Midterm 2 - Review Topics

In the forelimb, what is the saying regarding the position of the head when the sound hoof is touching the ground?

- "Down is sound"

When the painful forelimb is touching the ground, the head will be...

- Up

When the sound forelimb is touching the ground, the head will be...

- Down

When the painful pelvic limb is touching the ground, the head will be...

- Down

When the sound pelvic limb is touching the ground, the head will be...

- Up

Explain how to perform a radiocarpal joint injection.

- Flex the carpus to increase the space between the distal radius and the proximal row of carpal bones. Palpate the distal radius and proximal row of carpal bones and insert the needle medial or lateral to the extensor carpi radialis tendon.

Explain how to perform a middle carpal joint injection. What does this joint communicate with?

- Flex the carpus to increase the space between the distal row of carpal bones and the proximal row of carpal bones. Palpate the distal row of carpal bones and proximal row of carpal bones and insert the needle medial or lateral to the extensor carpi radialis tendon.

- Communicates with the carpometacarpal joint

If a penetrative puncture at the level of the navicular bone were to occur on the palmar aspect of the region, which structures would likely be affected?

- Impar ligament (Distal sesamoidean ligament)

- DDF

- Navicular bursa

Explain how to perform a palmar digital nerve block. What nerves are block? What area is desensitized?

- Block medially and laterally midway between the coronet and the fetlock in the palmar pastern region, palmar to the palmar digital vein and artery.

- Nerves blocked: Medial and lateral palmar digitalnerves (not including their dorsal branches)

- Area desensitized: Palmar 1/3 of the foot

Explain how to perform an abaxial nerve block. What nerves are blocked? What areas are desensitized?

- Block medially and laterally at the abaxial surface of the proximal sesamoids.

- Nerves blocked: Medial and lateral palmar digital nerves (Including their dorsal branches)

- Areas desensitized: Everything distal to the fetlock

Explain how to perform a low 4-point nerve block. What nerves are blocked? What areas are desensitized?

- Block at the distal extent of the splint bone (Medial and lateral palmar metacarpal nerves) after sterilely prepping the area, being careful to avoid the proximal palmar pouch of the fetlock joint. Block at the level of the distal extent of the splint bone between the interosseous and DDF (Medial and lateral palmar digital nerves).

- Nerves blocked: Medial and lateral palmar digital nerves, medial and lateral palmar metacarpal nerves

- Areas desensitized: The fetlock and everything distal to the fetlcok

Explain how to perform a high 4-point nerve block. What nerves are blocked? What areas are desensitized?

- Block distal to the carpometacarpal joint, between the palmar surface of the cannon bone and the axial surface of metacarpals II and IV (Medial and lateral palmar metacarpal nerves). Block distal to the carpometacarpal joint medially and laterally adjacent to DDF (Medial and lateral palmar nerves)

- Nerves blocked: Medial and lateral palmar metacarpal nerves, medial and lateral palmar nerves

- Areas desensitized: Blocks the metacarpal region, the fetlock, and everything distal to the fetlock.

Explain how to perform a lateral palmar nerve block. What nerves are blocked? What areas are desensitized?

- Block as it courses medial to the accessory carpal bone, prior to the origin of the deep branch which innervates interosseous m. and gives rise to the palmar metacarpal nerves (medial and lateral)

- Nerves blocked: Lateral palmar nerve (and all its branches -> Deep branch, medial and lateral palmar metacarpal nerves)

- Areas desensitized: Interosseous and MCs II and IV

Explain how to perform a median nerve block. What nerves are blocked? What areas are desensitized?

- Block on the caudomedial aspect of the radius, just distal to the elbow joint, where the ventral edge of the transverse pectoral m. inserts on the antebrachial fascia.

- Nerves blocked: Median n.

- Areas desensitized: Partially anesthetizes the carpus and distal antebrachium and the structures innervated by the medial and lateral palmar nerves.

Explain how to perform an ulnar nerve block. What nerves are blocked? What areas are desensitized?

- Block approximately 4 inches proximal to the accessory carpal bone. Nerves is below the skin in a groove formed by flexor carpi ulnaris m. and extensor carpi ulnaris m.

- Nerves blocked: Ulnar n.

- Areas desensitized: Skin of lateral forelimb distal to the injection site to the level of the fetlock. Structures partially anesthetized include the accessory carpal bone and surrounding structures, MCs II and IV and their interosseous ligaments, interosseous.

What muscles are innervated by the lateral thoracic nerve?

- Cutaneous trunci m.

- Cutaneous omobrachialis m.

- Deep pectoral m.

What muscles are innervated by the long thoracic nerve?

- Serratus ventralis thoracis m.

What muscles are innervated by the thoracodorsal nerve?

- Latissimus dorsi m.

What muscles are innervated by the cranial/caudal pectoral nn.?

- Pectoral mm.

What muscles are innervated by the suprascapular n.?

- Supraspinatus m.

- Infraspinatus m.

What muscles are innervated by the subscapular n.?

- Subscapularis m.

What muscles are innervated by the musculocutaneous n.?

- Biceps brachii m.

- Coracobrachialis m

- Brachialis m.

What muscles are innervated by the axillary n.?

- Teres major m.

- Teres minor m.

- Deltoideus m.

- Caudal part of subscapularis m.

What muscles are innervated by the radial n.?

- Triceps brachii m.

- Anconeus m.

- Tensor fasciae antebrachii m.

- Extensor of the antebrachium and manus

What muscles are innervated by the median n.?

- DDF (Humeral and radial heads), flexor carpi radialis m.

- Also SDF, flexor carpi ulnaris m., and pronator teres m. in ruminants

What muscles are innervated by the ulnar n.?

- SDF, DDF (ulnar head), flexor carpi ulnaris, interosseous m. (Palmar branch)

Explain how the collateral cartilages of the hoof in horses change with age.

- Young horses -> Hyaline cartilage

- Middle-aged horses -> Fibrocartilage

- Older horses -> Ossify into side bones

How do ruminant hooves differ from equine hooves?

- Ruminant hooves are composed of two digits, have no frog, have no bars, and have no secondary dermal/epidermal laminae. Ruminant hooves also have interdigital ligaments (Proximal and distal).

What is the autonomous zone of the median n.?

- Pastern region

What is the autonomous zone of the ulnar n.?

- Caudal antebrachium + dorsolateral metacarpus and carpus

What is the autonomous zone of the musculocutaneous n.?

- Medial antebrachium + Dorsal metacarpal region

What is the autonomous zone of the axillary n.?

- Lateral brachium + Cranial antebrachium

What is the autonomous zone of the radial n.?

- Lateral brachium + Craniolateral distal 1/3 of antebrachium

Explain the arterial blood supply to the hoof region in the horse.

- The median artery gives rise a palmar branch of the median artery, which continues as the lateral palmar artery.

- The median artery continues as the medial palmar artery, and gives rise to both the medial and lateral palmar digital arteries.

- The medial and lateral palmar metacarpal arteries arise from the deep palmar arch. These unite distally and join the lateral palmar artery

Explain the arterial blood supply to the hoof region in the ox.

- The median artery gives rise to a radial artery

- The median artery continues as the palmar common digital artery III.

Explain the venous drainage of the hoof region in the horse.

- The palmar venous plexus drains into the medial and lateral palmar digital veins.

- The medial and lateral palmar digital veins drain respectively into the medial and lateral palmar veins.

- The medial and lateral palmar metacarpal veins drain into the medial palmar vein

- The lateral palmar vein drains into the cephalic vein

- The medial palmar vein drains into the median vein or the cephalic vein.

Explain the venous drainage of the hoof region in the ox.

- The dorsal common digital vein drains into the accessory cephalic vein.

Describe the difference in the external structure of the equine and bovine lungs.

- Ox: Pronounced lobation, lobulated by thick CT septae

- Horse: No evidence of external lobation except the accessory lobe of the right lung.

The __________ bovine lung is larger. What about in the horse?

- Right

- In the horse, the lung are approximately equal in size

What are the lobes of the bovine lung?

- Right: Cranial (Cranial and caudal parts), caudal, middle, accessory

- Left: Cranial (Cranial and caudal parts), caudal

What are the lobes of the equine lung?

- Right: Cranial, caudal, accessory

- Left: Cranial, caudal

Explain how the coronary circulation differs in ruminants and horses.

- In the horse, the right coronary artery gives rise to a right circumflex branch of the right coronary artery, which then gives rise to the subsinuosal interventricular branch. The left coronary artery immediately splits into the left circumflex branch of the left coronary artery and the paraconal interventricular branch

- In the ox, the right coronary artery gives rise to a right circumflex branch of the right coronary artery. The left coronary artery immediately splits into the paraconal interventricular branch and the left circumflex branch of the left coronary artery which then gives rise to the subsinuosal interventricular branch.

Which species is more at risk for fatality with a blockage of the left coronary artery, the ruminant or the horse?

- The ruminant

Which type of displaced abomasum is more common?

- Left

What happens during a left displaced abomasum?

- The abomasum fills with gas and moves under the rumen and to the upper left side, usually between the body wall and rumen

What happens during a right displaced abomasum?

- The abomasum is found higher than normal on the right side, usually filled with gas

Which type of displaced abomasum is generally more of an emergency?

- Right displaced abomasum, especially if torsion has occurred

How does one treat a displaced abomasum?

- Treat by decreasing the amount of gas during surgery or by rolling the animal

When can displaced abomasums commonly occur?

- During late stages of pregnancy or during early postpartum

How can recurrence of displaced abomasum be prevented?

- Abomasum can be attached to the body wall (abomasopexy)

Describe the topography of the abomasum.

- The fundic region sits on the floor of the abdomen, a little to the left, but close to the midline by the xiphoid cartilage. The body also sits on the midline. The pyrloric region shifts to the right and continues with the descending duodenum.

What are the landmarks for auscultation/percussion of the lungs in the horse?

- Caudal angle of the scapula

- Olecranon

- Dorsal end of the 16th rib

What are the landmarks for auscultation/percussion of the lungs in the ox?

- Lateral extent of the epaxial muscles

- Triceps brachii m.

- Line from the olecranon to the dorsal end of the 11th rib

Explain what happens during traumatic pericarditis and hardware disease. How is this treated?

- When a wire or piece of metal penetrates the pericardium after migrating through the diaphragm from the most cranial portion of the stomach (which sits against the abdominal surface) of the diaphragm, traumatic pericarditis can occur.

- Surgery is sometimes performed to treat pericarditis. Cut the 5th or 6th rib for entrance into the thoracic cavity.

Explain what happens during traumatic reticuloperitonitis and hardware disease. How is this treated?

- When cattle swallow nails, wires, etc they pass through the cardia into the ruminoreticulum, where they usually drop into the bottom of the reticulum. Reticular contractions can cause the sharp object to be forced through the wall of the reticulum.

In what species is traumatic reticuloperitonitis more common?

- Dairy cattle

How can one reduce incidence of traumatic reticuloperitonitis?

- By introducing a magnet into the reticulum

Where does one perform a liver biopsy in the ox?

- Draw a line from the olecranon to the tuber coxae. Where this line intersects the 11th intercostal space on the right side is where it should be performed.

Where does one perform a liver biopsy in the horse?

- Draw a line from the tuber coxae to the olecranon. Draw another line from the tuber coxae to the point of the shoulder. It should be performed on the right side anywhere between these two lines between the 11th and 14th rib.

The liver is displaced more to the _________ of the median plane in the ruminant.

- Right

Explain the different number of bands found on each section of the large colon in the horse.

- Cecum: 4

- Right ventral colon: 4

- Left ventral colon: 4

- Left dorsal colon: 1

- Right dorsal colon: 3

- Transverse colon: 2

- Descending colon: 2

What structures are palpabe via transrectal palpation on the left side in the horse?

- Spleen

- Renosplenic ligament

- Left kidney

- (Vaginal ring)

- Left ventral colon

- Pelvic flexure

- Left dorsal colon

- Descending colon

- Jejunum

- Ileum

What structures are palpabe via transrectal palpation on the right side in the horse?

- Cuadal duodenal flexure

- Ileocecal junction

- Base of the cecum

- Jejunum

- Ileum

- Descending colon

What structures are palpabe via transrectal palpation on the left side in the ox?

- Rumen

- Left kidney

- Body and apex of cecum

- Jejunum

- Ileum

What structures are palpabe via transrectal palpation on the right side in the ox?

- Caudal duodenal flexure

- Jejunum

- Ileum

- Base of cecum

- Spiral colon

Where does the cecocolic fold course?

- Courses between the cecum (lateral cecal band) and the right ventral colon

Where does the duodenocolic fold course?

- Between the ascending duodenum and the descending colon

Where does the ileocecal fold course?

- Courses between the antimesenteric surface of the ileum and the dorsal band of the cecum

What is the course of the greater omentum in horses?

- 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 to the dorsal body wall)

What is the course of the lesser omentum in horses?

- Connects the lesser curvature of the stomach and the first part of the duodenum with the liver

What is the course of the greater omentum in the ox?

- Deep leaf: Dorsal body wall on the right side -> Right longitudinal groove of the rumen

- Superficial leaf: Dorsal body wall on the right side -> Left longitudinal groove of the rumen

Where is the omental bursa located?

- Located between the superficial and deep layers of the greater omentum

Explain how to perform a paravertebral block in cows.

- T13 spinal nerve -> Palpate the last rib and transverse processes of L1 and L2; Insert needle vertically 5 cm in ox (3 cm in sheep/goat) from dorsal midline in a transverse plane at the cranial angles of the tips of the transverse process of L1.