Physical Examination to distinguish UMN Lesion from LMN Lesion (C6 vs Median Nerve) Introduction ¨ Introduces Self ¨ Washes Hands ¨ Exposes and Drapes Patient Accordingly and Appropriately Part 1: Examine for UMN vs LMN Lesion Inspection LMN: ¨ Muscular Atrophy (or late UMN) ¨ Fasciculations Tone UMN ¨ Spasticity – most pronounced in opposite muscles to those that are weak. ¨ Clonus – provoked by sudden hyperextension of the wrist in the upper limb, and sudden dorsiflexion and eversion of the ankle in the lower limb LMN ¨ Normal/Flaccid Motor UMN ¨ Assess for weakness more pronounced in the extensors than flexors (Upper Extremity) ¨ Pronator Drift: Positive - Weakness of supination more pronounced than pronation LMN ¨ Distribution of weakness would differ depending on the area of the nerve root or peripheral nerve involved (see below) Reflexes ¨ Deep Tendon Reflexes, hyperreflexia: UMN – hyperreflexic; LMN – normal/hyporeflexic o Biceps tendon (C5/6; musculocutaneous) o Brachioradialis (C5,6; radial) o Triceps (C6,7) ¨ Pathologic reflexes: Present in UMN lesions, not LMN o Hoffman LMN ¨ Depressed Deep Tendon Reflexes (see above) Part 2: Differentiate a C6 lesion from a median nerve lesion Inspection ¨ Atrophy of Thenar eminence: Median Nerve ¨ Ape Hand Deformity (thumb adducted and laterally rotated) : Median nerve Motor ¨ Shoulder Abduction o Root – C5,6; Peripheral Nerve – Axillary o Weakness in C6 Palsy ¨ Elbow Flexion o Root - C5,6; Peripheral Nerve – Musculocutaneous o Weakness in C6 Palsy ¨ Elbow Extension o Root – C6,7; Peripheral Nerve – Radial o Weakness in C6 Palsy ¨ Wrist Extension o Root – C6,7; Peripheral Nerve – Radial o Weakness in C6 Palsy ¨ Finger Flexion o Root – C8; Peripheral Nerve – Median o Weakness in Median Nerve Palsy ¨ Thumb abduction & opposition o Weakness in Median Nerve Palsy ¨ Distal Thumb Flexion o Root – C8; Peripheral Nerve – Median o Weakness in Median Nerve Palsy Sensory ¨ Pinprick sensation to the tip of the 3rd finger (dorsal or ventral side) is differentiating spot Reflexes: ¨ Deep Tendon Reflexes, hyperreflexia: o Biceps tendon (C5/6; musculocutaneous) o Brachioradialis (C5,6; radial) o Triceps (C6,7) References: 1. Robblee J. and Katzberg H. Distinguishing Radiculopathies from Mononeuropathies. Front Neurol 2016, 13(7):111. doi: 10.3389/fneur.2016.00111 2. Gelb DJ. Introduction to Clinical Neurology. 5th Edition. New York, NY: Oxford University Press 2016. Pp: 80-87. Web. Accessed September 13, 2017. 3. Russell S and Triola M. “Deep Tendon Reflexes”. The Precise Neurologic Exam. New York University School of Medicine. Accessed September 13, 2017. https://informatics.med.nyu.edu/modules/pub/neurosurgery/reflexes.html 4. Rutkove SB. Overview of Upper Extremity Peripheral Nerve Syndromes. December 9, 2016. Uptodate. Wolters Kluwer. Accessed November 11, 2017. 5. iKnowledge Website. Figure 7-13. https://clinicalgate.com/forearm-wrist-and-hand-2/. Accessed November 11, 2017. 6. Jones O. The Median Nerve, Figure 2. TeachMeAnatomy.info. September 30, 2017. http://teachmeanatomy.info/upper-limb/nerves/the-median-nerve/. Accessed November 11, 2017. 7. COMMON CERVICAL AND LUMBOSACRAL ROOT LESIONS. Department of Neurology. Case School of Medicine. Case Western Reserve University. 2004. http://casemed.case.edu/clerkships/neurology/NeurLrngObjectives/Root.htm. Accessed February 1, 2018. .