| sesamoid bone | A bone formed in a tendon where it passes over a joint. Synonym: os sesamoideum. (05 Mar 2000) |
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| shank bone | <anatomy> The large bone between the knee and foot that supports 5/6 of the body weight (fibula supports 1/6). (27 Sep 1997) |
| sheath process of sphenoid bone | A thin lamina of bone that extends medially under the body of the sphenoid bone from the medial lamina of the pterygoid process; it articulates with the vomer and the palatine bone. Synonym: processus vaginalis ossis sphenoidalis, sheath process of sphenoid bone. (05 Mar 2000) |
| short bone | One whose dimensions are approximately equal; it consists of a layer of cortical substance enclosing spongy substance and narrow. Compare: long bone. Synonym: os breve. (05 Mar 2000) |
| hyoid bone | <anatomy> A U-shaped bone lying between the mandible and the larynx, suspended from the styloid processes by slender stylohyoid ligaments. See: hyoid apparatus. Synonym: os hyoideum, lingual bone, tongue bone. (05 Mar 2000) |
| sickle cell anaemia: bone manifestations | <radiology> 8-13% of blacks carry sickling factor, symptoms: chronic ulcers, pain crises, many infections, priapism X-ray findings: deossification due to marrow hyperplasia, decreased bone density in skull with widened diploe, H-shaped vertebrae or fish vertebrae, rib notching, thrombosis and infarction, avascular necrosis, especially femoral head, periosteal treatmentn (bone within bone), secondary osteomyelitis, Staph. Aureus greater than Salmonella, dactylitis = hand foot syndrome, growth effects, bone shortening secondary to diminished blood supply, death less than 40y (12 Dec 1998) |
| sieve bone | A horizontal lamina from which are suspended the labyrinth, on either side, and the lamina perpendicularis in the centre; it fits into the ethmoidal notch of the frontal bone and supports the olfactory lobes of the cerebrum, being pierced with numerous openings for the passage of the olfactory nerves. Synonym: lamina cribrosa ossis ethmoidalis, cribrum, sieve bone, sieve plate. (05 Mar 2000) |
| simple bone cyst | <radiology> Unicameral or solitary bone cyst, lytic, unilocular, central, meta-diaphyseal, humerus (most common site), age 0 - 10 yrs Differential diagnosis: bubbly bone lesions (12 Dec 1998) |
| solitary bone cyst | A unilocular cyst containing serous fluid and lined with a thin layer of connective tissue, occurring usually in the shaft of a long bone in a child. Synonym: idiopathic bone cavity, osteocystoma, simple bone cyst, traumatic bone cyst, unicameral bone cyst. (05 Mar 2000) |
| sphenoidal angle of parietal bone | The anterior inferior angle of the parietal bone. Synonym: angulus sphenoidalis ossis parietalis, sphenoid angle, sphenoidal angle, Welcker's angle. (05 Mar 2000) |
| sphenoidal border of temporal bone | The part of the border of the squamous part of the temporal bone that articulates with the greater wing of the sphenoid. Synonym: margo sphenoidalis ossis temporalis. (05 Mar 2000) |
| sphenoid bone | A bone of most irregular shape occupying the base of the skull; it is described as consisting of a central portion, or body, and six processes: two greater wings, two lesser wings and two pterygoid processes; it articulates with the occipital, frontal, ethmoid, and vomer, and with the paired temporal, parietal, zygomatic, palatine and sphenoidal concha bones. Synonym: os sphenoidale, sphenoid. (05 Mar 2000) |
| sphenoid process of palatine bone | The posterior and smaller of the two processes at the extremity of the vertical plate of the palatine bone; processus sphenoidalis cartilaginis septi nasi, processus posterior cartilaginis septi nasi. Synonym: processus sphenoidalis, sphenoid process. (05 Mar 2000) |
| splint bone | The second or fourth, or internal or external small metacarpal bone's in the horse; these are splinter-like in shape and lie on either side of the metacarpal or cannon bone. Synonym: fibula. (05 Mar 2000) |
| spongy bone | A turbinated bone. (05 Mar 2000) |