•The Sciatic nerve is the largest nerve in the Human Body and is the continuation of the main part of the Sacral Plexus.
•The rami (branches) converge at the inferior border of the piriformisto form the sicatic nerve.
•The sciatic nerve is the lateral most structure emerging from the Greater sciatic foramen.
Course of the nerve
•The nerve enters the glutealregion via the greater sciatic foramen inferior to piriformis and deep to gluteus maximus;
•Descends in posterior thigh deep to biceps femoris;.
•The sciatic is really two nerves, the tibial nerve, and the common fibular nerve, which are loosely bound together in the same connective sheath.
Nerve roots and Branches
•Anterior and posterior divisions of rami of L4-S3.
•The tibial nerve, derived from anterior divisions of the anterior rami .
•The common fibular nerve, derived from the posterior divisions of the anterior rami.
The common fibular nerve is also known as the peroneal nerve
Where does it Bifurcate???
•Bifurcates into tibial and fibular nerves at apex of poplitealfossa/distal thigh.
•However in about 12% of people, the nerve bifurcates as they leave the pelvis.
•In this case the tibial nerve passes inferior to piriformis and the common fibular nerve pierces this muscle or passes superior to it.
•In 0.5% of cases the peroneal nerve passes superiorly to the piriformis muscle.
Innervations of Sciatic nerve
•Does Not supply muscles in Gluteal region!!!!!
•Supplies all Hamstring Muscle.
–Semitendinosus
–Semimembranosus
–Biceps Femoris
•Main action of the Hamstrings are the extension of the thigh and the hip and flexion of the leg at the knee.
•Also innervates the Hamstring part of the Adductor Longus.
•This also helps with the extension of the thigh.
Innervations of Peroneal nerve
•The peroneal nerve supplies skin on lateral part of posterior aspect of leg via the lateral sural cutaneous nerve;
•Also supplies knee joint via its articularbranch.
•Also the skin of the web between the great and 2nd toe via the Deep fibular nerve.
•The superficial fibular nerve innervates the skin of the anterolateral leg and dorsum of foot excluding the web space.
•The muscles of the anterior and lateral compartment of the leg and foot is supplied by the peroneal nerve via the deep and superficial fibular nerves.
•The tibial nerve supplies skin on medial part of posterior aspect of leg via the medial sural cutaneous nerve;
•The skin of medial and lateral sides of sole are innervated by the medial and lateral plantar nerve respectively. Their origin is the tibial nerve.
•The calcaneal nerve which has it origins from the tibial and sural nerves innervates the skin overlying the heel.
•All muscles of the posterior compartment of the thigh. tibialdivision provides all but short head of biceps, which is supplies by the fibular division.
•Also all muscles of the posterior compartment of leg and foot.
•The arc permits rotation(greatest degree of rotation) and some lateral flexion of the vertebral column
•b) Lumbar
• In the more sagittally oriented superior joints, the laterally facing facets of the inferior articular processes of the vertebra above are “gripped” by the medially facing facets of the superior processes of the vertebra below, thus facilitating flexion, extension and allowing lateral flexion but prohibiting rotation
6. Sandwich of hyaline cartilage within which there is a fibrocartilage.
7.Anulus fibrosus, nucleus pulposus
8. Notochord
9. Herniations of the nucleus pulposus usually extend posterior laterally.
Flexion of the vertebral column produces compression anteriorly and stretching or tension posteriorly, squeezing the nucleus pulposus further posteriorly toward the thinnest part of the annulus fibrosus. If the anulus fibrosus has degenerated, the nucleus pulposus may herniate into the vertebral canal and compress the spinal cord.
10. L4/L5
This is because the lumbar spine carries most of the body's weight. The lower back has a lot more motion than the thoracic spine and also carries all the weight of the torso, making it t
11. All day long gravity pushes down on our vertebrae, pushing water out from between our spinal disks. All this pressure can cause us to lose up to a centimeter off of our height during the day. At night, the water diffuses back between our disks, elongating us once again. Of course, since we are in a horizontal position, the force of gravity will not affect us negatively he most frequently injured area of the spine.
Hey folks, sorry for the lengthy post but it's because there's a slight possibility that I might not be able to come for tmr's PCL. Don't want you guys to be lost :P
p.s. click on the 'illustration of....' to view the pictures
Fractures
1.Subtype by Type of Fractures
A fracture is a partial or complete break in the bone. When a fracture occurs, it is classified as either open or closed:
open fracture (Also called compound fracture.) - the bone exits and is visible through the skin, or a deep wound that exposes the bone through the skin. These fractures are at especially high-risk of developing an infection, and generally require surgical treatment in all cases.
closed fracture (Also called simple fracture.) - the bone is broken, but the skin is intact.
Fractures have a variety of names. Below is a listing of the common types that may occur:
greenstick - incomplete fracture. The broken bone is not completely separated.
transverse - the break is in a straight line across the bone.
spiral - the break spirals around the bone; common in a twisting injury.
oblique - diagonal break across the bone.
compression - the bone is crushed, causing the broken bone to be wider or flatter in appearance.
The severity of a fracture depends upon its location and the damage done to the bone and tissue near it. Serious fractures can have dangerous complications if not treated promptly; possible complications include damage to blood vessels or nerves and infection of the bone ( osteomyelitis) or surrounding tissue. Recuperation time varies depending on the age and health of the patient and the type of fracture. A minor fracture in a child may heal within a few weeks; a serious fracture in an older person may take months to heal.
Stress fracture
·Overuse injury.
·Because of repeated micro-trauma, the bone can fail to absorb the shock that is being put upon it and become weakened.
·Most often it is seen in the lower leg, the shin bone (tibia), or foot. Athletes are at risk the most, because they have repeated footfalls on hard surfaces.
*Shin splints may have very similar symptoms as a stress fracture of the tibia but they are due to inflammation of the lining of the bone, called the periosteum. Shin splints are caused by overuse, especially in runners, walkers, dancers, including those who do aerobics. Muscles that run through the periosteum and the bone itself may also become inflamed.
Compression fracture
·As people age, there is a potential for the bones to develop osteoporosis. This makes bone more susceptible to breaking.
·Compression fracture to the spine, most often the thoracic or lumbar spine. Compression injuries of the back may or may not be associated with nerve or spinal cord injury.
2.Subtype by Location of Fractures
.a. Tibial Fractures
When determining treatment of a tibia fracture, the following factors must be considered:
Location of the fracture,
Displacement of the fracture,
Alignment of the fracture,
Associated injuries,
Soft-tissue condition around the fracture, and
Patient general health.
In general, tibia fractures can be separated into three categories based on the location of the fracture: (* Compound, fractures must be treated specially)
Tibial Shaft Fractures Tibial shaft fractures are the most common type of tibia fracture and occur between the knee and ankle joints. Most tibial shaft fractures can be treated in a long leg cast. However, some fractures have too much displacement or angulation and may require surgery to realign and secure the bones.
Tibial Plateau Fractures Tibial plateau fractures occur just below the knee joint. These fractures require consideration of the knee joint and its cartilage surface. Tibial plateau fractures can lead to a chance of developing knee arthritis. This fracture occurs at the top of the shin bone, and involves the cartilage surface of the knee joint.
Tibial Plafond Fractures Tibial plafond fractures occur at the bottom of the shin bone around the ankle joint. These fractures also require special consideration because of the ankle cartilage surface. Tibial plafond fractures are also concerning because of potential damage to surrounding soft-tissues.
Note the fracture line extends into the ankle joint.
b. Femur Fracture
Generally separated into three broad categories:
·Proximal Femur Fractures Proximal femur fractures, or hip fractures, involve the upper-most portion of the thigh bone, just adjacent to the hip joint. These fractures are further subdivided into different types of hip fractures :
·Femoral Shaft Fractures A femoral shaft fracture is a severe injury that generally occurs in high-speed motor vehicle collisions and significant falls. These injuries are often one of several major injuries experienced by a patient.
The treatment of a femoral shaft facture is almost always with surgery.
·Supracondylar Femur Fractures A supracondylar femur fracture is an unusual injury to the femur just above the knee joint. These fractures often involve the cartilage surface of the knee joint, and must be treated with this cartilage injury in mind. Patients who sustain a supracondylar femur fracture are often at high risk of developing knee arthritis later in life.
Hip fracture is more common in elderly persons who have fallen. It also can be caused by a direct blow or a motor vehicle or motorcycle crash. After the hip is fractured, it is common for the leg to turn outward and shorten.
Femur (thighbone) fracture usually is the result of a major force or trauma. It requires a considerable force to break a normal femur — the longest and strongest bone in the body.
Patella (kneecap) fracture usually is the result of direct trauma to the knee. It can be caused by a fall, motor vehicle crash, motorcycle crash or automobile-pedestrian crash.
Tibial and/or fibular (lower leg) fracture usually is the result of direct trauma to the lower leg. The causes of this type of fracture include falls from a height and motor vehicle collisions. The force of the trauma will directly influence the severity of the injury.
Ankle fracture can be caused by a variety of trauma types, such as a fall, a direct blow to the ankle, or a motor vehicle collision.
Calcaneus (heel) fracture usually is the result of a fall from a significant height when the patient lands directly on the feet. This type of injury usually causes great swelling and is often accompanied by fractures to the back.
