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Neuroscience Chapter 12: Peripheral Nervous System

Terms in this set (46)

Case 4 A 22-year-old man sprained his ankle last week and during the physical therapy history mentioned that his ankles seem to gradually be getting weaker. He reported difficulty walking on uneven ground and in the dark. Examination revealed the following: •Manual muscle tests bilaterally normal for muscles of the hips and knees. Unable to walk on heels; ankle dorsiflexion 4−/5 bilaterally. Unable to rise on toes. All foot intrinsic muscles weak. Upper limb normal strength except 4/5 finger extension and finger abduction •Observation: hammer toes (flexion contractures affecting the proximal interphalangeal joint of all toes) and high arches both feet •Pinprick: normal in all tested digits (digits 1, 3, and 5 of both hands and feet). Vibration (128 Hz tuning fork): absent bilaterally at hallux interphalangeal joint and first metatarsal head, present for 4 seconds over medial malleoli. Normal bilaterally at distal interphalangeal joint of the index fingers and at the ulnar styloid process. Proprioception: at toes, unable to detect position or movement direction accurately; ankles, 75% accuracy regarding position, able to detect direction of passive movements greater than 5 degrees accurately; knee and upper limb proprioception normal •Steppage gait (high stepping to clear mild drop foot) •Phasic stretch reflexes cannot be elicited with Achilles tendon tap, quadriceps tendon tap, or brachioradialis tendon tap. Trace phasic stretch reflexes can be elicited with biceps tendon tap.
Questions
1. What is the location of the lesion(s)?
2. What is the probable diagnosis? What is the next step for the patient?