Knowledge Base
Anatomy of lower body muscles, innervation and their action
- Hip Flexion: Iliopsoas (L2,3,4)
- Hip extension: Gluteus maximus
- Hip abduction: (L4,5,S1)
- Hip adduction: (L2,3,4)
- Knee flexion: Hamstrings (L4,5,S1,2)
- Knee extension: Quadriceps (L2,3,4)
- Ankle dorsiflexion: Tibialis anterior (L4,5,S1)
- Ankle plantar flexion: Gastrocnemius (S1,2)
Leg innervation
Distribution and degree of weakness as a diagnostic clue to site of lesion
- Segmental (Nerve root)
- Territory of (One peripheral nerve)
- Proximal (Myopathies)
- Distal (Neuropathy)
- One-sided (Upper motor neurone)
- Spinal level/Paraplegia (Spinal cord)
- Generalized (Wasting disorders)
Diseases causing lesions of nerve or muscle
- Nerve root: (Herniated disc, Cauda equina syndrome)
- Peripheral nerve: (Trauma, mononeuritis, diabetes, distant malignant manifestation)
- Muscle: (Myopathy, myasthenia)
- Upper motor neurone: (CVA, intracranial space occupying lesion)
- Spinal cord: (Injury, transverse myelitis, multiple sclerosis)
- General: (Malnutrition, thyrotoxicosis, malignancy, prolonged bed rest)
Refs:
- Bates, A Guide to Physical Exam....485-495.
- Review Dr. McNulty's lesson, "Master Muscle List".