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Questions and Answers
Which nerve is responsible for innervating the skin of the groin?
Which nerve is responsible for innervating the skin of the groin?
- Pudendal nerve
- Lateral femoral cutaneous nerve
- Genitofemoral nerve
- Ilioinguinal nerve (correct)
Which nerve is the main branch of the sacral plexus?
Which nerve is the main branch of the sacral plexus?
- Tibial nerve
- Common fibular nerve
- Sciatic nerve (correct)
- Superior gluteal nerve
What is the function of the genitofemoral nerve?
What is the function of the genitofemoral nerve?
- Sensory innervation of the posterior thigh
- Motor innervation of gluteal muscles
- Motor innervation of the piriformis muscle
- Sensory innervation to the groin and scrotum/labium majus (correct)
Where do all branches of the sacral plexus exit the pelvis?
Where do all branches of the sacral plexus exit the pelvis?
Which nerve innervates the gluteus medius, minimus, and tensor fascia lata muscles?
Which nerve innervates the gluteus medius, minimus, and tensor fascia lata muscles?
What is the path of the lateral femoral cutaneous nerve?
What is the path of the lateral femoral cutaneous nerve?
Which nerve provides cutaneous innervation to the inferior part of the gluteal region?
Which nerve provides cutaneous innervation to the inferior part of the gluteal region?
Which of the following nerves does NOT have a terminal branch associated with it?
Which of the following nerves does NOT have a terminal branch associated with it?
Which nerve separates from the sciatic nerve halfway down the thigh?
Which nerve separates from the sciatic nerve halfway down the thigh?
What region does the lumbosacral plexus primarily innervate?
What region does the lumbosacral plexus primarily innervate?
Which spinal nerves primarily form the lumbar plexus?
Which spinal nerves primarily form the lumbar plexus?
What is the main function of the obturator nerve?
What is the main function of the obturator nerve?
Which of the following nerves is NOT a branch of the femoral nerve?
Which of the following nerves is NOT a branch of the femoral nerve?
Which nerve provides cutaneous innervation to the skin of the gluteal region?
Which nerve provides cutaneous innervation to the skin of the gluteal region?
What is the thickest branch of the lumbar plexus?
What is the thickest branch of the lumbar plexus?
Which muscle does the femoral nerve give motor innervation to?
Which muscle does the femoral nerve give motor innervation to?
What part of the spinal nerves contribute to the iliohypogastric and ilioinguinal nerves?
What part of the spinal nerves contribute to the iliohypogastric and ilioinguinal nerves?
Which nerve primarily provides sensation to the medial part of the thigh?
Which nerve primarily provides sensation to the medial part of the thigh?
What is the path of the obturator nerve after it pierces the psoas fascia?
What is the path of the obturator nerve after it pierces the psoas fascia?
Which lumbar plexus nerve is associated with sensory innervation to the anterior part of the thigh?
Which lumbar plexus nerve is associated with sensory innervation to the anterior part of the thigh?
What is the primary function of the obturator nerve?
What is the primary function of the obturator nerve?
Which of the following nerves is often derived from a common stem of T12-L1?
Which of the following nerves is often derived from a common stem of T12-L1?
Which nerve emerges between the psoas major and iliacus muscles?
Which nerve emerges between the psoas major and iliacus muscles?
What type of innervation does the medial cutaneous nerve of the thigh primarily provide?
What type of innervation does the medial cutaneous nerve of the thigh primarily provide?
Which spinal nerves contribute to the formation of the lumbar plexus?
Which spinal nerves contribute to the formation of the lumbar plexus?
What type of branches does the femoral nerve have?
What type of branches does the femoral nerve have?
Which nerve is primarily responsible for cutaneous innervation of the anterior thigh?
Which nerve is primarily responsible for cutaneous innervation of the anterior thigh?
What is the position of the obturator nerve as it descends through the body?
What is the position of the obturator nerve as it descends through the body?
Which nerve is the thickest branch of the lumbar plexus?
Which nerve is the thickest branch of the lumbar plexus?
What does the lateral branch of the iliohypogastric nerve supply?
What does the lateral branch of the iliohypogastric nerve supply?
Which nerve supplies cutaneous innervation to the anterior-lateral thigh?
Which nerve supplies cutaneous innervation to the anterior-lateral thigh?
Which of the following statements about the sciatic nerve is correct?
Which of the following statements about the sciatic nerve is correct?
Which is true regarding the sacral plexus?
Which is true regarding the sacral plexus?
What muscles are innervated by the inferior gluteal nerve?
What muscles are innervated by the inferior gluteal nerve?
The pudendal nerve is primarily responsible for innervating which area?
The pudendal nerve is primarily responsible for innervating which area?
Which nerve branches from the lumbosacral trunk?
Which nerve branches from the lumbosacral trunk?
What is the primary role of the posterior femoral cutaneous nerve?
What is the primary role of the posterior femoral cutaneous nerve?
Where does the lateral femoral cutaneous nerve exit?
Where does the lateral femoral cutaneous nerve exit?
Which nerves are contained within the same epineurium as the sciatic nerve?
Which nerves are contained within the same epineurium as the sciatic nerve?
What is the primary function of the superior gluteal nerve?
What is the primary function of the superior gluteal nerve?
What is the main source of the lumbar plexus?
What is the main source of the lumbar plexus?
The obturator nerve provides motor innervation to which of the following muscles?
The obturator nerve provides motor innervation to which of the following muscles?
Which nerve is often derived from T12-L1 and can supply the skin of the gluteal region?
Which nerve is often derived from T12-L1 and can supply the skin of the gluteal region?
What is the primary function of the femoral nerve?
What is the primary function of the femoral nerve?
Which of the following is a cutaneous branch of the femoral nerve?
Which of the following is a cutaneous branch of the femoral nerve?
What is the relationship of the obturator nerve to the psoas major muscle?
What is the relationship of the obturator nerve to the psoas major muscle?
Which of the following muscles is innervated by the iliohypogastric nerve?
Which of the following muscles is innervated by the iliohypogastric nerve?
Where does the femoral nerve emerge in relation to the psoas major and iliacus muscles?
Where does the femoral nerve emerge in relation to the psoas major and iliacus muscles?
What type of innervation do the medial and intermediate cutaneous nerves of the thigh provide?
What type of innervation do the medial and intermediate cutaneous nerves of the thigh provide?
In what percentage of cases does the subcostal nerve (T12) contribute to the lumbar plexus?
In what percentage of cases does the subcostal nerve (T12) contribute to the lumbar plexus?
What is the function of the tibial nerve?
What is the function of the tibial nerve?
Which nerve is associated with the anterior surface of the psoas major muscle?
Which nerve is associated with the anterior surface of the psoas major muscle?
Which structure does the posterior femoral cutaneous nerve NOT supply?
Which structure does the posterior femoral cutaneous nerve NOT supply?
What is the pathway of the pudendal nerve in relation to the piriformis muscle?
What is the pathway of the pudendal nerve in relation to the piriformis muscle?
Which nerve exits the pelvis through the greater sciatic foramen except for its branch supplying the piriformis muscle?
Which nerve exits the pelvis through the greater sciatic foramen except for its branch supplying the piriformis muscle?
Which of the following nerves is most closely related to the piriformis muscle?
Which of the following nerves is most closely related to the piriformis muscle?
What is the primary action facilitated by the superior gluteal nerve?
What is the primary action facilitated by the superior gluteal nerve?
Which of the following options is correct regarding the separation of the sciatic nerve's terminal branches?
Which of the following options is correct regarding the separation of the sciatic nerve's terminal branches?
Which spinal nerves contribute to the formation of the lumbosacral trunk?
Which spinal nerves contribute to the formation of the lumbosacral trunk?
Which of the following nerves is most responsible for sensory innervation to the ant-lat thigh?
Which of the following nerves is most responsible for sensory innervation to the ant-lat thigh?
Study Notes
Lumbar Plexus
- Located within the psoas major muscle
- Formed by the ventral rami of L1-L3 and the superior part of L4 spinal nerves
- 50% of cases show a contribution from T12 (subcostal nerve)
Largest Branches of the Lumbar Plexus
- Obturator nerve
- Femoral nerve
Obturator Nerve (L2, L3, L4)
- Descends through the psoas major muscle
- Pierces the psoas fascia
- Crosses the sacroiliac joint
- Emerges from the obturator canal
- Provides cutaneous innervation to the medial part of the thigh
- Provides motor innervation to the adductor muscles of the thigh
Femoral Nerve (L2, L3, L4)
- Emerges between the psoas major and iliacus muscles
- Thickest branch of the lumbar plexus
- Cutaneous branches:
- Medial cutaneous nerve of the thigh
- Intermediate cutaneous nerve of the thigh
- Saphenous nerve
- Motor branches:
- Muscles located at the anterior part of the thigh:
- Pectineus muscle
- Muscles located at the anterior part of the thigh:
Iliohypogastric and Ilioinguinal Nerves
- Derived from T12-L1, often by a common stem
Iliohypogastric Nerve (T12, L1)
- Lateral branch supplies the skin of the gluteal region
- Anterior branch supplies the skin of the hypogastric region
Ilioinguinal Nerve (T12, L1)
- Passes through the superficial inguinal ring
- Supplies the skin of the groin, scrotum, or labium majus pudendi
Genitofemoral Nerve (L1, L2)
- Runs on the anterior surface of the psoas major muscle
- Femoral branch: supplies the skin of the thigh
- Genital branch: runs through the inguinal canal
Lateral Femoral Cutaneous Nerve (L2, L3)
- Passes through the psoas major muscle and iliac crest
- Supplies the skin over the anterolateral thigh
Lumbosacral Plexus
- Nerve plexus in the lumbar and sacral region
- The ventral rami of L1-L3 nerves and the superior branch of L4 form the lumbar plexus
- The inferior branch of L4 and all of L5 form the lumbosacral trunk, which descends to the sacral plexus
Sacral Plexus
- Located in the lesser pelvis (true pelvis)
- Closely related to the piriformis muscle
- Formed by the:
- lumbosacral trunk
- ventral rami of S1-S3
- part of S4
Branches of the Sacral Plexus
- All branches of the sacral plexus leave the pelvis through the greater sciatic foramen, except for the nerve to the piriformis muscle
Sciatic Nerve (L4, L5, S1, S2, S3)
- Main branch of the sacral plexus
- Largest nerve in the body
- Converges on the anterior surface of the piriformis muscle
- Enters the gluteal region
- Passes through the greater sciatic foramen
- Usually does not supply structures in the gluteal region
- Two terminal branches:
- Tibial nerve
- Common fibular (peroneal) nerve:
- Superficial peroneal nerve
- Deep peroneal nerve
Tibial Nerve
- One of the two terminal branches of the sciatic nerve
Common Fibular (Peroneal) Nerve
- One of the two terminal branches of the sciatic nerve
- The tibial and common fibular nerves are bound together in the same epineurium
- They usually separate from each other halfway down the thigh
Pudendal Nerve (S2, S3, S4)
- Most medially located at the inferior edge of the piriformis muscle
- Innervates the structures in the perineum
Posterior Femoral Cutaneous Nerve (S2, S3)
- Supplies cutaneous innervation to the:
- Inferior part of the gluteal region
- Posterior side of the thigh
- Proximal part of the leg
- Passes through the infrapiriform foramen
Superior Gluteal Nerve (L4, L5, S1)
- Passes through the greater sciatic foramen (suprapiriform foramen)
- Runs along the superior gluteal vessels
- Innervates the gluteus medius, minimus, and tensor fascia lata muscles
Inferior Gluteal Nerve (L5, S1, S2)
- Leaves the pelvis at the inferior part of the greater sciatic foramen (infrapiriform foramen)
- Alongside the inferior gluteal vessels
Lumbar Plexus
- Formed by the ventral rami of L1-L3 and the superior part of L4 spinal nerves
- Often has a contribution from T12 (subcostal nerve) in 50% of cases
- Located within the psoas major muscle
Major Branches of the Lumbar Plexus
- Obturator nerve: (L2, L3, L4)
- Innervates the adductor muscles of the thigh
- Provides cutaneous innervation to the medial part of the thigh
- Femoral nerve: (L2, L3, L4)
- Thickest branch of the lumbar plexus
- Supplies motor innervation to the anterior muscles of the thigh
- Provides cutaneous innervation via:
- Medial cutaneous nerve of thigh
- Intermediate cutaneous nerve of thigh
- Saphenous nerve
Other Branches of the Lumbar Plexus
- Iliohypogastric nerve: (T12, L1)
- Supplies skin of the gluteal region (lateral branch)
- Supplies skin of the hypogastric region (anterior branch)
- Ilioinguinal nerve: (T12, L1)
- Passes through the superficial inguinal ring
- Supplies skin of the groin, scrotum, or labium majus pudendi
- Genitofemoral nerve: (L1, L2)
- Travels along the anterior surface of the psoas major muscle
- Branches into:
- Femoral branch
- Genital branch (passes through the inguinal canal)
- Lateral femoral cutaneous nerve: (L2, L3)
- Passes through the psoas major muscle and iliac crest
- Supplies skin over the antero-lateral thigh
Lumbosacral Plexus
- Formed by the ventral rami of L1-L3 and the superior branch of L4 (lumbar plexus)
- Inferior branch of L4 and L5 (lumbosacral trunk) descend to form the sacral plexus
Sacral Plexus
- Located in the lesser pelvis
- Closely related to the piriformis muscle
- Formed by:
- Lumbosacral trunk
- Ventral rami of S1-S3
- Part of S4
Major Branches of the Sacral Plexus
- Sciatic nerve: (L4, L5, S1, S2, S3)
- Largest nerve in the body
- Usually does not innervate structures in the gluteal region
- Main branch of the sacral plexus
- Passes through the greater sciatic foramen
- Branches into:
- Tibial nerve
- Common fibular (peroneal) nerve
- Superficial peroneal nerve
- Deep peroneal nerve
- Pudendal nerve: (S2, S3, S4)
- Innervates the perineum
- Most medially located nerve at the inferior edge of the piriformis muscle
- Posterior femoral cutaneous nerve: (S2, S3)
- Provides cutaneous innervation to the inferior part of the gluteal region, posterior side of the thigh, and proximal part of the leg
- Passes through the infrapiriform foramen
Other Branches of the Sacral Plexus
- Superior gluteal nerve: (L4, L5, S1)
- Passes through the suprapiriform foramen
- Innervates the gluteus medius, minimus, and tensor fascia lata muscles
- Inferior gluteal nerve: (L5, S1, S2)
- Passes through the infrapiriform foramen
- Innervates the gluteus maximus muscle
Lumbar Plexus
- Located within the psoas major muscle
- Formed by the ventral rami of L1-L3 and the superior part of L4 spinal nerves
- In 50% of cases, receives a contribution from T12 (subcostal nerve)
Major Branches of the Lumbar Plexus (L2-L4)
-
Obturator Nerve:
- Descends through the psoas major muscle
- Pierces the psoas fascia
- Crosses the sacroiliac joint
- Emerges from the obturator canal
- Provides cutaneous innervation to the medial part of the thigh
- Provides motor innervation to the adductor muscles of the thigh
-
Femoral Nerve:
- Emerges between the psoas major and iliacus muscles
- Thickest branch of the lumbar plexus
- Cutaneous Branches:
- Medial cutaneous nerve of the thigh
- Intermediate cutaneous nerve of the thigh
- Saphenous nerve
- Motor Branches:
- Muscles located at the anterior part of the thigh
- Pectineus muscle
Other Branches
-
Iliohypogastric Nerve (T12, L1):
- Sends a lateral branch to supply the skin of the gluteal region
- Sends an anterior branch to the skin of the hypogastric region
-
Ilioinguinal Nerve (T12, L1):
- Passes through the superficial inguinal ring
- Innervates the skin of the groin, scrotum, or labium majus pudendi
-
Genitofemoral Nerve (L1, L2):
- Runs along the anterior surface of the psoas major muscle
- Femoral Branch:
- Genital Branch: Passes through the inguinal canal
-
Lateral Femoral Cutaneous Nerve (L2, L3):
- Passes through the psoas major muscle and iliac crest
- Supplies skin over the anterolateral thigh
Lumbosacral Plexus
- Nerve plexus in the lumbar and sacral region
- Formed by the ventral rami of L1-L3 nerves, the superior branch of L4, and the inferior branch of L4 and all of L5
- Lumbosacral trunk descends to the sacral plexus
Sacral Plexus
- Located in the lesser pelvis (true pelvis)
- Closely related to the piriformis muscle
- Formed by:
- The lumbosacral trunk
- The ventral rami of S1-S3
- Part of S4
Branches of the Sacral Plexus
-
All branches leave the pelvis through the greater sciatic foramen, except for the nerve to the piriformis muscle
-
Sciatic Nerve (L4, L5, S1, S2, S3):
- Main branch of the sacral plexus
- Largest nerve in the body
- Converges on the anterior surface of the piriformis muscle
- Enters the gluteal region and passes through the greater sciatic foramen
- Usually supplies no structures in the gluteal region
- Has two terminal branches:
- Tibial Nerve
- Common Fibular (Peroneal) Nerve:
- Superficial Peroneal Nerve
- Deep Peroneal Nerve
- Tibial and common fibular nerves are bound together in the same epineurium (usually separate halfway down the thigh)
-
Pudendal Nerve (S2, S3, S4):
- Located most medially at the inferior edge of the piriformis muscle
- Innervates structures in the perineum
-
Posterior Femoral Cutaneous Nerve (S2, S3):
- Supplies cutaneous innervation to:
- The inferior part of the gluteal region
- The posterior side of the thigh and proximal part of the leg
- Passes through the infrapiriform foramen
- Supplies cutaneous innervation to:
-
Superior Gluteal Nerve (L4, L5, S1):
- Passes through the greater sciatic foramen (suprapiriform foramen) along with the superior gluteal vessels
- Innervates the gluteus medius, minimus, and tensor fascia lata muscles
-
Inferior Gluteal Nerve (L5, S1, S2):
- Leaves the pelvis at the inferior part of the greater sciatic foramen (infrapiriform foramen) alongside the inferior gluteal vessels
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Description
Test your knowledge on the anatomy of the lumbar plexus, including its location, major branches, and nerve functions. This quiz covers essential details such as the obturator and femoral nerves, along with their anatomical pathways and innervations. Perfect for students of anatomy and physiology!
