Abdomen Flashcards
1
Q
Describe the structure of the abdominopelvic cavity and state its superior definition
A
Structure: continuous cavity of the abdomen and pelvis, arbitrarily separated by the pelvic inlet
Superior definition: diaphragm; however arching means upper abdomen may extend into thorax and be protected by ribcage
2
Q
State the visceral structures of the abdominopelvic cavity
A
Gastrointestinal organs, hepatobiliary organs, urinary system organs, reproductive organs and abdominal vessels
3
Q
Draw a crude diagram of the pelvis, identifying the bony landmarks and pelvic inlet
A
””
4
Q
Demonstrate the bony and cartilaginous landmarks of the abdomen (not pelvis)
A
”
Sternum/Xiphoid process:TIX/X level
Costal Cartilage: of the 6th-10th ribs forms the costal margin to which the diaphragm is attached”
5
Q
Demonstrate the bony and cartilaginous landmarks of the pelvis (not abdomen)
A
” Iliac Crest: most superior border of the ilium
Iliac Fossa: internal face of the ilium
Anterior Superior Iliac Spine: protrusion at the most anterior part of the iliac crest
Pubic Symphysis: cartilage where the pubic tubercles are joined
Pelvic Inlet: enclosed laterally by the pelvic brim, anteriorly by the pubic tubercles and posteriorly by the sacrum”
6
Q
Draw a 3x3 grid to illustrate the regions of the abdomen, stating the planes used to divide such, and the names of each region
A
”
Subcostal Plane: transverse plane at the lower edge of the 10th costal cartilage
Intertubercular Plane: transverse plane that divides the left and right iliac tubercles”
7
Q
Draw a 2x2 grid to illustrate the quadrants of the abdomen, including the planes used to define each quadrant and the organs found in each
A
””
8
Q
Describe the superficial fascia of the abdominal wall
A
Superficial to deep
1) Skin
2) Camper’s fascia: superficial fatty layer; continuous with inguinal ligament
3) Scarpa’s fascia: deeper membranous layer; little/no fat
9
Q
Describe the superficial lymphatics of the abdominal walls
A
Lymphatics accompany subcutaneous veins
Superior to the umbilicus: drains to pectoral group of axillary nodes
Inferior to the umbilicus: drains to superficial inguinal nodes
10
Q
Describe the deeplymphatics of the abdominal walls
A
Lymphatics accompany deep veins
Superior to the umbilicus: drains to mediastinal nodes
Inferior to the umbilicus: drains to external iliac/para-aortic nodes
11
Q
State the muscles of the posterior, anterolateral (superficial to deep)and anterior walls of the abdomen
A
Posterior: Psoas major, quadratus lumborum
Anterolateral: external oblique, internal oblique, transversus abdominis
Anterior: rectus abdominis (enclosed by rectus sheath)
12
Q
“Adominal Wall Muscles - External Oblique
Wall:{{c1::anterolateral}}
Function: {{c1::compress abdominal contents; turning of abdomen}}
Direction of muscle fibres: {{c1::inferiomedially}}
Attachments: {{c1::outer surfaces of ribs 5-12}} to {{c1::lateral lip of iliac crest/aponeurosis}}
Innervation: {{c1::anterior rami of T7-12}}
“
A
INFERIOMEDIALLY = downwards and forwards
13
Q
“Adominal Wall Muscles - Internal Oblique
Wall:{{c1::anterolateral}}
Function: {{c1::compress abdominal contents; turning of abdomen}}
Direction of muscle fibres: {{c1::superiomedially}}
Attachments: {{c1::inferior surfaces of ribs 10-12/costal cartilage}} to {{c1::iliac crest and inguinal ligament (lateral half)}}
Innervation: {{c1::anterior rami of T7-12 and L1}}
“
A
SUPERIOMEDIALLY = downwards and backwards
14
Q
Describe the formation of an aponeurosis by anterolateral abdominal wall muscles
A
Muscle fibres passing anterolaterally are replaced by an aponeurosis near the midline to form the rectus sheath to contain the rectus abdominis muscles; aponeuroses join at the linea alba
15
Q
State the vessels supplying the flank muscles
A
Intercostal arteries, subcostal artery, lumbar arteries and deep circumflex iliac arteries
16
Q
Describe the structure of the rectus sheath above and below the umbilicus
A
”
Superior to the umbilicus (A): the aponeurosis of the internal oblique muscles split to enclose the rectus abdominis muscles, with the external oblique anteriorly and transversus abdominis posteriorly
Inferior to the umbilicus (B): all aponeuroses run anteriorly to the rectus abdominis, with only the transversalis fascia and parietal peritoneum posterior to the rectus abdominis
“
17
Q
State where the neurovascular plane is situated in the abdominal walls
A
between the internal oblique and abdominis muscles
18
Q
State where the inguinal region is, the defined border, and why this is clinically relevant
A
Junction between anterior abdominal wall and thigh
Border defined as the line between the ASIS and pubic tubercle (where the anterior abdominal wall is weakened)
19
Q
Describe the formation of the inguinal ligament
A
Formed by the rolling of the lower border of the aponeurosis of the external oblique muscle, this thickened and reinforced edge passes between the ASIS and the pubic tubercle, folding under itself to form a trough (forming the inguinal canal)
20
Q
State the beginning and end-points of the inguinal canal, and their locations
A
Start: deep inguinal ring (a hole in the transversalis fascia - just above midpoint of ligament)
End:superficial inguinal ring (hole in external oblique aponeurosis - superior and medial to the pubic tubercle)
21
Q
State the contents of the inguinal canal in males and females
A
Males: spermatic cord and ilioinguinal nerve
Females: round ligament and ilioinguinal nerve
22
Q
State the walls of the inguinal canal
A
Primarily formed by the external oblique aponeurosis, but posteriorly by the transversalis fascia and superiorly by the internal oblique and transversus abdominis
23
Q
Define hernia, stating its clinical presentation and the anatomical defects in abdominal hernias
A
Part or whole of an organ or tissue abnormally protruding through the wall of the structure containing the organ or tissue, presenting as a lump/protrusion that appears either intermittently/all the timeAnatomically, a defect in the wall allows the peritoneum to protrude through and form the hernial sac, covered in hernial coverings and containing abdominal viscera
24
Q
Compare the incidence of hernias in males and females
A
Comparison:males > females
Males: mainly inguinal (2.5% femoral)
Females: mainly femoral (risk /\ with age and no. pregnancies)
25
State the borders of Hesselbach's triangle
Rectis abdominis, inguinal ligament and the inferior epigastric vessels
26
State where direct hernias pass through, whether these are congenital, the associations present and the location relative to the inferior epigastric vessels
"Pass through: Hesselbach's triangle
Congenital? NO - acquired
Associations: weak muscles and chronic straining
Location: MEDIAL to inferior epigastric vessels
"
27
State where indirect hernias pass through, whether these are congenital, the associations present and the location relative to the inferior epigastric vessels
"Pass through: deep inguinal ring
Congenital? YES
Associations: dilated deep ring
Location: LATERAL to inferior epigastric vessels
"
28
Describe the location of the femoral canal and how femoral hernias may be distinguished from inguinal
Femoral canal: passes inferior to the inguinal ligament and allows passage of femoral artery and vein; hernias tend to be irreducible and hot/painful
Distinguishing from inguinal: tend to be inferior and lateral to pubic tubercle vs inguinal hernias that are superior and medial to the tubercle
29
Describe the structure of the peritoneum and peritoneal cavity
Peritoneum: single continuous simple squamous mesothelium that lines the abdminal cavity and is supported by connective tissue
Peritoneal cavity: potential space within the peritoneum that normally only has a small volume of fluid
30
Differentiate between intra and retroperitoneal organs giving examples
Intraperitoneal organs: lie within the cavity, surrounded by visceral peritoneum, and suspended by the mesentery (e.g. Small intestine)
Retroperitoneal organs: lie behind the cavity, with the visceral peritoneum covering one surface (e.g. Kidneys and great vessels)
31
List the retroperitoneal viscera and structures
- Kidneys and ureters- Suprarenal glands- Great vessels- Nerves- Oesophagus- Rectum- Duodenum- Pancreas - Asc/Desc Colon
32
Describe the divisions of the GI tract to the fore/mid/hind gut
Foregut: distal 1/3rd of oesophagus to 2nd part of duodenum at entrance of bile duct
Midgut: 2nd part of duodenum to 2/3rd along the transverse colon
Hindgut: distal 1/3rd of the transverse colon to the rectum
33
Define mesenteries and state the role of the dorsal and ventral mesentery
Mesenteries: peritoneal folds that attach viscera to the abdominal wall, acting as conduits for nerves, vessels and lymphatics for the viscera
Dorsal: suspends the whole gut tube
Ventral: suspends the foregut
34
Describe the embryogenesis of the gut
"Gut tube originates from the endoderm and splanchnic mesoderm Liver, stomach and spleen originally midline, but liver moves right, and spleen to the left, so the original ""right"" half of the peritoneal cavity becomes posterior - the lesser sac of the cavity "
35
State where the greater omentum is derived from, its structure and its location
Derived from: Dorsal mesentery
Structure: large apron-like structure that attaches to greater curvature of stomach and first part of duodenum to drape inferiorly over the transverse colon and jejunum/ileum Then turns posteriorly to ascend and associate with the peritoneum on the superior surface of the transverse colon
36
State where the lesser omentum is derived from, its structure and its location
Derived from: ventral mesentery
Structure: extends from lesser curvature of the stomach/duodenum to the inferior surface of the liver, divided into the:- Medial hepatogastric ligament: connecting the stomach and liver
- Lateral hepatoduodenal ligament: connects the duodenum and the liver (free edge contains the hepatic artery, bile duct and portal vein)
37
State what is meant by the omental bursa
Space within the peritoneum between the lesser omentum and the parietal peritoneum on the posterior abdominal wall
38
Differentiate between the lesser and greater sac of the abdomen
Greater sac: present anteriorly to the lesser omentum and superficially to the greater omentum - hence surrounding the intestines Lesser sac: present posteriorly to the lesser omentum and deep to the greater omentum
39
Describe the compartments of the abdomen
Paracolic gutters: run laterally to the colon
Infracolic compartments: inferior to the mesentery of the transverse colon (right/left divided by mesentery of small intestine - right = superior, left = inferior)
Supracolic compartment: above the mesentery of the transverse colon
40
Describe the normal movement of fluid in the abdomen, and that seen with inflammatory exudate
Normally: peritoneal fluid produced in cavity and generally moves superiorly to diaphragm for reabsorption (uses paracolic gutters and subphrenic spaces)
Exudate: tends to move inferiorly to pelvis, using the subphrenic spaces, paracolic gutters and the infracolic compartments
41
Differentiate between parietal and visceral peritoneal pain sensation
Parietal peritoneum: innervated by somatic afferents carried in branches of associated spinal nerves so sensitive to well-localised pain
Visceral peritoneum: innervated by visceral afferents accompanying autonomic nerves to CNS, which when activated lead to referred and poorly localised discomfort/reflex visceral motor activity
42
Describe the structure, location and contents of the Mesentery (not mesenteries)
Structure: large, fan-shaped, double layered fold of the peritoneum connecting the jejunum and ileum to posterior abdominal wall
Location: attaches to the duodenojejunal junction and ends at the ileocecal junction
Contents: contains the arteries, veins, nerves and lymphatics that supply the jejunum and ileum
43
Describe the structure, location and contents of the Transverse Mesocolon
Structure: fold of peritoneum that connects the transverse colon to the posterior abdominal wall
Location: attached to posterior wall and moves anteriorly over the head/body of the pancreas and surrounds the transverse colon
Contents: contains the arteries, veins, nerves and lymphatics that supply the transverse colon
44
Describe the structure, location and contents of the SiIgmoid Mesocolon
Structure: inverted, V-shaped peritoneal fold that attaches the sigmoid colon to the abdominal wall
Location: apex next to the division of the left common iliac artery and the left limb passing along the medial border of the left psoas muscle and right limb descending to the pelvis
Contents: contains the sigmoid and superior rectal vessels, alongside the nerves and lymphatics of the sigmoid colon
45
Describe the position and functional anatomy of the stomach
"
Position: inferior to the diaphragm on the left side of the body, positioned between the oesophagus and small intestines
- Greater curvature: most lateral curvature; point of attachment of gastrosplenic ligament and greater omentum
- Lesser curvature: most medial curvature; point of attachment of lesser omentum
- Cardial notch: superior angle created where the oesophagus enters
- Angular incisure: bend on the lesser curvature
"
46
Draw a diagram of the stomach, showing the parts (5)
"Fundus: superior to plane created by the cardial notch
Cardia: surrounds the opening
Body: bulk of the stomach, between the fundus and angular incisure
Pyloric antrum: between the pyloric canal and angular incisure
Pyloric canal: leads to the pyloric constriction where the pyloric sphincter controls flow to the duodenum
"
47
Describe the position of the duodenum, and describe the duodenojejunal flexure
Position: C-shaped structure adjacent to head of pancreas
| Duodenojejunal flexure: surrounded by fold of peritoneum (suspensory ligament of the duodenum)
48
Draw the structure of the duodenum, explaining where each part begins/ends
1) Superior part: aka ampulla; extends from pyloric orifice to neck of gallbladder, passing anterior to the bile duct, portal vein and IVC (only intraperitoneal part)
2) Descending part: extends from neck of gallbladder to the lower border of vertebra LIII; crossed anteriorly by the transverse colon, and right kidney is posterior; contains the duodenal papillae
a) Major duodenal papilla: entrance of bile/pancreatic ducts
b) Minor duodenal papilla: entrance of accessory pancreatic duct (and junction of foregut/midgut)
3) Inferior part: longest section, crossing IVC, aorta and vertebral column
4) Ascending part: passes upwards on the aorta to vertebra LII, terminating at the duodenojejunal flexure
49
Describe the locations of the jejunum and ileum
Jejunum: proximal 2/5ths of the small intestine (LUQ)
Ileum: distal 3/5ths of the small intestine (RLQ)
50
State the differences between the jejunum and ileum
- Walls: jejunum has a thicker wall with more prominent/frequent circular folds
- Lumen: jejunum larger
- Arterial arcades: more prominent in ileum
- Vasa recta: longer in the jejunum
- Mesenteric fat: larger in the ileum
51
Describe the parts of the large intestine
"1) Cecum: begins in the groin at the join of the ileum, with a small appendix at McBurney's point (1/3rd distance of the ASIS to the umbilicus)
2) Ascending colon: continuation of the large intestine to the right colic flexure below the liver
3) Transverse colon: (intraperitoneal) crosses the abdomen to the left colic flexure below the spleen
4) Descending colon: passes to the left groin
5) Sigmoid colon: associated with the sigmoid mesocolon and joins to the rectum
"
52
Explain what is meant by the omental appendices and taeniae coli of the large intestine
Omental appendices: peritoneal-covered accumulations of fat associated with the colon
Taeniae coli: segregation of longitudinal muscle into narrow bands
53
Describe the lymphatics of the abdomen and the locations of nodes
Lymphatics: follow arterial NOT venous supply, with all lymph draining to the cisterna chyli in front of L1/2 bodies where the thoracic duct commences
Node locations: coeliac trunk origin and around the origins of the superior and inferior mesenteric arteries
54
State the unpaired arteries of the anterior surface of the aorta and the viscera they supply
Coeliac trunk: foregut, liver, pancreas and spleen (splenic artery)
Superior mesenteric artery: midgut (2nd part of duodenum to 2/3rd along the transverse colon)
Inferior mesenteric artery: hindgut (distal 1/3rd of the transverse colon to the rectum)
55
State the branches of the coeliac axis and the viscera supplied
```
Left gastric artery: (small) supplies the stomach
Common hepatic artery (medium): supplies the stomach, liver and duodenum (via the gastroduodenal artery)
Splenic artery (large): supplies the spleen and branches to supply the pancreas
```
56
State the branches of the superior mesenteric artery and the viscera supplied
"Middle colic artery: supplies the transverse colon
Right colic artery: supplies the ascending colon
Ileocolic artery: supplies ascending colon and distal ileum
Ileal arteries: supply the ileum (shorter vasa recta and more prominent arterial arcades)
Jejunal arteries: supply the jejunum (longer vasa recta and less prominent arterial arcades)
"
57
State the branches of the inferior mesenteric artery and the viscera supplied
"Left colic artery: supplies the distal 1/3rd of the transverse colon and the descending colon
Sigmoid arteries: supply the sigmoid colon
Superior rectal artery: supplies the rectum
"
58
Describe the innervation of the abdominal viscera
ANS
PSNS: regulates reflexive gut function w/Vagus and Pelvic splanchnic (S2-4)
SNS Sensory: mediates pain - T5-L2
59
Catagorise the splanchnic nerves supplying the abdomen by spinal level
```
Greater Splanchnic: T5-9
Lesser Splanchnic: T10-11
Least Splanchnic: T12
Lumbar Splanchnic: L1-2
Pelvic Splanchnic: S2-4
```
60
Describe the route of the portal vein
Arises from the superior mesenteric and splenic veins posterior to 1st part of the duodenum, running in the free edge of the lesser omentum to the liver - drains blood from all abdominal viscera (spleen, pancreas, gall-bladder and GI tract) to the liver, where it forms branches
61
Describe how the splenic, SMV and LMV feed into the portal vein
"
Splenic vein: collects blood from the spleen, gastric veins, pancreatic veins and the inferior mesenteric vein
Superior mesenteric vein: collects blood from the small intestine, ascending colon and transverse colon
Inferior mesenteric vein: collects blood from the descending and sigmoid colon as well as the rectum, draining to the splenic vein
"
62
Describe the position of the liver
Largely right hypochondrium and epigastric, small extension to left hypochondrium
63
Describe the diaphragmatic and visceral surfaces of the liver
Diaphragmatic: anterior, superior and posterior directions; smooth and domed, lying against inferior surface of the diaphragm
Visceral: inferior direction; covered with visceral peritoneum except fossa for gallbladder and hepatic portal vein at the porta hepatis
64
State the four loves of the liver, and the structures that divide each
"Lobes: right, left, quadrate and caudateDivisions: - Anteriorly: falciform ligament splits the left and the right lobe- Quadrate: sits between the gallbladder and ligamentum teres- Caudate: sits between the IVC and ligamentum venosum
"
65
Describe the functional lobes of the liver
Left and right hepatic artery each supply half the liver, with the left functional lobe including the left and quadrate lobes and the right only the right lobeCaudate lobe functionally distinct
66
State the function of the porta hepatis
Carries the hepatic artery, portal vein, common bile duct and lymphatics into the liver
67
Describe the role of ligamentum teres and venosum
Ligamentum teres: remnant of the umbilical vein (anterior)
| Ligamentum venosum: remnant of the ductus venosus (posterior)
68
Describe the ligaments that are attached to the liver
- Falciform: attaches to anterior wall
- Hepatogastric: connects to stomach
- Hepatoduodenal: connects to duodenum
- R/L triangular & A/P coronary: attaches to diaphragm
69
Describe the hepatic blood supply
Blood supply: derived from coeliac trunk
- Splenic artery: forms posterior gastric, short gastric and gastro-omental arteries
- Common hepatic artery: forms the gastro-omental artery, gastroduodenal and right gastric- Left gastric artery
70
Describe the venous drainage to and from the liver
To: portal vein drains venous blood from GI tract and spleen to liver
IVC: drains blood from liver via three hepatic veins
71
Describe the role and sites of abodminal porto-systemic anatsomoses
Role: connect veins draining to IVC to those draining to portal venous system - may become dilated if portal flow obstructedSites:- Oesophageal vein (S) to left gastric (P)- Inferior rectal (S) to superior rectal (P) - Epigastric (S) to paraumbilical (P) - Retroperitoneal (S) to visceral (P)OesLGInferior2superior Epic paramedicRetro viscero
72
Describe the location and structure of the gall bladder
Location: pear shaped sac lying on the visceral surface between right and quadate lobes
Structure: rounded end (fundus), major part (body) and narrowing (neck) where mucosal folds form the spiral fold
73
State the arterial supply of the gallbladder
Cystic artery from right hepatic artery
74
Describe the structure of the biliary tree
Liver: left and right hepatic ducts form the common hepatic duct
Common bile duct: formed from the joining of the cystic and common bile ducts
Duodenal entrance: occurs at the major papilla in the second part after passing behind the head of the pancreas
Sphincter of Oddi: guards the ampulla of Vater
75
Describe how gallstones may enter the GI tract
If a cholecystoenteric fistula forms
76
Describe the attachment and location of the spleen
Attachment: suspended in dorsal foregut mesentery by gastro-splenic and spleno-renal ligaments
Location: posteriorly on left side under ribs 9-11
77
Describe the contents of the ligaments attached to the spleen
Splenorenal: contains splenic vessels and tail of the pancreas
Gastrosplenic: contains the short gastric and left gastro-omental vessels
78
Describe the organisation of the enteric nervous system
100m neurones extending the length of the GI tract arranged into ganglionated plexuses with interconnecting bundles of unmyelinated fibres
79
Recall the functions of the ENS and how the CNS can modulate its effects
ENS: reflexive absorption, mixing, gut movements
CNS: PSNS/SNS neurones can communicate with intrinsic neurones to modulate functions
80
Describe the two plexuses of the GI tract, and the lengths of tract they run along
```
Myenteric plexus (of Auerbach): found on the muscular layer of the GI tube beneath the serosa (runs oesophagus to anal canal)
Submucosal plexus (of Meissner): found within the submucosa (runs from the duodenum to the anal canal)
```
81
Describe the ANS supply to the abdomen, differentiating between the course of ANS nerves to the viscera and periphery
Motor: to smooth muscle and secretomotor to glands
SNS Afferents: pain
PSNS Afferents: stretch/functional sensation
ANS -> Viscera: run with arteries
ANS -> Periphery: run with somatic nerves
82
Describe the SNS innervation of the abdomen, recalling the ganglia and the organs they supply
Innervation: sympathetic trunk from T1-L2, carrying impulses to ganglia
- Coeliac: stomach, liver, pancreas, kidney and intestines
- Superior mesenteric: small intestine
- Inferior mesenteric and hypogastric plexus: colon, rectum, bladder and genitalia
83
Describe the PSNS innervation of the abdomen
PSNS: craniosacral outflow
- Vagus CNX: stomach, liver, pancreas, kidney and intestines
- S2-4: colon, rectum, bladder and genitalia
84
Recall the spinal levels that form each SNS splanchnic nerve
Greater splanchnic: T5-9
Lesser splanchnic: T10-11
Least splanchnic: T12
85
Describe the mechanism of referred pain
Cerebral cortex has no sensory map for visceral organs so cannot localise visceral pain sensation, and it is referred to dermatome supplied by same nerves
86
"Describe the region that foregut pain is referred "
(up to duodenal papilla) referred to the epigastric region (T7/T8); including stomach, proximal duodenum, pancreas, liver and gall bladder
87
"Describe the region that midgut pain is referred "
(from duodenal papilla to splenic flexure) referred to periumbilical region (T10)
88
"Describe the region that hindgut pain is referred "
(from splenic flexure) referred to suprapubic region (T12-L2) including descending/sigmoid colon, rectum and anal canal
89
Describe the pain of appendicitis
Inconsistent colicky pain begins in the umbilical region (as supplied by T10), and as becomes more inflamed, affects peritoneum surrounding it so becomes localised to right inguinal region (sharp and constant)
90
Recall the dermatomes of the abdominal wall
T7: immediately inferior to xiphoid process
T10: periumbilical region
T12-L2: inguinal region
91
List the primarily retroperitoneal organs
Kidneys, ureters, suprarenal glands, nerves, oesophagus, rectum, IVC and aorta
92
List the secondarily retroperitoneal organs
Pancreas, ascending colon, descending colon and 2nd/3rd parts of the duodenum
93
Describe the skeletal components of the pelvis, and the joints between each
"
Bones: sacrum, coccyx and hip bones (ileum, pubis and ischium)Joints:
- Pubic symphysis: secondary cartilaginous
- Sacro-iliac: synovial joint"
94
Describe the rami of the pelvis
Superior pubic: runs to the pubic tubercle to form the superior margin of the obturator foramen
Ischiopubic: composed of the inferior pubic ramus and the ramus of ischium, this forms the inferior margin of the obturator foramen
95
Describe the true pelvis and the axis of the pelvic cavity
True pelvis: inferior to the pelvic inlet
| Axis: 45 deg to that of the abdomen
96
"Muscles of the pelvic wall - Obturator Internus:
Origin: {{c1::anterolateral wall of the true pelvis}}
Insertion: {{c1::medial surface of the greater trochanter}}
Innervation: {{c1::L5/S1}}
Function: {{c1::lateral rotation of extended hip joint and abduction of flexed hips}}"
""
97
"Muscles of the pelvic wall - Piriformis:
Origin: {{c1::anterior surface of the sacrum between the anterior foramina}}
Insertion: {{c1::medial side of the superior border of the greater trochanter}}
Innervation: {{c1::S1/2}}
Function: {{c1::lateral rotation of the extended hip joing and abduction of flexed hips}}"
""
98
Describe the function and attachment of the ligaments of the pelvic wall
"Function: stabilises the sacrum on the pelvic bones to resist upward tilting
Sacrospinous ligament: triangular and attached to ischial spine and sacrum
Sacrotuberous ligament: triangular and superficial to the spinous, attaching broadly to the sacrum and coccyx and then at the apex to medial margin of the ischial tuberosity
"
99
Describe the foramina created by the ligaments of the pelvic wall, and the path of the pudendal nerve
"Greater sciatic foramen: superior to the sacrospinous ligament while anterior to the sacrotuberous ligament
Lesser sciatic foramen: inferior to the sacrospinous ligament and superior to the sacrotuberous
Pudendal nerve: travels posteriorly to the sacrospinous ligament, leaving the cavity via the greater sciatic forament, to re-enter in the lesser
"
100
Recall the differences between the pelvis of males and females
- Pelvic inlet: circular in females and heart shaped in males
- Pubic arch angle: 80-85deg in females, 50-60deg in males
- Ischial spines: project more medially in males
101
Describe the role of the pelvic floor
Formed by the pelvic diaphragm (levator ani and coccygeal muscles) and perineal muscles in mindline to support the pelvic viscera
102
Recall the muscles that comprise the levator ani and the openings present
Muscles: iliococcygeus, pubococcygeus and puborectalis
Openings: urethral, anal and vaginal
103
Describe the anatomy of the male urethra
1) Pre-prostatic part: 1.5cm; runs from the bladder to the top of the prostate
2) Prostatic part: 2.5cm; runs through the prostate
3) Membranous: 2cm; runs through the deep perineal pouch and perineal membrane
First 90o bend as exits membranous part; Second bend mid-way through spongy area when flaccid
4) Spongy part: 15cm runs from perineal membrane through spongy tissue to the external urethral orifice (narrowest region)
104
Describe the relevance of a male's urethral anatomy in relation to catherisation
Narrowings: external orifice, second bend, prostatic part
Catheterisation: urinary catheter must negotiate a 90o bend as passes from perineum to pelvis, and could get caught in the prostatic utricle
105
Describe the course of the male reproductive tract
1) Testes hang in scrotum2) Vas deferens run upwards in spermatic cord to enter superficial ring3) Vas deferens exit deep ring and run to the ejaculatory ducts with the seminal vesicles, emptying to the prostatic urethra4) Urethra enters corpus spongiosum
106
Describe the formation and contents of the spermatic cord
Formed by an extension of the oblique aponeurosis to carry the testicular artery, veins, ilioinguinal nerve and lumen of the vas deferens
107
Describe the structure and vascular supply to the testes
"Structure: spermatoxoa produced in seminiferous tubules that drain to the rete testis, then to the epididymis that runs to the base (first coiled head, then body and tail that runs superiorly to the ductus deferens)
Vasculature: testicular artery from the abdominal aorta
"
108
Describe the location of the prostate gland, seminal vesicles and bulbourethral glands
Prostate gland: surrounds prostatic (first) region of the urethra; male bladder directly superior
Seminal vesicles: located on posterior bladder, opening to ductus deferens between ampulla and ejaculatory duct
Bulbourethral glands: bilaterally located in the deep perineal pouch and open to the urethra; contribute to lubrication of the urethra and pre-ejaculation
109
Outline the anatomy of the prostate
"
Internal urethral sphincter: smooth muscle that is only well organised in males, SNS closes during ejeculation
Glandular elements: surround urethra to empty via small ducts
Prostatic utricle: small dead-end that can lodge tips of catheters
Ejaculatory ducts: empty to the urethral crest
External urethral sphincter: skeletal muscle at base of the prostate in deep perineal pouch above the membrane "
110
Describe the vascualar supply to the prostate, bladder and ductus deferens
Inferior vesicular artery: prostate, bladder and ductus deferens
Superior vesicular artery: bladder and ductus deferens
111
Describe the anatomy of the penis
"Erectile tissues: corpora cavernosa (form the crura) and corpus spongiosum (forms the bulb and contains the urethra
Root: crura (corp cav) attached to pubic arch and bulb anchored to the perineal membrane (corp spon)
Body: covered by skin and formed by tethering proximal corpora (cavernosa superior, spongiosum inferior)
Glans: part of the corpus spongiosum and contains the external urethral orifice
"
112
Describe the muscles of the penis
"Ischiocavernosus: moves blood from crura to body for erection (surrounds the corpora cavernosa) - attached to ischiopubic ramus
Bulbospongiosus: moves blood to the glands, causes the removal of residual urine from the urethra and allows pulsatile semen release (surrounds the corpus spongiosum - attached to perineal membrane)
"
113
Describe the neurovascular supply to the penis
Arteries: main supply from the internal pudendal artery
- Deep artery: supplies the corpora cavernosa
- Dorsal artery: supplies the skin and connective tissues
- Artery of the bulb: supplies the bulb, corpus spongiosum, glans and urethra
PSNS: allows helicine arteries to relax and allow flow to cavernous spaces to erect penis
SNS: causes ejaculation
114
Describe the structure of the perineum
"Diamond shaped area between pubic symphysis, ischial tuberosities and coccyx divided to anterior (urogenital) and posterior (anal) triangles
"
115
Describe the anatomy of the urogenital compartment
"Defined laterally by ischiopubic rami and anteriorly by the pubic symphysis, and the roof is formed by the levator ani
Perineal membrane: thick triangular fascial structure attached to pubic arch anteriorly but free posteriorly, forming the deep perineal space above it, and superficial space below it
"
116
Describe the anatomy of the anal compartment
Definition: medial margins of the sacrotuberous ligaments and posteriorly by the coccyx
Contents: external anal sphincter with deep, superficial and subcutaneous muscle bands
117
Describe the innervation of the perineum and male genitalia
Somatic: S2-4 pudendal nerve uses lumbosacral plexus to innervate perineum, penis and scrotum (sensory to skin and motor to perineal muscles)
PSNS: S2-4 to cause erectile tissue vasodilation
SNS: L1-2 to cause contraction of smooth muscles of epididymis/vas deferens/seminal vesicle and prostate for emission
118
Describe the nervous control of erection and ejaculation
1) Erection: PSNS uses pudendal to relax arterioles and allow blood flow to the cavernous spaces of erectile tissue
2) Secretion: stimulation of PSNS ganglia on prostate and seminal vesicles to produce secretion
3) Emission: SNS pathway activated to produce smooth muscle contraction of vas deferens, prostate and seminal vesicles (internal urethral sphincter contracts and bladder contraction prevented)
4) Ejaculation: entry of semen to urethra triggers somatic reflex via the pudendal nerve to cause bulbospongiosus muscle contraction
5) Detumescence: SNS nerves supplying pudendal arterioles are activated to cause arteriolar constriction, restricting flow to cavernous spaces
119
Describe the anatomy of the ischio-anal fossae
Wedge shaped gutters between levator ani and pelvic walls to allow movement of diaphragm and expansion of anal canal - normally filled with fat
Definition: superomedial wall is levator ani and superolateral wall is obturator internus
Neurovascular supply: pudendal bundle in lateral wall
120
Describe the course of the female urethra
Passes directly inferiorly from the bladder with a poorly developed internal sphincter, so the external is more developed (within the deep perineal pouch)
121
Describe the peritoneal covering of the female pelvic contents
Parietal peritoneum: continues to the pelvic cavity but does not reach the floor
Vesico-uterine pouch: peritoneal fold between the anterior uterus and bladder
Recto-uterine pouch: peritoneal fold between the posterior uterus and rectum
122
Describe the ligaments of the female pelvic viscera
"Broad ligament: transverse mesenteries joining the uterus to the pelvic walls and containing the tubes/arteries
Mesometrium: extends from lateral pelvic walls to body of uterus
Mesoalphinx: most superior part, suspending uterine tubes and arteries
Mesovarium: posterior extension to attach the ovary
Ligament of the ovary: fibromuscular band of tissue containing ovarian vessels (then continues medially to uterus)
Round ligament: passes through inguinal canal to labium majus
"
123
Describe the structure of the cervical ligaments
"Pubocervical: attaches to the pubic symphysis
Uterosacral: attaches to the sacrum
Transverse: most important, attaching to the pelvic wall and piriformis
"
124
Describe and draw the structure of the uterus and uterine tubes
"
Uterus: consists of fundus, body and cervix; thick-walled muscular organ between bladder and rectum
Uterine tubes: consists of infundibulum (attaches to ovary and rimmed with fimbriae to collect eggs), ampulla (main tube), isthmus (narrowing after uterus) and uterine (connects to uterus) parts
"
125
Describe the structures of the cervix and vagina
Cervix: fibro-muscular cylinder, with a canal lined by mucous secreting simple columnar epithelium - held in place by cervical ligaments
Vagina: stratified squamous non-keratinised epithelium; fornices occur at upper end (attached more superiorly than where cervix ends); urethra fused with anterior wall
126
Describe the angles created between the uterine, cervical and vaginal axes
Angle of anteversion: <=90o angle between the cervical and vaginal axes, which meet at a right angle
Angle of anteflexion: >90o angle between the uterine and cervical axes
127
Describe the arterial supply to the female pelvis
Vasculature: supplied by internal iliac arteries- Superior Vesical: supplies the bladder
- Inferior Vesical (Vaginal): supplies the vagina
- Middle Rectal: supplies the rectum
- Uterine: bifurcate so that ascending branch supplies the uterus, and the descending the cervix and vagina
128
Describe the superficial structures of the female genitalia
Vulva: clitoris, vestibular apparatus and skin folds form the vulva
Labia: minora formed from thin skin folds that bifurcate, forming the frenulum; majora are broad folds that unite anteriorly to form the mons pubis superficially to the pubic symphysis
Hymen: thin mucosal fold that is normally perforated at the centre and torn after intercourse or child birth
129
Describe the attachments and function of the external urethral sphincter, compressor urethrae and sphincter urethrovaginalis
"External urethral: surrounds the urethra to compress the membranous urethra because the internal sphincter is less well developed in females
Compressor urethrae: attaches to the ischiopubic rami to stabilise the position of the perineal body
Sphincter urethrovaginalis: accessory sphincter
"
130
Outline the erectile tissues of the female and their associated muscles
Corpus cavernosum: attached to ischiopubic rami and surrounded by ischiocavernosus muscles
Corpus spongiosum: attached to the perineal membrane and surrounded by the bulbospongiosus muscles (also forms the glans clitoris)
131
Describe how the angle between the rectum and anal canal is formed
Puborectalis muscle forms a sling around the rectum to produce a 90deg angle, so damage leads to incontinence
132
Describe the boundaries of the ischio-anal fossae
Base: skin
Medial wall: anal canal and levator ani
Lateral wall: obturator internis and ischial tuberosity
133
Explain what is meant by variocele
Abnormal dilation of the pampiniform plexus of veins (e.g. due to defective valves or compresion by nearby structures) leads to scrotal swelling
134
Recall the arterial supply to the rectum
1) Superior Rectal (Inferior Mesenteric Artery)2) Middle Rectal (Internal Iliac Artery)
3) Inferior Rectal (Internal Pudendal)
135
Recall the cervical ligaments
Pubocervical ligament: pubis to cervix
Transverse ligament: attaches to wall - contains uterine artery to supply the uterus
Uterosacral ligament: attaches uterus/cervix to sacrum
136
Recall the openings (Os') of the cervix
Internal os: opening between body of the uterus and cavity of the cervix
External os: connection between the cervix and the vagina
