| oblique vein of left atrium | A small vein on the posterior wall of the left atrium which merges with the great cardiac vein to form the coronary sinus; it is developed from the left common cardinal vein, and occasionally persists as a left superior vena cava. Synonym: vena obliqua atrii sinistri, Marshall's oblique vein. (05 Mar 2000) |
|---|---|
| tendon sheath of superior oblique muscle | <anatomy> The synovial sheath enclosing the tendon of the superior oblique muscle as it passes through the trochlea. Synonym: vagina tendinis musculi obliqui superioris, synovial trochlear bursa, trochlear synovial bursa, vagina synovialis trochleae. (05 Mar 2000) |
| external oblique | <anatomy, muscle> Origin, fifth to twelfth ribs; insertion, anterior half of lateral lip of iliac crest, inguinal ligament, and anterior layer of the rectus sheath; action, diminishes capacity of abdomen, draws thorax downward; nerve supply, thoracoabdominal nerves. Synonym: musculus obliquus externus abdominis, abdominal external oblique muscle. (05 Mar 2000) |
| external oblique reflex | Contraction of the external oblique and rectus abdominis muscles upon tapping the anterior and outer part of the lower thoracic wall. (05 Mar 2000) |
| external oblique ridge | A horizontal bony crest on the external surface of the body of the mandible, inferior to the alveolar bone, marking the site of attachment of the buccinator muscle. (05 Mar 2000) |
| extinction oblique | <microscopy> Vibration directions oblique to the long direction of the crystal or fibre. (05 Aug 1998) |
| lateral oblique radiograph | A radiographic view of the mandible, revealing one side of the mandible from symphysis to condyle by displacing the other side upwards. (05 Mar 2000) |
| apophysial fracture | Separation of apophysis from bone. (05 Mar 2000) |
| articular fracture | A fracture involving the joint surface of a bone. (05 Mar 2000) |
| atlas fracture | <radiology> Incidence: 4% of cervical spine injuries, site: posterior arch, anterior arch, massa lateralis, Jefferson fracture associated with: fractures of C7 (25%), fractures of C2 pedicle (15%), extraspinal fractures (58%) (12 Dec 1998) |
| avulsion fracture | A fracture that occurs when a joint capsule, ligament, or muscle insertion of origin is pulled from the bone as a result of a sprain dislocation or strong contracture of the muscle against resistance; as the soft tissue is pulled away from the bone, a fragment or fragments of the bone may come away with it. (05 Mar 2000) |
| axis fracture | <radiology> Incidence: 6% of cervical spine injuries, associated with atlas fractures in 8%, hyperflexion injury: odontoid fracture, type I avulsion of tip of odontoid (5-8%) difficult to detect, type II fracture through base of dens (54-67%) complication: nonunion, type III subdental injury (30-33%) prognosis: good, Differential diagnosis: os odontoideum, ossiculum terminale, hypoplasia/aplasia of dens, hyperextension injury: hangman's fracture (12 Dec 1998) |
| barton fracture | <radiology> Intra-articular fracture of distal radius, dorsal displacement of separated fragment, due to fall on outstretched hand see: wrist fractures (12 Dec 1998) |
| Barton's fracture | Fracture of the distal radius with dislocation of the radiocarpal joint. (05 Mar 2000) |
| basal skull fracture | <orthopaedics> A fracture involving the base of the cranium. This fracture is often difficult to detect clinically. Findings may include raccoon eyes, Battle's sign, haemotympanum and cerebrospinal fluid rhinorrhoea. Plain skull X-ray will often not reveal the basal skull fracture, making a CT scan or MRI the most reliable diagnostic investigation. (15 Nov 1997) |