Anatomy - Theory Flashcards
1
Q
What is the term given to the muscles involved in chewing?
A
Muscles of mastication
2
Q
Which cranial nerve innervates the muscles of mastication?
A
Trigeminal nerve (CN V)
(CN V3 - only the third division is motor and innervates these muscles)
3
Q
What are the 4 pairs of muscles involved in chewing and what is the role (opening/closing) of each?
A
Masseter - closing
Temporalis - closing
Medial pterygoid - closing
Lateral pterygoid - opening
4
Q
Where are the attachement sites for the temporalis muscle?
A
Coronoid process of the mandible to the temporal fossa
5
Q
Where are the attachment sites for the masseter?
A
Angle of the mandible to the zygomatic arch
6
Q
What are the attachment sites of the lateral pterygoid?
A
Pterygoid plates of the sphenoid bone to the cartilagenous articular disc at the temporal mandibular joint
7
Q
What are the attachment sites of the medial pterygoid?
A
Angle of the mandible to pterygoid plates of the sphenoid bone
8
Q
Where does the trigeminal nerve originate and why is this unique?
A
The pons
It is the only cranial nerve to be associated with the pons
9
Q
Where do the two sensory divisions of the trigeminal nerve travel to after division?
A
Eyes and maxillary region
10
Q
The 3rd division of the trigeminal nerve heads where?
A
This is the mandibular division and heads straight down out of the cranium
11
Q
Where does the mandibular division of the trigeminal nerve exit the skull?
A
Foramen ovale
12
Q
The posterior 1/3rd of the tongue is within the oropharynx so is therefore innervated by which cranial nerve?
A
Glossopharyngeal
CN IX
13
Q
At which point does the anterior 2/3rd of the tongue begin and what is the name given to the tip of this region?
A
Terminal sulcus
Tip - foramen caecum
14
Q
Which cranial nerve confers taste to the tongue?
A
Facial nerve
(CN VII)
15
Q
Which cranial nerve confers general sensation to the tongue?
A
Mandibular division of the trigeminal nerve
(CN V3)
16
Q
What is the only form of papillae that confers general sensation?
A
Filiform
17
Q
Where does the facial nerve depart from the CNS?
A
The lateral aspect of the junction between the pons and medulla
18
Q
The facial nerve exits the cranium via which foramen?
A
Internal acousic meatus, then exits via stylomastoid foramen
19
Q
What is the name of the branch of the facial nerve that innervates the tongue and provides the sensation of taste?
A
Chorda tympani
(named as it passed through the typanic cavity)
20
Q
How does the chorda tympani reach the tongue?
A
It exits the middle ear and travels with the lingual nerve to enter the tongue
21
Q
The superior half of the oral cavity has general sensation due to which cranial nerve?
A
CN V2
(Trigeminal nerve)
22
Q
The inferior half of the oral cavity has its general sensation due to innervation by which cranial nerve?
A
Trigeminal
(CN V3)
23
Q
The sensory compinent for a gag reflex is conferred by which cranial nerve?
A
Glossopharyngeal
CN IX
24
Q
The motor component of the gag reflex is controlled by which cranial nerve(s)?
A
Glosspharyngeal CN IX
Vagus CN X
25
How does CN V2 exit the cranium?
The foramen rotundum in the sphenoid bone
26
Which modalities does CN V2 confer?
Only sensory
27
Where does the glosspharyngeal nerve exit the CNS?
The medulla
28
How does the glosspharyngeal nerve exit the cranium?
Jugular foramen
29
After exiting the cranial cavity, what path does the glosspharngeal nerve take next?
It passes down the back of the neck
30
What does the glossopharngeal nerve innervate?
* Tongue (posterior 1/3rd)
* Palate
* Nasopharynx
* Posterior wall of oropharynx
* Parasympathetics to paratid salivary glands
etc.
31
Which cranial nerve innervates the parotid gland?
Glossopharyngeal
CN IX
32
Which cranial nerve innervates the submandibular glands?
Facial nerve
CN VII
33
Where do the submandibular glands secrete salviva into the mouth?
Lingual caruncle
34
Which cranial nerve innervates the subligual glands?
Facial nerve
CN VII
35
What are the four extrinsic muscles of the tongue?
* Genioglossus
* Hypoglossus
* Palatoglossus
* Styloglossus
36
The extrinsic muscles of the tongue are all innervated by which cranial nerve, and what is the one exception?
Hypoglossal nerve
CN XII
(this nerve is exclusively motor)
Palatoglossus - innervated by the vagus nerve (CN X)
37
The hypoglossal nerves come off the CNS at which point?
Medulla
38
How does the hypoglossal nerve exit the cranial cavity?
Hypoglossal foramen
| (in anterior wall of foramen magnum)
39
After exiting the cranial cavity via the hypoglossal foramen, which path does the hypoglossal nerve take next?
It descends in the neck lateral to the carotid sheath
At the level of the hyoid bone it will move anteriorly to the lateral aspect of the tongue to supply the musculature
40
What are the two muscular components of the pharynx?
1. Circular
2. Longitudinal
41
What are the three constrictor muscles in the pharynx?
1. Superior
2. Middle
3. Inferior
42
What is the "proper" name for the upper oesophageal sphincter and where eactly is it located?
Cricopharyngeus
At the level of the cricoid cartilage
43
Which cranial nerve innervates all of the muscles of the pharynx?
Vagus nerve
CN X
44
Longitudinal muscles of the pharynx serve what purpose?
Pull up the pharynx
| (utilised in swallowing)
45
Describe the process of swallowing
1. Tongue pushes food towards oropharynx - CN XII
2. Soft palate and larynx elevate - CN IX and CN X
3. Circular layer of pharyngeal constrictor muscles contract - CN X
4. The bolus of food enters the oesophagus
46
At which vertebral level does the oesophagus commence?
T6
47
Laterally to the oesophagus at each side, which cranial nerve will be found?
Vagus nerve
CN X
48
The oesophageal plexus contains which types of nerves?
Parasympathetic - can influence smooth muscles in oesophageal wall
Sympathetic - from splanchnic nerves which can influence the enteric nervous system to speed up or slow down peristalisis
49
The lower oesophageal sphincter is a physiological sphincter
True or false?
True
50
There is a change in the mucosa between the oesophagus and stomach - what is the division line between them called?
Z-line
51
Why may the stomach sag in a lean person?
Lack of supportive fat tissue
52
In which region does the stomach lie?
Left hypochondrium
53
What are rugae?
Folds within the stomach that allow for expansion
54
What is the entrance area of the stomach called?
Cardia
55
What is stored in the pyloric antrum?
Chyme
56
What is the name given to the angle of the lesser curvature of the stomach?
Incisura angularis
57
The small intestine is made up of which three section?
1. Duodenum
2. Jejunum
3. Ileum
(DJ Ileum)
58
What is the caecum?
A pouch connecting the small and large intestines
59
The foregut contains which organs?
* Oesophagus to mid-duodenum
* Liver and gallbladder
* Spleen
* 1/2 of pancreas
60
The midgut contains which organs?
* Mid-duodenum to proximal 2/3rd of transverse colon
* 1/2 of pancrease
61
The hindgut conatins which organs?
Distal 1/3 or transverse colon to proximal 1/2 of anal canal
62
What is abdominal "guarding"?
When the abdomnial muscles contract to protect the internal organs after injury or infection
63
What is the peritoneum and where is it located?
It is a thin, transparent, semi-permeable serous membrane
It lines the walls of the abdominopelvic cavity and organs
64
The peritoneal cavity if formed from what?
Visceral and serous peritoneum
65
Where is the only opening in the human anatomy in the peritoneum?
Ovaries
66
Organs can be classed based on their relationship with the peritoneum. What are these classifications?
* Intraperitoneal
* Retroperitoneal
* With a mesentery
67
What is the mesentery of the small intestine called?
Mesentery proper
68
What is a mesentery?
A double layer of peritoneum with a core of blood and lymph vessels
69
Aside from the mesentery proper, what other mesenteries can be found?
* Transverse and sigmoid mesocolon
* Mesoappendix
70
What is the greater omentum?
A four layered structure that attaches to the greater curvature of the stomach and hangs down to the transverse colon
It has a role in preventign spread of infection
71
What is the lesser omentum?
A doube layer of peritoneum that extends down from the liver to the lesser curvature of the stomach and the first part of the duodenum
72
The connection the lesser omentum makes with the liver and lesser curvature of the stomach is called what?
Hepatogastric ligament
73
The connection the lesser omentum makes with the liver and first part of the duodeum is called what?
Hepatoduodenal ligament
74
What is the foramen of Winslow?
This is the free edge of the lesser omentum which provides a passage between greater and lesser sacs
75
In the free edge which structures lie?
The portal triad containing:
* Proper hepatic artery
* Hepatic portal vein
* Common bile duct
* Lymphatic vessels
* Branch of the vagus nerve
76
Which ligament joins the stomach and the spleen?
Gastrosplenic ligament
77
Which ligament joins the spleen and kidney?
Splenorenal ligament
78
The peritoneum can drape over the superior aspects of the pelvic organs creating pouches.
What are these pouches in males and females?
Males:
* Rectovesicle pouch
Females:
* Vesicouterine pouch
* Rectouterine pouch (pouch of Douglas)
79
What is acities?
Collection of fluid in the peritoneal cavity
80
What may cause acities?
* Liver cirrhosis
* Portal hypertension
81
What is an abdominocentesis?
A drainage process for acities
A needle is inserted laterally to the rectus sheath - avoids epigastric artery
Ultrasound guidance may be utilised
82
Sympathetic nerve fibres for the adrenal gland typically leave the spinal cord at which vertebral level?
T10/11
83
Where is pain felt for the flooing areas:
1. Foregut
2. Midgut
3. Hindgut
1. Epigastric
2. Umbilical
3. Pubic
84
Visceral afferents from:
* Foregut
* Midgut
* Hindut
Enter the spinal cord at which vertebral levels?
1. T6-9
2. T8-12
3. T10-L2
85
Where is the appendix usually located?
Right iliac fossa
86
Where is pain initially felt for apendicitis and why will it move?
Initially - umbilical region
Over time the appendix irritates the parietal peritoneum in the right iliac fossa and this is part of the body wall
Pain will now change from dull and aching to sharp and stabbing
87
What is a laparotomy?
A single midline verticle incision used for gastrointestinal and obstetrics surgies.
88
What does an increase in the blood levels of bilirubin lead to?
Yellowing of the sclera (whites of eyes) and skin
This is called jaundice
89
Where does bilirubin come from?
It is a normal breakdown product of red blood cells which ocurs mainly in the spleen
90
Why is bilirubin required for the body?
For the formation of bile
91
Which organ can store bile and therefore regulate the released concentration?
Gallbladder
92
In which quadrant is the liver housed?
Right upper quadrant
| (protected by ribs 7-11)
93
What are the four lobes of the liver?
1. Left
2. Right
3. Quadrate
4. Caudate
94
What is the name of the entrance for portal triad structures in the liver?
Porta hepatis
95
Within the potal triad, which three structures are contained?
1. Hepatic portal vein
2. Hepatic artery proper
3. Common hepatic bile duct
96
How many functional lobes exist within the liver?
8
| (there are only 4 anatomical lobes)
97
Each segment in the liver has its own what?
1. Branch of hepatic artery
2. Brach of hepatic portal vein
3. Bile drainage to bile duct
4. Venous drainage to vena cava
98
Why is central venous pressure directed at the liver?
The inferior vena cava and hepatic veins lack valves
99
The hepatoduodenal ligament houses which structures?
The portal triad
1. Hepatic artery proper
2. Hepatic portal vein
3. Common hepatic bile duct
100
The lesser omentum is joined by which two ligaments?
1. Hepatoduodenal ligament
2. Hepatogastric ligament
101
Which is the first of the three midline branches off from the aorta?
Coeliac trunk
102
At which vertebral level does the coeliac trunk leave the aorta?
T12
103
Which artery is reponsible for supplying the foregut organs?
The coeliac trunk
104
Which branches doe the coeliac trunk divide?
* Splenic artery
* Common hepatic artery
* Left gastric artery
105
Which quadrant is the spleen located?
Left hypochondrium
| (protected by ribs 9-11)
106
Which arteries supply the stomach at the lesser curvature?
Right and left gastric arteries (anastomose together)
107
Where does the posterior gastric artery originate?
Splenic artery
108
Which arteries supply the stomach at the greater curvature?
Right and left gastro-omental arteries (anastomose together)
109
What is the arterial blood supply to the liver and where do these vessels originate?
Right and left hepatic arteries
(Comes from common hepatic artery...
...which comes from coeliac trunk)
110
Most of the blood in the liver comes from which vessel?
Hepatic portal vein
111
What is the dual blood supply of the liver?
1. Hepatic arteries (left and right)
2. Hepatic portal vein
112
The peritoneal cavity is related to the liver in which two ways?
1. Hepatorenal recess (Morison's pouch)
2. Sub-phrenic recess
113
What is the term given to fluid build-up in the peritoneum?
Ascities
114
The hepatic portal vein is formed from which veins?
* Splenic vein
* Superior mesenteric vein
(the inferior mesenteric vein firstly drains into the splenic vein)
115
Which duct allows for bile to flow in and out of the gallbladder?
Cystic duct
116
What is the blood supply to the gallbladder and what is this a branch of?
Cystic artery
(branch of right hepatic artery in most people)
117
Where will pain be felt if the gallbladder is the site of injury, and why will pain be felt there?
Epigastric region
Visceral afferents enter the vertebral level at T6-9
(pain may be felt in the hypochondrium and it can also radiate to the shoulder)
118
What is the term given to surgical removal of the gallbladder?
Cholecystectomy
119
Which part of the duodenum (1, 2, 3 or 4) does the biliary tree enter?
2
120
What is formed when the right and left hepatic ducts come together?
Common hepatic duct
121
When the common hepatic duct joins with the cystic duct, what duct is formed?
Bile duct
122
What are the four parts of the duodenum?
1. Superior
2. Descending
3. Horizontal
4. Ascending
123
Which sphincter muscle signifies the start of the duodenum?
Pyloric sphincter
124
Which peptide hormones are released in the duodenum?
* CCK
* Gastrin
125
Pain from the duodenum presents in which region?
Epigastric
126
The pancreas is an intraperitoneal organ.
True or false?
False
It is a retroperitoneal organ
127
What are the four parts of the pancreas?
1. Head (and uncinate process)
2. Neck
3. Body
4. Tail
128
The pancreas has two main functions, describe each
1. Endocrine function - blood system - islets of Langerhans - isulin and glucagnon
2. Exocrine function - duct system - acinar cells - pancreatic digestive enzymes into main pancreatic duct
129
What is the name of the joint between the main pancreatic duct and the the bile duct?
Ampulla of Vater
| (Hepatopancreatic ampulla)
130
What is the point entry for the Ampulla of Vater into the duodenum called?
Major duodenal papilla
131
If there is a minor duodenal papilla, what is this due to?
Entry of accessory pancreatic ducts
132
What controls the flow of bile in the biliary system?
Sphincter muscles
* Bile duct sphincter
* Panceatic duct sphincter
* Sphincter of Oddi - major duodenal papilla
*
133
What is ERCP?
Endoscopic Retrograde Cholangiopancreatography
The endoscope enters through the oral cavity, into the stomach and duodenum
It is sued to study the pancreas and biliary tree
A camera can even be instered into the major duodenal papilla
134
What may be the cause of jaundice in relation to the biliary tree?
* Obstruction in the biliary tree (gallstones, carcinoma)
* Physiological jaundice in newborn infants
135
By which other name is jaundice known?
Icterus
136
Where does the blood supply for the pancreas originate?
Coeliac trunk
Superior mesenteric artery
137
Which two vessels anastomose when supplying the pancreas?
Coeliac trunk and SMA
The superior pancreaticoduodenal artery comes from the coeliac trunk and the inferior pancreaticoduodenal artery comes from the SMA - it is these vessels which anastomose directly
Both vessels split into anterior and posterior portions to sandwich the pancreas
138
How does the splenic artery contribute to pancreatic blood supply?
Dorsal pancreatic arteries supply the pancreas
These are branches from the splenic artery
139
Where will pancreatic pain be felt?
Epigastric region
(potentially umbilical region)
Pain can radiate to the back
140
Blockage of the ampulla of Vater by a gallstone will result in what?
Bile will be diverted to the pancreas
This can cause acute pancreatitis as bile reflux and pancreatic juice enters into the main pancreatic duct
141
In severe cases of pancreatitis what can occur and what signs can show this?
Vascular haemorrhage
Blood travels into the retroperitoneal space and manifests at the two signs below
142
Which parts of the duodenum are foregut?
1 and 2
143
Where does the jejunum begin?
Duodenaljejunal flexure
144
Where does the ilieum end?
Ileocaecal junction
145
How does the jejunum differ from the ileum in terms of colour?
Jejunum - deep red
Ileum - lighter pink
146
How does the jejunum differ from the ileum in terms of their walls?
Jejunum - thicker and heavier
Ileum - thinner and lighter
147
How does the jejunum differ from the ileum in terms of vascularity?
Jejunum - more vascular
Ileum - less vascular
148
How does the jejunum differ from the ileum in terms of the amount of mesenteric fat?
Jejunum - less mesenteric fat
Ileum - more mesenteric fat
149
How does the jejunum differ from the ileum in terms of the circular folds in the lumen?
Jejunum - large, tall and closely packed folds
Ileum - low and sparse folds which becoem absent distally
150
How does the jejunum differ from the ileum in terms of lymphoid tissue?
Jejunum - Peyer's patches present
Ileum - Peyer's patches not present
151
How does the jejunum differ from the ileum in terms of absorptive function?
Jejunum - most absorptive function
Ileum - less absorptive function
152
What is the blood supply to the jejunum and ileum?
Superior mesentic artery
| (Via jejunal and ileal arteries)
153
What is the venous drainage from the jejunum and ileum?
Jejunal/ileal veins to superior mesenteric vein
154
What is the name given to the loops of arteries around the jejunum and ileum?
Arterial arcades
(intermesenteric arterial anastomoses or Riolan arcades)
155
At which vertebral level does the superior mesenteric artery leave the aorta?
L1
156
Describe the path of the superior mesenteric artery
It travels posterior to the neck of the pancreas, and anterior to the uncinate process of the pancreas
It can then enter the mesentery proper
157
What is a lacteal?
A specialised lymph vessel in the small intestine to pick up chylomicrons
158
What are the main lymph nodes associated with the abdomen?
* Celiac - forgut
* Superior mesenteric - midgut
* Inferior mesenteric - hindgut
* Lumbar - kidneys, posterior abdomen wall, pelvis and lower limbs
159
The left venous angle is associate with lymphatic drainage from the ___________ \_\_\_\_\_
Thoracic duct
160
The right venous angle is associated with lymphatic drainage from the _______ \_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_
Right lymphatic duct
161
What are the three main functions of the large intestine?
1. Defence - commensal bacteria
2. Absorption - H2O and electrolytes
3. Excretion - of formed stool
162
The caecum is retroperitoneal
True or false?
False
The caecum is intraperitoneal
163
What are paracolic gutters and where do they lie?
They form part of the greater sac of the peritoneal cavity
They lie between the lateral edge of the ascending and descending colon and the abdoninal wall
164
What are the small fatty deposits on the wall of the colon called?
Omental appendices
165
The three longitudinal muscle bands on the large intestine have what collective name?
Teniae coli
166
What is the name of the individual pouches that make up the colon and how are they formed?
Haustra
Formed due to contraction of the teniae coli
167
Where do the caecum and appendix lie?
Right iliac fossa
168
Where is the most common location for the appendix?
Retrocaecal
(there are many variations for its location)
169
What is the point at which the appendix joins the caecum?
Appendiceal orifice
170
How is the ileocaecal valve distinguishable within the caecum?
It is invaginated within the caecum giving a lipped appearance on the inside
171
Which surface anatomy point corresponds to the location of the appendiceal orifice?
McBurney's point
172
How is McBurney's point found?
It is 2/3rd of the way from the umbilicus to the anterior superior iliac spine
173
Where does the sigmoid colon lie?
Left iliac fossa
174
The sigmoid colon has a mesentery which can potentially cause what?
A sigmoid volvulus
This is twisting of the sigmoid colon causing bowel onstruction and potentially infarction
175
What are the three midline branches of the abdominal aorta?
1. Coeliac artery
2. Superior mesenteric artery
3. Inferior mesenteric artery
176
What are the lateral branches of the abdominal aorta?
* Renal arteries
* Gonadal arteries
* Lumbar arteries
177
Which vessels doe the abdominal aorta bifurcate to create?
Common iliac arteries
(which bifurcate further to produce the internal and external iliac arteries)
178
Name the branches of the superior mesenteric arteries and the areas they provide
1. Inferior pancreaticoduodenal artery - pancreas and duodenum
2. Middle colic artery - transverse colon
3. Right colic artery - ascending colon
4. Ileocolic artery
5. Jejunal and ileal arteries
179
How does the structure of the blood vessel supply to the jejunum and ileum differ?
* The jejunum has longer vasa rectae and larger and fewer arcades
* The ileum has shorter vasa rectae and many arcades
180
The inferior mesenteric artery is given of at which vertebral level?
L3
181
Which branches does the inferior mesenteric artery give off?
* Left colic artery
* Sigmoidal artery - supplies sigmoid colon
* Superior rectal artery
182
What is the name of the anastomosis formed between the SMA and IMA branches?
The marginal artery of Drummond
183
Why is the marginal artery of Drummond useful?
In the case of blockage, it provides many alternative routes for blood to take preventing ischaemia
184
The hindgut extends to which anatomical line?
Pectinate line
185
If the ther superior rectal artery supplies down to the pectinate line, which vessel(s) suupply the area below the pectinate line?
Middle and inferior rectal arteries
(these are branches of the internal iliac artery)
186
Where are the 3 main portal-systemic anastomosis
1. Oesophagus (distal end)
2. Skin around umbilicus
3. Rectum/anal canal
187
What allows for the anastomosis between portal and systemic circulations?
Small collateral vessels that can flow in both directions due to the absence of valves
188
Describe the venous drainage of the rectum
Above pectinate line:
Superior rectal vein to IMV
Below pectinate line:
Middle and inferior rectal veins to internal iliac vein
189
Why can the portal-systemic anastomoses become varicosed?
Portal hypertension
190
What is the term given to the dilation of para-umbilical and epigastric veins called?
Caput medusa
191
Haematemesis occurs as a result of what?
Peptic or duodenal ulcers that erode through the mucosa causing the stomach to fill with blood
(varices may also cause this due to their thin walls)
192
The pelvic cavity lies between which two things?
Pelvic inlet and pelvic floor
193
Which muscle helps form the pelvic floor?
Levator ani muscle
194
At which vertebral level does the sigmoid colon become the rectum?
S3
195
What is the rectal ampulla?
Dilated section of the rectum immediately superior to the levator ani muscle and anal canal
196
What is the purpose of the rectal ampulla?
Its walls can relax to hold faeces
Sphincter muscles can hold faeces here until it is appropriate to defecate
197
Which folds does the rectum have?
* Superior
* Middle
* Inferior
198
Which muscles make up the levator ani?
1. Iliococcygeus
2. Pubococcygeus
3. Puborectalis
199
Why are pelvic organs continually supported?
The muscles of the levator ani continually support the pelvic organs due to tonic contraction
200
Which nerve innervates the levator ani muscle?
Nerve to levator ani
This is a branch of the sacral plexus combines with the pudendal nerve (S2, 3 and 4)
201
Which type of muscle is the levator ani composed of?
Skeletal muscle
202
What role does the puborectalis have?
It maintains continence by looping round the anal canal creating a kink and decreasing the anal angle
203
How mnay anal sphincters exist?
2
* Internal
* External
204
The pectinate line is an embrylogical remnant of what?
Where the endoderm and ectoderm came together
205
What stimulates contraction/relaxation of the internal anal sphincter?
The autonomic nervous system
206
Contraction of the external anal sphincter is conferred by which nerve?
Pudendal
207
How does the nerve supply vary between the pelvic cavity and perineum?
Pelvic cavity - within a body cavity - ANS, visceral afferent
Perineum - within body wall - somatic motor and sensory
208
Where does sympathetic thoracolumbar outflow come from (for rectum/anal canal), and what influence does it have?
T12-L2
Travels to inferio mesenteri ganglia, then via periarterial plexuses around the branches of the IMA
It allows for the contraction of the internal anal sphincter and inhibition of peristalsis
209
Where does parasympthic sacral outflow come from (for rectum/anal canal), and what influence does it have?
S2-S4
Nerves synapse in the walls of the rectum
It allows for the inhibition of the internal anal sphincter and allows for the stimulaion of peristalsis
210
Where do visceral afferents travel to from (for rectum/anal canal), and what influence does it have?
S2-S4
They run with parasympathetics
They allow for sensation of stretch, ischaemia etc to be transmitted
211
Where do somatic motor nerve come from (for rectum/anal canal), and what influence does it have?
Pudendal nerve (S2-S4) and nerve to levator ani (S3 and S4)
It allows for the contraction of the external anal sphincter and puborectalis
212
How does the pudendal nerve enter the pelvis?
Via the greater sciatic foramen
213
How does the pudendal nerve enter the perineum?
Via the lesser sciatic foramen
214
During childbirth, which two structures are most likely to be damaged?
* Pudendal nerve
* Puborectalis
215
How does arterial supply differ above the pectinate line and below it?
Above - IMA
Below - Internal iliac artery
216
How does venous drainage differ above the pectinate line and below it?
Above - IMV (then to portal system)
Below - Internal iliac vein (then to systemic system)
217
How does lymphatic drainage differ above the pectinate line and below it?
Above - Inferior mesenteric nodes
Below - Superficial inguinal nodes
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What are the main groups of lymph nodes in the pelvis?
Internal iliac - inferior pelvic structures
External iliac - lower limb and more superior pelvic structures
Common iliac - drains external and internal iliac nodes to lumbar nodes
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Describe the difference between rectal varices and haemorrhoids
Rectal varices - form due to portal hypertension - they are the dilaatation of collateral veins between the portal and systemic systems
Haemorrhoids - prolapses of rectal venous plexuses
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What causes haemorrhoids?
Raised intra-abdominal pressure
e.g. chronic consipation, pregancy etc
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Which type of haemorrhoids, internal or external, are more painful and why?
External
They have somatic innervation
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What is an ischioanal fossa?
A fat filled space with loose connective tissue that allows for expansion during defecation, it also provides protection for nerves
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What is most important during a digital rectal examination
* To assess anal tone
* Palpate prostate - should not feel
* Palpate cervix - should not feel
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What is a proctoscopy?
A technique to view the interior of the rectum using an endoscope
