Anatomy Flashcards
(165 cards)
1
Q
What are intrinsic muscles?
A
Have origin and insertion inside the limb.
2
Q
Discuss the brachial plexus.
A
Nerves branch from ventral portion of spinal cord.
Thoracic intumescence - widening due to nerves branching from it.
C6-T1
Involves muscles and skin of thoracic limb except for the brachiocephalicus, omotransversarius, trapezius, and upper shoulder skin.
3
Q
Which nerves are invovled in the brachial plexus?
A
ALL THESE NERVES ORIGINATE ON MEDIAL SIDE OF LIMB.
Lateral thoracic - ‘long nerve’, C8-T1, motor to deep pectorial and cutaneous trunci, sensory to skin on lateral thorax and skin over triceps. Most caudal.
Subscapular - C6-7, single or double, motor to subscapularis, long-5cm. Most cranial.
Suprascapular - C6-7, motor nerve to supraspinatus, infraspinatus, shoulder joint. Injury to neck of scapula can damage (weight bearing and forward/backward movements affected).
Axillary - C7-8, motor to flexors of shoulder joint, sensory to dorsal area, injury is rare due to its short length and protection by limb externally; if it does occur may be from wrenching.
Radial - C7-T1, supplies all extensor muscles of elbow, carpal and digital joints plus some muscles. Injury can occur easily over supracondylar crest of humerus (kiss hand reflex).
Musculocutaneous - C7-8, branches to coracobrachialis, biceps brachii, brachialis. Sensory to medial skin of antebrachium, lesions are uncommon.
Median - C8-T1, communicating branch to musculocutaneous, supplies some flexors and pronator teres, sensory skin on palmar surface of metacarpus and digits. In cats injuries are more common due to supracondraforamen (nerve runs through here).
Ulnar - C8-T1, close association with radial and medial nerves, motor supply to some flexors, sensory to skin caudal to antebrachium, dorsolateral on metacarpus and digit.
4
Q
What is the cutaneous (panniculus) reflex?
A
Muscle shiver.
Think horse with fly.
5
Q
C6 is the origin of which nerves?
A
Subscapular
Suprascapular
6
Q
C7 is the origin of which nerves?
A
Suprascapular/subscapular
Axillary/Musculocutaneous
Radial
7
Q
C8 is the origin of which nerves?
A
Axillary/Musculocutaneous
Radial
Median/Ulnar/Lateral thoracic
8
Q
T1 is the origin of which nerves?
A
Radial
Median/Ulnar/Lateral thoracic
9
Q
What are some of the test that can be used for examination of some nerves?
A
Withdrawal reflex - used during anaesthetics. Works for median, axillary, musculocutaneous, etc. C6-T1.
Triceps tendon reflex
Biceps tendon reflex
Cutaneous (panniculus) muscle reflex
10
Q
Describe the components of the shoulder joint.
A
Spheroidal/simple joint - glenoid cavity of scapula and head of humerus.
Flexion and extension.
Part of joint capsule surrounds the tendon of origin of m. biceps brachii (held by transverse humeral ligament/transverse retinaculum).
Medial and lateral glenohumeral ligaments.
Muscular collateral ligaments (span from one bone to another, limiting movement); subscapularis, infraspinatus, supraspinatus.
11
Q
Describe the components of the elbow (cubital) joint.
A
Composite joint, 3 bones;
Humero-radial joint - humeral condyle and head of radius, ginglymus (hinged joint, limited medial and lateral movement).
Humero-ulnar joint - humeral condyle, trochlear notch of the ulna, ginglymus, snapping hinge joint.
Proximal radio-ulnar joint - articular circumference of radius and radial notch of ulna, trochoid joint, rotation of radius on its long axis.
All 3 joints are within single articular capsule and articular cavity. All ligaments are extracapsular.
Thickenings of the fibrous membrane of the articular capsule gives more stability .
Lateral and medial collateral ligaments - attach lateral and medial epicondyles of humerus to radius and ulna.
Annular (ring) ligament of the radius - deep to collateral ligaments, partially encircles the head of radius, allows radial rotation.
Oblique ligament - crosses flexor angle of cubital articulation, humerus to ulna, prevents overextension.
Olecranon ligament - anconeal process of ulna to caudal surface of medial epicondylar crest.
Luxations of this joint are infrequent due to shape, condyle is prone to fracture.
Distal radioulnar joint - ulnar notch of radius and radial circumference of ulna, trochoid/simple, rotation of radius on long axis.
12
Q
What are the 3 major joint areas of the carpal joint?
A
Antebrachiocarpal joint - trochlea of radius, ulna, radial carpal bone, ulnar carpal bone. Ellipsoid, compound joint, predominantly a hinge joint with slight abduction/adduction.
Middle carpal joint - proximal and distal rows of the carpal bone, condylar/compound joint.
Carpometacarpal joint - carpal bones I-IV and metacarpal I-IV. Plane/compound joint.
13
Q
What is the intercarpal joint?
A
Joints between the carpal bones in a row, plane/compound joint.
14
Q
What is the accessory carpal bone?
A
Bone that sticks out.
Part of plane/compound joint.
Amphiarthrosis (little movement).
15
Q
Discuss the carpal joint as a whole.
A
Joint cavity has 2 main parts; antebrachium and proximal row or carpal bones, and proximal and distal rows of carpal bones and between the distal carpal and metacarpal bones.
Extensor retinaculum supplies dorsal fascial reinforcement and keeps extensor tendons in position. Stabilises.
Flexor retinaculum is present on palmar aspect and bridges the carpal canal. Stabilises.
Lateral and medial collateral ligaments are relatively short and only bridge the antebrachiocarpal joint.
16
Q
Discuss the metacarpophalangeal joints.
A
Proximal phalanges, proximal sesamoids (paired except P1), dorsal sesamoid (single) and metacarpal bones.
Compound joint.
Multiple joint capsules that have dorsal and palmar outpouchings - attach to margin of articular surface of participating sesamoids.
Collateral ligaments.
Mainly hinge joint with slight abduction and adduction as well as axial rotation.
17
Q
Discuss the proximal and distal interphalangeal joints.
A
Between respective phalanges; proximal and middle, middle and distal.
Saddle/simple joint.
Collateral ligaments.
Digital pads located on palmar surface of distal interphalangeal articulations.
18
Q
What are the 2 sets of veins on the thoracic limb?
A
Superficial
Deep
19
Q
What are the superficial veins present on the thoracic limb?
A
Cephalic
Accessory cephalic
Axillobrachial
Omobrachial
20
Q
Discuss the cephalic vein.
A
Collects blood from palmar surface of manus.
Passes dorsoproximally across medial surface of distal antebrachium to cranial surface.
Close proximity to branches of radial nerve (clinical significance).
Proximal brachial region from a superficial position over triceps to deep under brachiocephalicus to external jugular.
21
Q
Discuss the accessory cephalic vein.
A
Collects blood from dorsal area of manus.
Arises in dorsal metacarpal region from digital veins.
Joins cephalic vein on distal cranial surface of the antebrachium.
22
Q
Discuss the axillobrachial vein.
A
Large vessel, proximal to cephalic vein.
Lateral proximal surface of brachium.
Passes deep into muscle mass caudal to scapulo-humeral articulation.
Joins axillary vein in the axilla.
23
Q
Discuss the omobrachial vein.
A
Branch from axillobrachial.
Crosses superficial to deltoid and brachiocephalicus.
Has no muscular tributaries, only small vessels from skin and fascia.
Ends at external jugular.
24
Q
What are the deep veins of the thoracic limb?
A
Radial Ulnar Median Brachial Axillary
25
Discuss the radial vein.
Small vessel, arises from deep palmar venous arch.
Follows mediocaudal border of radius.
Joins small ulnar vein at top third of radius.
26
Discuss the ulnar vein.
Same diameter as accompanying artery.
From supracarpal venous arch, runs proximal to deep digital flexor.
Receives tributaries from most of the flexor muscles in antebrachium.
Joins small radial vein at junction of proximal and middle third of the antebrachium to form median vein.
27
Discuss the median vein.
Continuation of junction of radial and ulnar veins.
Branches from palmar antebrachial vein and common interosseous.
Communicates with the cephalic vein via the median cubital vein.
Crosses biceps in a sigmoid flexure, before becoming the brachial vein.
28
Discuss the brachial vein.
From junction of collateral ulnar and median veins.
Receives bicipital and deep brachial veins.
Continued by axillary vein.
29
Discuss the axillary vein.
Continuation of brachial vein in axilla (armpit).
Receives axillobrachial, cranial circumflex humeral, lateral thoracic and subscapular veins.
Terminates at the subclavian vein.
30
What are the major arteries of the thoracic limb?
Axillary
Brachial
Median
Radial
31
Discuss the axillary artery.
Continuation of subclavian artery.
Passes cranial surface of first rib.
Two proximal branches - external thoracic artery to superficial pectoral muscles cranially, and lateral thoracic artery caudally supplies axillary lymph nodes, lat dorsi, deep pecs as well as cutaneous trunci of lateral thoracic region.
Give off subscapular artery before becoming brachial artery.
32
Discuss the brachial artery.
Courses through brachium on the medial surface of the medial head of triceps brachii.
Between musculocutaneous nerve and median and ulnar nerves.
Deep brachial artery from caudal surface to triceps brachii muscle.
Small bicipital artery craniodorsally.
Distal brachium supplies biceps brachii muscle.
Continued by median artery after common interosseous artery branches.
33
Discuss the median artery.
Largest artery on the antebrachium.
Begins after brachial artery gives off common interosseous branch.
Main branches; deep antebrachial, radial, superficial palmar arch.
First branches supply caudal side of antebrachium.
Terminal branches supply the digits.
34
Discuss the radial artery.
Origin just proximal to middle of the antebrachium.
Runs distally under origin of flexor carpi radialis.
Closely follows caudomedial border of the radius.
At carpus, divides into palmar and dorsal branches.
35
What are some skin modifications present in response to environment and eating habits in the hindlimb?
Claws in carnivores
Nails in primates
Hooves in ungulates
These are tools, sensory organs, and weapons.
36
Discuss foot pads.
Modification to the distal limb in carnivores.
Three groups; carpal/tarsal pads (1-not a lot of function), metacarpal/metatarsal pads (1), digital pads (4).
Made of fat and large portion of fibrous tissue.
37
What are the 5 segments of the distal phalanx?
| Think layers of the claw.
Distinguished by location, structure, and horn production.
Perioplic - proximal part, near unguicular crest (proximal end of third phalanx), soft horn (wear).
Coronary - occupies floor of claw fold, tubular horn, middle layer of wall.
Wall - direct contact with unguicular process of distal phalanx.
Sole - ground surface, non-tubular soft, crumbly horn (soft cornification).
Footpads - digital, bulb in primates.
38
How many vessels are there on each digit?
4; 2 axial, and 2 abaxial.
39
Why is retractability an important modification in cat claws? How does it occur?
Prevents wear.
Retracts via medial dorsal elastic ligament and lateral dorsal elastic ligament. When both are tense, the claw is extended.
3rd digit is also slightly off centre to allow retraction.
40
What are the nerves to the Hindlimb?
```
Lumbosacral plexus (L4-7, S1-3)
Obturator Nerve
Femoral nerve
Sciatic (Ischiatic) nerve
Fibular (Peroneal) nerve
Tibial branch of sciatic nerve
```
41
Discuss the obturator nerve.
Adductor of thigh, no cutaneous sensory field, section has little observable effect on gait.
May show partial paralysis or slight weakness in large animals when pressure applied.
42
Discuss the femoral nerve.
Extensors of stifle, sensory to medial thigh, section results in lack of stifle fixation or weight bearing.
43
Discuss the sciatic nerve.
Largest nerve in the body.
Extensors of hip and flexors of stifle.
Sensory to lateral leg and everything below stifle.
Section causes over-extension of the paw and paralysis of all muscles of leg except stifle extensors (femoral).
Animal can bear weight.
2 branches; fibular, tibial.
Clinical significance; femoral head and injections.
44
Discuss the fibular branch of the sciatic nerve.
Peroneal nerve, smaller branch of two.
Flexor of hock and extensors of digits.
Sensory to dorsal leg, hock and paw.
Section causes hock to straighten and paw to knuckle over.
45
Discuss the tibial branch of the sciatic nerve.
Extensors of hock and digital flexors.
Sensory to caudal hind paw.
Similar path to radial nerve - same clinical signs.
46
What are the ligaments involved in the sacroiliac joint?
Dorsal ligament - stronger, on dorsal surface between sacrum and ilium.
Ventral ligaments - two groups, ventral surface between sacrum and ilium.
47
Discuss the sacrotuberous ligament.
Fattened at both ends, runs from caudolateral apex of sacrum and first caudal vertebra transverse process, to the ischiatic tuberosity.
Provides support and structure, important for females during childbirth.
48
What are the 7 bones of the stifle?
Femur, tibia, fibula, sesamoids, fabella (lateral/medial), popliteal, patella.
49
What are the external ligaments of the stifle?
Lateral femoropatellar ligament - fabella lateral head of gastrocnemius.
Medial femoropatellar ligament - smaller, blends with periosteum of medial epicondyle of femur.
Patella ligament - main stabiliser
Lateral collateral ligament
Meniscofemoral ligament
Caudal cruciate ligament
50
Discuss the patella ligament?
Fat pad that is separate from the joint capsule.
Synovial bursa.
Inserts on tibial tuberosity.
51
Discuss the internal structures of the stifle.
Cruciate ligaments - cranial and caudal.
Cranial is more likely to be damaged, if it breaks you get a draw forward motion of the tibia against the femur. Opposite occurs if caudal breaks.
Cranial and caudal ligaments runs from femur to tibia, creates an x.
Menisci - semilunar, fibrocartilagenous, concave axial borders and conves abaxial borders. Lateral is thicker than medial.
52
What are the different types of skull in dogs?
Dolichocephalic - long (greyhound)
Mesaticephalic - middle (lab)
Brachycephalic - short (boxer)
53
What is the oral vestibule?
The area bounded by the teeth and lips.
| Labial vestibule and buccal vestibule are both sections of this.
54
What are the sections of the oral cavity?
```
Oral vestibule
Oral cavity proper - bordered by teeth.
Hard palate
Soft palate
Teeth
Tongue
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55
Describe the different tooth (dens) types.
Brachyodont - cease to grow after eruption is complete, short crown exposed within oral cavity once eruption is complete, neck is embraced by gingiva, one or more relatively long roots are embedded in the jaw, all carnivore teeth, all pig teeth except canine, incisors of ruminants.
Hypsodont - present in areas where wear and tear is high, longer and continue to grow following eruption, short roots that form when growth ceases.
56
Discuss the tooth crown.
Encased in enamel, clinically it is the section exposed above the gingival margin.
Brachyodont teeth crown is primarily exposed above the gingival margin.
Hypsodont teeth the crown is part concealed below the surface.
57
What is the neck of a tooth?
Constricted portion of tooth located at the gum margin.
| Not present on all teeth.
58
What is the root portion of a tooth?
Embedded in the alveolus (bony socket), covered by cementum.
59
What is the dentition in a dog?
Deciduous Di 3/3, Dc 1/1., Dp 3/3 (total 28)
Permanent I3/3, C1/1, P4/4, M2/3 (total 42)
FIRST NUMBER IS UPPER JAW, SECOND IS LOWER.
Only account for one side of mouth.
60
When does eruption of deciduous teeth occur? What is different between them and permanent teeth?
Commences postnatally 3 weeks, complete at 6 weeks.
| Smaller than permanent, have sharp, pointed crowns and slender roots.
61
What is diphyodonty?
When an animal only has 2 sets of teeth over entire life, compared to multiple.
62
What are the replacement times of teeth?
```
Substantial variation between breeds, some variation between individuals.
Incisors - 3-5months
Canines - 5-7months
Premolars (2nd to 4th) - 2-5months
1st premolars erupt at 4-5 months.
```
63
What do incisors look like?
Distinct crown and neck and single long root.
Crowns of upper are trilobed and lower are bilobed.
Increase in size from medial to lateral.
Upper incisors normally overhang lower.
Nibbling and grooming.
Enamel is densely calcified tissue of ectodermal origin, acellular.
64
What do canines look like?
Very large, crowns are curved slightly caudally and are conical in shape.
Root is longer than the crown, curves caudally within the alveolus.
65
How are the teeth supplied with their blood supply?
Teeth are supplied by superior and inferior alveolar veins, arteries and nerves.
66
Describe premolars?
Shearing function, laterally compressed and form a discontinuous serrated cutting edge.
1st premolar teeth have single roots, upper 4th premolars have 3 roots, remaining premolars have 2 roots.
67
Describe molars.
Rounded prominences on occlusal surfaces.
1st and 2nd upper molars have 3 roots.
1st and 2nd lower molars have two roots and 3rd molars are small and have one root.
68
What are carnassal teeth?
Largest shearing teeth in upper and lower jaws - these are PM4 in upper jaw and M1 in the lower.
69
What is the occlusal surface of a tooth?
Extensive working area of the tooth, not the cutting edge.
70
What is the dentition of a cat?
Di 3/3 Dc1/1 Dp 3/2 (total 26)
| I 3/3 C1/1 P3/2 M1/1 (total 30)
71
What are the mechanical papillae present on the tongue?
Filliform - smallest and most common
Conical - caudal end of tongue
Marginal - younger animals, present when suckling (seal around nipple).
72
What are the gustatory papillae present on the tongue?
Taste
Fungiform - mushroom shaped, front 2/3
Vallate - caudal, larger, circular
Foliate - caudal, edges.
73
What is the major innervation of the tongue?
Lingual nerve
74
What are the salivary glands present in canines?
Parotid
Mandibular
Sublingual
Zygomatic
75
Discuss the parotid gland.
Present at junction of head and neck, V shaped.
Dark, flesh colour, lobulated.
Mixed seromucosus - digests food and protects oesophagus from damage.
Close nerve association, swollen duct will compress nerve and cause facial paralysis.
Parotid lymph node
Close to external ear canal.
76
What is the parotid duct?
2-3 converging radicles to single duct opening into buccal cavity (near papilla and 4th upper premolar). Runs close to masseter.
77
Discuss the mandibular gland.
Ovoid body - external and internal maxillary veins.
Close association with sublingual gland.
Mixed secretions - seromucus.
Cranial and caudal poles, superficial and deep surfaces.
Mandibular duct - sublingual papilla-frenulum of tongue.
78
Discuss the sublingual gland.
```
Sero-mucoid.
Monostomatic part (one opening) - aggregation largest near mandibular gland, 4-6 excretory ducts combine as major sublingual duct, open on sublingual papillae near mandibular duct.
Polystomatic part (multiple openings) - 6-12 isolated lobules under mucosa of tongue, discharge directly into oral cavity.
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79
Discuss the zygomatic gland.
Also known as orbital gland, ventral to zygomatic arch.
Only in dog and cat.
Pyramidal in shape, one major duct and 2-4 minor ducts.
Open near PM4 on ridge 1cm caudal to parotid papillae.
DONT CONFUSE WITH LACRIMAL GLAND WHICH IS DORSAL TO EYE
80
What are the muscles of mastication?
All derived from first pharyngeal arch and supplied by the mandibular nerve.
Masseter - superficial, mandibular, deep.
Temporalis
Pterygoideus - medial, lateral
Digastricus - caudal, rostral
81
Discuss the masseter muscle.
Lies on lateral ramus of mandible ventral to zygomatic arch. Three layers; superficial, middle, deep.
O: zygomatic arch
I: masseteric fossa of mandible
Action is to raise mandible/close mouth.
Innervated by masseteric nerve (branch of mandibular nerve from the trigeminal cranial nerve).
82
Discuss the Temporalis.
Largest and strongest muscle of the head.
Origin: temporal fossa of skull.
Insert: coronoid process of mandible
Action is to raise mandible/close mouth.
Innervation via N. temporalis, branch of mandibular nerve from trigeminal.
83
Discuss the pterygoideus.
```
Medial and lateral.
O: Pterygoid fossa
I: caudal border of mandible
Action to raise mandible.
Innervated by pterygoid nerve, branch of mandibular nerve.
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84
Discuss the digastricus.
Origin: jugular process of the occipital bone
Insert: ventral border of mandible.
Appears as single bellied muscle in dog but has tendinous intersection (caudal belly - facial nerve, rostral belly - mandibular nerve).
Action is to open the jaw.
85
What is the TMJ? Discuss it
Temporomandibular joint.
Between condylar process of mandible and mandibular fossa of the zygomatic process of the squamous part of the temporal bone.
Condylar joint allows sliding movement, there is a think articular disc, loose joint capsule forming dorsal and lateral compartments and lateral ligament.
Problems here can affect the inner ear and cause head tilt.
86
What are the prominent veins of the head?
Facial vein - lateral and dorsal nasal, angularis oculi, deep facial vein. Drain superficial structures.
Linguofacial - drains superficial structures.
Maxillary - drains deep structures.
These are all 'enastimos' - form circular structure back to jugular.
87
What are the major arteries of the head?
Common carotid - branches into caudal/cranial thyroid, internal/external carotid, occipital, cranial laryngeal, lingual, facial, sublingual, caudal auricular, superficial temporal.
Maxillary
88
What are the functions of the upper airways.
Modify or regulate the flow of air.
Serve as olfactory receptors.
Facilitate water and heat exchange.
Make phonation possible.
89
What are the components of the upper airway? What are their respective functions?
Nasal cavity and conchae - warm and moisten air, remove foreign material. Part of first defense mechanism.
Pharynx - respiratory and digestive (lies behind mouth and continues into oesophagus, dorsal to larynx). Serves as passage for both respiratory and digestive systems.
Larynx - respiratory only, guards entrance to trachea, functions in vocalisation, regulates both inspiration and expiration.
90
Discuss the external nose.
Fixed bony case. Incisive bone, maxillae, paired nasal bone (roof).
Moveable cartilages - control air in and out of passages, include nasal septum, dorsolateral nasal cartilage, ventrolateral nasal cartilage, accessory cartilage.
91
Discuss the nasal cavity.
Divided into right and left by nasal septum.
Bony, cartilagenous and membranous components.
Important for olfaction and respiration.
92
What are the nasal conchae?
Cartilagenous or slightly ossified scrolls - scroll outwards from maxillary bones.
Include; dorsal (long, central), ventral (ventral at end of nose) and ethmoidal (3 compartments, one below and 2 above dorsal).
Olfactory epithelium in caudal part of nasal cavity.
Cribiform plate of the ethmoid bone allows egress of olfactory nerves.
93
What are the nasal meatuses?
Fast flow areas to lungs.
Dorsal nasal meatus (most dorsal)
Middle nasal meatus (middle)
Ventral nasal meatus (lowest, just dorsal to hard palate).
Common nasal meatus - longitudinal, narrow space either side of nasal septum.
Nasopharyngeal meatus - ends caudally and ventrally to conchae.
94
What are paranasal sinuses?
Frontal sinus - divided into L and R sides by septum, dog has lateral, medial and rostral parts. Not divided in cats.
Lined by respiratory epithelium and function to lighten the skull.
Maxillary recess - out pocket of respiratory system, can get infections. Not true sinuses as not between internal and external plates of cranial bone, bordered laterally by maxilla, lacrimal and palatine bones. Medially the orbital plate of ethmoid.
95
What are the precursors to the trachea? Is it dorsal or ventral to the oesophagus?
Ventral to oesophagus.
| Nasal cavity, nasopharynx, interpharyngeal osteum, larynx, trachea.
96
What are the precursors to the oesophagus? Is it dorsal or ventral to the trachea?
Dorsal to trachea.
Oral cavity, oropharynx, laryngo-pharynx, oesphagus.
Think x diagram.
97
What is the larynx?
Musculocartilaginous organ that guards the entrance to the trachea, aids vocalisation, and prevents inspiration of foreign material.
Has 4 different carilages.
98
What are the 4 different cartilages of the larynx?
Epiglottic - forms a basis of the epiglottis.
Thyroid cartilage - largest cartilage, right and left laminae united ventrally, caudal thyroid notch.
Cricoid cartilage - forms complete ring, just before trachea.
Arytenoid cartilage - paired cartilage, one either side, number of processes. Dorsal, sits just above thyroid cartilage.
99
What are the muscles of the larynx?
Extrinsic; thyrohyoideus, hyoepiglotticus, sternothyroideus.
Intrinsic; pass from one laryngeal cartilage to another, principally phonation and reflex closing of glottis.
Cricothyroideus, cricoarytenoideus dorsalis, cricoarytenoideus lateralis, arytenoideus transversus (constricts glottis and adducts vocal folds), thyroarytenoideus (vocalis and ventricularis).
100
What are the two folds present near the epiglottis?
Vocal fold - from vocal process of arytenoid cartilage to thyroid cartilage.
Vestibular fold - from cuneiform process to dorsal surface of thyroid cartilage.
101
What are the major nerves of the larynx?
Cranial laryngeal - from vagus.
| Caudal laryngeal - terminal branch of recurrent laryngeal, also from vagus).
102
What structures make up the thoracic wall?
```
Ribs
Vertebrae
Sternebrae
Muscles - costal and diaphragm
Pleura
```
103
Discuss ribs.
13 pairs.
first 9 articulate with sternum, last 4 are free (asternal).
They have a number of articulations that allow movement for respiration; costovertebral joint - head ball and socket with limited movement, costotransverse joint - tubercle (sliding), costosternal joint - synovial, pivot, interchondral joint - asternal ribs, elastic syndesmoses, and intersternal joints - synchondroses.
104
What are the main functions of the thorax muscles?
Primarily concerned with respiration.
Most inspiratory and enlarge thoracic cavity.
Few are expiratory and decrease volume of cavity.
Includes muscles located between ribs, lateral to ribs and diaphragm. Generally 3 layers.
105
Discuss the external intercostal muscles.
Span single intercostal space.
Fibres run caudoventrally (caudal border to cranial border).
From costochondral junction but not to sternum.
4-5mm in large dogs, weaker over floating ribs.
Involved in inspiration.
106
Discuss the levator costae.
12 special formations of external intercostals. Caudoventral fibres.
Involved in inspiration, fixed point is transverse processes of vertebrae (pull ribs forward/up).
Small muscle right at top of ribs, joining to vertebrae.
107
Discuss internal intercostal muscles.
```
Weaker internal layer.
2-3mm thick in large dogs.
Cranioventral fibres (cranial border of one rib to caudal border of next rib).
Angle of inclination varies 78-71 degrees near vertebral column, 68-54 degrees near sternum.
Act to draw ribs together.
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108
Discuss the transverse thoracis.
Flat, fleshy, on inner surface of sternum and sternal cartilages.
Continuous triangular leaf covering second to eighth costal cartilages.
109
Discuss the rectus thoracis.
Flat, almost rectangular.
Runs caudoventrally from first rib to ventral part of scaleneus.
Involved in inspiration.
110
Discuss the scaleneus.
From first 3 ribs to cervical vertebrae.
Superficial and deep portions.
Acts in inspiration when neck is fixed downwards.
111
Discuss the serratus dorsalis.
From raphe of neck and thoracic spines to proximal portion of ribs.
2 parts with antagonistic effects.
Cranialis - inspiration, dorsal surface of thorax, fibres directed cordoventrally.
Caudalis - expiratory, 3 distally isolated portions, from thoracolumbar fascia fibres run cranioventrally ending on caudal border of 11th, 12th and 13th ribs and occassionally the 10th. Draw last 3-4 ribs caudally for expiration.
112
What is the diaphragm?
Musculotendinous division between thoracic and abdominal cavities. Dome shaped, convex cranially.
Central tendon, muscular periphery divided into lumbar, costal and sternal portions.
Lumbar portion - left and right crura from ventral aspect of 1st 3-4 lumbar vertebra by stout tendon.
113
What are the openings in the diaphragm?
Aortic hiatus - lumbar vertebrae, crural tendons, aorta, azygos vein and thoracic duct.
Oesophageal hiatus - more ventral, between medial and lumbar portions, oesophagus, dorsal and ventral vagus nerves.
Caval foramen - central tendon, caudal vena cava, fascia fuses with adventia, therefore fixed.
114
Discuss the act of breathing.
Ribs compromise between rigidity and movement.
Respiratory action most evident caudal ribs and abdomen.
Costal and abdominal (diaphragmatic breathing).
Approx 70% breathing is diaphragm movement.
Diaphragm contraction compresses abdominal contents, last ribs pulled inwards, others pulled forward and out, overall effect widens and shortens cavity.
Some quadrupeds including dog sternum also moves ventrally.
Diaphragm is further back when contracted, forward when relaxed.
Expiration is mainly passive, elastic recoil of lungs, some muscle contractions assist.
If diaphragm looses function, phrenic nerve can continue breathing movement. Herniation.
115
What are the pleura layers within the abdominal cavity?
Parietal - costal (borders ribs), diaphragmatic (borders diaphragm), mediastinal (borders the midline-oesophagus).
Visceral (pulmonary) - on the inside of the parietal pleura, in direct contact with the lung surface.
116
What are the lobes of the right lung?
```
Cranial
Middle
Caudal
Accessory
Larger than L lung, cardiac notch on middle lobe.
```
117
What are the lobes of the left lung?
Cranial - cranial and caudal parts
| Caudal
118
What are the sections of bronchi called?
```
Principal bronchi (largest, 2)
Lobar bronchi (branch of principle)
Segmental bronchi
```
119
What is the main blood supply to the lungs?
Pulmonary circulation
| Broncho-oesophageal artery and vein.
120
Discuss the topography of the heart in the dog.
Axis is 45 degrees to axis of animal.
Base lies in middle of thorax.
Amount of air in lungs between heart and surface of thorax affects audibility.
121
Where are the best positions to hear sounds created by the heart valves?
Left atrioventricular AV - left 5th intercostal (IC) space at level of costochondral junction.
Aortic valve - left 4th IC ventral to dorsal plane through the humeral articulation.
Right AV - right third or fourth IC space, near the dorsal plane of the costochondral junction.
Pulmonary valve - left third IC spae, ventrally near sternum.
122
What is the direction of blood flow through the heart?
Right atrium, right ventricle, pulmonary trunk, left atrium, left ventricle, ascending aorta.
123
What are the pericardial layers?
Pericardial mediastinal pleura - outermost
Pericardial cavity - space between heart and pleura
Parietal pericardium - layer on inside of pleura, superficial to parietal cavity.
Visceral pericardium (epicardium) - layer on heart.
124
What are some important external features of the heart?
```
Auricles - point towards right ventricular outflow.
Coronary groove
Conus arteriosus
Paraconal interventricular groove
Subsinosal interventricular groove
```
125
What are the prominent features on the right side of the heart?
```
Vena cava
Right azygous vein
Right auricle
Sinus venarium cavarum
Intervenous tubercle - directs blood flow down from vena cava
Coronary sinus
Fossa ovalis - remnant from opening between right and left sides.
Pectinate muscles
```
126
What are some important ventricular structures?
```
Atrioventricular valve
Papillary muscles
Chordae tendinae
Trabeculae carnae
Trabeculae septomarginalis
```
127
What is the myocardium?
Fibre spirals (layers of myocardium seperated by connective tissue) that form a figure 8, contraction pulls apex towards the atrio-ventricular junction 'wringing out blood'.
128
Do both sides of the heart have equal volume?
Yes, difference is between the pressure in each side, hence difference in muscular thickness.
129
How does the heart contract?
Sinatrial node - sends impulses through purkinje fibres to AV node.
Atrioventricular node - main contraction driving force, located near entrance to coronary sinus.
Trabecula septomarginalis - mainly on right side, specialised fibres running from central wall to lateral walls. Carries impulse to outer edges and allows controlled contraction.
130
What are the major vessels branching from the heart?
```
Aortic arch
Coronary arteries
Cardiac veins
Brachiocephalic trunk
Left subclavian
Ligamentum arteriosum
```
131
What are the major nerves to the heart?
Vagus - tenth cranial nerve, parasympathetic nerve, acts to slow heart rate.
Sympathetic cardiac fibres - spinal nerves from thorax and abdomen, sympathetic nerve, acts to speed up heart rate and increase contractile force.
132
What are the major lymph nodes of the head?
```
Parotid
Mandibular (rostral to mandibular salivary gland)
Retropharyngeal (just above trachea at point of larynx, just below wing of atlas)
```
133
What are the major lymph nodes of the forelimb?
Superficial cervical
| Axillary
134
What are the major lymph nodes of the hind limb?
Inguinofemoral
| Poplieteal
135
What are the major lymph nodes of the pelvic region?
Iliosacral - medial iliac, hypogastric, sacral.
| Iliofemoral
136
What are the major lymph nodes of the abdominal region?
Thoracic duct (flowing into) Cisterna chyli - be aware of in surgery as thoracic duct sits right alongside oesophagus.
Celiac - Hepatic, splenic, gastric, pancreaticduodenal
Cranial mesenteric - jejunal, right colic, middle colic
Caudal mesenteric
Lumbar
137
What are the major lymph nodes of the thoracic cavity?
Dorsal thoracic - intercostal.
Ventral thoracic - sternal
Mediastinal - cranial
Bronchial - tracheobronchia (right, left, middle - where waste products from air are dumped), pulmonary.
138
Where do all abdominal lymph vessels drain to?
Cisterna chyli
139
Discuss lymph vessel vasculature.
Thin walls, no musculature and have vessels to prevent backflow. Movement of lymph is via muscles around vessels.
140
List the flexors of the forelimb digits, give their origins, insertions, actions and innervations.
Flexor carpi radialis; O: Medial epicondyle of humerus, I: Metacarpals, I: Median n., A: flex carpal joint.
Flexor digitorium superficialis; O: Medial epicondyle of humerus, I: Middle phalanges, I: Median n., A: flexes digits and carpal joint.
Flexor digitorium profundus; O: Medial epicondyle of humerus, I: All distal phalanges, I: Median/ulnar n., A: flex digits and carpal joint.
Flexor carpi ulnaris; O: Medial epicondyle of humerus, I: Accessory carpal bone, I: Ulnar n., A: flex carpal joint.
Pronator teres; O: Medial epicondyle of humerus, I: Radius, I: Median n., A: rotates forelimb.
141
List the extensors of the forelimb digits, give their origins, insertions, actions and innervations.
Extensor carpi radialis; O: Lateral epicondyle of humerus, I: Metacarpal bones, I: Radial n. A: extends carpal joint.
Extensor digitorium communis; O: Lateral epicondyle of humerus, I: All distal phalanges, I: Radial n., A: extends carpal joint and digits.
Extensor digitorium lateralis; O: Lateral epicondyle of humerus, I: Lateral distal phalanges, I: Radial n., A: extends carpal joint and digits.
Extensor carpi ulnaris; O: Lateral epicondyle of humerus, I: Accessory carpal bone, metacarpal V, I: Radial n., A: can flex and extend carpal joint.
142
What is the mediastinum?
Central compartment, outside of mediastinal parietal pleura.
143
What is the pleural cupulae?
Region where lungs extend past the ribs.
144
What is the costodiaphragmatic recess?
Space at base of left lung between diaphragm and lung pleura.
145
What are the extensors of the hindlimb?
Extensor digitorium longus; O: extensor fossa of femur, I: All distal phalanges, I: fibular n., A: flexes hock, extends digits.
Extensor digitorium brevis; O: Metatarsal bones, I: All distal phalanges, I: Fibular (peroneal) n., A: flexes hock, extends digits.
Extensor digitorium lateralis; O: fibula, I: lateral distal phalanges, I: fibular n., A: extends digits, flexes hock.
Tibialis Cranialis; O: Tibua, I: 1st/2nd metatarsal bones, I: Fibular n., A: flexes hock.
Fibularis longus (peroneus); O: tibia and fibula, I: metatarsal bones, I: fibular n., A: rotates femur (supination)
146
What are the extensors of the stifle?
```
Quadriceps femoris (rectus femoris, vastus medialis/lateralis/intermedius)
Tensor fascia latae
```
147
What are the flexors of the stifle?
```
Biceps femoris
Semimembranosus
Semitendinosus
Popliteus
Extensors of hock - gastrocnemius, superficial digital flexor.
```
148
What are extensors of the hip?
Biceps femoris
Semitendinosus
Semimembranosus
Gluteus medius
149
What are flexors of the hip?
```
Iliacus
Psoas major
Sartorius
Rectus femoris
Tensor fascia latae
```
150
Where are the extensors in the forelimb located?
Craniolateral
151
Where are the flexors located in the forelimb?
caudal
152
Where are the extensors located in the crus?
craniolateral
153
Where are the flexors located in the crus?
caudal
154
List the major vessels linking the cephalic vein to the brain.
Cephalic v. - axillary v. - subclavian v. - superior (cranial) vena cava - (R) atrium - (R) ventricle - pulmonary trunk - pulmonary a. - lung - pulmonary v. - (L) atrium - (L) ventricle - ascending aorta - aortic arch - common carotid artery - carotid bifurcation - internal/external carotid arteries
155
Describe the intestinal blood supply.
Aorta splits into cranial and caudal mesenteric arteries.
Cranial mesenteric splits into jejunal a. and ileocolic a. Ileocolic a. splits into middle colic, right coliv and mesenteric ileal branch.
Caudal mesenteric splits into (L) colic a., and cranial rectal a.
156
Which lymph nodes are palpable clinically?
Head, shoulder and armpit, inguinal and popliteal areas easier to feel.
Parotid, mandibular, lateral retropharyngeal, supeficial cervical, axillary, popliteal, accessory axillary, superficial inguinal, femoral.
157
What are the major differences between the parasympathetic and sympathetic nervous systems?
Parasympathetic; cranio-sacral central nervous origin, long preganglionic neurons, ganglia located far from the central nervous system, acetylcholine neurotransmitter from both pre- and post- ganglionic fibres, concerned with maintaining homeostasis.
Sympathetic; thoraco-lumbar central nervous origin, short preganglionic neurons, ganglia located close to the central nervous system, noradrenaline neurotransmitter from post-ganglionic fibres, controls reactions to adverse environmental stimuli.
158
Discuss the location and insertion of the lateral thoracic nerve.
C8-T1
Location: passes caudally on the trunk, medial to axillary lymph node and then between deep pectorial and lat. dorsi. Most caudal of brachial plexus nerves.
Insertion: Cutaneous muscle on lateroventral thorax and abdomen (deep pectorial). Sensory to skin on lateral thorax and skin over triceps.
159
Discuss the location and insertion of the subscapular n.
C7
Location: 3rd branch of C7.
Insertion: Subscapular m.
160
Discuss the location and insertion of suprascapular n.
C6-C7
Location: passes over dorsal surface of the neck of scapula between supraspinatus and subscapular. Most cranial nerve of brachial plexus.
Insertion: Lateral nerve innervates supraspinatus and infraspinatus. Shoulder joint.
161
Discuss the location and insertion of the Axillary n.
C8
Location: Passes into flexion angle of shoulder joint and then to lateral aspect.
Insertion: Teres major, teres minor, deltoids (flexors of shoulder joint).
Sensory to dorsal area.
162
Discuss the radial n. location and insertion.
C7-T1
Location: Passes deeply caudal to humerus, between long and medial heads of triceps. Emerges laterally from caudal aspect of humerus to lie between lateral heads of triceps and brachialis.
Insertion: Triceps, antibrachii, anconeus. Continues distally to antebrachial extensor group (x4), supinator, abductor pollicis longus.
163
Discuss the musculocutaneous n. location and insertion.
C7-C8
Location: Passes alongside and branches proximally to supply biceps. Passes under biceps brachi.
Insertion: Coracobrachialis, biceps, brachialis. Sensory to skin of antebrachium.
164
Discuss the location and insertion of the median n.
C8-T1
Location: Runs caudally down medial aspect of humerus, enters forearm over medial collateral ligament. Divides into carpal canal.
Insertion: All flexors except flexor carpi ulnaris. Pronator teres. Sensory to skin on palmar surafce of metacarpus and digits.
165
Discuss the location and insertion of the ulnar n.
C8-T1
Location: Caudal to elbow, runs with median n.
Insertion: Ulnar carpal flexor, deep digital flexor. Sensory to skin caudally on antebrachium and dorsolateral on metacarpus and digit.
Close association with radial and median nerves.
