Anatomy Flashcards
(176 cards)
1
Q
Jaw opening occurs at which location (2)
A
Temporomandibular joint
Located at temporal bone, articular tubercle and head of condylar process
2
Q
3 pairs of jaw closing muscles
A
Masseter
Temporalis
Medial Pterygoid
3
Q
Pair of jaw opening muscles
A
Lateral Pterygoid
4
Q
What nerve supplies the jaw muscle pairs (2)
A
Mandibular division of trigeminal nerve (3rd division) - CN V3
Contains sensory and motor fibres
5
Q
Course of CN V3 (3)
A
From pons
Through foramen ovale
To muscles of mastication (chewing) and sensory area
6
Q
Vestibule of oral cavity location
A
Between lips and teeth
7
Q
Adult dentition (4)
A
32 teeth
All erupt by age 18
Consists of 4 quadrants (Upper left, upper right, lower left, lower right)
Incisor (1 and 2), Canine (3), Premolars (4 and 5), Molars (6 to 8)
8
Q
Why ask for loose teeth/fillings
A
For choking hazard or aspiration risk
9
Q
Major salivary glands types and locations in mouth (3)
A
Parotid - Duct arises at buckle of 2nd molar
Submandibular - Arises at frenulum of tongue
Sublingual - Under tongue
10
Q
Sensation of superior half of oral cavity (2)
A
Sensation of CN V2
At gingiva of oral cavity and palate
11
Q
Sensation of inferior half of oral cavity (2)
A
Sensation of CN V3
At gingiva of oral cavity and floor of mouth
12
Q
Course of CN V2 (3)
A
Has sensory fibres from pons
Through foramen ovale
To sensory area
13
Q
Spraying a local anaesthetic in oral cavity blocks AP in which nerves (4)
A
CN V2
CN V3
CN VII
CN IX
14
Q
Anterior 2/3 tongue sensation (4)
A
Horizontal
In oral cavity
General sensory mediated by CN V3
Special sensory mediated by CN VII
15
Q
Posterior 1/3 tongue sensation (3)
A
Vertical
Not in oral cavity
General and sensory mediated by CN IX
16
Q
Components and course of CN VII (3)
A
Has special sensory, sensory, motor and parasympathetic fibres
From pontomedullary junction
Travel through temporal bone via internal acoustic meatus then stylomastoid foramen
17
Q
CN VII supplies (3)
A
Taste anterior 2/3 of tongue
Muscles of facial expression - Via chorda tympani branch
Glands in floor of mouth
18
Q
4 pairs of tongue extrinsic muscles and function
A
Palatoglossus Styloglossus Hyoglossus Genioglossus Changes position of tongue during speech, mastication and swallowing
19
Q
4 pairs of intrinsic skeletal muscle location and function
A
Located mainly dorsally/posteriorly
Modify the shape of the tongue during function
20
Q
Supply of tongue muscle (2)
A
CN XII
EXCEPT palatoglossus
21
Q
Components and course of CN XII (4)
A
Has motor fibres
From medulla
Through hypoglossal canal
To extrinsic and intrinsic muscle of tongue
22
Q
Components and course of CN XII (4)
A
Has motor fibres
From medulla
Through hypoglossal canal
To extrinsic and intrinsic muscle of tongue
23
Q
Upper oesophageal sphincter location
A
Anterior to C6
24
Q
Longitudinal muscles of pharynx features (6)
A
Inner layer Supplied mainly by CN X and IX Elevate pharynx and larynx Attaches to larynx too Contract to shorten pharynx Raises larynx to close over the laryngeal inlet
25
Anatomy of swallowing (5)
Close lips to prevent drooling
Tongue pushes the bolus posteriorly towards the
oropharynx
Sequentially contract the pharyngeal constrictor muscles to push the bolus inferiorly towards the oesophagus
At same time the inner longitudinal layer of pharyngeal muscles contracts to raise larynx, shortening the pharynx and closing
off the laryngeal inlet to help prevent aspiration
The bolus reaches the oesophagus
26
Oesophagus (3)
Inferior continuation of laryngopharynx
Begins at inferior edge of cricopharyngeus muscle (vertebral level C6)
Has an anatomical upper sphincter (cricopharyngeus) and a physiological lower oesophageal sphincter
27
Oesophageal plexus (5)
Runs on smooth muscle surface within walls
Contains parasympathetic and sympathetic nerve fibres
Parasympathetic speeds up peristalsis
Sympathetic reduces peristalsis
Terminates by entering stomach cardia
28
Oesophageal constriction points (3)
Cervical constriction - Cricopharyngeus muscle
Thoracic constriction - At aortic arch and left main bronchus
Diaphragmatic constriction - At T10, result of passing through diaphragm
(Lower oesophageal sphincter)
29
Lower Oesophageal Sphincter (4)
Physiological
Sphincter effect caused by diaphragm contraction, higher intrabdominal then intragastric pressure, oblique angle where oesophagus meets stomach cardia
30
Stomach location and shape
Lies in left hypochondrium, epigastric and umbilical regions when the patient is supine
J shaped - 50 to 1000 ml capacity
31
Presence of hiatus hernia and lower oesophageal sphincter (3)
Increases reflux occurrence
Lies immediately superior to gastro-oesophageal junction
Abrupt change in mucosa lining type - Forms Z line
32
Large intestine from proximal to distal features (9)
Caecum => Appendix => Ascending colon => Transverse colon => Descending colon => Sigmoid colon => Rectum => Anal canal => Anus
33
All organs in each foregut, midgut or hindgut region are supplied by (4)
Arterial blood from common artery
Venous drain from common vein
Lymphatic drainage via shared route
Nerve supply from common route
34
9 abdominal regions
```
Left/Right Hypochondrium
Epigastric
Left/Right Lumbar (Flank)
Umbilical
Left/Right Inguinal (Iliac fossa)
Pubic (Suprapubic)
```
35
4 abdominal quadrants
Right/Left Upper Quadrants
| Right/Left Lower Quadrants
36
Peritoneal Cavity characteristics (5)
Thin, transparent, semi permeable serous membrane
Continuous lining of abdominopelvic cavity wall
Is in contact with body wall (soma) is parietal and with the organs is visceral - Has peritoneal cavity in between layers
Is sensitive with nerve supply
Secretes small amount of lubricating fluid
37
Organ class in relationship to peritoneal cavity (3)
Intraperitoneal - Completely wrapped
Retroperitoneal - Partially wrapped
With a mesentery - Double layer
38
Intraperitoneal organ
Liver
39
Retroperitoneal organs (2)
Pancreas
| Kidney
40
Organs with a mesentery organs
Parts of intestines
41
Peritoneum condensations (4)
Double layers
Attach organs to each other or to abdominal wall
Secondary to growth and rotation of GI tract during embryology
Visible during dissection and surgery
42
Peritoneum condensations examples
Greater omentum
| Lesser omentum
43
Greater omentum (2)
Has nerves, lymphatics and blood vessels
| During infection of abdominal cavity its wraps around the infected region preventing further infection
44
Omenta division parts (4)
Greater sac
Lesser sac
They communicate through omental foramen
Portal triad lies in free edge of lesser omentum
45
Inferior part of peritoneum
Drapes over superior pelvic organs
1 pouch in males - Rectovesical
2 pouches in females - Vesico-uterine and recto-uterine
Pouches are part of greater sacs
46
Ascites (3)
Excess fluid in peritoneal cavity
Secondary to liver disease
Drained by paracentesis
47
Paracentesis procedure (2)
Needle placed lateral to rectus sheath - Avoids inferior epigastric artery
Ultrasound guidance is available
48
Abdominal pain main questions (4)
Location - Anatomy and is pain localized
Character - Visceral (dull, achy, nauseating) or somatic (sharp, stabbing)
Timing - 'Colicky pain'
Pain referral pattern - Is it showing classical distribution suggesting pathology of a specific organ
49
Abdomen nerves of organs (3)
INCLUDES visceral peritoneum
Visceral afferents
Autonomic motor nerves (Parasympathetic and Sympathetic) - Influences enteric nervous system
50
Abdomen nerves of body wall (3)
Somatic sensory
Somatic motor
Sympathetic nerve fibres
51
Sympathetic nerve pathway (4)
Leave spinal cord at levels T5 and L2
Enter sympathetic chains bilaterally but DO NOT synapse
Leave sympathetic chains within abdominopelvic splanchnic nerves
Synapse at prevertebral ganglia located anterior to aorta at the exit points of the major branches of abdominal aorta
52
Sympathetic nerve pathway - After synapsing
Postsynaptic sympathetic nerve fibres pass from prevertebral ganglia onto surface of arterial branches leaving the abdominal aorta
53
Sympathetic nerves to adrenal gland (3)
Same as the rest but leaves spinal cord at T10 - L1
Are carried with periarterial plexuses to adrenal gland
Synapse directly onto cells
54
Parasympathetic nerve pathway - Vagus nerve (4)
Presynaptic parasympathetic nerve fibres enter abdominal cavity on surface of oesophagus
Travels into periarterial plexuses around abdominal aorta
Carried to walls of organs where they synapse in ganglia
Supply Parasympathetic nerve fibres to the GI tract + abdominal organs up to distal end of the transverse colon
55
Parasympathetic nerve pathway - Pelvic Splanchnic Nerves (S2,3,4)
(2)
Presynaptic parasympathetic nerve fibres
| Smooth muscle/glands of descending colon to anal canal
56
Abdominal pain regions
Foregut - Felt in epigastric region
Midgut - Felt in umbilical region
Hindgut - Felt in pubic region
57
Visceral afferent nerve fibres (5)
Pain fibres from abdominal organs run alongside sympathetic fibres back to spinal cord
Foregut - T6 to T9
Midgut - T8 to T12
Hindgut - T10 to L2
Pain from these organs tends to be perceived by patient in dermatomes of the levels at which they enter the spinal cord - Refereed pain
58
Appendicitis (3)
Midgut organ - Located in right Iliac fossa
Dull pain is felt in umbilical region as visceral afferents of these organs enter spinal cord at T8 - T10
As it worsens appendix rubs on parietal peritoneum and since its part of the soma the pain from dull becomes sharp
59
Jandice is caused by
Build up of bilirubin
60
Bilirubin characteristics (2)
By-product of RBC break down - Occurs in spleen and liver
| Used to form bile in the liver
61
How does bile enter the duodenum
Through the biliary tree - Set of tubes connecting liver to 2nd part of duodenum
62
Portal triad (2)
Found in free edge of lesser momentum
| Consists of hepatic artery, hepatic portal vein (Both carry blood to liver) and common bile duct
63
Celiac trunk characteristics (6)
1st of 3 midline branches of abdominal aorta
Is retroperitoneal
Arises around T12 vertebral level
Supplies organs of foregut
Trifurcates into 3 branches - Splenic, Hepatic and Left Gastric arteries
Each of these arteries further branch out to gastroduodenal and Superior pancreatico-duodenal
64
Spleen characteristics (5)
Splenic artery has tortuous course - Superior pancreas border
Intraperitoneal organs within left hypochondrium
Protected by ribs 9-11
Functions within haematological and immunological systems
Has blood reserves and produces RBC in infancy
65
Spleen anatomically related to (4)
The diaphragm posteriorly
The stomach anteriorly
The splenic flexure inferiorly
The left kidney medially
66
Spleen palpation (3)
Felt during end inspiration
Has clinical implication
Normally not palpable - Palpation present with enlargement over 3 times its normal size
67
Blood supply of stomach (2)
Right and left gastric arteries - Anastomose and run on lesser curvature
Right and left gastro-omental - Anastomose and run over greater curvature
68
Blood supply of liver (3)
Hepatic artery
Branches into left and right hepatic arteries
Arteries account for around 25% of blood received - Rest is by hepatic portal vein
69
Liver characteristics (4)
Mainly in upper right quadrant
Major metabolic organ
Protected by ribs 7-11
Can be described as 4 anatomical segments or 8 functional segments
70
Liver anatomically related to (5)
The diaphragm superiorly, anteriorly, posteriorly
The anterior aspect of the stomach medially
The gallbladder posterior & inferiorly
The hepatic flexure inferiorly
The right kidney, right adrenal gland, IVC and abdominal aorta posteriorly
71
4 anatomical segments of liver - Grossly visible
Right lobe
Left lobe
Caudate lobe - Has tail segment
Quadrate lobe - Has 4 sides
72
8 functional segments of liver and their veins (3)
Has own blood supply, venous and bile drainage - So possible to perform segmentectomy
Venous drainage from liver is via 3 main hepatic veins into IVC - Except caudal which is direct
IVC and hepatic veins have no valves - So rise in central venous pressure is transmitted to liver causing hepatomegaly
73
Clinically important areas of peritoneal cavity related to liver (5)
Hepatorenal recess - Morison's pouch
Sub-phernic recess
Both recesses are within greater sac
Peritonitis results in a pus collection in these recesses leading to abscess formation
Hepatorenal recess is one of lowest parts of peritoneal cavity when patient is supine
74
Hepatic portal vein
Drains blood from foregut, midgut and hindgut to liver for first pass metabolism
75
Splenic vein
Drains blood from foregut to hepatic portal vein
76
Inferior mesenteric vein
Drains blood from hindgut to splenic vein
77
Superior mesenteric vein
Drains blood from midgut to hepatic portal vein
78
IVC (2)
Retroperitoneal
| Drains cleaned blood from hepatic veins into right atrium
79
Portal venous system composition (4)
Hepatic portal vein
Splenic vein
Superior mesenteric vein
Inferior mesenteric vein
80
Liver removal
Requires chords of coronary ligaments (attached to diaphragm) and ligamentum teres to be cut
81
Gallbladder characteristics (6)
Lies on posterior aspect of liver
Lies anterior to duodenum
Concentrates and stores bile
Has body and neck
Neck narrows to become cystic duct - Is potential site for gallstone impaction
Blood supply is via cystic artery - Branch of right hepatic artery in 75% of people
82
Gallbladder sensory innervation (4)
Forget organ where pain is felt in epigastric region
Visceral afferents enters spinal cord between T6 and T9
Pain can also be present in hypochondrium with/without pain referral to right shoulder
Result of anterior diaphragmatic irritation
83
Cholecystectomy (3)
Surgical removal of gallbladder
Must correctly identify the cystic duct and cystic artery
Variation can occur in both of these structures
84
Biliary Tree role and components (3)
Made of ducts that transports bile
Right and left hepatic ducts untie to make common hepatic duct
Common hepatic dust unites with cystic duct to make bile duct
85
Bile duct components (4)
Descends posteriorly to 1st part of duodenum
Travels into a groove on posterior aspect of pancreas
Then joins with main pancreatic duct to form ampulla of Vater (hepatopancreatic ampulla)
Both drains into 2nd part of duodenum through the major duodenal papilla
86
Sphincters involving the bile duct and their use (4)
Bile duct sphincter
Pancreatic duct sphincter
Sphincter of Oddi
Prevent digestive secretions and duodenal content reflux
87
Which sphincter is significant in controlling bile flow into the duodenum
Bile duct sphincter
88
Endoscopic Retrograde Cholangiopancreatograpy
| ERCP) (5
Investigation to study biliary tree and pancreas
Endoscope inserted through oral cavity into duodenum
Cannula placed into major duodenal papilla and radio-opaque dye injected back into biliary tree
Radiographic images are taken of the dye-filled biliary tree
Used to remove bile duct stones
89
Extrahepatic jaundice causes (2)
Biliary tree obstruction - Gallstones, carcinoma at pancreas head
Back up flow of bile to liver leading to overspill into blood
90
Parts of pancreas (4)
Head
Neck
Body
Tail
91
Description of head of pancreas
Surrounded by “C-shape” formed by duodenum
92
Pancreas anatomical relationships (5)
Retroperitoneal organ - Lies transversely across the posterior abdomen
Posteriorly lie the right kidney & adrenal gland, IVC, the bile duct, abdominal aorta, superior mesenteric vessels, left kidney & adrenal gland, part of the portal venous system
Anteriorly lies the stomach
Duodenum surrounds the head
Superoposteriorly to splenic vessels
93
Nerve supply of pancreas (3)
Sympathetic - Abdominopelvic splanchnic nerves
abdominopelvic splanchnic nerves
Parasympathetic - Vagus nerves
Both pass through diaphragm, follow arteries from celiac and superior mesenteric plexus to reach pancreas
94
Control of pancreas secretion (2)
Parasympathetic nerves have secretomotor function
| Actual secretion controlled by hormones formed in duodenum and intestinal mucosa as response from stomach acid contents
95
Pancreas arterial supply (3)
Main branches from splenic artery - Pancreatic branches
Gastroduodenal artery
supplies superior pancreaticoduodenal
Superior mesenteric artery supplies inferior pancreaticoduodenal
96
Pain from pancreas (2)
Presents in epigastric or/and umbilical region
| Radiates to patients back
97
Pancreatitis causes (2)
Secondary to inflammation
| Blockage of ampulla by gallstone - Bile is diverted into pancreas causing irritation and inflammation
98
Duodenum parts (4)
Superior (Duodenal cap) - Intraperitoneal
Descending - Retroperitoneal
Horizontal - Retroperitoneal
Ascending - Retroperitoneal
99
Duodenum characteristics
Secretes peptide hormones - Gastrin, CCK
| Begins at pyloric sphincter
100
Pyloric sphincter properties (3)
Controls chyme flow into duodenum
Sympathetic innervation causes contraction
Parasympathetic innervation causes relaxation
101
Duodenum arterial supply (2)
Gastroduodenal artery
supplies superior pancreaticoduodenal
Superior mesenteric artery supplies inferior pancreaticoduodenal
102
Duodenal-jejunal flexure (3)
Junction between duodenum and jejunum
Found at L2 vertebral level
Few centimeters to left of midline
103
Jejunum and Ileum locations (3)
Found in all quadrants
Jejunum mostly located in upper left quadrant
Ileum mostly located in lower right quadrants
104
Jejunum differences to Ileum (3)
Larger diameter
Thicker walls
Mesentery associated has less fat
105
Jejunum and Ileum arterial supply (2)
From superior mesenteric artery via jejunal and ileal arteries
Jejunum has more vascularity with long vasa recta (straight arteries) and few large loops of arterial arcades (where arteries unite to form arches)
106
Jejunum and Ileum venous drainage (3)
Jejunal and ileum veins => Superior mesenteric vein => hepatic portal vein
107
Fat absorption (3)
Bile aids from GI tract into intestinal cells
Fats within chylomicrons are absorbed from intestinal cells to lacteals
Lacteals travel via lymphatic system to drain into venous system at left venous angle
108
Main lymph nodes draining abdominal organs (4)
Celiac - Foregut organs
Superior mesenteric - Midgut organs
Inferior mesenteric - Hindgut organs
Lumbar - Kidneys, posterior abdominal wall, pelvis, lower limbs
109
Lymphatics of abdomen (4)
Lymph drains either into thoracic duct (from ¾ of body) or right lymphatic duct (from ¼ of body)
Eventually drains into venous system for recycling at venous angles - Junction between subclavian and internal jugular vein
Left venous angle - Thoracic duct
Right venous angle - Right lymphatic duct
110
Paracolic Gutters properties (3)
2 of them - Left and right
Located between lateral edge of ascending, descending colon and abdominal wall
Part of greater sac of peritoneal cavity - Potential site for pus collection
111
Which parts of the colon are retroperitoneal - Fixed in location (3)
Ascending colon
Descending colon
Rectum
112
Which parts of the colon are intraperitoneal - Mobile in location (4)
Caecum
Appendix
Transverse colon
Sigmoid colon
113
Types of colon flexures and which one is more superior (2)
Hepatic flexure
| Splenic flexure - More superior
114
What is a haustra
Tonic contraction of teniae coli
115
Caecum and appendix properties (3)
Both lie in right iliac fossa
Appendix position is variable - Mostly retrocaecal
Appendiceal orifice lies on posteromedial wall of caecum - Corresponds to
McBurney’s point on the anterior abdominal wall
116
McBurney's point location
1/3 of way between right anterior superior iliac spine to umbilicus
117
Sigmoid colon properties (3)
Lies in left iliac fossa
Has long mesentery called sigmoid mesocolon
Allows mobility but has risk of twisting itself (sigmoid volvulus) causing bowel obstruction
118
Abdominal aorta properties (5)
Midline, retroperitoneal structure
Lies anterior to vertebral bodies and to left of IVC
3 midline branches; Celiac trunk (foregut), superior mesenteric artery (midgut), inferior mesenteric artery (hindgut)
Lateral branches supply kidneys, adrenal glands, gonads, body wall
Bifurcates into common iliacs which then bifurcates into external and internal iliacs
119
What is the Marginal artery of Drummond and its importance
Arterial anastomoses of SMA and IMA
Depending on health of anastomotic vessels and speed at which vessel obstruction occurs, these anastomoses prevents intestinal ischaemia
120
Rectum and anal canal blood supply (2)
IMA supplies until proximal half of anal canal - Pectinate line
Remainder is supplied by internal iliac artery - There is degree of anastomoses between vessels
121
Pectinate line classification and importance
Above line is visceral and below is parietal
| Vital implication for blood supply/drainage, lymphatic drainage, nerve supply for structures
122
Haematemasis (3)
Presents with patient vomiting blood
Due to peptic ulcer in stomach/duodenum wall that erodes through mucosa
Gastromental artery ruptures as it fills stomach/duodenum with blood
Could also be from bleeding oesophageal varices
123
What are varices (3)
Abnormal dilated veins
Thin walled where more likely to rupture
Formed by pathology affecting portal venous system
124
3 portal systemic anastomes
Distal end of oesophagus
Skin around umbilicus
Rectum/Anal canal
125
Collateral veins characteristics (3)
Blood flow in both ways either into systemic or portal venous system
No valves are present in small collateral veins
Normally little blood flow
126
Distal end of oesophagus anastomoses features (2)
Most inferior part drains to hepatic portal vein
| Most superior part drains to azygous vein
127
Skin around umbilicus anastomoses feature
Normally the ligamentum teres remains closed throughout adult life and blood flows from
the skin around umbilicus via inferior epigastric veins to IVC
128
Rectum/Anal canal anastomoses features (2)
Drains to inferior mesenteric artery
| Most inferior part of GI tract drains to internal iliac veins
129
Rectum and anal canal drainage pathways - Superior to middle to inferior (3)
Superior rectal vein => Inferior mesenteric vein
Middle rectal vein => Internal iliac vein
Inferior rectal vein => Internal iliac vein
130
Portal hypertension definition, cause and consequences (3)
Clinical term of increased BP within portal veins
Caused by liver pathology - Cirrhosis
In this event blood is diverted through collateral veins back to systemic venous system
These veins have a larger volume than usual causing them to dilate becoming varicose
131
Portal hypertension presentation (3)
Oesophageal varices
Caput medusac - Dilated collateral and epigastric veins
Rectal varices - NOT haemorrhoids
132
Control of faeces defecation requirements (4)
Holding area - Stores faeces
Normal visceral afferent nerve fibres - Sense rectum 'fullness'
Functioning muscle sphincters - Respond to 'fullness' by contraction preventing defecation and relaxation allowing defecation
Normal cerebral function to control appropriate time to defecate
133
faecal continence can be affected by (2)
Drugs
| Natural-age related degeneration of nerve innervation of muscle - Affected by stool consistency
134
Pelvic cavity (3)
Lies within pelvis between pelvic inlet and pelvic floor
Continues with abdominal cavity
Rectum is located within cavity
135
Pelvic floor (2)
Openings in pelvic floor permit distal parts of alimentary, renal and reproductive tracts to pass from pelvic cavity into perineum
Rectum and anal canal pass through wall
136
When does the sigmoid colon become the rectum (2)
At the rectosigmoid junction
| Anterior to S3
137
When does the rectum become the anal canal
Anterior to coccyx tip prior to passing through the levator ani muscle
138
Which organs are in the perineum (2)
Anal canal
| Anus
139
Rectum features (3)
Rectal ampulla lies immediately superior to levator ani muscle
Its walls can relax to accommodate faecal material
Functioning muscles and muscle sphincters are required to hold faeces in ampulla until appropriate to defecate
140
Anatomical relationships to rectum (4)
Peritoneum covers superior rectum
Rectouterine/rectovesical pouch lie anterior to superior rectum
In the male, the prostate gland lies anterior to inferior rectum
In the female, the vagina and cervix lies anterior to inferior/middle rectum
141
Levator Ani muscles features (7)
Skeletal muscle
Forms most of pelvic diaphragm with fascial coverings
Forms most of pelvis floor/perineum roof
Provides continual support for the pelvic organs - Tonically contracted
Reflexively contracts further during increase in intra-abdominal pressure
Muscle relaxes to allow defecation and urination
Supplied by “nerve to levator ani” - Branch of the sacral plexus and pudendal (S2, 3, 4)
142
Levator Ani smaller muscles - Medial to lateral (3)
Puborectalis
Pubocoocygeus
Iliococcygeus
143
Puborectalis (3)
Vital for maintaining faecal continence
Contraction decreases anorectal angle - Acting like a sphincter
When the rectal ampulla is relaxed and filled with faeces, voluntary contraction helps maintain continence
144
Internal anal sphincter features (5)
Smooth muscle
Superior 2/3 of anal canal
Contraction is stimulated by sympathetic nerves
Contraction is inhibited by parasympathetic nerves
Contracted all the time, - Relaxes reflexively in response to distension (filling) of rectal ampulla
145
External anal sphincter features (4)
Skeletal muscle
Inferior 2/3 of anal canal
Contraction is stimulated by pudendal nerve
Voluntarily contracted in response to rectal ampulla distension and internal sphincter relaxation
146
Sympathetic supply of rectum/anal canal (3) and its actions (2)
```
From T12-L2
Synapse at inferior mesenteric ganglia
Reaches rectum via periarterial plexuses around branches of IMA
Contracts internal anal sphincter
Inhibits peristalsis
```
147
Parasympathetic supply of rectum/anal canal (3) and its action (2)
```
From S2-S4
Via pelvic splanchnic
Synapses in walls of rectum
Inhibits internal anal sphincter
Stimulate peristalsis
```
148
Somatic motor fibres of rectum/anal canal supply (2) and action
From pudendal nerve (S2-S4)
Nerve to levator ani (S3,S4)
Contracts external anal sphincter and puborectalis
149
Visceral afferents of rectum/anal canal and function
S2-S4 - Run with parasympathetics
| Senses stretch and ischaemia
150
Pudendal nerve (6)
Branch of sacral plexus
S2-S4 anterior rami
Supplies external anal sphincter
Exits pelvis via greater sciatic foramen
Enters perineum via lesser sciatic foramen
Branches to supply structures of perineum
151
Pudendal nerve and labour (2)
Branches could be stretched causing fibres to be torn
| Results in weakened muscle and faecal incontinence
152
Above pectinate line nerve supply, arterial supply, venous drainage, lymphatic drainage
Nerve supply - Autonomic
Arterial supply - Inferior mesenteric artery
Venous drainage - Portal venous system (IMV)
Lymphatic drainage - Inferior mesenteric nodes (Internal iliac nodes)
153
Below pectinate line nerve supply, arterial supply, venous drainage, lymphatic drainage
Nerve supply - Somatic
Arterial supply - Internal iliac artery
Venous drainage - Systemic venous system (Internal iliac)
Lymphatic drainage - Superficial inguinal nodes
154
Lymphatics of pelvis (5)
Lie alongside arteries
Internal iliac drains inferior pelvic structures
External iliac drains lower limb and superior pelvic structures
Common iliac drains lymph from external and internal iliac nodes
Lymph draining through common iliac nodes then drains to lumbar nodes
155
Rectal varices (2)
Form in relation to portal hypertension
| Dilation of collateral veins between portal and systemic venous systems
156
Haemorrhoids (2)
Prolapses of rectal venous plexuses
| Development is due to raised pressure (constipation) - NOT portal hypertension
157
Ischioanal Fossae features (4)
Lie on each side of anal canal
Filled with fat and loose connective tissue
The 2 fossae communicate with each other posteriorly
An infection within the ischioanal fossa is called an ischioanal abscess
158
What is a protoscopy
Views the interior of the rectum
159
What to look for in a rectal exam (3)
Assess anal tone - Strength of external anal sphincter
In males palpate the prostate anteriorly
In females palpate the cervix
160
Factors required for hernia development (2)
Structural weaknesses
| Increased intra abdominal pressure
161
Normal anatomical hernia weaknesses (4)
Diaphragmatic
Inguinal
Femoral
Umbilicus
162
Abnormal weaknesses of hernia (2)
Incisional
| Congenital diaphragmatic
163
Common causes of increased abdominal pressure (4)
Chronic cough
Pregnancy
Strenuous activity
Straining during bowel movement or urination
164
Linea semilunalis
Grossly visible line that separates anterior abdominal wall from lateral abdominal wall
165
Inguinal ligament (4)
An inferior thickening of external oblique muscle
Marks an anterior boundary between abdomen and thigh
Attaches anterior superior iliac spine and pubic tubercle
Medial half of inguinal ligament is curved to become inguinal canal floor
166
Parts related to inguinal ligament and function (2)
Above ligament is inguinal canal - Abdominal communication with perineum
Below ligament is subinguinal space - Communicates with thigh
167
Inguinal canal features (5)
Oblique passage between abdomen and perineum
4cm long
Directed inferomedially
Lies along superior border of inguinal ligament
Entrance is deep inguinal ring and exit is superficial inguinal ring
168
Inguinal canal contents (4)
Spermatic cord - Males
Round ligament of the uterus - Females
Blood and lymphatic vessels
Iloinguinal nerve
169
Testis and inguinal canal (3)
Testes develop on posterior abdominal wall then descend during fetal development
Gubernaculum contracts pulling attached testes inferiorly
Testes move through inguinal canal into scrotum
170
Inguinal canal boundaries (4)
Anterior - External oblique aponeurosis and internal oblique muscle (laterally)
Posterior - Transversalis fascia (laterally) and conjoint tendon (medially)
Roof - Transversalis fascia (laterally), Arches of internal oblique and transversus abdominus aponeurosis (centrally), external oblique aponeurosis (medially)
Floor - Gutter of infolded inguinal ligament
171
Hesselbach's triangle indication and borders (3)
Site of direct inguinal herniation
Medial border - Lateral border of rectus abdominis
Superolateral side - Inferior epigastric artery and veins
Inferior border- Inguinal ligament
172
Direct inguinal hernia features (4)
Directly through abdominal wall structures
Medial to inferior epigastric artery
Passes through Hesselbach's triangle to superficial ring
Parallel to spermatic cord
173
Indirect inguinal hernia features (4)
Uses inguinal canal and deep inguinal ring
Lateral to inferior epigastric artery
Passes through superficial ring
Within spermatic cord or abdominal wall layers
174
Femoral hernia anatomy (3)
Subinguinal space is posterior and inferior to inguinal ligament
Contains hip flexors, femoral artery and vein, lymphatics and nerves
Medial to the vessels is the femoral canal - Potential site for herniation
175
Which area is the most common for having weakness
Myopectineal orifice
176
Surface anatomy of inguinal rings (2)
Deep - Superior to half way point along inguinal ligament
| Superficial - Superior and lateral to pubic tubercle
