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=Costae=

=Costae=

[[Image:Thorax skeleton.png|thumb|right|150px|Canine thorax showing placement of mitral valve - Wikimedia Commons 2008]]

[[Image:Thorax skeleton.png|thumb|right|150px|Canine thorax showing placement of mitral valve - Wikimedia Commons 2008]]

Costae are arranged in pairs and articulate with two successive vertebrae. Inidividual ribs have a bony dorsal part, a body of rib, and ventral costal cartilage. They increase in length, curvature and amount of cartilage craniocaudally. The cartilage of last rib may fail to join that of its neighbor and is said to be a '''floating''' rib. Costae join ventrally on the midline at the '''sternum''', which is comprised of three parts, the '''manubrium''', '''sternebrae''' and '''xiphoid cartilage'''. The '''manubrium''' is the most cranial and projects beyond the first set of ribs and can be palpated in most species. The '''sternebrae''' is joined by cartilage in young animals that is later replaced by bone and is the main body joining the ribs on the midline. The '''xiphoid cartilage''' is caudal and projects between lower ends of costal arches, providing attachment for the '''linea alba'''.

Costae are arranged in pairs and articulate with two successive vertebrae. Individual ribs have a bony dorsal part, a body of rib, and ventral costal cartilage. They increase in length, curvature and amount of cartilage craniocaudally. The cartilage of last rib may fail to join that of its neighbour and is said to be a '''floating''' rib. Costae join ventrally on the midline at the '''sternum''', which is composed of three parts, the '''manubrium''', '''sternebrae''' and '''xiphoid cartilage'''. The '''manubrium''' is the most cranial and projects beyond the first set of ribs and can be palpated in most species. The '''sternebrae''' is joined by cartilage in young animals that is later replaced by bone and is the main body joining the ribs on the midline. The '''xiphoid cartilage''' is caudal and projects between lower ends of costal arches, providing attachment for the '''linea alba'''.

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=Thoracic Musculature=

=Thoracic Musculature=

[[Image: Cat diaphragm.jpg|thumb|right|150px|Cat diaphragm- Copyright Uwe Gille]]

[[Image: Cat diaphragm.jpg|thumb|right|150px|Cat diaphragm- Copyright Uwe Gille]]

The thoracic muscles are primarily concerned with respiration. Inspiratory muscles enlarge the thoracic cavity whilst expiratory muscles diminish the cavity and force air out. The most important thoracic muscle is the '''''diaphragm''''', which separates the thoracic and abdominal cavities. It is dome-shaped and convex on its cranial surface. Central tendons form the vertex of the diaphragm. In a neutral position (between full inspiration and full expiration) the diaphragm is located at the 6th rib behind the '''olecranon'''. The diaphragm attaches via a muscular periphery to the costal arch.

The thoracic muscles are primarily concerned with respiration. Inspiratory muscles enlarge the thoracic cavity whilst expiratory muscles diminish the cavity and force air out. The most important thoracic muscle is the [[Diaphragm - Anatomy & Physiology|'''''diaphragm''''']], which separates the thoracic and abdominal cavities. It is dome-shaped and convex on its cranial surface. Central tendons form the vertex of the diaphragm. In a neutral position (between full inspiration and full expiration) the diaphragm is located at the 6th rib behind the '''olecranon'''. The diaphragm attaches via a muscular periphery to the costal arch.

[[Image: Intercostal.JPG|thumb|right|150px|Intercostal muscles with nerve and vessels- Copyright C. Clarkson and T.F. Fletcher, University of Minnesota]]

[[Image: Intercostal.JPG|thumb|right|150px|Intercostal muscles with nerve and vessels- Copyright C. Clarkson and T.F. Fletcher, University of Minnesota]]

The diaphragm has three openings; the '''aortic hilus''' which conveys the aorta, azygous vein, and thoracic duct, the '''oesophageal hiatus''' which conveys the oesophagus, vagal trunks and supplying vessels and the '''caval foramen''' within central tendon conveying the [[Liver - Anatomy & Physiology#Vasculature|caudal vena cava]]. The diaphragm is innervated by the '''phrenic nerve''', which arises from the caudal cervical nerves (C5-C7).

The diaphragm has three openings; the '''aortic hilus''' which conveys the aorta, azygous vein, and thoracic duct, the '''oesophageal hiatus''' which conveys the oesophagus, vagal trunks and supplying vessels and the '''caval foramen''' within central tendon conveying the [[Liver - Anatomy & Physiology#Vasculature|caudal vena cava]]. The diaphragm is innervated by the '''phrenic nerve''', which arises from the caudal cervical nerves (C5-C7).

[[Category:Musculoskeletal System - Anatomy & Physiology]]

[[Category:Musculoskeletal System - Anatomy & Physiology]]

[[Category:To Do - Review]]

[[Category:A&P Done]]