Lumbosacral Plexus
From WikiMSK
The lumbosacral plexus can be divided into two anatomical parts: the upper lumbar plexus and the lower lumbosacral plexus.
Lumbar Plexus
The lumbar plexus is located within the psoas muscle. It contains the canterior rami of the T12 to L4 nerve roots. Only the femoral nerve can be reliably tested by EMG. The lateral femoral cutaneous nerve can be tested but it is unreliable.
Nerve | Motor Supply | Sensory Supply | EMG |
---|---|---|---|
Iliohypogastric nerve (T12/L1) | Transverse and internal oblique muscles | Lower abdomen | |
Ilioinguinal nerve (L1) | - | Inguinal region, small area of media thigh, and upper scrotum/labia | |
Genitofemoral nerve (L1, L2) | Cremasteric muscle in men | Skin of femoral triangle. Lower scrotum/labia | |
Lateral femoral cutaneous nerve (L2,L3) | - | Lateral thigh | |
Obturator nerve (L2, L3, L4 anterior rami) | Thigh adductors | Medial thigh | |
Femoral nerve (L2, L3, L4 anterior rami, posterior divisions) | Iliopsoas, sartorius, quadriceps | Medial lower leg (through saphenous nerve |
Lumbosacral Plexus
Nerve | Motor Supply | Sensory Supply |
---|---|---|
Lumbosacral trunk / furcal nerve (L4-5, mainly L5) | Ankle dorsiflexion, eversion, inversion | L5 sensory loss |
Superior gluteal nerve (L4, L5, S1) | Tensor Fascia Lata, Gluteus Medius, Gluteus Minimus | - |
Inferior gluteal nerve (L5, S1, S2) | Gluteus Maximus | - |
Sciatic trunk/nerve (L5โS3) | Posterior thigh muscles (except biceps femoris short head), and leg through common peroneal and tibial nerves | - |
Pudendal nerve (S2-4) | - | -
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