Changes

=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]]

*Primarily concerned with respiration

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.

**Inspiratory muscles enlarge the thoracic cavity

**Expiratory muscles diminish the cavity and force air out

*The most important thoracic muscle is the '''''Diaphragm''''', which separates the thoracic and abdominal cavities

**Dome-shaped, convex on its cranial surface

**Central tendon forms the vertex

***Neutral position (between full inspiration and full expiration): 6th rib behind the '''olecranon'''

**Attaches via 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 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).

***'''Aortic hilus''' conveying the aorta, azygous vien, and thoracic duct

***'''Oesophageal hiatus''' conveying the oesophagus, vagal trunks and supplying vessels

***'''Caval foramen''' within central tendon conveying [[Liver - Anatomy & Physiology#Vasculature|caudal vena cava]]

The '''intercostal muscles''' are external muscle fibers that run caudoventrally and internal muscle fibers run cranioventrally, although each is confined to a single intercostal space. The '''transversus thoracis''' arises from and covers the dorsal sternum and inserts on sternal ribs close to the costochondral junctions. The '''rectus thoracis''' covers the ends of the first four ribs in continuation of the '''rectus abdominus'''. The '''serratus dorsalis''' overlies the dorsal aspect of the ribs. Innervation of the intercostal muscles is supplied by the '''intercostal nerves''', which are ventral branches of the thoracic spinal nerves.

**Innervated by the '''phrenic nerve''', which arises from the caudal cervical nerves (C5-C7)

 

 

*''Intercostal muscles''

**External fibers run caudoventrally and internal fibers run cranioventrally

**Each is confined to a single intercostal space

*''Transversus thoracis'' arises from and covers the dorsal sternum and inserts on sternal ribs close to the costochondral junctions

*''Rectus thoracis'' covers the ends of the first four ribs in continuation of the ''rectus abdominus''

*''Serratus dorsalis'' overlies the dorsal aspect of the ribs

*Innervation of these muscles is supplied by the '''Intercostal nerves''', which are ventral branches of the thoracic spinal nerves

=Abdominal Musculature=

=Abdominal Musculature=