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SACCULAR ANEURYSM – A balloon-like outpouching of a vessel (the more common type of aneurysm).

SACRAL – Five fused segments of the lower spine, below the end of the spinal column, that connect to the pelvis and have four formina on each side.

SACRAL AGENESIS – Absence, failure of formation, or imperfect development of the lower portions of the spinal column and pelvis.

SACRAL ALA – Lateral portions of the sacral bone.

SACRAL CYST – Abnormality in the spinal fluid sac in the sacrum.

SACRALGIA – Pain in the sacrum.

SACRALIZATION – Fusion of L-5 to the first segment of the sacrum, so that the sacrum consists of six segments; with this abnormality, it is called BERTOLOTTI syndrome.

SACRALIZED TRANSVERSE PROCES – One or both of the lumbar spinous transverse processes abnormally joining with the sacrum; sacralization.

SACRODYNIA – Pain perceived to be in the area of the sacrum but may originate elsewhere; referred pain.

SACROILITIS – Inflammation of the sacroiliac joint. A very painful, often one-sided sacral area pain that follows delivery, is not due to sepsis, and will subside gradually and completely; acute postpardum sacroilitis.

SACRUM – A part of the spine that is also part of the pelvis. It articulates with the ilia at the sacroiliac joints and articulates with the lumbar spine at the lumbosacral joint. The sacrum consists of five fused vertebrae that have no intervertebral discs.

SAGITTAL -Longitudinal.

SCALENUS – The deep lateral muscles of the anterior neck, including anterior scalene m. (scalenus anticus), middle scalene m. (scalenus medius), and posterior scalene m. (scalenus posticus).

SCAPULA – A large triangular flattened bone lying over the ribs, posteriorly on either side.

SCHEUERMANN’S DISEASE – Inflammation of the anterior cartilage of the bodies of the lower thoracic and upper segments, causing pain in some older, growing children. There is more than 5 degrees of wedging of at least three adjacent vertebrae as seen on radiographs.

SCHMORL NODES – Developmental change resulting in inferior or superior extension of the intervertebral disc into the vertebral bodies.

SCHOLLNER COSTOPLASTY – For rib deformity or scoliosis; multiple rib partial excisions.

SCIATICA – A lay term indicating pain along the course of a sciatic nerve, especially noted in the back of the thigh and below the knee. Pain radiating down the sciatic nerve into the posterior thigh and leg; can be caused by irritation of a nerve anywhere from the back to the thigh.

SCOLIORACHITIS – Disease of the spine caused by rickets; abnormal bone mineralization.

SCOLIOSIS – Lateral (sideways) curvature of the spine.

SCOTOMA – An area of decreased vision surrounded by an area of less depressed or normal vision.

SCOTT – Use of cross-wire fixation transverse process to inferior pedicle in stabilization of spondylolysis fusion.

SEDDON – Drainage of thoracic spinal abscess through anterolateral approach with partial resection of rib.

SEGMENTAL INSTABILITY – Abnormal response to applied loads characterized by motion in the motor segment beyond normal constraints.

SEPSIS – A state of infection of tissue due to disease-producing bacteria or toxins.

SEPTUM – A thin wall dividing two cavities or masses of softer tissue.

SEQUESTRATION – Displaced material escapes as free fragment(s), which may migrate elsewhere.

SHUNT – A tube or device implanted in the body (usually made of Silastic) to redivert excess CSF away from the brain to another place in the body.

SIMMONS – Use of keystoned-shaped graft in anterior fusion. For cervical spinal kyphosis; a posterior osteotomy.

SKELETON – The rigid framework of bones that gives form to the body, protects and supports the soft organs and tissues, and provides attachments for muscles.

SOUTHWICK – A posterior fusion with wire attaching bone graft to the facet joints.

SPEED (KELLOGG SPEED) – For spondylolisthesis spine fusion and anterior interbody fusion by using tibial cortical graft.

SPETZLER – Approach to anterior C-1 to C-3 by using a transoral approach for fusion following excision of tumor.

SPINA BIFIDA – A congenital defect of the spine marked by the absence of a portion of the spine.

SPINAL ACCESSORY NERVE (eleventh cranial) – The nerve from the brainstem that supplies the sternocleidomastoid muscles.

SPINAL CANAL – The bony channel that is formed by the intravertebral foramen of the vertebrae and in which contains the spinal cord and nerve roots. The space between the vertebral body anteriorly and the lamina and spinal process posteriorly.

SPINAL COLUMN – See Spine.

SPINAL CORD – The longitudinal cord of nerve tissue that is enclosed in the spinal canal. It serves not only as a pathway for nervous impulses to and from the brain, but as a center for carrying out and coordinating many reflex actions independently of the brain.

SPINAL DISC – See Disc (Intervertebral).

SPINAL FUSION – Operative method of strengthening and limiting motion of the spinal column. Can be performed with a variety of metal instruments and bone grafts, or bone grafts alone.

SPINAL STENOSIS – General term denoting narrowing of the spinal canal in the lumbar area leading to nerve root compromise; term often used for developmental abnormality that leaves a narrow, bony canal. There are four subgroups of this condition: achondroplastic stenosis, constitutional stenosis, degenerative stenosis, and combined stenosis.

SPINAL THALAMIC TRACT – The main tract of pain to the brain.

SPINE – The flexible bone column extending from the base of the skull to the tailbone. It is made up of 33 bones, known as vertebrae. The first 24 vertebrae are separated by discs known as intervertebral discs, and bound together by ligaments and muscles. Five vertebrae are fused together to form the sacrum and 4 vertebrae are fused together to form the coccyx. The spine is also referred to as the vertebral column, spinal column, or backbone.

SPINOUS PROCESS – The portion of the vertebrae that protrudes posteriorly from the spinal column. The spinous processes create the “bumps” felt on the midline of the back. The most posterior extension of the spine arising from the laminae.

SPONDYLALGIA – Pain in vertebra(e).

SPONDYLARTHRITIS – Arthritis of the spine.

SPONDYLARTHROCACE – Tuberculosis of the spine; spondylocace.

SPONDYLEXARTHROSIS – Dislocation of a vertebra.

SPONDYLITIS – Inflammation of vertebrae, including types such as ankylosing, rheumatoid, traumatic, spondylitis deformans, Kümmel, and Marie-Strümpell d.

SPONDYLIZEMA – Depression or downward displacement of a vertebra, with destruction or softening of one below it.

SPONDYLODYNIA – Pain in vertebra(e).

SPONDYLOEPIPHYSEAL DYSPLASIA – Disorder of growth affecting both the spine and the ends of long bones.

SPONDYLOLISTHESIS – A defect in the construct of bone between the superior and inferior facets with varying degrees of displacement so the vertebra with the defect and the spine above that vertebra are displaced forward in relationship to the vertebrae below. It Is usually due to a developmental defect or the result of a fracture.

SPONDYLOLYSIS – Displacement of one vertebrae over another with fracture of a posterior portion of the vertebra. A defect in the neural arch between the superior and inferior facets of vertebrae without separation at the defect and therefore no displacement of the vertebrae. It may be unilateral or bilateral and is usually due to a developmental defect but may be secondary to a fracture.

SPONDYLOMALACIA – Softening of vertebrae; Kümmell disease.

SPONDYLOPATHY – Any vertebral disorder.

SPONDYLOPYOSIS – Infection in vertebra(e).

SPONDYLOSCHISIS – Congenital fissure (splitting) of vertebral arch.

SPONDYLOSIS – Ankylosis of the vertebra; often applied nonspecifically to any lesion of the spine of a degenerative nature. Bony replacement of ligaments around the disc spaces of the spine, associated with decreased mobility and eventual fusion; marginal osteophyte.

SPONDYLOSYNDESIS – Surgical immobilization or ankylosis by fusion of the vertebral bodies with a short bone graft in cases of tuberculosis of the spine; spondylodesis, Albee procedure.

SPONDYLOTOMY – Incision into a vertebra or vertebral column; rachiotomy.

SPRAIN – An injury to a ligament when the joint is carried through a range of motion greater than normal, but without dislocation or fracture.

STAINLESS STEEL – Iron-based metal containing chromium that is highly resistant to stain, rust, and corrosion. Certain grades of stainless steel are commonly used to make surgical implants and instruments.

STEFFEE PLATE – For posterolateral fusion fixation; plate and screw device.

STENOSIS – Reduction in the diameter of the spinal canal due to new bone formation which may result in pressure on the spinal cord or nerve roots.

STEREOTACTIC – Originated from the Greek words stereo meaning three dimensional and tactos meaning touched and relating to stereotaxy.

STEREOTAXY – A precise method of destroying deep-seated brain structures located by use of three dimension coordinates.

STEREOTACTIC RADIOSURGERY – The precise delivery of radiation to a preselected stereotactically localized target.

STERILE – Free from living organisms. Relating to or characterized by sterility.

STERILITY – In general, the incapability of fertilization or reproduction.

STERILIZATION – The method used to render a material free from living organisms. Usual methods include steam under pressure, gas, and ionizing radiation.

STERNOCLEIDOMASTOID – Large externally visible muscle of the anterior neck, enabling the head to turn to either side.

STERNUM – The breast bone; further divided into three segments. manubrium: upper portion, proximal end; sternum: main portion; xiphoid: the dagger-like tip of the sternum, distal end.

STRABISMUS – Deviation of eye movement which prevents the two eyes from moving in a parallel fashion.

STRAIN – To injure by overuse or improper use.

STRAP MUSCLES – A general term applied to the ribbon-like muscles in the anterior neck; they include omohyoid, sternhyoid, sternthyroid, and thyrohyoid.

STRUCTURAL CURVE – A fixed lateral curve of the spinal column.

SUBARACHNOID HEMORRHAGE – Blood in, or bleeding into, the space under the arachnoid membrane, most commonly from trauma or from rupture of an aneurysm.

SUBDURAL HEMATOMA – a collection of blood (clot) trapped under the dura matter, the outermost membrane surrounding the brain and spinal cord.

SUBLUXATION – An incomplete luxation or dislocation; though a relationship is altered, contact between joint surfaces remains.

SUPERIOR – Situated above or directed upward toward the head of an individual

SURGERY – The branch of medicine concerned with the treatment of disease, injury, and deformity by operation or manipulation. The performance or procedures of an operation.

SYNDROME – The aggregate of signs and symptoms associated with any morbid process, and constitution together the picture of the disease.

SYRINGOMYELIA – A fluid filled cavity in the spinal cord. Usually involving upper segments initially and involving the shoulder muscles.