Local leg lesions

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Lower extremity: Motor & Sensory innervation ¹

Roots
Root lesions

Arms

Nerves
Femoral
Lateral femoral cutaneous
Obturator
Peroneal, Common
Deep
Superficial

		Roots
Muscle	Nerve	L1	L2	L3	L4	L5	S1	S2	S3
Psoas minor	Lumbar Plexus	+	+	.	.	.	.	.	.
Psoas major	Lumbar plexus	+	+	+	.	.	.	.	.
Sartorius	Femoral	.	+	+	.	.	.	.	.
Quadriceps (Vasti; Rectus)	Femoral	.	+	+	+	.	.	.	.
Adductor longus	Obturator	.	+	+	+	.	.	.	.
Adductor magnus	Obturator Sciatic, Tibial portion	.	+	+	+	+	+	.	.
Gracilis	Obturator	.	+	+	+	.	.	.	.
Gluteus med & min	Superior gluteal	.	.	.	+	+	+	.	.
Tensor fascia lata	Superior gluteal	.	.	.	+	+	+	.	.
Gluteus maximus	Inferior gluteal	.	.	.	.	+	+	+	.
Piriformis	Sacral Plexus	.	.	.	.	.	+	+	.
Biceps (short head)	Sciatic (Peroneal)	.	.	.	.	+	+	+	.
Biceps (long head)	Sciatic (Tibial)	.	.	.	.	ą	+	+	ą
Semimembranosus	Sciatic (Tibial)	.	.	.	+	+	+	.	.
Semitendinosus	Sciatic (Tibial)	.	.	.	+	+	+	+	.
Anterior tibial	Deep peroneal	.	.	.	+	+	.	.	.
Ext. hallucis longus	Deep peroneal	.	.	.	.	+	+	.	.
Peronei, except tertius	Superficial peroneal	.	.	.	.	+	+	.	.
Posterior tibial	Tibial	.	.	.	.	+	+	.	.
Gastrocnemius	Tibial	.	.	.	.	.	+	+	.
Soleus	Tibial	.	.	.	.	.	+	+	.
Flexor digitorum brevis	Medial plantar	.	.	.	.	+	+	.	.
Abductor hallucis	Medial plantar	.	.	.	.	.	+	+	.
Interossei	Lateral plantar	.	.	.	.	.	+	+	.

Lumbar & Lumbosacral Root Lesions: Clinical Features
Root	Motor Involvement	Sensory Loss	Pain Location	Reflex Disorder
L1	None	Inguinal	Inguinal	None
L2	Psoas	Thigh, Lateral & Anterior	Groin Thigh, Anterior	None
L3	Psoas Quadriceps Hip adductors	Thigh, Medial Knee	Thigh, Anterior Leg, Anterior	Knee
L4	Quadriceps Hip adductors Tibialis anterior	Leg, Lower medial	Leg Anterior & Medial	Knee
L5	Toes: Extensor ± Flexor Ankle: Dorsiflex, Inversion & Eversion Hip: Abduction (Gluteus medius & minimus) Gait: Trendelenburg	Leg, Lower lateral Foot, Dorsum Middle toes ≥ Great toe	Thigh, Lateral Leg, Lower lateral Foot, Dorsum	? Hamstring
S1	Gastrocnemius Hamstrings Gluteus maximus Toe flexors	Foot, Lateral 2 toes & Plantar Ankle, Lateral	Thigh, Posterior Leg, Lower posterior Foot, Posterior	Ankle
S2-4	None	Buttocks, Medial Perineum Perianal	Buttocks, Medial	Bulbocavernosus Anal wink
Also see: Lumbosacral plexopathies

Trendelenburg Gait

Nosology: Gluteus medius lurch
Anatomy: Leg abductor weakness
- Nerves: Superior gluteal nerve; Lower lumbar radiculopathy
- Muscles: Gluteus medius; Gluteus minimus
- Also: Hip dysplasia or disease
Gait disorder
- Pelvis drops instead of rising on unsupported side opposite lesion

Elys (Femoral nerve stretch) test

Distal Weakness Pattern
- Weak: Ankle dorsiflexion, eversion & inversion
- Spared: Toe flexion
Gait: Trendelenburg
Disc herniations
- Posterolateral
  - Level: L4-5
- Foraminal (Very lateral)
  - Level: L5-S1
  - Positive stratight leg raising sign (30° to 70°)
Sacroiliac joint injury
- Lumbosacral plexus involvement: Especially L5
Sacral fracture
- Displaced
- Especially ala involvement
Spondylolisthesis

Iliohypogastric: T12, L1; Suprapubic, Upper buttock
Ilioinguinal: L1; Scrotum & Root of penis, upper medial thigh
Lateral femoral cutaneous nerve of the thigh: L2,L3; Anterolateral thigh
Genitofemoral: L1, L2
- Cremasteric muscle & reflex
- Genital branch: Scrotum, Mons pubis, Labium majus
- Femoral branch: Anterior & Medial, Upper thigh
Obturator: L3; Upper medial thigh
Pudendal: S2-S4; Perineum & Scrotum or Labia
- Damage: Childbirth