Cracking: Applied surgical anatomy Flashcards
Abdominal aorta: Where does it begin and end?
Starts at T12 as it transverses the diaphragm Ends at L4 where it bifurcates into the common iliac arteries
Abdominal aorta: What are it’s relations?
Passes in the midline in the retroperitoneum Anterior: Left renal vein, pancreas, lesser sac Posterior: anterior longitudinal ligament, vertebral bodies Right: Cisterna chyli, thoracic duct, azygos vein Left: duodenojejunal flexure
Abdominal aorta: What are it’s branches and at what level do they branch?
Paired: T12 Inferior phrenic artery ->adrenal gland and diaphragm T12 Adrenal artery -> Adrenal gland L2 Renal artery -> Kidneys, adrenal glands, ureter L2-3 Gonadal artery -> Gonads, ureters L2-3 Lumbar arteries (4 pairs) -> lumbar musculature L4 Iliac arteries (terminal) -> legs and pelvic viscera Unpaired: T12 Coeliac trunk - foregut + liver, spleen, pancreat L1 SMA - midgut L3 IMA - hindgut L4 Median sacral artery - sacrum
Anal Canal: What is the embryology?
Starts off as an endodermal tube Ectoderm invaginates and meets the endoderm to form the anal canal So, distal half is ectoderm (proctoderm) derived, whilst the proximal half is endoderm derived
Anal Canal: What is the anatomy? - relations
Posterior: anococcygeal body and coccyx Laterally: ischiorectal fossa Anterior: perineal body (M&F), penis (M), Vagina (F)
Anal Canal: What is the anatomy? - structure above v below the dentate line
Anal Canal: What is the anatomy? - sphincters
External sphincter - voluntary control. 3 parts: subcutaneous, superficial, deep (parts)
+Puborectalis sling around anal canal/lower rectum -> acute angle to help maintain continence
Internal sphincter - autonomic control
Anal Canal: What is the sequence of events in defecation?
Faeces arrive at the rectum from emptying of the distal large bowel -> urge to defecate
Intra-abdominal pressure rises with increased in diaphragmatic and abdo muscle pressures
Anal sphincterns voluntarily relax
Faeces are evacuated
Biliary system: anatomy?
Divided into intra-hepatic and extra-hepatic systems
Biliary tree starts intra-hepatically as bile canaliculi which divide into bile ductules and small interlobular tributaries of the bile ducts. These join each other to form larger ducts.
R hepatic duct drain the right lobe and the left the left. These two ducts leave the liver at the porta hepatis to become extra-hepatic
The then join (amalgamates) to form the common hepatic duct
This then joins (accepts) the cystic duct to for the common bile duct
The CBD with the hepatic artery (left) and portal vein (behind) travels in the free edge of the lesser omentum at the porta hepatis
At the distal edge it joins (accepts) the pancreatic duct
The CBD terminates at the sphincter of Oddi/ampulla of Vater which opens into the medial aspect of the second part of the duodenum
Biliary system: Relations of the common bile duct?
It is 8cm in length
Diameter: 6mm = upper limit of normal (but get’s 1mm larger every 10 years after 60yo + is larger post cholecystectomy)
Travels in the free edge of the lesser omentum in the porta hepatis with the common hepatic artery (left) and the portal vein (behind)
Biliary system: CBD is divided into three parts…
- First part: anterior to the opening of the Lesser sac
- Second part: Posterior to the first part of the duodenum
- Third part: Posterior surface of the head of the pancreas
Biliary system: what is the histiological layout of the biliary system?
Liver is divided into functional units - lobules
At the periphery of each are the portal triads - bile ductule, terminal hepatic artery branch, terminal portal vein tributary
Each lobule had a central terminal hepatic venule
Blood flows from the portal triad (portal vein & hepatic artery), in the sinusoids, to the central venule. Peripherally to centrally.
These venules then transport blood to the hepatic vein
Bile flows through the canaliculi in the opposite direction to the portal triads peripherally
Biliary system: Gallbladder anatomy
- Pear shaped viscus
- Lines with columnar epithelium
- Contains some smooth muscle in the wall
- Can hold 50mL bile
- Consists of fundus, body, neck
- Lies in the gallbladder fossa attached to ventral surface of the right lobe of the liver
- Neck is continuouse with the systic duct, a small diverticulum at this point, Hartmann’s pouch, is where stones can impact
Arterial supply - cystic artery
Venous drainage - snall veins into the substance of the liver
Lymphatic drainage - cystic node in Calot’s triangle
Biliary system: What is pringle’s manoeuvre?
Place a clamp over the free edge of the lesser omentum and occlude the vessels descrived above
Useful, temporary measure for controlling heavy bleeding from liver, e.g. trauma, by occluding the liver’s blood supply, because it can be done quickly
Biliary system: What is Calot’s triangle?
Triangle formed by the liver, Common hepatic duct, Cystic duct
The cystic artery runs within it.
It is important in identification of the cystic artery in laparoscopic cholecystectomies
Blood supply to the heart:
Anatomy of Right Coronary Artery
Arises from right (anterior) aortic sinus
Runs between pulmonary trunk and Rt auricle
Gives off marginal branch @junction of posterior interventricular groove and AV sulcus (which descends over the front of the ventricle),
and continues as the posterior interventricular artery continueing in the interventricular groove and anastomoses with anterior interventricular artery
It supplies the right ventricle, SAN (60%) and AVN, and part of the left ventricle
Blood supply to the heart:
Anatomy of Left Coronary Artery
Arises from the left (posterior) aortic sinus and divides into circumflex and anterior interventricular (left anterior descending)
Circumflex travels in AV sulcus to anastomose with the RCA
the anterior interventricular (LAD) travels in the interventricular groove to anastomose with the posterior interventricular artery
Blood supply to heart: Venous drainage
All V except for anterior cardiac V drain into coronary sinus which opens into post wall of R atrium
Anterior cardiac V runs across surface of R ventricl and drains directly into r atrium
Tributaries:
- Great cardiac V: travels with anterior interventricular artery and drains into left prox aspect of CS
- Middle cardiac V: travels with posterior interventricular artery and drains into CS
- Small Cardialc V : drain proximally into CS (Right marginal vein travels along the interior surfaceof heart and drains into the SCV)
The Diaphragm:
Anatomy
- Consists of peripheral muscular part and inserts via central tendon which fuses with the pericardium
- Bi-domes, reaching the fifth rib at its highest extent
- 2 crura - sites of origin of the diaphragm:
- R crus - from first 3 lumbar vertebrae
- L crus - from first 2 lumbar vertebra
- Right crus - sling around oesophagus and prevents reflux
- Medial and lateral arcuate ligaments are lateral to crura, contribute to origin of diaphragm
- Supplied by phrenic nerve (C3,4,5 keeps the diaphragm alive)
The Diaphragm: Development
Develops from septum transversum, pleuroperitoneal membranes, paraxial mesoderm of abdo wall and oesophageal mesenchyme
Spetum transversum, which initially forms an embryonic partition between thorax & abdo (emb wk 5-7) -> Central tendon
Crura of the diaphragm are derived from foregut mesenchyme
The Diaphragm: Diaphragmatic Hernias
through persisting pleuroperitoneal communications (where above contributions fail to fuse)
Morgani hernia - through foramen of M - into anterior mediatinum
Bonchdalek hernia - through foramen of B - posteriorly
diagnosed by CT
The Diaphragm: Openings
- T8 - IVC, and right phrenic nerve
- T10 - Oesophagus, and vagus nerve
- T12 - Abdominal aorta, and thoracic duct + azygos vein
Subcostal nerve - under lateral arcuate ligament
Sympathetic chain - behind medial arcuate ligament
Left phrenic nerve - pierces muscular portion of diaphragm
Great, lesser, least splanchnic N - pierces crura
The Diaphragm: Functions
- Main muscle of respiration
- Aids venous return to <3 (intermittent increased intra-abdo pressure on resp)
- Straining - defecation and micturition
- Support to vertebral columm
Femoral Triangle: Boundaries
- Superiorly: inguinal ligament
- Medially: medial border of adductor longus
- Laterally: medial border of sartorius
- Roof: Fascia lata
- Floor (M->L): adductor longus, adductor brevis, pectineus, iliopsoas
Femoral Triangle: Contents
(Lateral to Medial)
Nerve, Artery, Vein, (Y fronts)
Femoral Sheath: Contents
Contains: Femoral canal (potential space containing fat and Coquet’s lymph note, in which vein can expand during increased venous return), Vein and Artery
i.e. does not contain femoral nerve
Femoral branch of genitogemoral nerve runs in the sheath and pierces is anteriorly to supply the skin overlying the triangle
Kidney: structure
- Retroperitoneal
- R lower than left (due to liver)
- 12x6x3cm
- Left hilum = Transpyloric plane (L1)
- L1 = superior pole of right kidney
- Enclosed in fibrous capsule and embedded in fat, bounded by gerotas’s fascia
- GF is attached to the renal pelvis but n inferior opening allows pus to track out in renal disease
- Divided into outer cortex (nephrons), inner medulla (collective ducts and loop of henle)
- Cortical pyramids -> papillae -> calyces -> denal pelvis - > ureter
- Pyramids = seperated by columns of Bertin
- Hilum of kidney = vein, arteryx2, ureter, artery (Ant to post)
Kidney: relations
- Posteriorly: diaphragm, quadratus lumborum muscle, psoas, subcostal, iliohypogastric, ilioinguinal nerves, 11th + 12th ribs
- Anteriorly: liver, 2nd part of duodenum, hepatic flexure, spleen, stomach, pancreas, splenic flexure
- Superiorly: suprarenal glands, pleural reflexion
Kidney: Blood supply and lymphatic drainage
Renal arteries bilaterally <- branches of aorta
Renal veins -> IVC
Lymphatics follow arteries -> para-aortic lyph nodes
Renal: What is the significance of left varicocele?
Left testicular vein -> Left renal vein -> IVC
(Right testicular vein -> IVC)
RCC on left, invades renal vein -> obstruction of left gonadal (testicular) vein
Left varicocele -> Renal USS
Renal: Nerve supply
Renal sympathetic plexus via renal vessels -> pain and vasomotor tone
Renal: Development and anomalies
Day 32:
Definitive kidney (metanephros) is induced by the primitive ureteric bud (from the mesonephric duct) to form sacral intermediate mesoderm
The ureteric bud is induced to branch by metanephros, these branches = calyces
Metanephros ascends from the sacral area to the lumbar region
- Failure to ascent = pelvic kidney*
- ‘If caught under IMA -> Fuse = Horseshoe kidney*
Liver: Development
Develops as ventral endoderm bud within off the gut tube, and forms within the ventral mesentry (attaching to the anterior abdo wall)
The attachment to the anterior abdo wall -becomes-> falciform ligament
The attachment to the gut tube/stomach -becomes-> lesser omentum
(The free edge of the lesser omentums is the point up to which the ventral mesentery involutes embryologically)
In addulthood the liver is almost completely covered in peritoneum with the exception of the bare area of the liver
Liver: Blood supply
Liver has a dual blood supply
- Portal system: 70%. Products of digestion for liver metabolism
- Hepatic Artery: 30%. Oxygenated blood
Drainage = hepatic vein -> IVC
Embryologically, umbilical vein (oxygenated) venous blood from the placenta bypasses the liver via the ductus venosus
Liver: Relations
- Superior: diaphragm
- Inferior: duodenum, stomach, gallbladder, hepatic flexure
- Posterior: R kidney and adrenal, retroperitoneum, oesophagus, aorta, IVB
Liver: surface markings
Upper border = 6th rib mid-clavicular line
Span = c.12.5cm
Liver: mesenteric attachments and ligaments of liver
- Falciform ligament: 2 layered fold of peritoneum from umbilicus to superior surface of liver, longitudinally
- superiorly, falciform ligament splits onto 2
- Right = coronary ligament
- Right triangular = most extreme part of coronary lig
- Left = left triangular
- Right = coronary ligament
- superiorly, falciform ligament splits onto 2
- Lesser omentum: attached to lesser curve of stomach and porta hepatis = ventral mesentery
- Free edge carries = portal vein, hepatic artery, bile duct
- Ligamentum teres: obliterated umbilical vein
- joins left branch of portal vein in porta hepatis
- Ligamentum venosum: obliterated ductus venosus.
- Joins left branch of portal vein to be attached to SVC
Liver: Lymphatics
Liver produced 1/3rs of body lumph
Lymphatics pass through porta hepatis nodes -> coeliac nodes
Liver: Nerve sypply
Coealiac plexus (sympathetic and parasympathetic)
Liver: anatomy
- Largest gland in the body
- Lies in RUQ of abdo
- Anatomical lobes: at levels of falciform
- Right
- Left = caudate + quadrate
- Functional lobes:
- Right & left hepatic arter/portal vein territories, divided at a line drawns from the middle of gallbladder
- 8 segments:
- Caudate = 1&2
- Left (anatomica) = 3&4
- Right = 5, 6, 7, 8
- Gallbladder = undersurface of Rt lobs of liver
Median nerve: What is the course of the median nerve?
C5, 6, 7, 8, T1 nerve roots
Medial and lateral cords of brachial plexus in axilla
Initially medial to brachial artery, crosses in front
Enters antecubital fossa, passes over corachobrachialis and brachialis, lies MEDIAL to brachial artery in cubital fossa, leaves by passing between 2 heads of pronator teres
Travels in forearm, between FDS and FDP
Gives off Anterior Interosseus N in forearm - runs on interosseus membrane
Gives off palmar cutaneous branch proximal to wrist -> superficial to flexor retinaculum
Enters carpal tunnel and divides into terminal branches -> supply hand
Median nerve: what does it supply?
Motor Supply:
- Flexors of forearm: PT, FCR, PL, FDS
- Anterior interosseus: FPL, 1/2 FDP
- Lat lumbricals, opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis
Intrinsic muscles of hand = ulnar nerve exceps LOAF (from median)
Sensory supply:
- Lat 3.5 fingers and lat 2/3rds of palm
note - palmar cutaneous br supplies lat palmar skin and is therefore spares by division of median N @ carpan tunnel, whereas if M Nerve is divided in upper arm whol median nerve teritory becomes insensate
Median Nerve: What are the differences between dividing the median nerve at the elbow and wrist?
Wrist:
- most common
- Loss of sesnation - lat 2/3rds of hand and lat 3.5 fingers
- loss of motor function of LOAF - test ABductor pollicis brevis for pute median nerve function - point thumb to ceiling with palm upwards and test resisted abduction of thumb (push thimb down and lateral from its base) & Look for thenar wasting
Elbow:
- 2nd to sharp trauma/supracondular # of humerus
- Long flexors - medial 1/2 of FDP, FPL, Pronator teres
- Hand held supinated (loss of pronation)
- Loss of flexion of dital phalanc of thumb (loss of FPL)
- index and middle fingers remain straight when asked to make a fist (loss of FDP)
- Wasting of bulk of flexor compartment of forearm
Median nerve: Specific signs for CTS
- Tinel’s test: Tap CT -> electric shock in sensory distribution of nerve
- Phalen’s test: forced flexion of wrist -> electric shock in sensory distribution of nerve
Pancreas: structure
- Exocrine and endocrie gland
- Retroperitoneal organ, crosses transpyloric plane
- Divided into head, body, tail
- Head lies in concavity of duodenum and pancreatic duct drains into 2nd part
- Tail lies in lienorenal ligament and contacts hilum of spleen. It can be damaged in splenectomy -> distula formation
Pancreas: relations
- Posteriorly (Right to Left): CBD, Portal vein, splenic vein, IVC, aorta, SMA, left psoas, left kidney & adrenal, hilum of spleen
- Anteriorly: transverse colon, transverse mesocolon, lesser sac, stomach
Pancreas: blood supply and lymphatic drainage
- Splenic artery, superior and inferior pancreaticoduodenal arteries
- Corresponding veins drain into portal system
- Lymphatics follow arteries to coeliac and superior mesenteric nodes
Pancreas: nerve supply
Sympathetic branches of vagus
Pancreas: development and anomalies
- Day 26 D&V pancreatic buds arise from gut tube @ level of duodenum
- ventral pancreatic bud migrates posteriorly around the duodenum & fuses with dorsal bud -> uncinate prod
- Anomaly - 2 ventral buds migrate in opposite directions -> annular pancreas
- Duct systems fuse, ventral ducts -> main pancreatic duct, dorsal duct -> involutes or -> accessory duct of Santorini
Phrenic nerve: Course
Phrenic nerve, front
What would be the effect of a spinal cord transection at C6 on respiration?
Phrenic nerve (C3/4/5) would not be involved therefore diaphragm would not be paralysed
HOWEVER
intercostals below would not be spared -> some difficulties ventilating -> LRTI
Vagus nerve
What is the consequence of bilateral recurrent laryngeal nerve division?
Rare complication of thyroidectomy
Surgical EMERGENCY
Adduction of both true vocal cords -> acute airway obstruction
-> Surgical cricothyroidotomy & tracheostomy
What is a portal circulation? Where in the body would you find one?
- Two sets of capillaries in series
- Seen in hepatic portal system and the pituitary
- Pituitary portal system starts as capillaries in hypothalamus and ends in anterior pituitary gland
- Releases hormones from hypothalamus to pituitary
Heparic portal system
Portal capilaries in the organs drained (intestinal organs) and ends as capillaries within the liver
Portal vein:
- formed behind pancreatic neck by union of the superior mesenteric and splenic veins @L2 (R. of midline)
- 5cm long
- Runs posterior to 1st part of duodenum
- Runs in free edge of lesser omentum into porta hepatis, posterior to bile duct and hepatic artery
Hepatic portal system: Portosystemic anastomoses
Where portal capillaries are in continuation with systemic capillaries
Usual direction of flow is towards the liver, not portal to systemic
Portal hypertension - blood flows portal to systemic & anastomoses dilate
Sites:
Radial Nerve: course
- C5-T1
- Posterior cord of brachial plexus
- Posterior cutaneous nerve of forearm is given off in axilla
- Passes between long and medial heads of triceps
- Passes along humerus in spiral groove posteriorly, accompanied by profunda vessels
- Pierces (& supplies) anconeus
- Continues into ACF between brachialis and brachioradialis (& supplies elbow J)
- In ACF, divides into deep and superficial branches
- Superficial = sensory = hand
- Deep = motor = extensors of forearm
Radial nerve: Motor supply
- Radial nerve:
- Triceps, brachialis, brachioradialis
- Deep radial nerve:
- Extensors fo forearm: Extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, abductor pollicis longus, extensor pollicis longus, extensor pollicis brevis, extensor indicis
Radial nerve: Sensory supply
- Superficial branch of radial nerve:
- Radial 1.5 fingers dorsally
- Posterior cutaneous nerve of forearm:
- Posterior aspect of forearm
Radial nerve: What coexisting injuries would you be worries about if a patient suffers a spiral fracture of humerus?
- i.e. division at the level of the spiral groove
- Superficial and deep branches of radial nerve in forearm
- loss of sensation and motor
- paralysis of extensors of forearm (leaving unopposed flexors)
- Wrist drop
- loss of synergy of flexors & extensors
- loss of grip strength
- paraesthesia over 1st dorsal interosseus
- paralysis of extensors of forearm (leaving unopposed flexors)
- loss of sensation and motor
Salivary glands: Parotid Gland Anatomy
- Paired
- Largest
- Serous
- Wedge shaped
- Surrounded by connective tissue capsule - investing layer of deep cervical fascia
- Divided into superficial and deep lobes by 5 division of facial nerve
- Overlies angle of the mandible
- Superior margin extends behind TMJ
- Anterior margin superficial to masseter
- Deep part between medial pterygoid and ramus of mandible
- Parotid duct - from facial process of glant (anterior aspect) over masseter. Pierces buccinator, runs submucosal course, until opens into papilla opposite upper 2nd molar tooth
Salivary glands: Parotid Gland Content
- Facial nerve - and branches:
- Temporal/zygomatic/buccal/marginal mandibular branch/cervical branch
- Retromandibular vein
- External carotid artery
- Parotid lymph nodes
Note - superficial parotidectomy spared the facial nerve
Salivary glands: Parotid Gland
Blood supply
External carotid artery
Salivary glands: Parotid Gland
Lymphatic drainage
Parotid and deep cervical nodes
Salivary glands: Submandibular glands anatomy
- Paired
- Serous and mucinous acini
- Connective tissue capsule, derived from investing layer of deep cervical fascia
- Superficial and deep part - in continuity with each other around posterior border of mylohyoid
- Superficial part lies within digastric(anterio) triangle of neck
Salivary glands: Submandibular glands Relations
- Lateral: medial aspect of mandible, facial nerve (cervical), facial vein
- Medial: hyoglossus, styloglossus
- Anterior: Anterior belly of digastric
- Posterior: stylohyoid, posterior belly of digastric, lingual N, hypoglossal N
- Superiorly: lingual N
- Inferiorly: Hypoglossal N
Salivary glands: Submandibular glands
Blood supply
Facial and lingual arteries
Salivary glands: Submandibular glands
Lymphatic drainage
Submandibular, deep cervical nodes
Salivary glands: Submandibular glands
What is at risk during excision?
If incision is made low - Medibular branch of facial N -> angle of mouth will droop
Salivary glands: Sublingual glands anatomy
- Smallest
- Paired
- Serous and mucinous
- Submucosally near midline
Salivary glands: Sublingual glands relations
- Anterior: opposite gland
- Posterior: Deep submandibular gland
- Medial: Genioglossus, Lingual N
- Lateral: Mandible
- Inferior: Mylohyoid muscle
Serveral ducts open into the floor of the mouth adj to submandibular duct opening
Stomach: Parts
- Fundus
- Carida
- Body
- Antrum
- Pylorus
J shaped
Stomach: Relations
- Anterior: Abdo wall, left costal margin, diaphragm, left lobe of liver
- Posteriorly: lesser sac (seperates stomach from pancreas), transverse mesocolon, left colic flexure, upper pole of left kidney, left suprarenal gland, spleen and splenic artery
- Superiorly: left dome of diaphragm
Lesser omentum is attached along lesser curvature of stomach, greater omentum along greater curvature
Omenta contain vascular and lymphatic supply of stomach
Stomach: Blood supply
- Left gastric artery - coeliac axis
- Right gastric artery - hepatic artery
- Right gastroepiploic artery - gastroduodenal branch of hepatic artery
- Left gastroepiploic artery - splenic artery
- Short gastric arteries - splenic artery
Both sets anastomose with each other and gastric curvatures
during oesophagectomy - short gastrics, left gastroepiploic, left gastric arteries are divided to mobilise upper part of stomach in order to form neo-oesophagus
Stomach then derives its blood supply solely from R gastric and R gastroepiploic arteries
Stomach: Venous drainage
Corresponding veins (as per arterial supply) which then drain into portal system
Stomach: Lymphatic drainage
3 drainage zones:
- Area I: Superior 2/3rds drain along left and right gastric vessels to aortic nodes
- Areal II: R 2.3rds of inferior 1/3rd drains along R gastroepiploic to subpyloric nodes to aortic nodes
- Area IIIL left 1.3 of greater curvature along short gastric arteries and splenic vessels in gastrosplenic and lienorenal ligaments, via suprapancreatic nodes to aortic group
Clinical implications: extensive lymphatic drainage and technical difficulty of complete removal makes stomach cancer surgery v difficult with poor results.
Nodes around splenic vessels - removal of spleen and ligaments, body and tail of pancreas
Gastroepiploic LN - excise greater omentum
v. difficult to remove LN around aorta and head of pancreas!
Stomach: Gastric innervation
- Anterior and posterior vagi - motility and secretion
- Both vagi enter via oseophageal hiatus
- Anterior vagus:
- Lies close to stomach wall
- supplies cardia, lesser curve, runs with left gastric artery
- aka anterior nerve of Latarget
- branches to anterior stomach and large hepatic branch to pyloric antrum
- Posterior vagus:
- Back of lesser omentum behind anterior trunk
- aka posterior nerve fo Latarget
- Supplies ant and post aspect of body of stomach
- Bulk of nerve = coeliac branch
Truncal vagotomy
- Management of complicated peptic ulcer disease
- both trunks at lower oesophagus -> reduced gastric secretion & paralysis of pyloric antrum
- resultant gastric stasis requires drainage procedure
- .e.g pyloriplasty/gastrojejunostomy
- Highly selective vagotomy - targets nerves supplying acid production @body/antrum, spares pylorus
- Posterior truncal vagotomy - spared anterior pyloric nerves
- coupled with anterior seromyotomy
Thyroid gland: anatomy
- 2 lobes - L & R
- Connected by isthmus
- Occasionally 3rd, pyramidal, lobe - projecting up from isthmus
- Surrounded by sheath derived from pretracheal layer of deep cervical fascia
- Anterior triangle of neck
- Follicular tissue -> Thyroxine (T4) and Triiodothyronine (T3)
- Medullary C-Cells -> Calcitonin
Thyroid: Relations
- Posteriolateral: carotid sheath - common carotid artery, internal jugular vein, vagus nerve
- Anterolateral: strap muscles
- Medially: larynx, trachea, oesophagus, recurrent laryngeal N (breanch of vagus N in groove between trachea and oesophagus)
Thyroid: blood supply
- 2 arteries - superior, inferior
- 3 veins - superior, middle, inferior
- Superior thyroid artery - br of external carotid
- Inferior thyroid artery - br of thyrocervical, from subclavian
- Superior and middle thyroid V - internal jugular V
- Inferior thyroid V - left brachicephalic V
Thyroid: lymphatic drainage
Deep cervical nodes
Thyroid: Development
derived from foramen cecum @ divide between ant 2/3rds and post 1/3 of tongue, guided by thyroglossal duct to final position (ant to trachea)
Thyroglossal duct hooks behind hyoid bone - must be excised with central part of hyoid bone in duct excision during Sistrunk’s operation
Parathyroid gland: anatomy
- 4
- PTH and in turn mediat calcium homeostasis
- Ochre in colour but stained by methylene blue -> blue
- 2 superior glands = posterior border at level of mid-thyroid
- 2 inferior glands = at inferior thyroid, can lie in thyrothymic ligament or superior meiastinum
- Supplied by superior and inferior thyroid arteries
Surface marking of gallbladder
9th costal margin mid clavicular line
Subcostal plan
Across lower margins of thoracic cage formed by 10th costal cartilage on each side
Level of 3rd lumbar vertebra
Level of origin on IMA
Where is the transpyloric plane?
AKA transpyloric plane of addison
Perpendicular line connecting jugular notch and pubic symphysis
Passes through L1
1/2 way between xiphisternum and umbilicu
Surfact anatomy c. hand’s bredth below xiphoid process
What structures are found at the transpyloric plane?
- fundus of gallbladder
- lower border of L1 vertebra
- End of spinal cord
- Pylorus of stomach
- Neck of pancreas
- Attachment of transverse mesocolon
- SMA - branching off aorta
- Portal V - formed from superior mesenteric vein & splenic vein
- Hilum of spleen
- Hilum of kidneys and their vascular pedicles
- Duodenojejunal junction
What level does the umbilicus bifurcate
L4 - level of umbilicus - dermatome T10
Triangles of neck: names
Posteriorr triangle
Anterior traingle:
- Carotid
- Digastric
- Submental
- Muscular
Posterior triangle: borders
- Anterior: posterior border of SCM
- Posterior: Anterior boder of trapezium
- Inferior: clavicle
Posterior triangle: Contents
- Muscles (floor): splenius capitis, levator scapulae, scalenus medius (scalenus anterior, serratus anterior)
- Nerves: Br of cervical plexus, spinal accessory nerve (from 1/3rd way down posterior border of SCM to trapezius); trunks of brachial plexus
- Other: LN (occipital/supraclavicular), subclavian artery. Transverse cervical and suprascapular vessel
The Trunks are in The Triangle
Anterior triangle: borders
- Midline
- Posterior border of SCM
- Ramus of mandible
Anterior triangle: borders of subtriangle
- Carotid: SCM, post belly of digastric, sup belly of omohyoid
- Key content: common and ext carotid artery
- Digastric triangle: mandible, anterior and posterior bellies of digastric
- Key content: submandibular gland
- Submental triangle: ant bellies of digastric, body of hyoid
- Key content: ant jugular veins
- Muscular triangle: sternocleidomastoid, superior belly of omohyoid, midline
- Key content: larynx, trachea, thyroid gland, parathyroid gland
Anterior triangle: subtriangle key contents
- Carotid: Key content: common and ext carotid artery
- Digastric triangle: Key content: submandibular gland
- Submental triangle:Key content: ant jugular veins
- Muscular triangle: Key content: larynx, trachea, thyroid gland, parathyroid gland
Anterior triangle of neck: contents
- Suprahyoid muscles
- digastric, styohyoid, mylohyoid, geniohyoid
- Strap uscles:
- thyrohyoid, sternothyroid, sternohyoid
- Nerves:
- Ansa cervicalis, hypoglossal, vagus
- recurrent and external laryngeal nerves (from vagus)
- Ansa cervicalis, hypoglossal, vagus
- Vessels:
- common carotid artery + bifurcation, branches of external carotid artery, jugular vein
- Other:
- Thyroid gland, parathyroid gland, submandibular gland, trachea, oesophagus
Ulnar nerve: Course
- Origin: C7/8/T1 roots
- Medial cord of brachial plexus, in axilla
- Runs between axillary artery and vein, in upper arm
- Lies on coracobrachialis, medial to brachial artery
- Passes behind medial epicondyle of humerus
- Passes between 2 heads of FCU (supplies it)
- Lies between FDP and FCU
- Passes superficial to carpal tunnel
- Divides into terminal br at pisiform
Ulnar nerve: Motor supply
- Forearm: ulnar 1/2 of FDP, FCU
- Intrinsic hand muscles, with exception of LOAF (median N)
Ulnar nerve: what is ulnar paradox
Division of ulnar N : wrist -> severely clawed ulnar fingers due to loss of lumbrical and interossei innervation (FDP remains in tact giving flexion)
Division of ulnar N : elvor -> less severely clawed hand as intrinsic AND FDP are loss resulting in less flexion of ulnar 2 fingers
Ulnar nerve: What do the lumbricals do and how many are there?
4 lumbrical muscles
lateral 2 = median nerve
medial 2 = ulnar nerve
Originate from FDP tendons, Insert into corresponding extensor expansion
Act to flex the metacarpophalangeal joints and extend the interphalangeal joints
In conjunction with interossei enable coordination of fine movements of fingers e.g. writing/playing musical instrument
Ulnar nerve: What do the interossei do and how many are there?
4 palmar and 4 dorsal interossei
supplied by ulnar nerve
Origin: metacarpal base
Insertion: proximal phalanx
Palmar interossei adduct
Dorsal interossei: aBduct
PAD DAB
Ulnar nerve: Sensory supply
medial 1.5 fingers and medial 1/3rd of palm
Clinical test for ulnar nerve
Wasting of small muscle of hand - hypothenar eminence
Test grip of paper between middle and ring finger
Froment’s sign - grip paper between thumb and lateral aspect of forefinger -> patient will flex thumb as adductor is lost
Sensory distribution - loss of medial 1.5 fingers and medial 1/3rd of palm
Ureter: Course and relations
Ureter: Key facts
- 25cm long
- Lined by transitional epithelium - possible TCC
- Blood supply
- Superiorly: ureteric branch of renal artery
- Inferiorly: superior vesiccal and gonadal
- Middle: aorta, gonadal, iliac vessels
- Lymph drainage - with arteries
- superior: para-aortic LN
- inferior: iliac LN
- Autonomic nerve supply - pain fibres accompany sympathetics
Ureter: course of the ureter on a KUB film
passes down level with tips of transverse processes of lumbar vertebrae, commending at medial aspect of kideny
Turns medially at level of ischial spine
Points of narrowing:
- Pelviureteric junction (PUJ)- over brim of pelvis
- Vesicoureteric junction (VUJ) - at point of entry to the bladder
^points of impaction of ureteric stone
What organs are palpable in the normal abdomen?
Aorta
lower pole of left kidney
Pathological: hepatomagaly, splenomegaly
