Weakness Around a Leg Joint

CLINICAL DIAGNOSTIC MANUAL

Weakness around a leg joint can be a sign of various neuromuscular conditions affecting the innervation and function of surrounding muscles. This weakness may result from nerve injuries, radicular compressions, or neuromuscular diseases that compromise nerve transmission and muscle strength. Identifying the specific cause of weakness is crucial for appropriate management and functional recovery. Clinical evaluation should include a detailed medical history and physical examination, complemented by appropriate diagnostic studies.

Condition	Clinical Symptoms and Signs	Suspected Diagnosis	Confirmatory Diagnosis
Femoral nerve injury	Weakness in knee extension, difficulty climbing stairs, loss of patellar reflex, anterior thigh pain	Clinical history, neurological exam, quadriceps weakness	EMG, nerve conduction studies, lumbar spine MRI
Obturator nerve injury	Weakness in thigh adduction, difficulty crossing legs, pain in the inner thigh	Clinical history, neurological exam, adductor weakness	EMG, nerve conduction studies
L3-L4 root lesion	Radicular pain in the anterior thigh, weakness in knee extension, loss of patellar reflex	Clinical history, neurological exam, radicular signs	Lumbar spine MRI, nerve conduction studies
Tibial nerve injury	Weakness in plantar flexion, loss of Achilles reflex, difficulty walking on toes	Clinical history, neurological exam, calf muscle weakness	EMG, nerve conduction studies
Common peroneal nerve injury	Foot drop, weakness in dorsiflexion and eversion, sensory loss on the top of the foot	Clinical history, neurological exam, foot drop signs	EMG, nerve conduction studies
Sciatic nerve injury	Radicular leg pain, weakness in knee flexion and calf muscles, loss of Achilles reflex	Clinical history, neurological exam, radicular and muscle weakness signs	Lumbar spine MRI, nerve conduction studies
Lateral popliteal nerve palsy	Weakness in dorsiflexion and eversion, foot drop, sensory loss in the lateral leg and dorsum of the foot	Clinical history, neurological exam, foot drop signs	EMG, nerve conduction studies