Important Blood Supply of Bones Animation - Everything You Need to Know - Dr. Nabil Ebraheim, M.D. скачать в хорошем качестве

Important Blood Supply of Bones Animation - Everything You Need to Know - Dr. Nabil Ebraheim, M.D.

Dr. Ebraheim’s educational animated video about AVASCULAR NECROSIS - AVN. There are at least seven bones with very important blood supply. •Talus •Fifth metatarsal •Scaphoid •Navicular •Proximal femoral head •Proximal humerus •Lunate Fracture of these bones or dislocations of their joints can interrupt this peculiar blood supply causing the threat of death of the bone which is called avascular necrosis of the bone. It may also delay in healing of the bone or nonunion of fractures. Fractures in these areas usually result from trauma or stress-related injuries. The most important blood supply of the talus comes from an artery of the tarsal canal (main blood supply of the talus). The deltoid branch arises from the posterior tibial artery. Fracture of the talar neck will interrupt the blood supply and cause nonunion of the fracture or death of the bone. There are three types of fractures of the proximal fifth metatarsal. Zone I tuberosity avulsion fracture Zone II jones fracture. The jones fracture compromises the blood supply which leads to nonunion of the fracture. It is called jones fracture when it occurs at the level of articulation of the 4th and 5th metatarsals. Treatment of jones fracture is non-weight bearing with a cast or intramedullary screw fixation. The majority of patients will have intramedullary screw fixation. intramedullary screw fixation is usually done in athletes and in active individuals. If the fracture occurs distal to the 4th and 5th metatarsal articulation, the fracture probably results due to stress and does not heal very well without some form of fixation. If the fracture occurs in the rich area of the tuberosity, which is proximal, then this fracture will heal. (pseudo-jones fracture). You can give the patient a boot and the patient will do very well. The blood supply of the scaphoid is unique and tenous. The main blood supply of the scaphoid comes from the dorsal branch of the radial artery. The dorsal branch of the radial artery supplies approximately 70-80% of the blood supply and it occurs in a retrograde fashion. Scaphoid fractures can lead to nonunion and avascular necrosis due to interruption of the blood supply. Avascular necrosis is best seen with MRI. MRI is also helpful in diagnosing occult fractures. The more proximal the fracture, the more likely the fracture may develop AVN because of the retrograde circulation. AVN of the proximal fifth of the scaphoid in up to 100% of the cases. Navicular fractures are uncommon, but popular. Its blood supply is unique. Branches of the dorsal pedis artery supply the dorsum of the navicular while the medial plantar branch of the posterior tibial artery supplies the plantar surface of the bone. The navicular tuberosity receives its blood supply from an anastomosis between these two vessels. The area where stress fractures may occur is avascular. The center 1/3 of the navicular is relatively avascular and has the greatest stress. The medial femoral circumflex artery is the primary source of blood supply to the femoral head. Damage to the MFCA due to trauma, fractures or dislocations may lead to avascular necrosis of the femoral head (AVN). The risk of AVN will increase with delay in reduction of a dislocated hip. The hip should be reduced within 6 hours or injury. AVN of the femoral head occurs due to interruption of the terminal branches of the MFCA. Blood supply of the proximal humerus is controversial. There are two important arteries •Anterior humeral circumflex artery •Posterior humeral circumflex artery The arcuate artery was considered to be the artery that gives the majority of blood supply to the humeral head. The arcuate artery is the terminal branch and is one of the primary blood supply to the humeral head. Recent studies are suggesting that the posterior humeral circumflex artery provides the main blood supply to the humeral head, so it is controversial. AVN of the humeral head usually occurs in four-part fractures. Fractures or dislocations of the humeral head may result in avascular necrosis. AVN may also be a result of the disrupted medial hinge. If there is avascular necrosis of the humeral head, you may want to also look at the hips of the patient. Avascular necrosis of the lunate bone is called Keinbock’s disease. Keinbock’s disease is usually associated with a negative ulnar variance that will lead to increased stress on the lunate area. There are lunate vascularity variances. Treatment Shortening osteotomy of the radius is the main procedure used to treat Keinbock’s disease when it is symptomatic and in stage II (can be used on x-ray as sclerosis of the lunate). When the patient has a negative ulnar variance.