Entry 5

Coronary Occulsion and Conducting System of Heart

            The normal electrical conduction of the heart allows electrical propagation to be transmitted from the Sinoatrial Node (SA Node), the pace maker of the heart, through both atria to the Atrioventricular Node (AV Node). Baseline physiology allows the further propagation from the AV node to the purkinje fibers and repective bundle branches and fascicles. The SA and AV nodes stimulate the myocardium and proper, time ordered stimulation of the myocardium allows efficient contraction of all four chambers of the heart.

            Damage to the conducting system of the heart, often a result from ischemia, improper blood flow, caused by coronary artery disease. This produces disturbance in the myocardium, and since the anterioter intraventricular branch of the left coronary artery and the right coronary artery supply the AV and/or SA node a heart block could occur. There are several circumstances that could affect the AV and/or SA. When the AV node is affected the ventricles will begin to contract independently at their own rate but allowing the atria to contract at a normal rate. Under these circumstances a cardiac pacemaker would be implanted to control the rate of the ventricles.

http://en.wikipedia.org/wiki/Electrical_conduction_system_of_the_heart

 

Coronary Angioplasty

            Angioplasty is the surgical technique of mechanically widening a narrowed or obstructed blood vessel. An empty and collapsed balloon catheter, guided by a wire, is passed into the narrowed location and then inflated to a fixed size using water pressure normal to blood pressure. The balloon is responsible for crushing the fatty deposits and opening the blood vessel allowing for improved flow. The balloon is then collapsed and withdrawn.

            Percutaneous transluminal coronary angioplasty is a surgical approach for the treatment of stenotic coronary artery disease, and is caused by cholesterol-laden plaques that form due to atherosclerosis. Access to these blood vessels is gained through the femoral artery called percutaneous access. Real time X-ray visualization is used to guide the guiding catheter, which is pushed through the femoral artery ascending until it reaches the coronary artery that is infected. The guide wire is then pushed through the guiding catheter and this serves as the pathway for the balloon. A pharmaceutical aid called Heparin is used to thin the blood and reduce blood clots to help maintain blood flow.

http://en.wikipedia.org/wiki/Percutaneous_coronary_intervention

Fibrillation of Heart

Fibrillation is the rapid, irregular, and unsynchronized contraction of muscle fibers. Two types of cardiac fibrillation exist: artial fibrillation and ventricular fibrillation. During atrial fibrillation the normal rhythmical contractions of the atria are replaced by rapid irregular and uncoordinated twitching of different parts of the atrial walls. During ventricular fibrillation the ventricular contractions are replaced by rapid irregular twitching movements; stop the pumping action of the heart.

Artial fibrillation is usually easily treated with anticoagulation drugs and sometime with a conversion to normal sinus rhythm. The use of drugs are using sufficient in controlling either rate or rhythm, different. Ventricular fibrillation is the most serious condition because it inhibites the proper pumping of blood by the heart. One treatment of V-fib uses an electric defibrillator which can reverse the fibrillation by an electric discharge of direct current to the heart. This method is not always successful. Another treatment method is the implantation of a cardioverter defibrillator, which has been shown to be beneficial. 

http://en.wikipedia.org/wiki/Fibrillation

Entry Four

Mallet/Baseball Finger

            The extensor digitorum tendon at the distal interphalangeal joint is the location of trauma during mallet finger. The extensor digitorum muscle is located in the posterior forearm extending from the lateral epicondyle of the humerus and distally attaching to extensor expansions of medial four digits,. Interphalangeal joints are hinge joints between the phalanges of the hand; the distal interphalangeal joints are those between the second and third phalanges.

            This trauma results from the distal interphalangeal joint suddenly being forced into extreme flexion, for example, while a baseball is miscaught or a finger is jammed into the base pad. Treatment may or may not include a surgical intervention, depending on the severity of the deformity a Mallet splint can be worn for 6 to 8 weeks. The splint allows the tendon to return to normal length on its own. Surgery is used to reattach the tendon and is usually performed within a week of the injury.

 http://orthoinfo.aaos.org/topic.cfm?topic=A00018

Fracture of Olecranon

            The olecranon process of the ulna is a thick curved bony eminence  of the forearm that projects behind the elbow. It is located at the proximal end of the ulna and aids in the hinge joint of the elbow. The olecranon process of the ulna is the distal attachment point for the triceps brachii and the anconeus muscle. Branches of the ulnar nerve are found lying over the olecranon process of the ulna.

            Fracture of the olecranon is called a “fractured elbow”, that’s definitely a proper name for it. Typical trauma is caused by a fall on the elbow combined with sudden powerful contraction of the triceps brachii or an indirect fracture can occur from landing on an outstretched arm. The person lands on the wrist with elbow locked out straight. The triceps muscle on the back of the arm pull the olecranon off the ulna. Surgical intervention is usually always warranted in this type of trauma. Because of the traction produced by the tonus of the triceps on the olecranon fragment, pinning is required.
http://orthoinfo.aaos.org/topic.cfm?topic=A00503

           

Injury of Ulnar Nerve at Elbow

            The Ulnar nerve originates from the medial cord of the brachial plexuses. It runs down the posteromedial aspect of the humerus, over the elbow between the medial epicondyle of the humerus and the olecranon process of the ulna. The nerve continues down the forearm through the two heads of the flexor carpi ulnaris and runs alongside the ulna. The ulnar nerve innervates one and a half muscles in the forearm: the flexor carpi ulnaris and ½ of the flexor digitorum profundus. It also innervates the hypothenar muscles and provides sensory innervation to the 5^th digit and the medial half of the 4^th digit and corresponding part of the palm.

            More than 27% of nerve lesions of the upper limb affect the ulnar nerve. Injuries usually occur in four places: posterior to the medial epicondyle of the humerus, in the cubital tunnel formed by the tendinous arch connecting the humeral and ulnar heads of the FCU, at the wrist, and in the hand. The most common trauma occurs posterior to the medial epicondyle of the humerus. The trauma occurs when the medial part of the elbow hits a hard surface, fracturing the medial epicondyle, commonly know “the funny bone”. Other trauma can result in the extensive motor and sensory loss to the hand. An injury to the nerve in the distal part of the forearm denervates most intrinsic hand muscles. Surgical interventions are, most of the time, unsuccessful in reattaching the ulnar nerve.
http://orthoinfo.aaos.org/topic.cfm?topic=a00069

Entry Three

Rupture Calcaneal Tendon

            The calcaneal tendon, also referred to the Achilles tendon (named after the Greek war hero in Homer’s Iliad). The calcaneal tendon is the strongest, thickest, and most powerful tendon in the body. It is an extension of two leg muscles: the gastrocnemius and soleus; the tendon is approximately 15cm long. The strength of the tendon was proved during a stress test, which showed that the tendon could with stand a load of 3.9 times body weight while walking and about twice that when running. The tendon begins at middle of the triceps surae and distally attaches to the posterior surface of the calcaneal tuberosity.

            The rupturing of the calcaneal tendon is very traumatic and is often seen in poorly conditioned people. The trauma is typically experienced as an audible snap during a forceful plantarflexion with the knee extended followed by sudden triceps surae pain and dorsiflexion of the plantarflexed foot. The rupturing of the calcaneal tendon is the most serve acute muscular problem of the leg. Ambulation is possible but only when the limb is laterally rotated. A hematoma appears in the malleolar region; along with a lump on the calf owing to the shorting of the triceps surae. Surgical intervention is necessary for athletes and people with active lifestyles, but older and non-athletic  people usually are able to rehab without a surgical intervention.

http://en.wikipedia.org/wiki/Achilles_tendon

Hamstring Injuries

            The Hamstring is comprised of three posterior thigh muscles: biceps femoris, semitendinosus, and semimembranosus. The hamstrings cross and act upon two joints: the hip and knee. The semitendinosus and semimembanosus extend the hip when the trunk is fixed; they also flex the knee and medially rotate the lower leg. The biceps femoris extends the hip during walking; short and long heads flex the knee and laterally rotates the lower leg when the knee is bent. The hamstrings play a crucial role in many daily activities like walking, jumping, and controlling some movement in the trunk. The hamstring acts as an antagonist to the quadriceps during most of the activities listed above.

            Hamstring trauma, pulled and/or torn, are common in individuals who run and/or kick hard during athletic activities. This trauma is twice as common as quadriceps strains. The violent muscular exertion required to excel in these sports may avulse part of the proximal tendinous attachments of the hamstrings to the ischial tuberosity. Tearing of the hamstrings is a very painful trauma, and are often caused by inadequate warm up and stretching before physical activity.  Depending on the servarity of the trauma to the hamstrings the rehab regime is straight forward; us cold therapy and compression bandages during the first 48hrs of injury followed by messaging and stretching the muscle. Only under extreme cercumstances is a surgical intervention necessary.

http://en.wikipedia.org/wiki/Hamstring

  

Femoral Hernias

            A hernia occurs when the contents of the abdomen, usually part of the small intestine, push through a weak point or tear the thin muscular wall of the abdomen, which holds the abdominal organs in place. The femoral rings, the base of the femoral canal, is a weak area in the anterior abdominal wall. It’s a long diameter measures about 1.25cm, and its boarder includes the inguinal ligament, pectineus muscle, lacunar ligament, and the medial side of the femoral vein.

            The femoral ring is the usual site for femoral hernias, a protrusion of abdominal viscera through the femoral ring into the femoral canal. The hernia appears as a mass in the femoral triangle, inferolateral to the pubic tubercle. The hernial sac compresses the contents of the femoral canal and distends the wall of the canal. Initially the hernia is small because it is contained within the canal, but it can enlarge by passing inferiorly through the saphenous opening into the subcutaneous tissue of the thigh. Femoral hernias are more common in women because of their wider pelves. Necrosis can occur during strangulation of a femoral hernia because of the sharp, rigid boundaries of the femoral ring, particularly the concave margin of the lacunar ligament. Treatment is usually a surgical intervention, often a piece of plastic mesh is surgically placed to repair the defect in the abdominal wall.

http://en.wikipedia.org/wiki/Femoral_hernia