Anatomy Flashcards
What is the main structure of the temporomandibular joint?
head of the condylar process sits in the mandibular fossa next to the articular tubercle
What are the cavities in the temperomandibular joint for?
superior: for translation
inferior: for rotation
What nerve supplies the muscles of mastication?
mandibular division of the trigeminal nerve so CNV3
What structure tenses to move food between the teeth?
buccinator
Where does CNV3 travel?
from the pons, through the foramen oval and to the muscles of mastication and the sensory area (only nerve that comes off the pons)
What are the muscles of mastication and where do they attach at either end?
- Temporalis: coronoid process of mandible to temporal fossa
- Masseter: angle of mandible to zygomatic arch
- Lateral pterygoid (only one that opens): condyle of mandible to pterygoid plates of sphenoid bone
- Medial pterygoid: angle of mandible to pterygoid plates of sphenoid bone
What is the dens?
the spiky bit at C2 on a radiograph
What is the gingiva?
the frontal gums
What nerve is the sensation in the mouth supplied by?
top half is CN V2 and inferior half is CN V3
What is the pathway of the CNV2 nerve?
from pons through foramen rotundum to sensory area
What are the three salivary glands, where do they secrete to and which nerve supplies them?
- Parotid gland: CNIX- side of the face, in front of the ear and secretes into mouth at upper 2nd molar
- Submandibular gland: CNVII- secretes via lingual caruncle
- Sublingual gland: CNVII- secretes via several ducts superiorly
What nerve is the posterior 1/3rd of the tongue supplied by?
CNIX for both taste and sensation
What nerve is the anterior 2/3rds of the tongue supplied by?
CNVII for taste
CNV3 for general sensation
Which papillae have taste buds?
foliate, vallate and fungiform do
filiform doesn’t
What is the course of the facial nerve?
from the pontomedullary junction, through the temporal bone via the internal acoustic meatus then stylomastoid foramen
What does the facial nerve supply?
taste to anterior 2/3rd, facial expression and glands on floor of mouth
What nerve innervates the tongue muscles?
CNXII except (palatoglossus)
What is the path of CNXII?
from the medulla, through hypoglossal canal to the extrinsic and intrinsic muscle of the tongue
What nerves make the gag reflex possible and how does it come about?
- mucosa is sensory CNIX at the back of the oral cavity
- motor part of the reflex is CNIX and CNX
- reflex acts to constrict the pharynx
What nerves does the anaesthetic act on for an endoscopy act?
CNV2, CNV3, CNVII and CNIX
Where does CNIX run?
glossopharyngeal nerve that runs from the medulla through the jugular foramen to the posterior wall of the oropharynx, parotid gland and to posterior 1/3rd of tongue
What are the muscles of the pharynx and what nerves are they supplied by?
- three circular muscles that are voluntary and are innervated by CNX and all insert onto midline raphe
- three longitudinal muscles supplied by CNX and CNIX
What is involved in the process of swallowing?
- Tongue (CNXII) pushes food towards oropharynx (Voluntary)
- Soft palate and larynx elevated (CNIX and CNX for pharyngeal muscles) (Involuntary)
- Circular layer of pharyngeal (CNX) constrictor muscles contract (Involuntary)
- Food bolus enters oesophagus and travels inferiorly by peristalsis (Involuntary)
Where does the oesophagus start and where does it go through the diaphragm?
C6 begins
T10 crosses diaphragm
What heart chamber does the oesophagus run down the back of?
posterior of the left atrium
Where are the constrictions in the oesophagus?
cervical, thoracic and diaphragmatic
What is the place where the oesophagus becomes the stomach called?
Z-line
What areas does the stomach lie in when the patient is supine?
left hypochondrium, epigastric and umbillical regions
What layer of the embryo does the gut tube come from?
the endoderm
What are the main types of folding to form the gut tube?
lateral and craniocaudal to form the tube within a tube
What is the pathological condition where the vitelline duct is affected?
Meckel’s diverticulum which can form cyst or fistula
2s: children under 2, males twice as often, 2 inches in length and 2% of population
What is the vitelline duct?
the midgut is initially open into the yolk sac but narrows into the vitelline duct which is incorporated into the umbilical cord
What are the major blood vessels supplying the foregut, midgut and handout organs?
- Coeliac trunk supplies foregut organs
- Superior mesenteric artery supplies midgut organs
- Inferior mesenteric artery supplies hindgut organs
What can a short oesophagus result in?
hiatal hernia
What is involved in the stomach formation?
- starts as fusiform dilation
- dorsal wall has rapid growth to form greater curvature and ventral wall growth is slower so there is less curvature
- rotates clockwise 90 degrees LARP (left anterior, right posterior)
- pylorus upwards and fundus downwards.
What are mesenteries?
a continuous layer of serous membrane and attach gut tube to anterior and posterior walls of the abdomen
What is the omental bursa?
space posterior to the stomach and the rest of the space is the greater sac
What does the epiploic foramen do?
connects the lesser and greater sac (gut embryology)
How is the greater momentum formed?
dorsal mesentery develops as a double layered sac that fuses to form the the greater omentum which is an apron-like structure
How does the duodenum develop?
- rotation of the stomach causes the duodenum to move from the midline to the right side of the abdominal cavity
- dorsal mesentery fuses with peritoneum so parts 2, 3 and the pancreas become retroperitoneal
How does the midgut develop?
- cranial and caudal limb develop
- rapid growth so intestinal loops move out through the umbilical cord and lie outside the embryo
- midgut rotates 90 degrees clockwise and herniates through the umbilical cord so the growth continues to form coils
- rotation around the superior mesenteric artery
- comes back into the embryo so the jejunum comes in follwed by the caecum
- caecal bud descends from the right lobe of the liver to right iliac fossa
What do the cranial and caudal limbs of the midgut become?
- cranial: forms distal duodenum, jejunum and upper ileum
- caudal limb: lower ileum, cecum, ascending colon and proximal 2/3rd of transverse colon
What is the disease Ompahlocele?
failure of the intestines to return to the body
What is the disease Gastroschisis?
protrusion of abdominal content through the wall lateral to the umbilical cord
What are the changes in the mesenteries in embryology?
- dorsal mesentery of gut connects to posterior abdominal wall around the axis of the superior mesenteric artery
- ascending and descending colon mesentery fuse with peritoneum and become retroperitoneal
What is involved in the formation of the hindgut?
- terminal end is called the cloaca
- membrane that eventually ruptures
- urorectal septum partitions the cloaca into the rectum and the anal canal
- septum and the cloacal membrane fuse at the future site of the perineal body
How does the liver develop?
- hepatic diverticulum for the liver and the cranial part becomes the liver and the caudal part becomes the bile duct
- liver then forms hepatic cords which join with umbilical and vitelline veins to give hepatic sinusoids
- endoderm forms the epithelial parts
- septum transversum is derived from the mesoderm
How does the pancreas develop?
dorsal and a ventral pancreatic bud which then come together by LARP rotation
What is a possible pathological condition with pancreatic development?
pancreas can pathologically encircle duodenum so there can be occlusion of the duodenum
What layer is the spleen derived from?
mesoderm
initially it is haematopoietic
What are all the muscles of the anterolateral abdominal wall?
- rectus abdominis
- external oblique (hands in pockets)
- internal oblique (arms hugging)
- transversus abdominis
- parietal peritoneum
- rectus abdominis
What is guarding?
when muscles contract at site of injury to guard the abdominal organs (can also occur in peritonitis)
What organs are in the foregut?
Oesophagus to mid-duodenum
Liver and gall bladder spleen
Half of the pancreas
What organs are in the midgut?
Mid-duodenum to proximal 2/3rds of the transverse colon
Half of the pancreas
What organs are in the hindgut?
Distal 1/3rd of transverse colon to proximal half to anal canal
What separates the foregut, midgut and hindgut?
- Foregut and midgut divides half-way between the duodenum
- Midgut and hindgut divides proximal 2/3rds of transverse colon
What lines are used to divide the abdomen into quadrants?
The midline goes from the xiphoid process to the pubic symphysis and the horizontal line goes through the umbilicus to divide the abdomen into quadrants
What are the nine regions of the abdomen?
- right and left hypochondrium and epigastric
- right and left lumbar and umbilical
- right and left inguinal and pubic
What are the names of the horizontal lines that divide the nine regions?
The horizontal line under the top three regions is the subcostal plane
The horizontal line over the lower three regions is the transtubecular plane
What is peritoneum?
thin, transparent and semi-permeable membrane that lines the abdominopelvic cavity and is a continuous sheet
(where it touches the body wall is parietal and where it touches the organs it is visceral)
What are the features of retroperitoneal organs and what are some examples of these?
only has visceral peritoneum on the anterior surface so the organ is located in the retroperitoneum
eg pancreas, ascending and descending colon
What are the features of intraperitoneal organs and what are some examples of these?
almost completely covered in visceral peritoneum so it not very mobile
eg liver, gallbladder, stomach, parts of small intestine and transverse colon
What are the common peritoneal formations?
- Mesentery: connects organ to posterior body wall
- Omentum: double layer of peritoneum that passes from stomach to adjacent organs
- Peritoneal ligaments: double layer of peritoneum connect organs to one another or body wall
What are the features of mesentery?
- has connective tissue with blood, lymph vessels, nerve, lymph nodes and fat
- mesentery proper attaches the small intestine to the body wall
- transverse and sigmoid mesocolon and mesoappendix
- gives a high level of mobility
What are the greater and lesser omentums?
- The greater omentum is four-layered sheet that hangs like an apron, it attaches the greater curvature of stomach to the transverse colon
- The lesser omentum is a double-layered sheet and runs between lesser curvature of the stomach and duodenum to liver
What is the Pringle manoeuvre?
the surgeon places his fingers through the omental foramen and into the lesser omentum to surround the hepatoduodenal ligament which contains the portal triad so the blood flow from the liver to the duodenum will be stopped
What do the greater and lesser sacs communicate through?
the omental foramen but the omenta divides the peritoneal cavity into the these two sacs
Where does the portal triad lie in relation to the omentum?
in the free edge of the lesser omentum
within the hepatoduodenal ligament
What are the pouches that are present in males and females?
Males have a rectovesical pouch
Females have a vesico-uterine pouch and a recto-uterine pouch
These pouches are effectively draped over the superior aspect of the pelvic organs
What is ascites?
a disease where there is a build-up of fluid in the peritoneal cavity which can be caused by cirrhosis or portal hypertension in the liver
How is ascites relieved?
by doing a type of paracentesis called an abdominocentesis to drain the ascitic fluid
the needle is placed lateral to the rectus sheath to avoid the inferior epigastric artery which arises from the external iliac
What are the most important things to ascertain when finding out about GI pain?
location, character, timing and pain referral pattern
What is colicky pain?
‘Colicky pain’ comes and goes in waves because it is with peristalsis
What are organs in the abdominal cavity supplied by in terms of nerves?
(including the visceral peritoneum)
are supplied by visceral afferents, the ENS, parasympathetic nerves which speed peristalsis and sympathetic nerves which slow peristalsis down
What is the abdominal wall supplied by in terms of nerves?
uses somatic sensory and motor nerves and sympathetic nerve fibres
What is the sympathetic outflow to the GI tract?
T5-L2
the nerves do not synapse here
they carry on within the abdominopelvic splanchnic nerves and synapse at the pre-vertebral ganglia
they then go along the arterial branches off the aorta to form periarterial plexuses
Why is the nerve characteristic of the adrenal gland different to normal?
synapses in wall of adrenal gland so long presynaptic neurone and short postsynaptic neurone