Lumbosacral plexus
- Nerve with anterior and posterior division
- Sciatic nerve 45123
- Posterior femoral cutaneous nerve 123
- Perforating cutaneous nerve 23
- Nerve with anterior division only
- Tibial segment of sciatic nerve 45123
- Nerve to quadratus femoris/inferior glemelius 451
- Nerve to obturator internus 512
- Pudendal nerve 234
- Nerve with posterior division only
- Peroneal segment of sciatic nerve 512
- Superior gluteal nerve 451
- Inferior gluteal nerve 512
- Piriformis muscle 2
Major Nerves | Important Motor Supply | Motor Test | Sensory Supply |
Superior gluteal | Gluteus medius - Gluteus minimus - Tensor fascia lata | Hip abduction; Trendelenburg sign | — |
Inferior gluteal | Gluteus maximus | Hip extension | — |
Sciatic Nerve (L4–S3) | Hamstrings -Adductor magnus (medial) | Knee flexion | — |
Tibial nerve (L4–S3) | Gastrocnemius/Soleus - Tibialis posterior - Flexor digitorum longus - Flexor hallucis longus - Medial and lateral plantar nerves - Intrinsic foot muscles | Ankle plantarflexion - Ankle inversion | Medial sural cutaneous - Lower posterolateral calf - Lateral aspect of foot - Medial and lateral calcaneal - Heel of foot - Medial plantar - Digits 1–3 and medial sole of foot - Lateral plantar - 4th+5th digits and lateral sole of foot |
Common peroneal nerve (L4–S2) | Superficial peroneal - Peroneus longus - Peroneus brevis - Deep peroneal - Tibialis anterior - EDL/EDB - EHL/EDB - Peroneus tertius | — | Lateral sural cutaneous - Upper posterolateral calf - Superficial peroneal - Dorsum of foot & medial 3 toes - Deep peroneal - Space between 1st & 2nd toes |
Pudendal nerve (S2–4) | Inferior rectal nerve - External anal sphincter - Perineal nerve - External urethral sphincter, Bulbospongiosus Ischiocavernosus | — | Inferior rectal nerve - Below pectinate line - Perineal nerve - Posterior scrotum - Dorsal nerve of penis/clitoris - Skin of penis/clitoris |
Images
Clinical association
Hohmann’s retractor
- Placed at tip of TP to help dissection
- Danger of damaging lumbar nerves: Sekharappa 2013
- Placement that can damage lumbar plexus:
- Anterior to transverse process and lateral to vertebral body
- Near the IAP in the axillae of the TP
- Nerve most likely pressed is the femoral nerve followed by the obturator nerve
- Especially at the L4 and L5 level.
- Associated anatomy:
- In cadavers:
- lumbar plexus was situated directly over the transverse process of vertebra with very little muscle fibers of psoas behind the plexus.
- Above L3 transverse process the L2 nerve root was situated medially close to L2 vertebral body, while just above L4 and L5 transverse process, the branches forming the femoral and obturator nerves progressively coursed away from the vertebral bodies.
- At the level of L4 vertebral body, femoral nerve was situated lateral to the vertebral bodies by about 1.5–2 cm
Made with Bullet