Chapter 61 - Penis and prepuce Flashcards
1
Q
What are the three main anatomical parts of the horse penis?
A
Root, body (shaft), and glans penis.
2
Q
What tissue composes the penis?
A
Erectile tissue, musculocavernous
3
Q
Where does the penis originate?
A
caudally at the root,
which is fixed to the lateral aspects of the ischial arch by two
crura (leg-like parts) that converge to form the shaft of the penis
4
Q
What is the term for the portion of the penis distal to the prepuce’s attachment?
A
Free part of the penis.
5
Q
What are the two main types of penile erectile bodies?
A
Corpus cavernosum penis (CCP) and corpus spongiosum penis (CSP).
6
Q
Which erectile body is responsible for erection?
A
Corpus cavernosum penis (CCP).
7
Q
What causes the penis to protrude from the prepuce?
A
Decreased tonus during micturition.
8
Q
What is the oval structure at the distal end of the penis called?
A
Glans penis.
9
Q
What is the function of the bulb of the penis?
A
It is the proximal enlargement of the CSP that plays a role in erection.
10
Q
How does the tunica albuginea vary between the CCP and CSP?
A
The tunica albuginea of the CSP is thinner and more elastic.
11
Q
What is the corona glandis?
A
The circular edge of the glans penis.
12
Q
What condition can large deposits of smegma in the urethral sinus cause?
A
They can form “beans,” which may interfere with urination.
13
Q
What is the fossa glandis?
A
deep depression on the cranial surface of the glans that contains the urethra.
14
Q
Define detumescence.
A
The process of penis returning to its non-erect state after ejaculation.
15
Q
What role do the bulbospongiosus muscles play during ejaculation?
A
They create rhythmic contractions to expel semen.
16
Q
Where does the corpus cavernosum penis originate?
A
Below the ischial arch at the junction of the crura.
17
Q
What is the urethral process?
A
The tubular protrusion of the urethra from the fossa glandis.
18
Q
What anatomical feature aids in maintaining an erection by preventing venous return?
A
Ischiocavernosus muscles.
19
Q
What happens to the blood vessels in the penis during erection?
A
Increased arterial blood flow and distention of the cavernous spaces.
20
Q
What is the main hemodynamic event that leads to penile erection?
A
Increased arterial flow to the cavernous spaces.
20
Q
What muscles assist in the release of seminal fluid during ejaculation?
A
Urethralis muscle.
21
Q
What symmetry exists within the structure of the penis?
A
the paired structures of crura and cavernous bodies are symmetrically arrange
22
Q
How does parasympathetic stimulation affect the penis during arousal?
A
It reduces pressure in the CCP, allowing increased blood flow
23
Q
What is the primary influence of the bulbospongiosus muscle on erection?
A
It helps achieve and maintain high pressure in the CSP during arousal.
24
What are the retracting actions of the retractor penis muscles?
They retract the penis into the prepuce after erection.
25
What is the role of the ischiourethral muscles?
They may assist in erection by compressing the dorsal veins.
26
What is the significance of the urethral groove?
It runs along the ventral surface of the CCP, accommodating the urethra.
27
What anatomical structure surrounds the urethra within the penis?
Corpus spongiosum penis (CSP).
28
How does the penis change in length during erection?
It can become up to three times longer than when quiescent.
29
What happens to arterial blood flow during detumescence?
It decreases as sympathetic impulses return the helicine arteries to a coiled state.
30
How does the anatomy of the glans penis differ from the shaft?
The glans has a thinner tunica albuginea, making it softer compared to the shaft.
30
What role does the bulbous structure at the base of the CSP play in erection?
It contributes to the pressure and expansion of the glans penis.
31
what two types of muscles are involved in the erection mechanism?
Smooth muscle in the cavernous spaces and skeletal muscles (like bulbospongios
32
What are the main arteries supplying the penis?
The internal pudendal, obturator, and external pudendal arteries.
33
Which artery is a major source of blood for the erectile tissue of the penis?
The cranial (or dorsal) artery of the penis, supplied by the external pudendal artery.
34
what does the internal pudendal artery terminate as, and what does it supply?
It terminates as the artery of the bulb of the penis, which supplies the corpus spongiosum penis (CSP).
35
from which arteries do the deep arteries of the penis originate?
The obturator arteries.
36
How is venous blood drained from the penis?
Through a venous plexus on the dorsum and sides, emptied by external pudendal and obturator veins.
37
What is the primary nervous supply to the penis?
The pudendal nerves and the pelvic plexus of the sympathetic nervous system.
38
Which muscles are supplied by the deep perineal and caudal rectal nerves?
The bulbospongiosus, ischiocavernosus, and retractor penis muscles.
39
What are the accessory genital glands found in horses?
The paired seminal vesicles, prostate, bulbourethral glands, and ampullae of the ductus deferens.
40
How do the accessory genital glands change between sexually mature stallions and geldings?
They are fully developed in stallions but revert to juvenile size in geldings.
41
What structure is formed by the widened distal sections of each deferent duct?
An ampulla with a thickened wall containing secretory glands.
42
Describe the location and shape of the seminal vesicles.
They are hollow, pear-shaped glands on the dorsal surface of the bladder neck, lateral to the ampullae.
43
What role do the seminal vesicles play in the ejaculate?
They provide the major portion of the ejaculate and nourish and buffer spermatozoa.
44
What is the significance of the ejaculatory duct?
It is formed by the combined terminal portion of the ampulla and excretory duct of the seminal vesicle.
45
What characterizes the secretions of the seminal vesicles?
The secretions are viscous and contribute significantly to the volume of ejaculate.
46
What is seminal vesiculitis and its related complications?
an inflammation of the seminal vesicles that may lead to infertility; surgical removal of infected vesicles might be required.
47
Describe the anatomy of the prostate in stallions.
A bilobed, nodular gland located dorsal to the neck of the bladder, measuring 5 to 9 cm long.
48
What is the function of the prostatic secretion?
It neutralizes acidity from fluids entering the urethra from the ductus deferens.
49
Where are the bulbourethral glands located, and what is their size?
They are located on the dorsolateral surface of the urethra at the ischial arch, measuring 4 to 5 cm long and 2.5 cm wide.
49
What is the primary function of the bulbourethral glands?
They produce an alkaline, mucinous secretion that clears the urethra of urine and lubricates for seminal fluid passage.
50
How do the excretory ducts of the bulbourethral glands function?
They open in longitudinal rows of small papillae on the dorsal surface of the pelvic urethra, caudal to the prostatic ducts.
51
Figure 61-1. The cranial end of the penis in median section in situ in the horse, medial aspect. a, Corpus cavernosum penis; b, corpus spongiosum glandis; c, urethra; d, urethral process; e, fossa glandis; f, external preputial orifice; g, preputial cavity (internal); h, plica preputialis; i, prepuce.
52
Figure 61-3. Cross section of the penis. a, Dorsal veins of penis; b, tunica albuginea; c, corpus cavernosum penis with dividing trabeculae; d, corpus spongiosum; e, urethra; f, bulbospongiosus; g, retractor penis muscle.
53
Figure 61-2. Perineum of stallion, deep dissection, caudal aspect. A, Cross section through root of tail; B, external anal sphincter; C, tuber ischiadicum; D, semitendinosus; D′, short head from tuber ischiadicum; D′′, vertebral head; E, obturator externus; F, adductor; G, ventral stump of semimembranosus (the dorsal part of the muscle has been removed); H, gracilis; J, caudal wall of scrotum; a, penile part of retractor penis; a′, a′′, rectal part of retractor penis; b, bulbospongiosus, partly removed on the left side to expose the urethra; c, right ischiocavernosus, covering right crus penis (broken line); c′, outline of left ischiocavernosus, which has been removed to expose left crus penis; 1, left crus penis; 2, outline of right crus penis under cover of ischiocavernosus; 3, union of crura penis; (4) corpus cavernosum penis; 5, urethra, surrounded by corpus spongiosum; 6, muscular branches of obturator vessels.
53
Figure 61-5. Extended penis of a stallion (protruded from the prepuce), left lateral aspect. a, Glans penis; b, free part of the penis; c, attachment of the inner lamina of the preputial fold to penis; d, inner lamina of the preputial fold; e, preputial ring; (f) outer lamina of the preputial fold; g, internal lamina of the external fold of the prepuce; h, fossa glandis; i, urethral process; j, corona glandis; k, collum glandis.
54
Figure 61-4. Distal end of the penis of the horse. (A) Caudoventral aspect of the glans, and of the terminal part of the urethra with corpus spongiosum; (B) ventrolateral aspect of corpus cavernosum; (C) lateral aspect of tip of the penis (the skin of the penis has been removed proximal to the corona glandis). a, a′, corpus cavernosum; a′′, dorsomedian process of corpus cavernosum; a′′′, ventrolateral processes of corpus cavernosum; aiv, urethral groove; b, urethra, surrounded by corpus spongiosum; b′, urethral process and external urethral orifice; b′′, stump of bulbospongiosus; c, fossa glandis; c′, corona glandis; c′′, collum glandis; c′′′, dorsal process of glans; civ, recesses on the interior of the glans for the three processes (a′′, a′′′) of the corpus cavernosum.
55
Figure 61-6. Graphic representation of the urogenital tract of the stallion. a, Penis; b, testes; c, kidneys; d, ureters; e, urinary bladder; f, ductus deferens; g, seminal vesicles; h, prostate gland; i, bulbourethral glands.
56
Figure 61-7. The pudendal nerves can be anesthetized where they course around the ischium by inserting a 20- to 22-gauge, 3.8-cm (112-in)
needle on the right and left side of the penis at the level of the ischium. The needles are inserted until their point strikes the ischium. Only the right needle has been inserted in this picture.
57
What is the prepuce?
A voluminous, folded sleeve of skin covering the mobile part of the quiescent penis.
57
What are the two laminae that compose the prepuce in horses?
The external lamina (haired, continuous with abdominal wall skin) and the internal lamina (in contact with the penis).
58
How far does the external lamina of the prepuce extend craniad from the scrotum?
It extends to within 5 to 8 cm of the umbilicus.
59
What anatomical structure divides the external lamina sagittally on its ventral midline?
The preputial raphe.
59
What supports the prepuce and from what is it derived?
An elastic suspensory ligament derived from the abdominal tunic.
60
What unique feature differentiates the prepuce of the horse from that of other species?It is formed by a double fold of preputial skin, one inside the other.
It is formed by a double fold of preputial skin, one inside the other.
61
What is the plica preputialis and when is it formed?
It is a cylindrical internal fold formed by the doubling of the internal lamina when the penis is retracted.
62
At birth, why is the penis not free in the preputial cavity in horses?
Because the epithelium of the internal lamina and the epithelium of the penis are fused into a single lamina.
62
What is the preputial ring?
The opening of the plica preputialis.
63
What process splits the lamina into external and internal laminae after birth?
A cytolytic process forming vesicles that coalesce to create the preputial cavity.
64
During which timeframe does the separation of the internal and external laminae occur in horses?
In the first month after birth.
64
What might difficulty in erection suggest in a breeding stallion?
Possible vascular shunt or fibrosis in the CCP.
65
What might a "bean" in the fossa glandis cause?
Stranguria, or painful urination.
66
What is a urethral rent?
tear in the urethra that may cause pain during ejaculation.
67
How can the penis be palpated when retracted?
By inserting a gloved hand through the preputial orifice and ring
68
what information from a horse's history is relevant when diagnosing preputial or penile abnormalities?
Copulatory performance, drug therapy, behavioral changes, conception rates, duration of disability, previous injuries, illnesses, or urogenital surgery.
69
What should be included in the physical examination of a horse with a penile or preputial disorder?
Observation of urination, palpation of the bladder, and palpation of the penis and prepuce.
70
How can a horse be stimulated to urinate during a clinical examination?
By placing it in a freshly bedded stall, shaking the bedding while whistling, or administering furosemide intravenously.
71
What condition should be suspected if a horse makes painful and unsuccessful attempts to urinate?
Urethral obstruction.
72
hat is a "bean" in the context of equine penile disorders and what condition can it cause?
large accumulation of hardened smegma within the fossa glandis, which can cause stranguria.
73
What could cause a breeding stallion's inability to achieve erection?
A vascular shunt from the CCP to a vessel outside the tunica albuginea or fibrosis of cavernous tissue from priapism.
74
What might a stallion that is reluctant to ejaculate or shows pain during ejaculation be suffering from?
A urethral rent or seminal vesiculitis.
74
How can fibrosis of cavernous tissue in stallions be assessed?
By palpating the cavernous tissue; fibrous, noncompliant tissue indicates permanent damage.
75
How is the penis palpated in a horse with phimosis?
By inserting a gloved and lubricated hand through the preputial orifice and preputial ring.
75
What diagnostic procedures are recommended if seminal vesiculitis is suspected?
Examining semen and urine for blood and endoscopic inspection of the urethra.
76
What can be evaluated by palpation of the prepuce and penis?
The external and internal preputial cavities, preputial ring, free part of the penis, urethral sinus, and process.
77
Which drugs should be avoided when protruding a stallion's penis and why?
Phenothiazine-derivative tranquilizers because they are associated with penile paralysis and priapism.
77
What is the significance of dense, brown-black, greasy smegma at the preputial fornix?
It is normally encountered and can be palpated during examination.
78
What is the preferred method to protrude a gelding’s penis?
Administering a tranquilizer or sedative, or using a loop of gauze and steady traction.
79
Why is chemical protrusion of the penis preferred over manual traction?
Because traction can cause discomfort to the horse and potential damage to the penis.
80
How can the penis be desensitized and extruded for examination?
By anesthetizing the pudendal nerves at the level of the ischial arch.
81
What should confirm the success of a pudendal nerve block?
Needle contact with bone during insertion.
81
What gauge needle is typically used for pudendal nerve block in horses?
A 20- to 22-gauge needle.
82
How long after depositing local anesthetic does the penis usually protrude?
Within 5 minutes.
83
Which local anesthetic is recommended for short-acting penile desensitization?
idocaine HCl.
84
What should be inspected for lesions when the penis is extended?
The urethral process and fossa glandis for cutaneous habronemiasis.
85
what structures should be evaluated for wounds, scars, hematomas, neoplasia, and granulomas?
The entire internal preputial lamina.
86
What differentiates a hematoma from an abscess in penile injuries?
Hematoma presents with penile swelling and ecchymosis; aspiration can confirm hematoma.
87
What should be evaluated in a horse with paraphimosis?
Penile sensory innervation, as paralysis may indicate permanent issues.
88
When preputial or penile neoplasia is suspected, what other areas should be examined?
The entire external genitalia, superficial inguinal lymph nodes, and internal lymph nodes via palpation per rectum.
88
How can superficial inguinal lymph node enlargement indicate neoplasia?
They may enlarge initially from inflammation and later from malignant infiltration.
89
What clinical signs suggest lymph nodes have been infiltrated by malignant emboli?
Lymph nodes adhered to overlying skin or with fistulous tracts.
90
What could be the cause of urinary leakage from a traumatized area of the penis?
Penile wounds penetrating the tunica albuginea or invading the urethra.
90
What additional structures should be examined if carcinoma of the external genitalia is recognized?
The third eyelids and the perineum.
91
What is the main use of endoscopy in equine urogenital diagnosis?
To identify hemorrhage sources during urination or ejaculation.
92
What type of endoscope is used for urethra and bladder examination in horses?
A flexible, sterile endoscope at least 100 cm long with a diameter no larger than 12 mm.
93
What is the preferred endoscope diameter for most male horses?
9 to 10 mm.
94
Why should the endoscope be capable of distending the urethra with air?
To ensure visibility of the urethral walls and prevent air restriction.
95
How is the urethra insufflated during an endoscopic examination?
By occluding the urethra around the endoscope while insufflating it with air.
96
Describe the normal appearance of the urethral mucosa when distended.
It appears reddened and smooth with a tubular configuration.
96
What anatomical feature should not be mistaken for inflamed mucosa?
The blood-filled cavernous spaces of the CSP surrounding the urethra.
97
Where are the openings of the bulbourethral gland ducts located?
On the dorsal surface of the pelvic urethra in two longitudinal rows.
98
What anatomical structure is marked by a round prominence on the dorsal urethra?
The colliculus seminalis.
99
How can a penile hematoma’s cause be identified?
Through ultrasonography to detect ruptures in the tunica albuginea.
99
What remnants does the uterus masculinus represent in male horses?
The ducts of Müller, homologous to the uterus and vagina.
100
How can infection in a seminal vesicle be detected?
By passing a 10-mm or smaller endoscope into the duct of the seminal vesicle.
101
What technique is used to identify urethral lesions like calculi?
Ultrasonography.
102
What medium is used in cavernosography for visualizing blood shunts?
Iohexol, a 24% water-soluble iodine contrast medium.
103
When is cavernosography used?
To determine the cause of persistent impotence.
104
What diagnostic procedure might be useful for urethral catheterization?
It helps to locate hemorrhage sources or collect seminal vesicle fluid for analysis.
105
Why might cytologic or histologic evaluation of penile lesions be necessary?
To differentiate between diseases like habronemiasis and squamous cell carcinoma.
106
List some causes of penile lacerations in horses.
Jumping barriers, coitus-related injuries, and falling on sharp objects.
107
What can cause a penile hematoma during pasture or breeding?
Trauma to an erect penis.
108
What does “fracture of the penis” refer to in equine medicine?
A rupture of the CCP due to severe bending or trauma.
109
What consequence can arise from a penile hematoma disrupting blood flow?
Deviation of the penis during erection.
109
What treatment prevents infection in penile lacerations?
Débridement and suturing of fresh wounds.
110
What causes severe penile hemorrhage due to a urethral sinus tear?
A tear in the sinus leading directly into the CSP.
111
How is urethral stenosis after injury sometimes treated?
By transendoscopic laser ablation.
112
What is a potential risk if the tunica albuginea is not repaired?
Formation of a shunt between erectile tissue and dorsal veins.
112
What is the purpose of hydrotherapy in treating penile injuries?
To induce vasoconstriction and reduce hemorrhage.
113
What type of bandage is used to treat penile hematomas?
A pneumatic or elastic bandage applied snugly from the glans to the preputial orifice.
114
Why should a horse with penile injury avoid sexual stimuli?
To prevent erection and further hemorrhage.
115
What condition may result from edema caused by penile trauma or castration?
Paraphimosis.
116
What type of nerve damage may lead to paraphimosis?
Damage to penile innervation, possibly from spinal injury or infection.
117
How might phenothiazine tranquilizers contribute to paraphimosis?
By blocking α-adrenergic fibers, reducing retractor penis muscle tone.
118
What complication results from prolonged penile protrusion?
Pooling and clotting of blood within the CCP.
119
Why does prolonged penile protrusion lead to penile rigidity?
Blood within the CCP clots, stiffening the penis.
120
What is balanoposthitis?
Inflammation of the penis and prepuce caused by bacterial infection.
121
What is cellulitis, and how does it develop in penile injuries?
A tissue infection due to bacterial invasion of inflamed, swollen tissue.
122
How can fibrosis of penile tissues occur in horses?
Through fibroblast invasion of edematous, inflamed tissue.
123
What effect does edema have on penile retraction capability?
It prevents the telescoping action of the prepuce, hindering retraction.
124
What effect does penile paralysis have on urination?
Urination is usually unaffected despite paralysis.
125
What happens to ejaculatory function in horses with penile paralysis?
Ejaculation may still occur, but erectile function is impaired.
126
Why might a paralyzed penis eventually curve caudoventrad?
Due to increased rigidity and edema causing the glans to point downward.
127
What is the main goal in treating paraphimosis in horses?
To control edema and prevent additional trauma.
128
Why should the penis be retained within the external preputial lamina?
To preserve normal venous and lymphatic drainage and prevent injury.
129
How can temporary retention of the penis be achieved, and why is it not long-term?
With sutures or towel clamps; these methods can damage the prepuce if used for more than a few days.
130
What can provide prolonged, atraumatic support for the penis?
A nylon net or hosiery suspended by a crupper and surcingle.
131
What is done if the penis is too edematous to replace within the preputial cavity?
Compress it against the abdomen with a bandage until edema reduces.
132
How can a pneumatic bandage help with paraphimosis?
It can reduce edema by applying direct compression.
133
What compound cream is applied daily for penile and preputial health?
A 2% testosterone cream mixed with udder cream.
134
What topical agents are effective with a compressive bandage?
Nonirritating, hydrophilic agents like glycerin or sulfa urea.
135
What does massaging the penis between bandage changes help with?
Dissipating edema.
136
Why apply antimicrobial ointment to the penis?
To prevent epithelial maceration and infection.
137
How is preputiotomy performed?
The preputial ring is severed with a longitudinal incision under anesthesia.
137
What surgical procedure can be performed if the preputial ring prevents penile retraction?
Preputiotomy.
138
What is the prognosis for paraphimosis resulting from acute trauma?
It usually resolves within days with prompt treatment.
139
What may be necessary if preputial cicatrization restricts preputial movement?
Excision of restrictive cicatricial tissue by segmental posthetomy (reefing).
140
What is phimosis in horses?
Inability to protrude the penis from the prepuce.
141
What are common causes of acquired phimosis?
Tumors, cicatrizing lesions, or impaired prepuce telescoping.
142
What are common causes of acquired phimosis?
Tumors, cicatrizing lesions, or impaired prepuce telescoping.
143
How is phimosis corrected when caused by ligament rupture?
By suturing the torn ligament.
144
What unusual cause of phimosis was noted?
Penis entrapment in a rent in the suspensory ligament of the prepuce.
145
What is the procedure for phimosis caused by a constricted preputial orifice?
Removing a wedge of external preputial lamina and suturing.
146
How is phimosis due to preputial ring constriction treated?
Removing a wedge from the internal preputial fold and suturing the inner and outer laminae.
147
How often does priapism result in impotence?
Frequently in affected species, including horses.
147
How often does priapism result in impotence?
Frequently in affected species, including horses.
148
What are common etiologic factors for priapism in horses?
Phenothiazine-derivative tranquilizers like acepromazine, general anesthesia, spinal cord issues, and pelvic neoplasia.
149
What is priapism?
Persistent erection without sexual excitement.
150
What causes low-flow priapism in horses?
Venous outflow disturbance, commonly due to vascular stasis.
151
How is low-flow priapism characterized?
Blood stasis within the corpus cavernosum penis (CCP), with low pH and high CO₂.
152
What symptoms indicate advanced priapism?
Penile fibrosis, decreased sinusoidal capacity, and pudendal nerve damage.
153
What are common clinical signs of priapism in horses?
A protruded or turgid penis, edema, and inability to manually reduce the penis.
154
Why might dysuria occur with priapism?
Due to edema and fibrosis in chronic case
155
What are potential long-term effects of unresolved priapism?
Loss of erectile function and penile sensitivity.
156
What is the initial supportive treatment for priapism?
Massage, emollient dressing, and compression against the body wall.
157
How does benztropine mesylate help in priapism treatment?
By reestablishing normal venous drainage through anticholinergic action.
158
What is the usual dose of benztropine mesylate for horses?
8 mg via slow IV injection.
159
What are side effects of higher doses of benztropine mesylate?
Paralytic ileus, impaction, dysuria, and muscle weakness.
160
What β2-adrenergic drugs have been considered for priapism treatment?
Terbutaline and clenbuterol.
161
What role do α-adrenergic agents play in priapism treatment?
162
.What role do α-adrenergic agents play in priapism treatment?
They promote detumescence by enhancing cavernous and arterial smooth muscle contraction
163
What is the recommended solution for injecting phenylephrine in horses?
10 mg of phenylephrine in 10 mL of physiological saline.
164
How often can phenylephrine be injected into the CCP in humans?
Every 15 minutes until detumescence occurs.
165
What response is typical for chronically affected horses after phenylephrine injection?
Temporary detumescence.
166
Why might priapism treatment be less effective in chronically affected horses?
Due to fibrotic changes and permanent vascular damage.
167
What indicates a need for CCP irrigation in horses?
Lack of response to cholinergic blockage or multiple α-adrenergic injections.
168
Why is dorsal recumbency preferred during CCP irrigation?
.It simplifies the procedure and allows better access.
168
What is the purpose of heparinized PSS in CCP irrigation?
To remove sickled erythrocytes and improve the acidotic environment
169
What needle size is recommended for CCP irrigation?
A 12-gauge needle.
170
Where is PSS introduced during CCP irrigation?
Proximal to the glans penis, under pressure.
171
How is stagnant blood removed from the CCP during irrigation?
Through needles or a stab incision caudal to the scrotum.
172
What does the appearance of fresh blood in the efflux indicate?
Successful removal of stagnant blood.
172
What does a lack of arterial blood in the efflux suggest?
Permanent damage to the arteriolar supply, potentially leading to impotence.
173
What drug may assist in fluid evacuation from the CCP post-irrigation?
Phenylephrine.
174
What happens to the stab incision after irrigation is complete?
It is sutured.
175
Why would a CCP-CSP shunt be created in a horse?
To facilitate blood drainage when CCP irrigation alone is insufficient.
176
Where is the CCP-CSP shunt usually created?
In the perineal region.
177
What advantage does the perineal region offer for shunt creation?
It allows thorough blood evacuation and minimizes urethral damage.
178
What muscle is retracted during shunt surgery to access the CSP?
The bulbospongiosus muscle.
179
What must be avoided when incising the CSP?
Extending the incision into the urethra.
180
What suture material is used to join the incisions in the CCP and CSP?
Absorbable suture material (USP size 3-0 or 2-0).
181
How is visibility maintained during the CSP incision?
Suction is typically required.
182
How is the bulbospongiosus muscle handled post-shunt creation?
It is sutured back to its origin on the tunica albuginea.
183
What post-surgery care is recommended for a stallion with a new shunt?
No sexual stimulation for at least a month.
184
What is a possible complication of a CCP-CSP shunt in men?
Impotence due to inability to maintain CCP pressure.
185
Can a shunt close after normal blood outflow resumes?
Yes, although it’s unclear if closure is necessary for potency.
186
What may cause a stallion’s failure to achieve erection after a shunt?
Tissue damage from prolonged priapism.
187
How can erectile function be enhanced in men with CCP tissue damage?
By injecting vasoactive drugs into the CCP.
188
What is the potential benefit of using imipramine in stallions with penile sensitivity loss?
To lower the ejaculatory threshold.
189
When might partial phallectomy be considered in a horse?
If all other priapism treatments fail.
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What may occur if a priapism-related CCP-CSP shunt fails in a bull?
The bull may become impotent.
191
How do stallions with reduced penile sensitivity achieve successful intromission?
With assistance or training for artificial insemination.
192
What is the main cause of increased smegma production in geldings and older horses?
Reduced penile retraction, leading to chronic irritation.
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Figure 61-8. Paraphimosis caused by severe debilitation. The preputial ring has become a constricting cuff.
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Figure 61-9. (A) Suspensory device manufactured from a lightweight aluminum tube and nylon net. (B) The device fitted to a horse.
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Figure 61-9. (A) Suspensory device manufactured from a lightweight aluminum tube and nylon net. (B) The device fitted to a horse. (
196
Figure 61-10. Phimosis in a horse caused by a cicatrix at the preputial ring.
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what are the main pathologies in the male urinary and penile system?
