Muscles

Inspiration is an active process, but normal expiration is a passive process. Forced expiration recruits the abdominal muscles to help force out air.   Muscles of breathing Diaphragm – this is the main muscle of inspiration. It flattens out. During normal quiet breathing it is only really the diaphragm that does any work (other muscles are often not involved). It is controlled by the phrenic nerve which has nerve roots in C3-5.  

This is a syndrome that results from swelling of a muscle. The muscle is retained in its fixed volume fascia, however, and thus the swelling of the muscle causes occlusion of the blood supply. this can result in infarction, and can cause an ischaemic contraction known as Volkmann’s Ischaemic Contracture.   It typically occurs in the forearm and calf, but can also occur in the thigh and foot.    

Fibromyalgia is a non-specific muscular disorder of unknown origin. It primarily affects insertions of tendons and associated soft tissues and presents with dull aching pains. It is much more common in women.  Epidemiology and Aetiology Cause is unknown Affects muscles rather than joints – although can often feel like joint pain Peak age of onset: 40-50 years M:F ratio 1:9  Pathology  

β2- agonists These act on β2adrenoceptors on bronchial smooth muscle, causing dilation of the smooth muscle whatever the cause. They are selective because they only target the β2 receptors (not β1) and thus do not act on the myocardium   Mechanism  

Myasthenia Gravis is an acquired, autoimmune condition. Antibodies attack the Acetylcholine receptor. This gives weakness in muscles, particularly the ocular, bulbar and proximal skeletal. Fatigability is a key symptom!  

Lung compliance is the ability of the lungs to expand. Elastance measures the work that has to be exerted by the muscles of inspiration to expand the lungs. Factors affecting these are discussed here.  

A 14 year old boy felt a mild aching discomfort in his left groin while playing rugby but still continued to play. He subsequently tackled an opponent and developed a severe pain of sudden onset in the left upper thigh and groin. A “snapping” sound was heard and he fell to the ground. He was unable to bear weight on the left leg and appeared pale, clammy, and nauseated. His pitch-side vital observations were normal and he was offered combined gaseous nitrous oxide and oxygen for pain relief. Ice was applied to the area of maximum discomfort and he was accompanied to the emergency department in an ambulance. At the emergency department he was advised that he had probably “strained” a muscle and was given conservative advice. He was discharged with crutches and analgesia.  

A 14 year old boy felt a mild aching discomfort in his left groin while playing rugby but still continued to play. He subsequently tackled an opponent and developed a severe pain of sudden onset in the left upper thigh and groin. A “snapping” sound was heard and he fell to the ground. He was unable to bear weight on the left leg and appeared pale, clammy, and nauseated. His pitch-side vital observations were normal and he was offered combined gaseous nitrous oxide and oxygen for pain relief. Ice was applied to the area of maximum discomfort and he was accompanied to the emergency department in an ambulance. At the emergency department he was advised that he had probably “strained” a muscle and was given conservative advice. He was discharged with crutches and analgesia.  

A group of MPs calls for the government to allow a newborn screening test for the deadly muscle-wasting condition Duchenne Muscular Dystrophy.  

Dogfish shark dissection for muscles, including extrinsic eye muscles.  

Cat musculature  

Musculature of the head and pectoral girdle  

http://www.ophthobook.com This lecture covers the retina, optic nerve, eye muscles, and the orbital bones. This was excerpted from the complete anatomy lectu...  

This is an uncommon ophthalmology finding. With this disorder, the superior oblique muscle spasmically fires, and the eye rotates. Look closely at one of the...  

This is an inclusion cyst on the conjunctiva of the eye. These can occur after surgery (often after muscle surgery) and are simply fluid/oil filled cyst from...  

http://www.kinesiologyprep.com - In this video, the action of controlling the extension of the wrist from a fully flexed position is an eccentric muscle cont...  

http://www.interactive-biology.com/107 - In this video, I go over the content I covered in the last 2 videos. I basically review the muscles, innervation and...  

Dr. Fabian explaining  

Muscles of the Lower Leg by Dr. Fabian  

Muscles and Tendons of the Forearm pt 2