Pudendal Nerve Block

PUDENDAL NERVE BLOCK

Q. 1

To provide anesthesia to a patient in the third stage of labor, an obstetrician palpates the ischial spine transvaginally, then injects a local anesthetic. Injection of anesthetic at this approximate location will most likely block which of the following nerves?

 A

Inferior gluteal nerve

 B

Lateral femoral cutaneous nerve

 C

Obturator nerve

 D

Pudendal nerve

Q. 1

To provide anesthesia to a patient in the third stage of labor, an obstetrician palpates the ischial spine transvaginally, then injects a local anesthetic. Injection of anesthetic at this approximate location will most likely block which of the following nerves?

 A

Inferior gluteal nerve

 B

Lateral femoral cutaneous nerve

 C

Obturator nerve

 D

Pudendal nerve

Ans. D

Explanation:

The pudendal nerve is often anesthetized to provide obstetric anesthesia (although epidural blocks are now more commonly used in preparation for delivery). The pudendal nerve arises from sacral segments 2, 3, and 4. It exits the pelvis by way of the greater sciatic foramen and then courses around the ischial spine (and sacrospinous ligament) to pass through the lesser sciatic foramen. It then runs through Alcock’s canal to supply the muscles and skin of the perineal area.

  • The inferior gluteal nerve leaves the pelvis by passing through the greater sciatic foramen to supply the gluteus maximus muscle.
  • The lateral femoral cutaneous nerve courses by the anterior superior iliac spine and supplies the anterolateral skin of the thigh.
  • The obturator nerve passes through the obturator foramen to supply muscles and skin in the medial thigh.

Q. 2

A patient with external hemorrhoids develops pain while passing stools. The nerve mediating this pain is:

 A

Hypogastric nerve

 B

Pudendal nerve

 C

Splachnic visceral nerve

 D

Sympathetic plexus

Q. 2

A patient with external hemorrhoids develops pain while passing stools. The nerve mediating this pain is:

 A

Hypogastric nerve

 B

Pudendal nerve

 C

Splachnic visceral nerve

 D

Sympathetic plexus

Ans. B

Explanation:

B i.e. Pudendal nerve

Transitional epithelium lies below the dentate line in middle third of anal canal.

–  Upper half of anal canal is insensitive to pain, lined by columnar epithelium, supplied by superior rectal vessels and drained by internal iliac lymph nodes.

Lower half of anal canal is sensitive to pain (through inferior rectal br of pudendal nerve), lined by stratified
squamous epithelium, supplied by inferior rectal vessels and drained by superficial inguinal lymph nodes.


Q. 3

Pudendal Nerve Block Involve

 A

LiL2L3

 B

L2L3L4

 C

SiS2S3

 D

S2S3S4

Q. 3

Pudendal Nerve Block Involve

 A

LiL2L3

 B

L2L3L4

 C

SiS2S3

 D

S2S3S4

Ans. D

Explanation:

D i.e. S2 S3 S4


Q. 4

To provide anesthesia to a patient in the third stage of labor, an obstetrician palpates the structure marked by a “red arrow” transvaginally in the picture below, then injects a local anesthetic. Injection of anesthetic at this approximate location will most likely block which of the following nerves? 

 A

Inferior gluteal nerve.

 B

Lateral femoral cutaneous nerve.

 C

Obturator nerve.

 D

Pudendal nerve.

Q. 4

To provide anesthesia to a patient in the third stage of labor, an obstetrician palpates the structure marked by a “red arrow” transvaginally in the picture below, then injects a local anesthetic. Injection of anesthetic at this approximate location will most likely block which of the following nerves? 

 A

Inferior gluteal nerve.

 B

Lateral femoral cutaneous nerve.

 C

Obturator nerve.

 D

Pudendal nerve.

Ans. D

Explanation:

The structure marked by a red arrow represents ischial spine.

The pudendal nerve is often anesthetized to provide obstetric anesthesia (although epidural blocks are now more commonly used in preparation for delivery). The pudendal nerve arises from sacral segments 2, 3, and 4. It exits the pelvis by way of the greater sciatic foramen and then courses around the ischial spine (and sacrospinous ligament) to pass through the lesser sciatic foramen. It then runs through Alcock’s canal to supply the muscles and skin of the perineal area.

  • The inferior gluteal nerve leaves the pelvis by passing through the greater sciatic foramen to supply the gluteus maximus muscle.
  • The lateral femoral cutaneous nerve courses by the anterior superior iliac spine and supplies the anterolateral skin of the thigh.
  • The obturator nerve passes through the obturator foramen to supply muscles and skin in the medial thigh.



Q. 5

Block given for Type of Delivery shown in Photograph

 

 A

Ilio-inguinal

 B

 Genitofemoral 

 C

 Pudendal 

 D

Posterior femoral

Q. 5

Block given for Type of Delivery shown in Photograph

 

 A

Ilio-inguinal

 B

 Genitofemoral 

 C

 Pudendal 

 D

Posterior femoral

Ans. C

Explanation:

Pudendal (Description: For Forceps delivery, Pudendal block is supplemented with perineal & Labial infiltration)

Pudendal anesthesia, also known as a pudendal block, or saddle block, is a form of local anesthesia commonly used in the practice of obstetrics to relieve pain during the delivery of baby by forceps. The pudendal nerve block prevents fainting during forceps delivery which was common before pudendal nerve block use was available. The anesthesia is produced by blocking the pudendal nerves near the ischial spine of the pelvis.[1][2] The ischial spine separates the greater and lesser sciatic foramina at the exit of the bony pelvis.


Q. 6

Pudendal nerve block ‑

 A

S1-3

 B

S2-4

 C

S3-5

 D

S4,5

Q. 6

Pudendal nerve block ‑

 A

S1-3

 B

S2-4

 C

S3-5

 D

S4,5

Ans. B

Explanation:

Ans. is ‘b’ i.e., S2-4

Pudendal Nerve Block

  • It is a peripheral nerve block that provides local anesthesia over S 2-4 dermatomes (majority of perineum and inferior quarter of vagina)
  • It does not block the superior birth canal so the mother is able to feel the uterine contractions.


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