Weakness is a symptom of a number of different conditions. The causes are many and can be divided into conditions that have true or perceived muscle weakness. True muscle weakness is a primary symptom of a variety of skeletal muscle diseases, including muscular dystrophy and inflammatory myopathy. It occurs in neuromuscular junction disorders, such as myasthenia gravis.
Edrophonium is a readily reversible acetylcholinesterase inhibitor. It prevents breakdown of the neurotransmitter acetylcholine and acts by competitively inhibiting the enzyme acetylcholinesterase, mainly at the neuromuscular junction. It is sold under the trade names Tensilon and Enlon.
A neuromuscular junction is a chemical synapse between a motor neuron and a muscle fiber.
The nasalis muscle is a sphincter-like muscle of the nose. It has a transverse part and an alar part. It compresses the nasal cartilages, and can "flare" the nostrils. Some people can use it to close the nostrils to prevent entry of water when underwater. It can be used to test the facial nerve (VII), which supplies it.
Neuromuscular-blocking drugs block neuromuscular transmission at the neuromuscular junction, causing paralysis of the affected skeletal muscles. This is accomplished via their action on the post-synaptic acetylcholine (Nm) receptors.
Intrafusal muscle fibers are skeletal muscle fibers that serve as specialized sensory organs (proprioceptors). They detect the amount and rate of change in length of a muscle. They constitute the muscle spindle, and are innervated by both sensory (afferent) and motor (efferent) fibers.
The thoracodorsal nerve is a nerve present in humans and other animals, also known as the middle subscapular nerve or the long subscapular nerve. It supplies the latissimus dorsi muscle.
The anterior superior iliac spine is a bony projection of the iliac bone, and an important landmark of surface anatomy. It refers to the anterior extremity of the iliac crest of the pelvis. It provides attachment for the inguinal ligament, and the sartorius muscle. The tensor fasciae latae muscle attaches to the lateral aspect of the superior anterior iliac spine, and also about 5 cm away at the iliac tubercle.
Extrafusal muscle fibers are the standard skeletal muscle fibers that are innervated by alpha motor neurons and generate tension by contracting, thereby allowing for skeletal movement. They make up the large mass of skeletal striated muscle tissue and are attached to bone by fibrous tissue extensions (tendons).
A cholinergic crisis is an over-stimulation at a neuromuscular junction due to an excess of acetylcholine (ACh), as a result of the inactivity of the AChE enzyme, which normally breaks down acetylcholine.
The gluteal tuberosity is the lateral one of the three upward prolongations of the linea aspera of the femur, extending to the base of the greater trochanter. It serves as the principal insertion site for the gluteus maximus muscle.
A neuromuscular disease is any disease affecting the peripheral nervous system (PNS), the neuromuscular junction, or skeletal muscle, all of which are components of the motor unit. Damage to any of these structures can cause muscle atrophy and weakness. Issues with sensation can also occur.
The long plantar ligament is a long ligament on the underside of the foot that connects the calcaneus with the 2nd to 5th metatarsal.
Aminosteroids are a group of steroids with a similar structure based on an amino-substituted steroid nucleus. They are neuromuscular blocking agents, acting as competitive antagonists of the nicotinic acetylcholine receptor (nAChR), and block the signaling of acetylcholine in the nervous system. These drugs include candocuronium iodide, dacuronium bromide, dihydrochandonium, dipyrandium, malouetine, pancuronium bromide, pipecuronium bromide, rapacuronium bromide, rocuronium bromide, stercuronium iodide, and vecuronium bromide.
The soleal line, also known as the popliteal line, is a prominent ridge on the posterior surface of the tibia. It is the site of many muscle origins and insertions, such as those of popliteus muscle, soleus muscle, flexor digitorum longus muscle, and tibialis posterior muscle.
The Bad Ragaz Ring Method (BRRM) is a type of aquatic therapy used for physical rehabilitation based on proprioceptive neuromuscular facilitation (PNF). BRRM is a water-based technique in which therapist-assisted strengthening and mobilizing exercises are performed while the patient lies horizontally in the water, with support provided by rings or floats around the neck, arms, pelvis, and legs.
Salivary gland hypoplasia is relative underdevelopment of the Salivary glands. Salivary gland hypoplasia tends to produce xerostomia, with all the associated problems this brings.
Dacuronium bromide is an aminosteroid neuromuscular blocking agent which was never marketed. It acts as a competitive antagonist of the nicotinic acetylcholine receptor (nAChR).
Nereistoxin is a natural product identified in 1962 as the toxic organic compound N,N-dimethyl-1,2-dithiolan-4-amine. It had first been isolated in 1934 from the marine annelid Lumbriconereis heteropoda and acts by blocking the nicotinic acetylcholine receptor. Researchers at Takeda in Japan investigated it as a possible insecticide. They subsequently developed a number of derivatives that were commercialised, including those with the ISO common names bensultap, cartap, thiocyclam and thiosultap.
