Lumbar and lumbosacral plexus Flashcards
*The entire lower limb is supplied by which 2 somatic nerve plexi?
1) Lumbar plexus (ventral rami of L1-L4)
2) Lumbosacral plexus (ventral rami of L4 and L5 joining the ventral rami from S1-S4)
*What does the lumbar plexus innervate?
Lumbar plexus (ventral rami of L1-L4) innervates – skin and muscles of the lower abdominal wall
- skin covering the root of the penis and anterior scrotum and the skin over the mons pubis and anterior portion of the labia majora
- skin and muscles in the anterior and medial compartments of the thigh
- skin of the lateral thigh
- skin of the medial side of the leg.
*What does the lumbosacral plexus innervate?
lumbosacral plexus (ventral rami of L4 and L5 joining the ventral rami from S1 to S4) innervates
- the skin and muscles of the gluteal region
- the skin and muscles of the perineum
- the skin and muscles of the posterior thigh
- the skin and muscles of the anterior, lateral, and posterior leg and the muscles of the medial leg
- the skin and muscles in the foot.
*Which plexus innervates the foot muscles?
lumbosacral (ventral rami of L4 and L5 joining the ventral rami of S1 to S4)
*Which plexus innervates the glute muscles?
lumbosacral (ventral rami of L4-L5 joining with S1-S4)
*Which plexus innervates the skin of the medial side of the leg?
lumbar plexus (ventral rami of L1-L4)
*Which plexus innervates the muscles of the anterior thigh?
lumbar plexus (ventral rami of L1-L4)
*Which plexus innervates the muscles of the medial thigh?
lumbar plexus (ventral rami of L1-L4)
*Which plexus innervates the skin of the anterior thigh?
lumbar plexus (ventral rami of L1-L4)
*Which plexus innervates the skin of the medial thigh?
lumbar plexus (ventral rami of L1-L4)
*Which plexus innervates the skin of the gluteal region?
lumbosacral plexus (L4-L5 and S1-S4)
*Which plexus innervates the foot skin?
lumbosacral plexus (L4-L5 and S1-S4)
*Which plexus innervates the muscles of the posterior thigh?
lumbosacral plexus (L4-L5 and S1-S4)
*Which plexus innervates the skin of the posterior thigh?
lumbosacral plexus (L4-L5 and S1-S4)
*Which plexus innervates most of the leg muscles and leg skin?
lumbosacral plexus (L4-L5 and S1-S4)
*What do the clunial nerves do?
provide cutaneous innervation to the skin of the gluteal region.
*What are the different groups of clunial nerves?
1) Superior clunial nerves (dorsal rami of L2, L3)
2) Middle clunial nerves (dorsal rami of S2, S3, S4)
3) Inferior clunial nerves (branches from posterior cutaneous nerve of the thigh– ventral rami of S2, S3)
*What are the superior clunial nerves and what do they supply?
derived from dorsal rami of L2, L3, L4. Supply the skin over the central and superior portion of this region.
*What are the middle clunial nerves and what do they supply?
derived from dorsal rami of S2, S3, and S4. Supply medial portion of the buttock.
*What are the inferior clunial nerves and what do they supply?
branches from posterior femoral cutaneous nerve of the thigh (which is a branch from the ventral rami of the sacral plexus). Inferior clunial nerves (S2 and S3) supply skin covering inferior portion of the buttock.
*Each paravertebral ganglion in the lumbar and sacral portion of the sympathetic chain is connected to a lumbar or sacral ventral ramus via?
grey ramus
*The lumbar and lumosacral plexi are what? What are they responsible for?
The lumbar and lumbosacral plexi are somatic nerve plexi responsible for supplying cutaneous sensaton from the skin and motor innervation to the muscles of the entire lower limb.
*What is responsible for the cremaster reflex? What is the cremaster reflex used for?
The L1 spinal nerve (the genital branch of the genitofemoral nerve off of the lumbar plexus) is responsible for the cremaster reflex. This reflex is used to determine integrity of the L1 spinal nerve. The cremaster muscle should contract (causing the testicles to retract lightly) if the L1 dermatome is stimulated (either by rubbing the skin of the anterior scrotum or upper thigh).
*Which is the largest nerve plexus in the body?
lumbosacral or sacral plexus
*preganglionic sympathetic neurons are found only as far inferior as the ___ region of the spinal cord? Axons from these neurons enter the sympathetic chain via ____?
Preganglionic sympathetic neurons are found only as far inferior as the L2 region of the spinal cord. Axons from these neurons enter the sympathetic chain via a white ramus that connects the first 2 lumbar ventral rami with the first 2 lumbar paravertebral ganglia.
*The first two lumbar paravertebral ganglia are attached to the first 2 lumbar ventral rami via ____?
both a white and grey ramus
*Any paravertebral ganglion below ____ is attached to the corresponding ventral ramus by ____?
Any paravertebral ganglion below the 2nd lumbar paravertebral ganglion is attached to the corresponding ventral ramus by a grey ramus only.
*How do preganglionic sympathetic axons reach the lower lumbar and sacral ganglia?
Those preganglionic neurons in the lower thoracic and upper lumbar regions of the spinal cord can descend down the chain before forming a synapse, in addition to synapsing in the ganglion in which they enter the sympathetic chain.
*A contribution from ___ may join ___ in the lumbar plexus.
A contribution from T12 ventral ramus may join L1 ventral ramus in the lumbar plexus.
*The L1 ventral ramus splits into…?
1) iliohypogastric nerve
2) ilioinguinal nerve
*What does the iliohypogastric nerve do and where is it derived?
Derived from L1, the iliohypogastric nerve supplies the muscles forming the lower portion of the abdominal wall (lower internal abdominal oblique). it is also sensory to the region of skin covering the abdominal wall over the pubic bone, just superior to the inguinal ligament.
*What does the ilioinguinal nerve do?
Derived from L1, the ilioinguinal nerve supplies the muscles forming the lower portion of the abdominal wall (lower internal abdominal oblique). It is also sensory to the region of skin covering the root of the penis and anterior scrotum in the male and the mons pubis and anterior labia in the female.
*What does the genitofemoral nerve do?
Derived from L1 and L2, the genitofemoral nerve is divided into two branches:
1) The femoral branch supplies the skin of he upper thigh, just below the inguinal ligament.
2) The genital branch in males goes through the inguinal canal to innervate the cremaster muscle.
*What does the lateral femoral cutaneous branch do?
Derived from L2 and L3 of the lumbar plexus, the lateral femoral cutaneous branch supplies the skin over the lateral thigh. The nerve becomes cutaneous as it passes under the lateral portion of the inguinal ligament.
*What is meralgia peristatica?
Meralgia Peristatica is a condition that leads to a burning sensation over the lateral thigh. This condition is caused by the entrapment of the lateral femoral cutaneous nerve (L2, L3) between the inguinal ligament and the ASIS. This compression can be caused by wearing tight hip-hugger pants.
*What is the femoral nerve?
Derived from L2, L3, and L4, the femoral nerve supplies motor innervation to the muscles of the anterior compartment of the thigh (quadriceps femoris and sartortius) and cutaneous sensation from the anterior and medal thigh and medial leg. The medial leg cutaneous innervation is supplied by the saphenous branch.
*What is the obturator nerve?
Derived from L2, L3, and L4, the obturator nerve supplies cutaneous innervation to a smakk region along the medial thigh near the knee and motor innervation to the obturator externus and adductors of the hip.
*What are the branches of the lumbar plexus?
1) Iliohypogastric (L1)
2) ilioinguinal (L1)
3) genitofemoral (L1, L2)– genital and femoral branches
4) lateral femoral cutaneous (L2, L3)
5) femoral (L2, L3, L4)– branches to psoas and saphenous
6) Obturator (L2, L3, L4)
*Which of the clunial nerves comes from ventral rami?
Inferior clunial nerve (off of the posterior femoral cutaneous nerve of the sacral plexus)
*what nerve is responsible for inversion of the foot?
L4
*what nerve is responsible for eversion of the foot?
S1
*What nerve is responsible for extension of the knee?
L2 and L3
*What nerve is responsible for hip flexion?
L1 and L2
*What nerve is responsible for ankle plantar flexion?
S1
*What nerve is responsible for ankle dorsiflexion?
L5
*The ventral rami of what nerves join to form the lumbosacral trunk of the sacral plexus?
L4 and L5
*The lumbosacral trunk is joined by the ventral rami of which nerves as it descends into the pelvis?
S1-S4, which enter through the ventral sacral foramina
*The branches from the lumbosacral plexus enter the ____ either above for below the ____ muscle.
The branches from the lumbosacral plexus enter the gluteal region either above or below the piriformis muscle.
What are the branches of the sacral plexus?
1) Superior gluteal nerve (L4, L5, S1)
2) inferior gluteal nerve (L5, S1, S2)
3) nerve to piriformis (L5, S1)
4) nerve to quadratus femoris and inferior gemellus (L4, L5, S1)
5) nerve to obturator internus and superior gemellus (L5, S1)
6) Posterior cutaneous nerve of the thigh (S1, S2, S3)
7) Pudendal nerve (S2, S3, S4)
8) Sciatic (Tibial– S2, S3, S4 and Common fibular division (L4, L5, S1, S2)
*What is the difference between peripheral nerve lesion and radiculopathy and spinal cord lesion?
1) A peripheral nerve lesion results in loss of function of muscle and atrophy because a peripheral nerve lesion will have more than one spinal segment associated with it and thus several associated dermatomes (e.g. femoral L2-L4).
2) A radiculopathy is associated with one dermatomy (eg L5). This will cause weakness of muscle and sensation loss restricted to one area.
3) a spinal cord lesion causes widespread muscle paralysis and loss of sensation below the site of the lesion.
*What is a common cause of a radiculopathy?
Herniated disc
***Radiculopathy of root L1 and L2 is associated with which dermatome and myotome?
dermatome = lower abdomen and upper thigh.
myotome = hip flexion.
***Radiculopathy of root L2 and L3 is associated with which dermatome and myotome?
dermatome: anterior and medial thigh
myotome: hip adduction and knee extension
***Radiculopathy of root L4 is associated with which dermatome and myotome?
Dermatome: medial leg
myotome: inversion and supination of tarsal joints
***Radiculopathy of root L5 is associated with which dermatome and myotome?
Dermatome: dorsum of foot.
myotome: hip abductors and dorsiflexion of ankle
***Radiculopathy of root S1 is associated with which dermatome and myotome?
dermatome: lateral and posterior leg
myotome: ankle plantar flexion. eversion and pronation of tarsal joints.
A herniated disc is usually a ____ injury wherein the nucleus bulges in a ______ direction. This is because the worn out annulus cannot contain the nucleus.
A herniated disc is usually a flexion injury wherein the nucleus bulges in a posterior lateral direction, blocking the intervertebral foramen and pressing on the spinal nerves. This is because the worn out annulus can not contain the nucleus.
What are three types of disc herniation?
1) Soft disc herniation. This is when the nucleus pulposus breaks through the annulus fibrosus. This commonly affects lumbar spine. This is because the elasticity and water content of the discs decrease with age in the nucleus pulposus, leaving 3-50 year old persons most susceptible.
2) hard disc herniation
3) combination of soft and hard disc herniation
What are the types of low back pain?
1) acute (6-12 weeks)
2) chronic (lasts more than 12 weeks; recurrent)
What are causes of low back pain?
1) lumbosacral strain (muscle tear),
2) sumbosacral sprain (tearing of ligaments),
3) herniated discs,
4) referred pain from visceral organs, metastases
What are the symptoms of low back pain?
localized, radiating
Lumbosacral radiculopathy usually affects ___ and may involve ____
lumbosacral radiculopathy usually affects cauda equina and may involve more than one root
lumbosacral spinal nerves exit ____ corresponding vertebrae
lumbosacral spinal nerves exit below corresponding vertebrae
*Disc L1,2 is associated with which spinal nerve, providing sensory and motor/function to…?
Disc L1, 2 is associated with spinal nerve L2, providing sensory to the mid-thigh and motor to the iliopsoas (hip flexion)
*Disc L2, L3 is associated with which spinal nerve, providing sensory and motor/function to?
Disc L2,3 is associated with spinal nerve L3, providing sesnory to the lower thigh and motor to quadriceps (knee extension) and adductors (hip adduction)
*Disc L3, L4 is associated with which spinal nerves, providing sensory and motor/function to?
Disc L3, L4 is associated with spinal nerve L4, providing sensory to the medial leg and motor to the tibalis anterior and posterior (foot inversion)
*Disc L4,L5 is associated with which spinal nerves, providing sensory and motor/function to?
Disc L4,L5 is associated with spinal nerve L5, providing sensory to the dorsum of the foot and motor to the anterior crural muscles (ankle dorsiflexion) and gluteus medius and minimus (hip abduction)
*Disc L5, S1 is associated with which spinal nerves, providing sensory and motor/function to?
Disc L5, S1 is associated with spinal nerve S1, providing sensory to the lateral leg and foot, and motor to the triceps surae (ankle plantar flexion)
*Squat tests?
quadriceps (L3)
*Heel walk tests?
L5– dorsiflexion (anterior crural muscles)
***Trendelenburg tests?
L5– hip abductors (gluteus medius and minimus)
*Toe walk tests?
S1– plantarflexion (triceps surae) and gastrocnemius and soleus
*During the straight leg raise test, if a patient experiences sciatic pain when the straight leg is at an angle of between ___ and ____ degrees, the test is positive and a ____ is likely to be the cause of the pain.
During the straight leg raise test, if a patient experiences sciatic pain when the straight leg is at an angle of between 30 and 70 degrees, the test is positive and a L5, S1 herniated disc is likely to be the cause of the pain.
*Approximately 90% of herniated discs occur at the ____ and ___ level, causing pain in the ___ or ____ nerve that radiates down the ____ nerve.
Approximately 90% of herniated discs occur at the L4-L5 and L5-S1 level, causing pain the the L5 or S1 nerve that radiates down the sciatic nerve.
How is a spinal cord lesion classified?
By the segments of cord that still function. For example, a C5 lesion means that all segments up to and including C5 are still functioning, and an L3 lesion means that all segments up to and including L3 are functioning.
If a person has a T10 spinal cord lesion would they be a paraplegic?
yes
The sacral paravertebral ganglia are connected to the ventral rami forming the sacral plexus by only a ____.
The sacral paravertebral ganglia are connected to the ventral rami forming the sacral plexus by only a grey ramus.
*The superior gluteal nerve is supplied by which roots and innervates what? The superior gluteal nerve enters the pelvis ____ the _____ muscle in company of _____?
The superior gluteal nerve of the sacral plexus is supplied by L4, L5, and S1. The superior gluteal nerve innervates the muscles attached from the outer portion of the body of the ilium, including the tensor fascia lata, gluteus medius and minimus. The superior gluteal nerve enters the pelvis above the piriformis muscle in company of the superior gluteal artery and vein.
*The inferior gluteal nerve is supplied by which roots and innervates what? The inferior gluteal nerve enters the pelvis ____ the ____ muscle in company of ____?
The inferior gluteal nerve is supplied by L5, S1, and S2 and innervates the gluteus maximus. The inferior gluteal nerve enters the pelvis below the piriformis muscle in company of the inferior gluteal artery and vein.
*The nerve to obturator internus is supplied by which roots and innervates what? The nerve to obturator internus exits the pelvis ____ to the ____ muscle.
The nerve to obturator internus is supplied by L5, S1, and S2 and innervates the obturator internus and superior gemellus muscles. The nerve to obturator internus exits the pelvis inferior to the piriformis muscle.
*The nerve to the quadratus femoris is supplied by which roots and innervates what?
The nerve to the quadratus femoris is supplied by L4, L5, and S1. It innervates the quadratus femoris and the inferior gemellus muscle as well as the hip joint.
*The pudendal nerve is supplied by which roots and innervates what? The pudendal nerve exits the pelvis ___ the ____ muscle in the company of ____?
The pudendal nerve is supplied by S2, S3, S4 and supplies the muscles associated with the external genitalia and sphincters of the anus and urethra. The pudendal nerve exits the pelvis below the piriformis muscle in the company of the pudendal artery and vein.
*The sciatic nerve is supplied by which roots and innervates what before diving into _____? The sciatic nerve exits the pelvis ____ the ____ muscle.
The sciatic nerve is supplied by L4, L5, S1, S2, S3, and S4. The sciatic nerve innervates the hamstring muscles in the posterior portion of the thigh before dividing into its terminal branches, the tibial and common fibular (peroneal) nerves. The sciatic nerve exits the pelvis below the piriformis muscle.
- The posterior femoral cutaneous nerve is supplied by which roots and innervates what?
The posterior femoral cutaneous nerve is supplied by S1, S2, and S3. The posterior femoral cutaneous nerve supplies the skin of the posterior thigh and popliteal region.
***A 21 year old female runner comes to your practice and complains that she has a hard time abducting her right hip. She also has a hard time coming out of the blocks when she is starting a 100 meter sprint. When she stands on her right leg with her left foot off the ground, you notice that her left iliac crest falls and on the right the crest rises. What muscles are involved with these symptoms? Do you think that there is a nerve involved? Do the symptoms suggest a nerve lesion or raciculopathy?
1
***A fifty five year old PT who was a good athlete when he was younger decides to lift a very heavy object by himself. The next day he wakes up with pain in his
back and radiating pain down the posterior of his thigh and leg. He has tingling sensation on the lateral and plantar surface of his foot. He has weak plantarflexion and has problems when asked to toe walk. His can abduct his hip but hip extension is somewhat weaker. Is this a nerve or nerve root problem? What are the differences? What nerve runs down the posterior of the thigh and leg? Do the dermatomes involve suggest a nerve lesion or does the distribution suggest a single dermatome? What does the toe walking test indicate? Can there be localized pain and radiating pain?
1
The developing strength of what muscle is responsible for the development of the lordotic curvature in the lumbar region?
iliopsoas
What about the lumbar region of the spine promotes mobility?
large vertebral bodies
Pain radiating along the back of the thigh and down the leg to the foot is indicative of ____?
nerve root impingement.
Radiculopathy can result from…?
intervertebral disc herniation, spinal stenosis, arthritis involving the intervertebral foramen
Any examination of low back pain should first try to rule out _____?
internal organ pain radiating to the low back region. Urinary system pain, pain with the reproductive system, or lower digestive system pain can all radiate back to the low back region.
lumbosacral strain usually involves which muscles?
true back muscles like the erector spinae.
lumbosacral sprains usually involve injury to…?
ligaments.
Which back ligaments are often injured?
posterior longitudinal, supraspinous, and ligamentum flavum. Flexion has a greater range of motion than extension. During flexion, the posterior longitudinal ligament, supraspinous ligament, and ligamentum flavum are required to help stabilize the lumbosacral spine. Thus, these are the most often injured
What is the most common cause of radiating back pain?
Radiculopathy due to herniated intervertebral disc
What movement puts most stress on intervertebral discs?
flexion coupled with lateral flexion, especially during lifting heavy objects.
Which regions of the vertebral column are affected most by herniated discs?
The C5-T1 region of the cervical spine and the L4-S1 region of the lumbar spine (the regions in which the largest amount of flexion takes place).
A herniation of the intervertebral disc between the C4 and C5 vertebrae will compress the ____ spinal nerve?
C5
A herniation between C6 and C7 vertebrae will affect the ___ spinal nerve?
C7
What is a classic sign of radiculopathy?
radiating pain
*If deep knee bends are difficult to perform then herniation affects which roots?
L2 and L3 (quadriceps femoris)
*If heel walk is difficult to perform then herniation affects which root?
L5 (anterior crural muscles– dorsiflexion)
*If toe walk is difficult to perform then herniation affects which root?
S1 (ankle plantar flexion– triceps surae)
Spinal cord lesion at C2 would result in?
quadriplegia and person cannot breath unassisted. There would be no sensation below upper region of the neck. They would have no motor reflexes.
spinal cord lesion at C6 would result in?
shoulder function, elbow flexion, wrist extension intact. No lower limb function. The neck, posterior lateral arm, and radial forearm would be unaffected. They would have biceps and brachioradialis reflexes.
spinal cord lesion in thoracic region would result in?
complete use of neck nad upper limb, but there would be lower limb paraplegia. The neck and upper limb would be intact, but there would be lower limb anesthesia. Depending upon the level injured there may or may not be sensation to the thorax and abdomen. Reflexes would include brachioradialis, biceps, and triceps.
spinal cord lesion in L2 would result in?
hip flexion and some adduction possible. Portion of anterior and medial thigh intact. No sensation in remainder of limb. No lower limb reflexes and incontinence.
spinal cord lesion in L4 would result in?
hip flexion, adduction, and knee flexion normal. anterior, medial thigh, medial leg and foot normal. patellar reflex possible and incontinence.
spinal cord lesion in S1 would result in?
hip, knee, and ankle dorsiflexors normal. Ankle plantar flexors and intrinsic muscles of the foot are weak. Lack of sensation in perineum but most of lower limb would lack sensation. Motor reflexes include patellar and achilles. Incontinence
