thoracic

Pertaining to the chest. thoracic cage See bony thorax.

Pertaining to the chest. See also thoracolumbar.

• t. asymmetry — if obviously distorted can mean that the flatter side has a collapsed lung. Not a helpful sign in cattle because of the normal asymmetry caused by the rumen.
• t. breath sounds — breath sounds produced in the bronchi, bronchioles and alveoli by the passage of air; contrast with tracheal breath sounds.
• t. cage — the bony structure enclosing the thorax, consisting of the ribs, vertebral column and sternum.
• t. cavity — see thorax; called also chest.
• t. duct ligation — a surgical procedure used in the treatment of chylothorax where medical management is unsuccessful.
• t. girdle — the incomplete ring of bones that support the thoracic limb, made up of the scapula, clavicle, coracoid and occasionally other elements. Mammals have no coracoids (except in monotremes) and nongrasping animals have no clavicle so that the girdle consists only of the scapula. Grasping or climbing animals have a clavicle. Birds have a complete bony girdle. Called also pectoral girdle.
• t. inlet — the entrance of the chest between the two first ribs, the manubrium, and the first thoracic vertebra.
• t. limb — forelimb.
• t. pain — such as that caused by broken ribs, torn intercostal muscles, pleurisy can cause a grunt at the end of each inspiration.
• t. peristaltic sounds — can be of assistance in diagnosing diaphragmatic hernia in a dog or cat but they occur commonly in normal horses and cattle.
• t. positioner — a sterilizable M-shaped metal trough which can be laid on an operating table and an animal propped up in it for surgery.
• t. respiration — the diaphragm and abdominal muscles remain immobilized and play little part in respiration, as in peritonitis with diaphragmatic hernia.
• t. segmental spinal cord degeneration — characteristic lesion in the inherited disease merino degenerative axonopathy.
• t. surgery — surgical procedures involving entrance into the chest cavity. Until techniques for endotracheal anesthesia were perfected, this type of surgery was extremely dangerous because of the possibility of lung collapse. By administering anesthesia under pressure through an endotracheal tube it is now possible to keep one or both lungs expanded, even when they are subjected to atmospheric pressure.
• t. symmetry — lack of symmetry between the two sides, viewed from above, can suggest lung collapse or a space-occupying lesion on the smaller side; in ruminants the presence of the rumen always enhances the size of the left side.
• t. tube — see chest tube.
• t. vertebrae — the vertebrae between the cervical and lumbar vertebrae, giving attachment to the ribs and forming part of the dorsal wall of the thorax.
• t. wall — includes the ribs, sternum and thoracic vertebrae, the intercostal, superficial and deep, muscles, and the external respiratory muscles (transverse thoracic, rectus thoracic, serratus dorsalis and scalenus), and the costal pleura.
• t. wall flap — a surgical approach to the thoracic cavity that combines an intercostal incision and sternotomy. It allows great exposure to structures of the cranial mediastinum and caudal cervical region.
• t. wall wound — penetration through to the pleural cavity results in pneumothorax and collapse of the lung on that side.