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Limb Muscles - Horse Anatomy (view source)
Revision as of 12:15, 15 October 2012
, 12:15, 15 October 2012→Extrinsic Musculature
===Extrinsic Musculature===
===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.
'''''Trapezius'''''
'''''Trapezius'''''
'''''Brachiocephalic'''''
'''''Brachiocephalic'''''
:'''Innervation''': Accessory n.
:'''Innervation''': Accessory n.
:Two parts separated by the clavicle, where it exists
:Two parts ('''cleidobrachial''' and '''cleidocephalic''' muscle) separated by the clavicle, where it exists
:'''Origin''': Mastoid process of temporal bone, nuchal crest, wing of atlas and the transverse processes of the 2nd-4th cervical vertebrae
:'''Origin''': Mastoid process of temporal bone, nuchal crest, wing of atlas and the transverse processes of the 2nd-4th cervical vertebrae
:'''Insertion''': Deltoid tuberosity and crest of the humerus
:'''Insertion''': Deltoid tuberosity and crest of the humerus
:'''Action''': Advances the limb and extends the shoulder joint when limb is in motion. Draws the head and neck ventrally when the limb is fixed
:'''Action''': Advances the limb and extends the shoulder joint when limb is in motion. Draws the head and neck ventrally when the limb is fixed
'''''Cleidomastoid'''''
:'''Innervatation''': Accessory n. and Axillary n.
:'''Origin''': Mastoid process of the temporal bone and nuchal crest
:'''Insertion''': Deltoid tuberosity, crest of the humerus and fascia of the shoulder as the '''cleidobrachialis''' muscle
:'''Action''': If acting bilaterally, it draws the head and neck down and backwards. If the acting with one shoulder fixed, it draws the head, upper arm fascia and neck to one side.
'''''Latissimus dorsi'''''
'''''Latissimus dorsi'''''
:'''Action''': Antagonist to the brachiocephalic m. It retracts the free limb and flexes shoulder joint. It also draws the trunk forward over the fixed limb.
:'''Action''': Antagonist to the brachiocephalic m. It retracts the free limb and flexes shoulder joint. It also draws the trunk forward over the fixed limb.
'''''Pectoral'''''
'''''Superficial Pectorals'''''
:'''Innervation''': brachial plexus
:'''Innervation''': brachial plexus
:Two superficial parts, cranial and caudal
:Two muscles, cranial ('''descending''') and caudal ('''transverse''')
:'''Origin''': Cranial sternum
:'''Origin''':
::Cranial ('''descending''') - Manubrium of the sternum
::Caudal ('''transverse''') - First six costal cartilages and ventral sternum
:'''Insertion''':
:'''Insertion''':
::Cranial ('''descending''') - The crest of the humerus, distal to the deltoid tuberosity
::Cranial ('''descending''') - The crest of the humerus, distal to the deltoid tuberosity
::Caudal ('''transverse''') - Covers the elbow joint to insert on the medial fascia of the forearm
::Caudal ('''transverse''') - Covers the elbow joint to insert on the medial fascia of the forearm
:'''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.
'''''Serratis ventralis'''''
'''''Serratis ventralis'''''
:'''Innervation''': branch of brachial plexus
:'''Innervation''': branch of brachial plexus
:'''Origin''': C4 to 10th rib
:'''Origin''': Ribs C4-C10
:'''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.
:'''Insertion''': Dorsal border and adjacent scapula
:'''Insertion''': Dorsal border and adjacent scapula
:'''Action''': Retracts the limb, may also raise limb
:'''Action''': Retracts the limb, may also raise limb
===Intrinsic Musculature===
===Intrinsic Musculature===