondary cartilaginous joint (symphysis) withhyaline cartilage on the symphyseal surface and united by fibrocartilage. Sacroiliac joints- synovial plane joints with a posterior fibrous component |
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ligaments of pelvis |
Ligaments of the SI joints are very strong and allow only limited movement of the pelvicjoints. Note; some increase in laxity during late pregnancy. names: Iliolumbar, Anterior sacroiliac, Posteriorsacroiliac, Sacrospinous, Sacrotuberous,Interosseous |
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orientation of bony pelvis |
The ASIS and pubic tubercles are in coronalplane, the superior symphysis pubis and coccyxare in horizontal plane.Planes of pelvic inlet, about 60o, outlet about 10oabove horizontal |
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Male vs female pelvis |
Thefemale compared to male pelvis (on average) has wider superior and inferior pelvicapertures, wider pubic arch, wider greater sciatic notch, narrower depth of true pelvis andthinner, lighter bones. A female can sometimes have more ‘male’ like pelvis, this is onereason for needing a caesarean. |
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measuring the pelvis |
The true conjugate (superior pubic symphysis to sacral promontory) can only bemeasured only on radiographic films. Its normal measurement is 11 cm or more. Thediagonal conjugate (inferior pubic symphysis to sacral promontory) can be estimatedusing an internal examination, it is normally 11.5 cm or more. The obstetric conjugate isthe shortest of the three measurements (sacral promontory to thickest part of the pubicsymphysis) and measures 10 cm or more. The inlet is said to be contracted when any ofthese diameters is smaller than normal Diagonal conjugate |
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P-S nerves to pelvic viscera |
Preganglionic cell bodies in lateral horn of S2-S4 spinal cord, travelvia Pelvic splanchnic nerves to the pelvic plexus (R & L inferior hypogastric plexus). P-Sfibres synapse in intramural ganglia with short post ganglionic fibres. In general the P-Ssystem is involved in contraction of rectum and bladder to release contents, also producesan erection |
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SNS nerves to pelvis viscera |
Preganglionic cell bodies in lateral horn of T10-L2/3 spinal cord. Usuallysynapse on ganglia located on the lower aorta. Mainly travel to the superior hypogastricplexus located just below the bifurcation of the aorta. Nerves then split into two bundlesand descend to the right and left inferior hypogastric plexuses (pelvic plexus) locatedlaterally to the rectum, inferolateral bladder and prostate/cervix. Sympathetics are mainlyvasomotor, also inhibits peristaltic contraction of the rectum and stimulates contraction ofthe internal genitalia during orgasm. |
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The pelvic pain line |
The pelvic plexus contains a mix of sympathetic and P-S fibres.Visceral painafferents travel with the sympathetics above the pelvic pain line or parasympatheticsbelow the line. The pelvic pain line isapproximately at the lowest level of the peritoneum |
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arterial supply of pelvis |
Internal iliac artery - supplies many of thepelvic viscera plus other regions, it has a variable branching pattern but is usuallydivided into anterior and posterior divisions. Anterior division - Obturator a., - Superior vesical a. (may bemultiple aa), - Umbilical a.(Aka obliterated umbilical a, it becomes medial umbilicalligament), - Uterine and - vaginal aa.(female) or Inferior vesical a.(male), - Middle rectal a., - Internalpudendal a (the arteries have int and ext branches, but nerves do not)., - Inferior gluteal artery(usually exits the pelvis betweenS1-2 or more commonly S2-S3). Posterior division - Suppliesposterior pelvic wall and part ofgluteal region. - Iliolumbar a., - Lateral sacral aa., - Superior gluteal a. (exits above S1). How to find on cadava 1. obt a goes through Obt foramen with obt n. 2. umbilical a become medial umbilicl lig - sup vesical aa, may be more that one, come off umbilical. 3. Uterine, inf vesical/vaginal a, middle rectal a - nedd to identify where they terminate in order to identify. 4. Three aa exit posterior to superior gluteal a (above S1) 5. Inf gluteal a ( usually between S1-2 or S2-3) 6. Int pudendal a (much smaller) 7. iliolumbar a (post and superior) 8. lateral sacral aa (post and lateral - may be more than one) Note there is variation. |
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Veinous supple of pelvis |
Veins generally accompany thearteries, note the communicationwith vertebral venous plexus vialateral sacral veins (spread ofpelvic cancers to vertebralcolumn) and the portal-cavalanastomosis - superior rectalveins (to inferior mesenteric veinto splenic vein to portal vein) andmiddle rectal veins (to internaliliac vein to common iliac vein toIVC). |
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Pelvic diaphragm |
Located below the pelvic viscera is the pelvic diaphragm which separates the pelviccavity from the perineum below. The pelvic diaphragm is the floor of abdominopelviccavity – supports pelvic viscera and allows passage of faecal material, urine and babiesand contains sphincters for continence. |
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Muscles of pelvis wall and floor |
Pelvic wall muscles Pirifomis; origin - anterior surface of sacrum,exits pelvis through greater sciatic foramen andinserts onto the greater trochanter of femur.Action - Lateral rotator of thighInnervation - ant rami S1-2 (nerve to piriformis). Obturator Internus; origin - internal surface ofobturator membrane and surrounding bone, itexits the pelvis through lesser sciatic foramenand inserts into the trochanteric fossa. Itcontributes to lateral wall of pelvis andperineum. Action -Lateral rotator of thighInnervation – nerve to obturator internus (L5-S2) Muscles of the pelvic floor Coccygeus (ischiococcygeus) is a small part of pelvic diaphragm. Runs from the ischialspine to coccyx. Located on the internal surface of sacrospinous ligament. Levator Ani - major part of the pelvic diaphragm, supports pelvic viscera and contributesto sphincter mechanism of the anal canal. Attaches to the body of pubis, ischial spine and tendinous arch (which runs across the inner surface of the obturator internus muscle) tothe perineal body, coccyx, and anococcygeal lig.Parts of the levator ani Puborectalis, Pubococcygeus, Iliococcygeus |
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Parts of pubococcygeus |
Male – Puboprostaticus, puboperinealis, pubo-analis, Female –Pubovaginalis, puboperinealis, pubo-analis. Muscular slips from Pubococcygeus extendinto the fascia surrounding the prostate, perineal body and anus in males and vagina,perineal body and anus in females. These are now considered to be parts of thePubococcygeus rather than separate muscles. |
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Innervation of pelvic diaphragm |
Levator ani – Nerve to levator ani (S4), inferior anal and coccygeal plexus. Coccygeus,S4-5 sacral segments. |
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Endopelvic fascia |
Immediately superior to the pelvicdiaphragm is the endopelvic fascia. Theendopelvic fascia is continuous withendoabdominal (transversalis) fascia andcontains multiple thickenings which helpto support pelvic viscera. Diaphragm and endopelvic fascia 6 support pelvic viscera, the pelvic diaphragm contributes to sphincter mechanisms.Weakness of pelvic diaphragm may lead to prolapse and incontinence. Damage toperineum, pelvic diaphragm and/or endopelvic fascia can occur during childbirthparticularly with a difficult birth or multiple births. The most common outcome is stressincontinence |
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\ The Perineum |
Diamond shaped region between thighs and buttocks below the pelvic diapgragm,subdivided into anal and urogenital triangles. The anal triangle contains the anus and analcanal. The urogenital triangle contains the urethra, external genitalia and inferior vagina. Most inferior part of the trunk – located below pelvic diaphragm. Boundaries: pubicsymphysis and body of pubis, ischiopubic ramus, ischial tuberosity, sacrotuberousligament, coccyx, obturator internus. |
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Ischioanal fossa |
Boundaries of ischioanal fossa: perineal skin, ischial tuberosities, obturator internus,levator ani, external anal sphincter. Contents; mostly fat and pudendal canal. |
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Pudendal Canal |
The Pudendal canal is located on the lateral wall of ischioanal fossa, on the obturatorinternus muscle. Contains internal pudendal vessels, pudendal nerve |
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Perineum – Anal Triangle |
l Anal triangle borders: coccyx, sacrotuberous ligaments, line between ischial tuberosities.Contents - anal canal from rectoanal junction (perineal flexure) to anus and ischioanal fossa |
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The Anal Canal |
Internal structure - anal columns contain terminal braches of superior rectal vessels, theyterminate at the anal valves - folds of mucosa that form the pectinate line. Just above thevalves are small recesses- anal sinuses – produce mucous to aid defecation. |
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Pectinate line |
marks the transition zone of innervation, lymphatics and epithelium type(approximately). Above pectinate line; blood supply is from the inferior mesenteric artery(sup rectal a) and veins drain to portal system, lymph to internal iliac nodes and nervesare autonomic. Below pectinate line; blood is from the internal iliac artery (middle andinf rectal aa) and veins drain to caval venous system. Lymph to superficial lymph nodes,somatomotor/sensory innervation. Below the pectinate is the pecten a transition areafrom the columnar epithelium of the rectum to a stratified squamous epithelium. |
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Internal anal sphincter - |
continuous with innercircular muscle layer ofrectum, it is composed ofsmooth muscle withautonomic innervation. |
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External (subcutaneous, superficial, deep) anal sphincter |
skeletal muscle(voluntary), innervated by inferior rectal n. (from pudendal n S2-4). 1 Puborectalis (part of levator ani) fuses with thedeep part of external anal sphincter. The superficial layer of the sphincter attaches tothe perineal body and anococcygeal ligament. |
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Perineal Body |
Perineal body = central tendon of the perineumattachment for many muscles that support thepelvic viscera. |
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The Urogenital Triangle |
The Urogenital Triangle is located below levator ani and anterior to anal triangle.Boundaries: pubic symphysis, ischiopubic ramus and a line between ischial tuberosities.Contents –perineal membrane, erectile tissues, muscles, opening for urethra and vaginaand perineal body. |
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The perineal membrane |
The perineal membrane divides the urogenital triangle into two spaces (pouches). Thedeep perineal pouch is located above the perineal membrane and below levator ani. Thesuperficial perineal pouch is below the perineal membrane. |
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Deep pouch -male |
Contains the intermediate part of the urethra,inferior part of the external urethral sphincter anda few threads of muscle from the sphincter to theischiopubic ramus (but not a ‘true’ compressorurethrae), the deep transverse perineal muscle (askeletal muscle strip at the posterior edge of theurogenital triangle). The Bulbourethral glands arelocated within or next to the sphincter or in thedeep transverse perineal m, the ducts join thespongy urethra. The paired bulbourethral(Cowper's) glands produce a small amount of fluid that neutralizes any acidic urinepresent in the urethra prior to ejaculation and to lubricate urethra for passage of sperm. |
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Deep pouch -female |
Contains the proximal urethra, urethral sphincter,compressor urethrae and urethrovaginal sphincter (themain mechanism to control the bladder is the urethralsphincter)There is a sheet of smooth muscle instead of the deeptransverse perineal muscle. Below the perineal membrane is the superficial perineal pouch - the main componentsof the superficial pouch are the erectile tissues, the crus and the bulb, which are encasedin muscle the ischiocavernosus and bulbospongiosus mm.Females also have Greater Vestibular (Bartholin’s) glands (function - lubrication) withducts opening near the external opening of the vagina; the superficial transverse perinealmuscle is also located at the posterior edge of the superficial side of the perinealmembrane. |
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Superficial pouch- Erectile tissues |
Two corpora cavernosa have a free end and an attached end. The attached ends join to thepubic arches; the two free ends travel together into the body of the penis or clitoris.Where the corpora cavernosa is joined to the pubic arches it is also called the crus (pluralcrura). The bulb is attached to superficial surface of perineal membrane. The bulb of penis -continues into body of penis as corpus spongiosum and contains the spongy urethra.In the female the bulb of vestibule is a paired structure either side of the opening of thevagina, it then continues into the glans clitoris |
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Superficial pouch- muscles |
The crura are covered by the ischiocavernosus muscle and the bulb is covered bybulbospongiosus muscle in both males and females. The posterior edge of the perinealmembrane is covered by the superficial transverse perineal muscle. All are innervated bybranches of the pudendal nerve. Ischiocavernosus aids in maintaining erection in males and females. Bulbospongiosus supports the pelvic floor and assists in erection; in males it aids in emptying urine and semen from the urethra, in females acts as a ‘vaginal sphincter’ 4 The superficial transverse perineal muscle supports the pelvic viscera and in malescontracts during erection to support the penis. All these muscles are more developed inthe male. |
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Fascia layers |
The superficial perineal fascia is continuous with dartos fascia of scrotum, superficialpenile fascia (labia majora) and mons pubis, and membranous layer of superficial fasciaof abdominal wall (green). Attaches to the posterior edge of the perineal membrane(orange) and lateral borders of the urogenital triangle. Deep perineal fascia - closely invests superficial muscles of the perineum, and iscontinuous with deep penile fascia (pink). |
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Perineal body (central tendon of perineum) |
The perineal body helps support thepelvic viscera (along with pelvicdiaphragm). Several muscles attachto the central tendon;bulbospongiosus, superficial & deeptransverse perineal m, external analsphincter and part of levator ani. Clinical importance duringchildbirth the perineal body may bedisrupted by a midline tear orepisiotomy incision to widen thebirth canal (this may continue intothe anus). A medio-lateral tear (orepisiotomy) appears to cause lessdamage to pelvic floor. |
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Penis |
Comprised of the root containing corpora cavernosa(crus) and corpus spongiosum, thebody containing corpora cavernous and corpus spongiosum and the glans contains corpusspongiosum. The spongy urethra travels through the corpus spongiosum. At the junctionto the body and glans penis a double layer of skin superficial fascia continue over theglans penis to form the prepuce (foreskin). Blood supply Arterial supply from internal pudendal arteries and drains to prostatic venous plexus orexternal pudendal vein. Note the location on the penis of the dorsal aa,v n., they faceanteriorly in the flaccid penis. This is because the anatomical position of the penis is inthe erect position therefore these neurovascular structures would be dorsally orientated. Internal pudendal a. from internal iliac a.- branches - Inferior rectal, perineal andposterior scrotal arteries and dorsal and deep arteries of penis (erectile tissues) External pudendal from femoral supplies superficial fascia of penis and anterior scrotum. Innervation The pudendal nerve (S2-4)- more specifically dorsal nerve of penis tobody and glans, perineal nerves to contents of perineal pouches and post scrotal nerves toscrotum. Lymphatics Lymph from skin to superficial inguinal lymph nodes, testis to – lumbar and preaorticnodes, urethra and cavernous bodies to internal iliac and deep inguinal nodes. |
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Female external genitalia (vulva/pudendum) |
Mons pubis, Labia majora (located on either side of the pudendal cleft). The vestibuleand labia minora are located within the pudendal cleft. The labia major unite anteriorly toform the anterior commissure and posteriorly to form the posterior commissure.The labia minora unite anteriorly to form the prepuce and frenulum of the clitoris andposteriorly to form the frenulum of the labia. The vestibule of the vagina is located between the labia minor, it contains the externalurethral orifice, orifice of vagina and openings of greater vestibular (Bartholin’s) glandswhich secrete mucous during sexual arousal. The hymen is a thin mucous membrane thatpartly (or fully) occludes the vaginal orifice, it has no known physiological function. Clitoris –(body and glans, crura and bulb of vestibule - erectile tissue), prepuce,frenulum. Arterial supply- external and internal pudendal arteries, mainly - Internal pudendal artery.Branches - inferior rectal a, perineal and posterior labial arteries, dorsal artery of theclitoris. The external pudendal artery from femoral artery supplies the anterior labiamajora. Drain via internal pudendal v. Innervation – mainly pudendal n, also ilioinguinal, genitofemoral, post cutaneous nerveof the thigh. |
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Blood Supply of the perineum-summary |
Internal pudendal from internal iliac branches - Inferior rectal, Perineal and posteriorscrotal / labial and Dorsal and deep aa of penis / clitoris (erectile tissues)External pudendal from femoral supplies superficial fascia of penis, anterior scrotum /labia majora Veins: follow arteries except deep dorsal vein of penis/clitoris to prostatic/vesical venousplexus. |
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Innervation of the perineum-summary |
Mainly pudendal S2-4 – Branches are Inferior rectal nn, Perineal nn (muscular andposterior scrotal/labial) and Dorsal n of penis/clitoris. Also Perineal branches of posteriorfemoral cutaneous n and branches of ilioinguinal and genitofemoral. Lymph drainage-mainly to superficial inguinal and some to internal iliac nodes. Erection – parasympathetics (S2-4) - dilate arteries of erectile tissues andbulbospongiosus and ischiocavernosus restrict venous drainage. Emission / ejaculation – sympathetics ( L1-L2) – closure of internal urethral sphincter,contraction of genital duct smooth muscle Aided by contraction of the urethral muscle – parasympathetic S2-4 and contraction ofbulbospongiosus- Pudendal n (S2-4). |
