Wired Up –
Muscle Mysteries
Muscle Mysteries
Innervation of short head of biceps femoris
What is common fibular (peroneal) nerve?
A patient with weakness of wrist flexion, weak finger extension, numbness of middle finger and forearm has radicular symptoms from this level
What is C7?
The effect of cooler limbs on waveforms? Eg: what happens to the amplitude, duration, onset, etc.
What is larger amplitude and longer duration?
This X-linked recessive disease is the most common type of dystrophic myopathy.
What is Duchenne Muscular Dystrophy?
This disorder involves progressive muscle weakness and stiffness due to an autoimmune attack on the voltage-gated calcium channels at the neuromuscular junction, often triggered by a paraneoplastic syndrome.
What is Lambert Eaton?
This nerve originates from the posterior cord of the brachial plexus, innervates the subscapularis, teres major, and latissimus dorsi
What is lower subscapular nerve?
Nerve that is damaged after proximal humerus fracture.
What is axillary nerve?
This percentage decreased in CMAP should be noted from the proximal to distal segment to diagnose a conduction block.
What is 20%? A 50% decrease usually indicates an axonal lesion.
This inflammatory myopathy, often associated with a positive anti-Jo-1 antibody, presents with proximal muscle weakness and characteristic EMG findings of fibrillation potentials, positive sharp waves, and short-duration, low-amplitude motor unit potentials.
What is polymyositis?
This medication should be avoided in patients with NMJ disorders.
What is Dantrolene?
Innervation of flexor pollicus longus, pronator quadratus, lateral half of flexor digitorum profundus
What is anterior interosseous nerve?
This condition occurs when a particular nerve is compressed as it passes through the spiral groove of the humerus, often due to prolonged pressure, resulting in wrist drop and weakened extension of the forearm and fingers.
What is radial nerve palsy?
The elbow is bent to 90 degrees to test the ulnar nerve to prevent this from occurring.
What is false slowing of the conduction velocity?
This factor signals an increased risk for malignancy in dermatomyositis.
What is elevated C-reactive protein?
In this NMJ disorder, you will see a 200-300% increment in amplitude change with high-rate repetitive stimulation.
What is Lambert Eaton?
This nerve is a branch of musculocutaneous nerve and provides innervation to the skin over the lateral forearm, as well as the muscles in the anterior compartment of the forearm, such as the flexor carpi radialis
What is lateral antebrachial cutaneous nerve?
Patient presents with foot drop, weak ankle dorsiflexion, weak great toe extension, and sensory loss over the dorsum of the foot due to an injury of this nerve at this common entrapment site
What is the common peroneal (fibular) nerve at the fibular head?
This study is used to assess for S1 radiculopathy but can also be used to assess for C6/7 radiculopathy.
What is H-reflex? Monosynaptic spinal reflex involving both motor and sensory, at submaximal stimulation.
An EMG study conducted in someone with polymyositis/dermatomyositis will show abnormal activity in this muscle(s).
What are the paraspinals?
In an EMG study, normal SNAP and CMAP are seen in this NMJ disorder.
What is Myasthenia Gravis?
This nerve, originating from the sacral plexus, provides motor innervation to the muscles responsible for hip extension, including the gluteus maximus, and also plays a key role in the function of the lower limb by innervating the hamstrings.
What is the inferior gluteal nerve?
Patient has weak knee extension, decreased patellar reflex, and numbness in the anterior thigh and medial leg due to an injury of this nerve and its corresponding spinal levels.
What is the femoral nerve and L3-L4?
This finding is characteristic of ALS when doing a single fiber EMG.
What is increased jitter and fiber density?
This autosomal dominant congenital myopathy is associated with malignant hyperthermia.
What is central core disease?
A variation between the interpotential discharge of two muscle fibers in a voluntary contraction.
What is a jitter?