Exam 2 Flashcards
``Lecture 14
The Equine and Bovine thorax
What are the boundaries of the horse’s thorax?
What muscles are lining the thorax?
Boundaries
Formula: C7 T18 L6 S5 Cd15-21
Cranial: 1st rib/cartilage, manubrium, T1
Caudal: Diaphragm
Latera: Ribs/cartilage and intercostal muscles
Dorsal: Thoracic vertebrae and longus colli m.
Ventral: Sternum, costal cartilage, transverse thoracic m.
Muscles lining the thorax
- Longus colli: Atlas to T6, flexor, hypaxial muscle.
- Diaphragm: main muscle of respiration
-Costal part: attaches to cartilages of ribs
-Sternal part: dorsal surface of xiphoid cartilage
-Lumbar part: right and left crura-lumbar vertebrae
Central tendon: inner part of diaphragm Tendons of origin of the crura (The crus of diaphragm (pl. crura), refers to one of two tendinous structures that extends below the diaphragm to the vertebral column. There is a right crus and a left crus, which together form a tether for muscular contraction. They take their name from their leg-shaped appearance – crus meaning leg in Latin.).
Contraction of diaphragm = expansion of thorax, which allows for inspiration
Relaxation of the diaphragm = recoil, expiration, cranially compresses thorax.
What are the openings of the Diaphragm?
Where does it extend to?
Openings
-Aortic hiatus: between the two cura. Where aorta, azygos veins and thoracic duct pass through.
-Esophageal hiatus: perforates the right crus near its junction with the central tendon
-Caval foramen (vena cava): courses through central tendon on the right side.
-Vagus nerve trunk: just ventral to esophagus
Extends to 6th intercostal space/6th rib in horse and Ox
Olecranon frequently found at 5th intercostal space
Diaphragm gives plenty or room for organs in the thoracic cavity (lungs), one of the theories as to why horses are so athletic
Locomotor respiratory Coupling
Horses take one breath per stride
Conditioning is important because they can’t change how many times they breathe per stride.
As they move at speed, the abdominal viscera moves and expands the thorax aiding inspiration
What are characteristic of the pleural cavity and thoracic cavity in horses?
What are the mediastinal contents?
Pleural cavity is separated by mediastinum
Parietal pleura: lines the thoracic cavity
-Mediastinal pleura: cranial, middle or pericardiac, and caudal
-Diaphragmatic pleura
-Costal pleura
Whatever happens in one side also happens on the other due to Mediastinum not being complete in the horse
Medialstinal contents
- Cranial
-Thymus (not seen in older horses)
-Cranial mediastinal lymph node
-Thoracic duct
-Left recurrent laryngeal nerve (branch of vagus): Long nerve predispose to injury or dysfunction. Paralysis of the left side of larynx “Roaring syndrome” sound during exercise
-Sympathetic trunk
-Esophagus
-Trachea
-Vagus nerve
-Left phrenic branch of vagus - Middle
-Tracheobronchial nerve - Caudal
-Caudal mediastinal lymph node: they are small in horses but larger in bovine
Pleural cavities
What/where is the Pleural cupula?
What are the clinical implications of injury to the pleural cupula?
Where are the lines of pleural reflection?
PROJECTION of the pleural space
The plural cupola is the cranial extent of the pleural cavity. Extends cranial to first rib, is larger on the right side.
Extends outside of the thorax
Air in pleura cupula = collapsed lungs
-Axilla injury penetration, SQ emphysema common, air expansion of SQ tissue
The pleural cavity contains only a scant amount of serous fluid.
Costomedialstinal recess ventral to lungs
Lines of Pleural reflection
Costodiaphragmatic recess place where draining penhose can be placed
Horse
-18th rib and 8th rib
Bovine
-13th rib and 8th rib
Abdomen what are the boundaries? Peritoneum, Greater and Lesser Omentum what do they connect?
-Cranial: diaphragm
-Caudal: pelvic inlet
-Dorsal: lumbar vertebrae, diaphragm, and sub lumbar muscles.
-Lateral: abdominal wall muscles and diaphragm
-Ventral: abdominal wall muscles, lines alba, prepubic tendon.
Sublumbar muscles
-Psoas minor: lumbar vertebrae to body of ilium
-Iliopsoas most important, flexor of the hip: Psoas major: lumbar vertebrae to lesser trochanter
-Iliacus: wing of ilium to lesser trochanter
-quadratus lumborum: transverse processes of lumbar vertebrae to wing of sacrum and ilium
Retroperitoneum
-Kidneys (except left kidney of ruminant)
-Adrenal glands
-Ureters for most of their length
-Vessels: aorta, caudal vena cava
Greater omentum
-Connects the greater curvature of the stomach and the initial part of the duodenum with the terminal part of the large colon and initial part of the small colon (which connects dorsally to body wall)
-Omental bursa: is the space between the layers of greater momentum that won’t see during colic surgery
Lesser omentum
-Connects the lesser curvature of the stomach and the first part of the duodenum with the liver.
-Hepatogastric ligament and hepatoduodenal ligament
Bovine Omentum
Different than equine
Lecture 15
Thorax, Lungs
What is the approximate lung capacity in horses?
Do horse lungs have lobation?
What does the hilus of the lung contain?
Which lung has a larger and deeper cardiac impression?
55 liters
No lobation, except accessory lobe of the right lung.
Right equine lung
-Cranial, caudal, accessory lobes
-Cardiac notch @ 3rd-4th intercostal spaces
-Caudal portion may get compressed by diaphragm
-Medialstinal view: Hilus (Bronchus, pulmonary artery, pulmonary vein, pulmonary nerves and lymphatics)
Right lung mediastinal view
-Cardiac impression
-Cranial lobe
-Accessory lobe
-Caudal lobe
-Impression of caudal vena cava
-Impression of cranial vena cava
-Azygous vein impression
-Aortic impression
-Esophageal impression
Right lung lateral view
-Dorsal border
-Basal Border
-Caudal lobe
-Cardiac notch
-Cranial lobe
Right lung medial view
-Pulmonary vein, artery, principal bronchus, pulmonary ligament, etc.
Caudal Diaphragmatic view
-Caudal lobe left and right lungs
-Impression of caudal vena cava
Left Equine Lung
Lateral costal view
-Cranial and caudal lobes
-Deep cardiac notch 3rd to 6th intercostal spaces
-Pericardium contact the thoracic wall at 3rd and 6th ribs
Medial view left lung (mediastinal)
-Hilus
-No accessory lobe
-Esophageal impression
-Aortic impression
-Vascular impression
-Cardiac impression (larger)
Lateral view
-Dorsal border
-Basal Border
-Caudal lobe
-Cardiac notch
-Cranial lobe
At what vertebrae numbers can you find the lungs carina?
Which is the primary (main) bronchus (left and right)?
Which is the Secondary bronchus (lobar bronchus)?
Tertiary (segmental) bronchus (3 caudal, cranial and accessory for Rt and cranial and caudal for left lung)?
Subsegmental bronchus?
Bronchioles?
Between T4-T5
Carina is the very last place where you find the trachea cartilage
It bifurcates to left and right bronchi
Where is the Basal border of the lung in a horse?
Where is the costodiaphragmatic recess (pleural recess) costsmediastinal recess?
How much is the border of the lungs separated from the line of pleural reflection?
Basal border of the lung:
- Dorsal region of Rib 16th to Rib 6th
-Middle of the 11th Rib
-Costochondral junction of the 6th rib (just caudal to olecranon)
Pleural Recesses
-Costomediastinal recess: space ventral to the lungs
-Costodiaphragmatic recess: space caudal to the basal border of the lungs
The basal border of the lungs is separated from the line of pleural reflection by approximately
What are the landmarks for Auscultation of the lungs in Horses?
How much does an equine heat weigh on average?
Caudal angle of scapula
Upper end of the 17th rib
Point of the elbow
Long head of triceps m.
Heart
-0.7% of total body weight
-Average pulse: 28-45 bpm in a mature horse, but it can reach more than 250 bpm during maximum exertion
Which is the auricular face and atrial face?
What can we find on the left and right view of the heart?
Left view auricular face
-Brachiocephalic trunk (cranially)
-Aorta (caudally)
-Pulmonary trunk ligamentum arteriosum
-Pulmonary valve (tricuspid)
-Pulmonary arteries
-Cranial vena cava
-Right auricle
-Right Atrium
-Right ventricle (opened = Conus arteriosus)
-Paraconal inter ventricular branch and Great cardiac vein (apex area)
-Left ventricle
-Left ventricle opened = papillary mm, chordae tendinaeae, Left atrioventricular valve (mitral)
-Left atrium
-Caudal vena cava
-Circumflex branch
-Pulmonary veins
Right view ventricular face
-Right Azygous vein
-Aorta
-Brachiocephalic trunk
-Cranial vena cava
-Right circumflex branch
-Right atrium
-Right atrioventricular valve
-Right ventricle
-Right papillary mm.
Trabecula septotmarginalis
-Subsinuosal inter ventricular brach and middle cardiac vein
-Left ventricle
-Circumflex branch and Great cardiac vein
-Caudal vena cava
-Inside caudal vena cava = coronary sinus, Fossa ovalis intravenous tubercle.
-Pulmonary veins
-Pulmonary arteries
Coronary circulation in the horse, left and right
Equine Heart: Points of maximal intensity
Left coronary artery
-Paraconal inter ventricular branch and great cardiac vein
-Circumflex branch and coronary sinus vein
Right Coronary artery
-Right circumflex branch and coronary sinus vein
-Subsinuosal inter ventricular branch and middle cardiac vein
Pulmonary Valve: left side, 3-4th intercostal space craniodorsal to the olecranon
Aortic valve: left side, 4th intercostal space, ventral to the shoulder joint
Left AV valve (mitral): left side, 5th intercostal space, caudodorsal to the olecranon
Right AV valve (tricuspid): right side, 4th intercostal space, caudodorsal to the olecranon.
Branching of the aortic arch
-Brachicephalic trunk (Huge in horses compared to dogs)
-Left subclavian a.
-Costocervical trunk a. (branch of subclavian a. )
-Deep cervical a. (branch of subclavian a. )
-Right subclavian a.
-Bicarotid truck a. ; Rt and Lt common carotid aa.
Branches of Subclavian a.
Deep cervical a. supplies what important structure?
Deep cervical a., Deep costocervical a. Nuchal ligament injection can lead to hematoma in foals
-From costocervical trunk on the right side, subclavian a. on the left side.
-Courses toward the head to supply cervical structures and musculature in the caudal neck region
Vertebral artery
What does it give rise to and supply?
-Courses cranially through transverse foramina of the cervical vertebrae
-Gives rise to spinal and muscular branches
-Courses through the alar foramen and lateral vertebral foramen of the atlas and enters the vertebral canal.
-Right and left vertebral aa. from basilar a. (horse)
Superficial cervical a.
Internal thoracic a.
Superficial cervical a.
-Supplies structures in the craniolateral shoulder region
Internal thoracic a.
-Ventral intercostal aa.
-supplies ventral part of the thoracic wall
Cranial epigastric a.
-supplies the ventral abdominal wall
Name the arteries
Left subclavian a.
Costocervical trunk a.
Deep cervical a.
Vertebral a.
Superficial cervical a.
Axillary a.
Internal thoracic a.
Horse main/clinical significant veins
Cranial vena cava
Subclavian vein
Bijugular trunk
External jugular veins
Right side
Cranial vena cava
Superficial cervical vein
Vertebral vein
Costocervical vein
Right Azygous vein
Caudal vena cava
General viceral Efferent Sympathetic Mediastinum
-Cervicothoracic ganglion
-Vertebral n.
-Ansa ssubclavia
-Vago sympathetic trunk
-Middle cervical ganglion
-Rami communicantes
-Sympathetic trunk
-Major Splanchnic n.
General visceral Parasympathetic Mediastinum
-Vago sympathetic trunk
-Recurrent laryngeal n.
Vagus n.
Recurrent laryngeal n.
-Dorsal vagal branch
-Ventral vagal branch
-Dorsal vagal trunk
-Ventral vagal trunk
Lecture 16 Ruminant Heart and Lung
How does the lung capacity compare between the Ox and Equine?
What is the clinical application?
Why is bloat a big issue in cattle?
What are the boundaries in the Ox?
The Ox has approx only 30% of the lung capacity of the horse
The Ox also has multiple lobes, horse doesn’t
We need to listen to multiple lobes in the Ox
If you auscultate too caudally in the Ox you hear gut sounds, not lung sounds.
Cattle are excellent at walling off infections, so one lobe may sound normal while the lobe next to it is grossly abnormal
-Wheezes: asthma, airway disease
-Crackles: fluid, edema, interstitial/pleural issues.
Boundaries in the Ox
-10-11th rib down to elbow
-Auscultate 4 spots
-They have a very small thoracic cavity compared to the equine, limited space for the lungs
Bloat
-Rumen enlargement can obstruct the lungs/breathing
-They can suffocate and die
Anatomy of the lungs in the Ox
How many lobes does the right and left lung have?
How does it compare to other species?
Left lung
-Two lobes: Cranial Lobe (Cranial and caudal part)
-Caudal lobe
Right lung
-Significantly larger
-Four lobes
-Cranial-ventilated independently by the tracheal bronchus
-Middle
-Caudal
-Accessory
Comparison
-Lobation is prominent and easily differentiated
-Lobulation: their lung tissue appears to be broken into lobules
Where is the cardiac notch located?
How or where to start lung auscultation?
Left lung
-Notch lies between the cranial and caudal portion of the cranial lobe
-From 3rd intercostal space to the 5th rib
-Deep to triceps
Right Lung
-smaller space than the left
-3rd and 4th intercostal spaces
-Entirely deep to the triceps
Placement of stethoscope
-Start at the elbow and draw an imaginary line to the dorsal aspect of the 10-11th rib
-Bovine formula C7 T13 L6 S5 Cd18-20.
-Animal standing squarely, stethoscope between elbow and body wall
-Proper auscultation requires practice since heart and lung sounds may be muffled by excess tissue cover
Bacterial pneumonia
-Often affect cranioventral lung lobes first
-Likely by sedimentation of the bacteria as they pass from the trachea to the lung tissue
Describe the flow of blood
1. Cranial and caudal vena cava
2. Right atrium
3. right ventricle
4. Pulmonary arteries
5. Lungs
6. Pulmonary veins
7. Left atrium
8.Left ventricle
9. Aorta, Systemic circulation
Heart anatomy, location and orientation
Similarities and differences, comparative anatomy
-Assymetrically placed with 60% being to the left of midline
-Lies between the 2nd and 5th intercostal space, and the apex stands on the sternum.
-The caudal border apposes the diaphragm, lines up with reticulum and liver
Comparisons
-The primary difference is the aorta
-In ruminants and horses only brachiocephalic artery arises from he aortic arch.
-Both subclavians arise from the brachiocephalic trunk
-Ruminants also have a left and right azygous vein.
Auscultation of the heart
Clinical application of Traumatic reticuloperitonitis
PAM 3,4,5 T4
-Pulmonary valve 3rd intercostal space
-Aortic valve 4th intercostal space
-Left AV valve (mitral) 5th intercostal space ventral to the aortic valve
Right
-Right AV valve (tricuspid) 3-4th intercostal space
Clinical application
-The heart is only separated from the reticulum by the diaphragm
-Consumption of foreign bodies can lead to penetrating the wall of the reticulum and causing reticuloperitonitis, penetration of the heart, sudden death.
Right heart failure
-blood backs up into the jugular veins causing them to appear distended
-Look for distention more the 2/3 of the way up the neck
Left side heart failure
-Fluid accumulation in the lungs causing a cough not associated with pneumonia
Mediastinum
Vagus nerve
Mediastinum
-The cleft or wall separating the thorax into two compartments
-Contains: heart, esophagus, trachea, aorta, thymus, various vessels, nerves, and lymphatic structures.
Vagus nerve
-Typically found in close proximity to the esophagus, and passing dorsal to the base of the heart in a cranial to caudal fashion
-It passes between the lungs within the mediastinum
Clinical application
-Mediastinum of horses, sheep, dogs, contain fenestrations allowing unilateral pneumothorax or pyothorax to become bilateral
-Cattle, goats, and pigs, do not have these fenestrations, making them somewhat resistant to the spread of these conditions.
Vagal Indigestion
-Type I vagal indigestion can be caused by inflammation of the structures in close proximity to the vagus nerve.
-Vagus nerve is involved with the rumen motility
-Localized peritonitis adhesions (potentially from traumatic reticuloperitonitis), or chronic pneumonia may contribute to the development of vagal indigestion.
Example:
-Chronic bloated calf, failure to thrive due to colostrum deficiency when born.
Lecture 17
Equine digestive Tract
Equine digestive tract parts, Hindgut phermentors
-Oral cavity
-Pharynx
-Esophagus
-Stomach
-Small intestine
-Large intestine
-Rectum and anus
Stomach
-Monogastric: one true stomach
-5-15 liters capacity
-Esophagus; oblique orientation
-Cardia (entry)
-Fundus
-Body
-Pylorus (exit)
-Greater curvature
-Lesser curvature
The terminal esophagus is a thick muscle, impressive lower esophageal sphincter
Horses can’t vomit, dilation of the stomach can lead to rapture
-Glandular portion and Non-glandular separated by MARGOT PLICATUS.
-Non-glandular portion is not protected from gastric acid, gastric ulcers are common.
-Rugal folds increase the surface area
Stomach positioning
-Contacts the diaphragm and liver cranially
-Contacts the colon, pancreas, and small intestine
-Attached to the spleen on the left by a gastrosplenic ligament: connects the dorsolateral greater curvature with lesser curvature of the spleen
Greater momentum and lesser Omentum
What does it connect?
It connects the greater curvature of the stomach and the initial part of the duodenum with terminal part of the large colon and initial part of the small colon, which connects to the dorsal body wall
Lesser Omentum
-Connects the lesser curvature of the stomach and the first part of the duodenum with the liver
-Hepatogastric ligament and hepatoduodenal ligament
Epiploic Foramen
What is it? what is it bounded by? Clinical significance?
It is the naturally occurring opening leading into the omental bursa Small intestine can get trapped in the omental
bursa
Bounded by
-The caudate lobe of the liver dorsocranially
-The caudal vena cava dorsally
-The portal vein ventrally
Equine Intestine
Small Intestine
-Duodenum, Jejunum, Ileum
Large Intestine
-Cecum
-Ascending “large colon”
-Transverse
-Descending “small colon”
-Rectum
-Anus
Duodenum
-Found dorsally on the horse’s right side. suspended from dorsal body wall by a short mesentery 3-5cm MESODUODENUM
-Cranial duodenal flexure
-Descending duodenum
-Caudal duodenal flexure: caudal to the cranial mesenteric artery
-Transverse duodenum (way caudally toward rectum)
-Ascending duodenum
-Duodenojejunal flexure - Duodenocolic ligament
-Duodenocolic fold
Small intestine - Jejunum (no tania, no huastra)
-Found from the left paralumbar fossa to the ventral abdominal floor
-Long mesentery ~ 65 ft (19.5 m)
-Long Mesojejunum: around cranial mesenteric artery “root of the mesentery” attachment site
Small intestine -Ileum
-Terminal small intestine
-More muscular
-Ileocecal fold Landmark for clinical decisions
Large Intestine
-Taenia: “Bands” longitudinal smooth muscle
-Haustra: Indentations, sacculations created by the tania. Transient
-CECUM: fills right paralambar fossa to ventral midline
-Base, body, and apex
-Ileocecal valve - papilla
-Cecocolic orifice - no valve common site of obstruction
-4 bands - ileocecal fold fold and cecocolic ligament
-Transverse colon: Right to left, cranial to the root of the mesentery, funnel shaped
-Descending colon: “small colon” long mesentery, mostly dorsal left caudal quadrant of abdomen, continues within pelvic canal as rectum.
Right ventral colon - sternal flexure - left ventral colon - pelvic flexure - left dorsal colon - diaphragmatic flexure - right dorsal colon.
444-1322 = Four on the floor (Cecum, right ventral, left ventral) One = left dorsal colon, 3 = right dorsal, 2 = transverse, 2 = Descending colon.
Lecture 18 Thorax and abdomen continuation
Which are the accessory digestive organs?
What is the basic blood flow through the GI tract?
Discuss the liver (Equine)
- Liver
- Pancreas
- Gallbladder
- Spleen
Liver
-Caudate lobe & caudate process of caudate lobe (no papillary process)
-Renal fossa is caudal part of caudate lobe
-Left lobe: left medial and left lateral parts
-Right lobe
-Quadrate lobe
-Diaphragmatic surface
-Visceral surface
-Marks related to ribs on diaphragmatic surface
-Caudal vena cava: dorsally and portal vein ventrally as well as the common hepatic duct
Topography of the liver
Is the liver easy to palpate?
What is the most convenient side for a liver biopsy?
-Almost imposible to palpate the liver
-Easiest on the Rt side for a FNA, liver biopsy
Equine Spleen
Where in the abdomen is it located?
In which direction does the tail or apex extend?
What are the ligaments associated with the spleen?
-It is located on the left dorsal abdomen
-Tail or apex extends cranially
-Caudal edge of greater curvature may be palpable per rectum
Nephrosplenic ligament #6 connects spleen and left kidney. Left dorsal displacement of large colon, sire for colic
Equine Pancreas
What are the associated papillae ?
-Located transversely across the abdomen, touching the dorsal body wall
-Heart shaped, around the portal vein.
Major duodenal papilla (bile duct entrance), Minor duodenal papilla (accessory pancreatic duct)
Blood supply
Describe the flow of blood through GI tract
Which part does not have dual blood supply and is predisposed to circulation injury?
- Celiac artery
-Splenic a. - left gastroepiploic a. (left side of greater curvature)
-Left gastric (left side of lesser curvature)
-Hepatic - right gastric - gastroduodenal a. - right gastroepiploic (right greater curvature)
- Cranial mesenteric artery
-Caudal pancreaticoduodenal a.
-Jejunal a.
-Ileocolic a. # 15 Colic branch #16 (ventral large colon)
-Right colic a. # 13 (dorsal large colon)
-Middle colic # 14 (small colon)
- Caudal mesenteric artery
-Left colic - small colon and rectal branches.
Cecum does not have dual blood supply and is predisposed to circulation injury
Landmark to identify the Ileum = ileocecal fold
Lecture 21 Thorax and abdomen continuation
Ruminant Abdominal Anatomy
What are the muscles of clinical importance of the abdominal wall in the OX?
What is the orientation of the fibers?
Superficial to deep
A. Cutaneous trunci m.
B. External abdominal Oblique m. CAUDOVENTRAL fibers
C. Internal Abdominal Oblique m. CRANIOVENTRAL fibers
D. Transverse Abdaminous m. DORSOVENTRAL
D. Rectus Abdominous m. ventral part of abdomen might not come into play
B. External abdominal oblique m. The most superficial muscle of the trunk. Arises from the caudal aspect of the last eight ribs. Fibers run caudoventrally to the lines alba. The most dorsal fibers will appear to run horizontally to the coral tuber.
C. Internal abdominal oblique m. is deep to external abdominal oblique m. fibers arise from the coxal tuber and the pelvic tendon of the external abdominal oblique m. It inserts on the last rib and linea alba. Fibers will appear to run in a cranioventral fashion.
D. Transverse abdominis m. Arises from the last rib and the extremities of the lumbar transverse processes. DEEPEST during C-section. It inserts into the aponeurosis immediately dorsal to the rectus abdominis m. Fibers run dorsal to ventral direction
D. Rectus abdominis m. Arises from the ventral surface of the last ten ribs and travels caudally to the pubic brim.
Which are the most important nerves that supply the abdominal wall in the Ox?
Describe the clinical importance and innervation
T13
L1
L2
They come out into dorsal and ventral branches and provide innervation to the flank area, sensation. The skin is supplied by the dorsal and ventral branches, the deeper structure are supplied by the ventral branches.
Topography of the nerves to the flank and udder
Lateral figure
- Last rib
- Spinous process of second lumbar vertebrae (L2)
- Coxal tuber
- 12 thoracic intercostal nerve. (T12)
- T13 nerve (costoabdominal n.)
- L1 nerve (iliohypogastric n.)
- L2 nerve (Ilioinguinal n.)
- L3 and L4 nerves (genitofemoral n.)
- L5 nerve
- Ventral perineal n.
Dorsal view figure
- Last rib
- First lumbar vertebrae L1
- Sixth lumbar vertebrae L6
- Coxal tuber
- Dorsal and ventral branches of T13 nerve
- Dorsal and ventral branches of L2 nerve
- Supraspinous ligament
The ruminant Stomach, Abdominal topography
- Esophagus
- Outline of the spleen
- Reticulum
- Dorsal sac of rumen
- Ventral sac of rumen (covered by superficial wall of greater omomentum)
- Funds of abomasum (covered by superficial wall of greater omentum
Chambers of the Stomach
- Reticulum
- Dorsal sac of rumen
- Reticular groove
- Body of abomasum
- Atrium ruminis
- Caudodorsal blind sac
- Caudoventral blind sac
- Ventral sac of rumen
- Esophagus
- Reticulum
- Body of abomasum
- Omasum covered by lesser omentum
- Descending duodenum
- Pyloric part of abomasum
- Greater Omentum covering the intestinal mass
- Lesset omentum cut away from the liver
The Rumen
-Along with the Reticulum, it is the fermentation part.
-It extends from the cardia (half way up the 8th rib) to the pelvic inlet, and from the floor of the abdomen to the ceiling.
-It fills the entire left side of the abdomen stretching over midline especially caudally and ventrally to the right flank
Rumen internal Anatomy
-Longitudinal pillar (right and left)
-Cranial pillar (9-12)
-Caudal pillar (10-11)
-Ruminoreticular fold (cranial portion of 12)
-Recessus ruminis (atrium of the rumen #9)
-The mucosa will appear as a sheet of papilla
Rumen Contents
-Gas bubble
-Coarse forage
-Finely ground material with more density than coarse forage
-Liquid
These layers can be assessed during PE
Reticulum
- Heart
- Diaphragm
- Atrium ruminis
- Reticular groove
- Reticulum
- Ruminoreticular groove
- Abomasum
- Ventral sac of abomasum
Functions virtually the same as the rumen
Boundaries
-Cranially by the diaphragm and liver
-Ventrally by the abomasum
-Caudally by the rumen
-Laterally by the abdominal wall
It is relatively fixed in place and not palpable per rectum. Mucosa forms a honeycomb pattern. Relatively larger in small ruminants
Reticular Groove
-A bounded gutter leading from the esophagus and cardia ventrally to the fundus and opening of the omasum
**In the unweaned animal the groove takes the shape of a tube to direct any ingested material directly into the omasum and abomasum **
Omasum
Where is it found, bounded by, can it be palpated rectally?
What is its function?
- Right AV valve
- Position of basal border of lung
- Cranial extent of diaphragm
- Field of liver percussion
- Omasum
- Field of percussion and auscultation of omasum.
-Found in the right side of the abdomen within the intrathoracic portion
-Bounded by the rumen and the reticulum on the left and the liver on the right and body wall on the right
-Found externally between the right 8th to 11th ribs
-Typically out of reach rectally, but can be auscultated through the body wall
Functions: water absorption, volatile fatty acids and electrolyte absorption. Filtering particles small enough to reach abomasum
Mucosa looks like pages pages of book
Displacements
Left and right abomasa displacements are one of the most common surgeries in dairy practice
The abomasum can filled with fluid or gas and rise to the right side of the rumen. Rectally palpated as a gas filled structure occasionally
Right side can become RVA
Neonate
-Stomach varies significantly from adult stomach
-The abomasum in neonates is much larger compared to the other chambers. It is the primary stomach chamber in neonates
Small Intestines & Hindgut
- Pyloric part of the abomasum
- Duodenum
- Jejunum
- Ileum
- Cecum
- Ileocecal fold
7-10: Ascending colon
7- proximal loop of ascending colon
8- Centripetal turns of spiral colon
9- Centrifugal turns of spiral colon
10- Distal loop of ascending colon
11- Transverse colon
12- Descending colon
13- Rectum
14- Jejunal Lymph nodes
15- Cranial mesenteric artery
The intestines lie almost entirely on the right side of the abdomen. The cranial most portion lies under the ribs
-Duodenum: initially courses doors-cranially towards the liver, but then turns caudally when it gets level to the coal tuber
-Normally seen through a high flank incision used for displacement surgeries, it should be traveling horizontally
Hindgut
-Duodenum
-Jejunum
-Ileum-ileocecal fold.
-Cecum
-Proximal ascending colon
-Spiral colon: centripetal turns (pedal in). Centrifugal turns (get the F out).
-Distal ascending colon
-Transverse colon
-Descending colon
Topography of the OX left and right side
Liver (11th intercostal space)
The liver is found almost entirely on the right side of the abdomen
Lies deep to the ribs from the ventral 3rd to 6th intercostal space to the upper part of the last rib
The liver can be palpated easily during abdominal exploratory as a solid organ immediately cranial to a high right flank incision. Edges of liver should be sharp
Lecture 24 thorax and abdomen 8
Ruminant
Unlike small animal surgery, you often can not see what your are working on
Abomasal displacement surgery as our model
-Normal
-Reverse D: Bloat
-Pear: Ascites, Intestinal Obstruction
-Apple: Hydrops, severe ascites, during pregnancy.
-D: Cecocolic volvulus, Abomasal volvulus.
-Papple: Abomasal impaction
What are the 4 types of Nerve Blocks used in flank surgeries?
- Proximal paravertebral
- Distal paravertebral
- Inverted L
- Line block
Proximal paravertebral
-First the spinous processes of L1, L2, and L3 are found
-The nerve roots are located lateral to the spinous processes
-A 6” spinal needle is inserted in a ventral fashion until the transverse process is hit. The needle then is walked off the caudal of the transverse process and lidocaine is injected
-This will anesthetize T13, L1 and L2
Distal Paravertebral
-Find the transverse processes of L1 and L2 and L4 (skip L3)
-Because the ventral and dorsal branches of the spinal nerve have separated at this point, lidocaine must be injected above and below the spinous process.
Pings
-Produced when a gas filled organ under pressure is in contact with the body wall
-Any organ can do this
Left side
-Rumen gas cap
-Left displaced abomasum
Right side
-Right displaced abomasum
-Right abomasum volvulus
-Cecal dilation
-Cecal volvulus
-Duodenal gas
-Colic gas (spiral colon)
-Uterine gas
-Free abdominal gas, can happen after c-section
Where will it ping?
-Draw a line from the elbow to the coral tuber. Usually left displaced abomasum are centered around this line on the right or left side
-Most DA will be found under the ribs on either side extending from rib 9-13th (they can extend further in extreme cases)
Lecture 25 Urogenital
The bony pelvis
-Sacrum
-Coxal bones = Ilium, ischium, pubis
Bovine
-Sacrosciatic ligament
-Round pelvic inlet
Pelvic inlet
-Terminal line = pelvic brim. Rounder in mare/cow, more ovoid in stallion
Pelvic Outlet
-Ischial tuberosity and arch
-Sacriosciatic ligament
-Semimembranosus, semitendinosus, and sacrosciatic ligament support pelvic outlet.
Sacroiliac Joint
-Modified diarthrosis: hyaline cartilage on scrum, fibrocartilage on ilium, supporting ligaments (Dorsal sacroiliac ligaments, dorsal and lateral)
-Tiny joint capsule
-Ventral sacroiliac ligament
-Interosseus ligament
-Pelvic symphysis
Pathogenic issues
-“hunter seat bump” on horses
Sacrosciatic Ligament
-Lateral sacrum to ilium and schium
-Greater ischiadic notch. Lumbrosacral trunk. CRANIAL GLUTEAL a. & v.
-Lesser ischiadic notch. Tendon of internal obturator in a horse
Bovine
-Within 24 hrs of birthing sacrosciatic ligament relaxes
The Urinary System
What are the 6 organs?
Two kidneys
Two Ureters
Bladder
Urethra
Right kidney is more cranial than left kidney
-Adrenal glands found cranially except in the horse
-Covered in perinephric fat and fibrous capsule
-Cat and ruminant - left kidney is pendulous
Kidney Parenchyma
-Cortex: renal corpuscles and convoluted tubules
-Medulla: long loops of henley and collecting ducts
-Unipapillary: renal crest = carnivores, horse, small ruminant.
-Multipapillary = pig, ox.
Equine kidney
-Unipapillary with renal crest
-Terminal recesses
-Mucus glands = makes urine frothy, foamy
Rt kidney: located ventral to the last two ribs and first lumbar transverse process. Find transcutaneously
Left kidney: located ventral to the last rib and first two or three lumbar processes. find transcutaneously
Bladder
-Retroperitoneal when empty
-Two lateral ligaments, one median ligament
Urogenital 2 Female Reproductive Anatomy
External anatomy
External Anatomy Vulva
The vulva is the exterior opening of the female reproductive tract
-It is located ventral to the anus
-Bounded laterally by the labia on either side that meet both dorsally and ventrally at the commissures
-Acts as the exterior opening for both repro and urinary tract
-Swelling of the vulva can be normal sign of estrus
-It is contained within the perineum which is defined as the area ventral to the tail and dorsal to the ventral commissure of the vulva
Clinical application
-Mares with recessed vulva towards the anus is considered poor conformation
-Breeding soundness exam
Windsucker, pneumovagina
-Conformational defect of the mare
-The vulvar lips do not properly oppose allowing air to be sucked into the vagina
-Can also lead to fecal contamination of the vagina
-Corrected with CASLICK’s Surgery
Epidurals
The pudendal nerve provides sensory innervation to the rectum, internal and external reproductive organs, and the perineal skin
Pudendal nerve also provides motor innervation to the striated perineal musculature
The pudendal nerve arises from S2-S4 in ruminants, and S(2)3-S4 in horses
Caudal epidural
-Placed in the sacrococcygeal space (S5-C1) or the first coccygeal space (C1-C2). This provides analgesia to the tail, vagina, vulva, anus, and rectum (also caudal prepuce in males)
-For procedures involving the cranial abdomen and lumbosacral epidural is given within the lumbrosacral space
Internal structures
Mare
- Ovary 1’ proper ligament of the ovary
- Uterine tube
- Uterine horn
- Uterine body
- Cervix
- Vaginal part of the cervix
- Fornix (mares unique)
- Vagina
Cervix
-Glandular, sphincter like muscle found immediately cranial to the vagina
-Excretes copious amounts of mucous
-Composed of smooth muscle, changes tone, size, color and secretions depending on the dominant hormone expressed at the time.
Estrogen: estrus = flaccid
Progesterone: diestrus = tight.
-It acts as the final line of defense of the uterus against contamination
Uterus
What is it suspended by?
What is the endometrium?
What is the glandular portion?
-Found immediately cranial to the cervix
-Can be divided into a body, and two horns
-It is suspended in the abdomen by the MESOMETRIUM of the broad ligament
-The lumen consists of gland-free core of connective tissue arranged in longitudinal folds, surrounded by a highly glandular endometrium
The Broad Ligament & Vessels
-It is a fold of peritoneum
-Suspends the female repro tract within the abdomen
Portions
- Mesosalpinx: encompasses the uterine tube
- Mesovarium: attaches ovary to the dorsolateral abdominal wall
- Mesometrium: attaches the uterine body and horns to the dorsolateral body wall. Includes the Uterine Vessels (palpable)
Uterine Vessels
-Found within the mesometrium
-Fremitus-vibration felts in the middle uterine artery during pregnancy in cows
-They course cranially along the sides of the uterus and uterine horns until they anastomose with the uterine branches of the ovarian arteries and veins
Species differences
Uterine horns and body
-Carnivores and sows have long horns compared to their uterine bodies. Adapted for litter bearing
-Mares: short horns, similar in length to uterine body
-Ruminants: have long horns and short bodies. The horns are bounded cranially by intercornual ligament
Location of the Ovaries
-Mare: lie caudal to the kidneys in the sub lumbar region
-Ruminants and sows: lie at the pelvic inlet
Cervix
-Mare: simple cervix that bulges into the vagina, forming a distinct vaginal recess
-Ruminants and sows: long cervixes with transverse folds that interdigitate with each other. The effectively closes the cervix during any time outside of estrus and parturition.
Clinical Application Rectal Palpation & surgical Considerations
-Enter the rectum
-Sweep the floor of the rectum just cranial to the anus until you find the cervix (will fill like a length of garden hose)
-continue moving cranially until you feel the bifurcation of the horns
-Grasp the intercornual ligament and flip the uterus up so that it is resting in your palm. Only applicable for cows
-Palpate the length of both horns choking for signs of pregnancy
Ovaries
-Larger in mares than in cattle
-Should find on either side of the pelvis
-Can appreciate follicles (cherry tomatoes) and corpus lutes (raised rough areas). Check both for signs of estrus
Ultrasound
-Know the order of the structures as they appear
vagina, cervix, bladder, ovaries (4 and 6 O’clock), uterine horns
Surgical Considerations
-Porcine c-section: typically lateral recumbency with the left leg lifted. Paramedic incision. Incision closer to the uterine body, which is longer than in ruminants and more forgiving, allows exploration of both uterine horns.
Bovine c-section
-Typically done standing animal
-In the left flank
-Rumen prevents viscera from being pushed out during contractions
-Incise the uterus distal to the uterine body bc the body is short and has very little cranial to caudal elasticity.
-Weight of the baby will make it setting to the ventral abdomen
Urogenital 3 Male Reproductive Anatomy
Equine: oriented horizontally
Ruminant: oriented vertically, and pendulous
Porcine: oriented vertically, held right to the body
External anatomy of the penis
-Fibroelastic: high connective tissue content means these will remain firm even when not erect. Ruminants and the boar
-Musculocavernous: low connective tissue content, will be flaccid when not erect. Horses and carnivores
Clinical implications - Breeding Soundness Exam
-Testes should be equal in size
-Flexed bicep consistency on palpation
-Move freely within the scrotum and be oriented vertically for bovine
-32-34 cm but ideally 35 cm in diameter
-Should measure at least 8 cm wide
-The penis of stallions and bulls should be examine for signs of scars, tumors, or other lesions.
-Defects may be present and prevent breeding ex: persistent frenulums, which should break naturally during birth. It can be removed surgically, but should not be bred
Descent of the Testes
-Testicles located retroperitoneal between the peritoneum and the body wall.
-Initially the gubernaculum passes ventrally through the inguinal canal into the scrotum
-It is followed by the testicle and epididymis
-As it moves through the inguinal canal it picks up parietal peritoneum and fascial layers of the inner and outer abdominal wall.
-These become the vaginal tunic once outside the abdomen
The Inguinal Canal
-It is a potential space between the flesh of the internal abdominal oblique and the aponeurosis of the external abdominal oblique
-The deep inguinal ring is found at the free edge of the internal abdominal oblique m.
-The superficial inguinal ring lies between the pelvic and abdominal tendons of the external abdominal oblique
Picture
- Testis
- Gubernaculum: jelly-like cord stretching from the testicle to the tail of the epididymis, and then into the inguinal canal. it becomes the scrotal ligament
- Vaginal process
- Testicular artery
Timing of Descent
-Ruminants and pigs: before birth
-Carnivores: slightly after birth
-Horse: 10-14 days before or after birth
Testicular Anatomy
- Testis
- Head of the epididymis: spermatozoan mature into sperm in the head and body of epididymis
2’ body of epididymis
2” tail of the epididymis - Deferent duct: continuation of the epididymis for transportation of sperm
- Pampiniform plexus: coil of testicular artery, drawing heat away from the artery to cool blood before reaching the testicle
- Mesorchium: the serial fold connecting the visceral and parietal vaginal tunics
- Proper ligament of the testis
- Ligament of the tail of the epididymis
- Cut edge of the fold of connecting visceral and parietal layers of the vaginal tunic
Clinical application Cryptorchidism
-Failure of one or both testicles to descend into the scrotum
-More commonly experience by horses or pigs
-Rare in ruminants
-May be bilateral or unilateral
-Affected animal should not be used for breeding
Types
- Inguinal: most common, undeveloped testicle found within the inguinal canal, or just outside the superficial inguinal ring.
- Descended epididymis: tail of the epididymis and the ductus deferens are located within the inguinal canal, but the testicle is within the abdomen
- Complete abdominal: testicle and epididymis lie with the abdominal cavity
Diagnosis can often be done by palpating the inguinal rings via the inguinal region, or rectally (in stallions and bulls).
Both inguinal and descended cryptorchids can be addressed in the field.
Complete abdominal cryptorchids require abdominal surgery
Clinical Application Castration
Open: refers to opening the vaginal cavity and thus the peritoneal cavity
Closed: clamping and removing without opening vaginal cavity
Penile Anatomy Ruminants
- Sigmoid flexure: common site for urethral calculi
- Retractor penis muscle-must relax to expose the penis for examination or treatment
- Preputial skin
Urethral Process
Occasionally uroliths may become lodged in the urethral process, making amputation necessary
Penile anatomy Stallion
- Glans penis
- Urethral process
- Fossa of the glans - traps smegma which builds up to form the ‘bean’
n. Preputial ring (in some horse it may be constricted leading aka phimosis)
Penile anatomy of the Boar
- Glans penis, note the twisting appearance
- Prepucial diverticulum, becomes filled with cell debris soaked in urine over time
A pheromone also collects here that encourages compliance from the female during mating
-If it becomes overly full it may look like a hernia
-Note the sigmoid flexure similar to ruminants.
Accessory Sex Glands
During breeding soundness exam, glands should be palpated rectally.
Assess for symmetry, and should not be overly sensitive
The veterinarian should make sure to palpate ALL accessory glands.
-In general they are associated with the urethra and add the liquid portion of the ejaculate
Rectal palpation
- Bulborethral gland
- Prostate
- Vesicular gland
