Canine Lumbosacral Plexus And Pelvic Limb Nerves Flashcards
What three nerves innervate the abdominal wall?
Costoabdominal n, cranial iliohypogastric n, caudal iliohypogastric n
What two components make up the lumbosacral plexus and what are their corresponding vertebra?
Lumbar component L3-L6
Sacral component S1-S3
What are intercostal nerves?
Intercostal nerves are the ventral branches of thoracic spinal nerves 1-12
What structures do intercostal nerves provide motor function for?
External and internal intercostal mm, transversus thoracis m, and rectus abdominis m
What provides the cutaneous sensory innervation from intercostal n?
Lateral cutaneous branch and ventral cutaneous branch
True or False: the nerves that innervate the abdominal wall all provide sensory and motor function.
True
What makes up the lumbosacral plexus?
Ventral branches of lumbar and sacral spinal nerves
The genitofemoral nerve is motor to what structure?
Cremaster muscle
The genitofemoral nerve is sensory for what?
From skin in inguinal region (inguinal mammary gland, prepuce) and proximal medial thigh
The genitofemoral nerve is formed by ventral branches of which vertebra spinal nerves?
L3 and L4
True or False: the genitofemoral nerves supplies motor function only in males.
True
The obturator nerve innervates adductors of pelvic limb, which includes what structures?
External obturator muscle, pectineus muscle, gracilis muscle, adductor muscle
The obturator nerve arises from which spinal nerves?
L4, L5, L6
The obturator nerves supplies what function?
Motor
The femoral nerve arises from which spinal nerves?
L4, L5, L6
The femoral nerve emerges from what structure?
Iliopsoas muscle
What structures does the femoral nerve innervate and provide motor function?
Iliopsoas muscle, quadriceps femoris muscle, sartorius muscle
The femoral nerve gives rise to what other nerve and what is its function?
Saphenous nerve
Cutaneous innervation to skin of medial femoral, genual, tibial and pes regions
Describe the afferent input, central connection, and efferent output of the patellar reflex.
Afferent input: the sensory receptor in the quadriceps muscle sends a signal along the afferent neuron to the spinal cord
Central connection: the signal synapses at the level of L3 and L4 in the spinal cord
Efferent output: an alpha motor neuron conducts efferent impulse back to the quadriceps femoris muscle, triggering contraction. Contraction causes the leg to kick.
The caudal cutaneous femoral nerve arises from which spinal nerves?
S1, S2, S3
The caudal cutaneous femoral nerve terminates where?
In skin on proximal caudal half of thigh
The caudal cutaneous femoral nerve follows the caudal gluteal artery to the level of what?
Ischiatic tuberosity
The lumbosacral trunk gives rise to what nerves?
Caudal gluteal nerve, cranial gluteal nerve, sciatic nerve (ischiatic nerve)
The lumbosacral trunk is formed by the ventral branches of?
L6, L7, S1, S2
The caudal gluteal nerve provides motor function to what structure?
Superficial gluteal muscle
The cranial gluteal nerve provides motor function to what structures?
Middle gluteal muscle, piriformis muscle, deep gluteal muscle, tensor fasciae latae muscle
The efferent sciatic nerve innervates what structures within the pelvis?
Internal obturator muscle, gemelli muscle, quadratus femoris muscle
The efferent sciatic nerve innervates what structures caudal to the hip?
Biceps femoris muscle, semimembranosus muscle, semitendinosus muscle
Describe the path of the sciatic nerve.
Courses over greater ischiatic notch, dorsal and caudal to the coxal joint
What nerves arise from the fibular and tibial components of sciatic nerve to supply cutaneous innervation to lateral and caudal surfaces of crus?
Lateral and caudal cutaneous sural nerves
Proximal to the stifle, the sciatic nerve divides into?
Common fibular (peroneal) nerve and tibial nerve
The common fibular (peroneal) nerve innervates?
Flexors of the tarsal joint and extensors of the digit
The tibial nerve innervates?
Extensors of the tarsal joint and flexors of the digit
The common fibular nerve divides into?
Deep and superficial peroneal (fibular) nerves
The deep fibular nerve innervates?
Cranial tibial muscle, long digital extensor muscle, peroneus longus muscle
The deep fibular nerve courses distally with what vessel?
Cranial tibial artery
The superficial fibular nerve innervates?
Lateral digital extensor muscle and peroneus brevis muscle
The tibial nerve arises from what spinal nerves?
L7, S1
The tibial nerve innervates?
Gastrocnemius muscle, superficial digital flexor muscle, deep digital flexor muscle, popliteus muscle
The tibial nerve divides into what sensory nerves?
Medial and lateral plantar nerves
The medial and lateral plantar nerves are sensory to?
Plantar surface of pes
What is/are the most probable muscle(s) affected (paralysis) in a total laceration of the tibial nerve at the level of the popliteal fossa?
Gastrocnemius, plantaris, popliteus, and soleus in cats
What is the cutaneous region with hypoesthesia or numbness, in a dog with the common fibular nerve sectioned?
Digit 2, 3, 4, and 5 then up the dorsal side of the tarsocrural joint
What are clunial nerves in the lumbar component of the lumbosacral plexus?
Dorsal cutaneous branches from the last four lumbar nerves that innervate the skin in the gluteal area
What are clunial nerves in the sacral component of the lumbosacral plexus?
Dorsal cutaneous branches from the sacral nerves that innervate the skin in the gluteal and dorsal areas of the pelvis
The pudendal nerve includes what nerve branches?
Dorsal rectal nerve, perineal nerve, dorsal nerve of the penis/nerve of the clitoris
Where is the most caudal end of the conus medullaris located in dogs and cats?
Located at the level of the caudal half of the L6 vertebra and the cranial part of the L7 vertebra
Can also be found at L7-S1 in cats depending on the individual
The pelvic nerve is from what spinal nerves?
S1, S2
The pelvic nerve fibers run into what structures before getting distributed to its target organs?
Pelvic plexus
The pelvic plexus lives lateral to what?
Rectum
