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Limb Muscles - Horse Anatomy (view source)
Revision as of 12:49, 15 October 2012
, 12:49, 15 October 2012→Extrinsic Musculature
These muscles are responsible for joining the forelimb to the trunk, forming a '''synsarcosis''' rather than a conventional joint. Collectively, they act to transfer the weight of the body to the forelimbs, as well as to stabilize the scapula.
These muscles are responsible for joining the forelimb to the trunk, forming a '''synsarcosis''' rather than a conventional joint. Collectively, they act to transfer the weight of the body to the forelimbs, as well as to stabilize the scapula.
====Superficial Musculature====
'''''Trapezius'''''
'''''Trapezius'''''
:'''Innervatation''': Accessory n.
:'''Innervatation''': Accessory n.
'''''Latissimus dorsi'''''
'''''Latissimus dorsi'''''
:'''Innervation''': local branch of brachial plexus
:'''Innervation''':Local branch of brachial plexus
:The broadest muscle of the back
:The broadest muscle of the back
:'''Origin''': Thoracolumbar fascia
:'''Origin''': Thoracolumbar fascia
'''''Superficial Pectorals'''''
'''''Superficial Pectorals'''''
:'''Innervation''': brachial plexus
:'''Innervation''': Brachial plexus
:Two muscles, cranial ('''descending''') and caudal ('''transverse''')
:Two muscles, cranial ('''descending''') and caudal ('''transverse''')
:'''Origin''':
:'''Origin''':
:'''Action''': Adducts the forelimb, assist in protraction and retraction
:'''Action''': Adducts the forelimb, assist in protraction and retraction
The cranial ('''descending''') pectoral muscle forms a visible prominence cranial to the sternum; extending between the manubrium and the humeral crest.
The cranial ('''descending''') pectoral muscle forms a visible prominence cranial to the sternum; extending between the manubrium and the humeral crest.
====Deep Musculature====
'''''Deep Pectorals'''''
:'''Innervation''': Cranial and caudal thoracic n.
:'''Origin''': Xiphoid and 4th costal cartilages of the sternum
:'''Insertion''': Two branches on the lesser and greater tubercles of the humerus, supraglenoid tubercle of scapula
:'''Action''':Draws the limb back, supports the trunk, moves the trunk cranially over an advanced limb and extends the shoulder.
'''''Serratis ventralis'''''
'''''Serratis ventralis'''''
:'''Innervation''': branch of brachial plexus
:Divided into cranial ('''cervical''') and caudal ('''thoracic''') parts.
:'''Origin''': Ribs C4-C10
:'''Innervation''': Dorsal and ventral Cervical n., long thoracic n.
:'''Origin''': 1st-7th rib, transverse process of cervical vertebrae
:'''Insertion''': Medial scapula and scapular cartilage
:'''Insertion''': Medial scapula and scapular cartilage
:'''Action''': Supports the weight of the trunk. It is reinforced by strong fascia. The cervical portion can retract the limb and the caudal portion can advance the limb.
:'''Action''': Supports the weight of the trunk. It is reinforced by strong fascia. The cervical portion can retract the limb and the caudal portion can advance the limb.
'''''Rhomboids'''''
'''''Rhomboids'''''
:'''Innervation''': brachial plexus, although in some species, dorsal spinal nerves can innervate
:Deep to the trapezius, forms the withers region. Divided into cervical and thoracic parts.
:'''Origin''': Median connective tissue from poll to withers, lying deep to the trapezius
:'''Innervation''': Dorsal and ventral branches of Cervical n., Long thoracic n.
:'''Insertion''': Dorsal border and adjacent scapula
:'''Origin''':
:'''Action''': Retracts the limb, may also raise limb
::Cervical - Nuchal ligament at the axis
::Thoracic - Spinous processes of 2nd-6th cervical and 7th thoracic vertebrae
:'''Insertion''':
::Cervical - Unites with trapezius to insert on scapular cartilage
::Thoracic - Scapula
:'''Action''': Draws the limb forward and elevates the limb and neck. Fixes the scapula against the trunk.
===Intrinsic Musculature===
===Intrinsic Musculature===