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Forelimb - Anatomy & Physiology (view source)
Revision as of 13:00, 15 August 2008
, 13:00, 15 August 2008→Extrinsic Musculature
These muscle are responsible for joining tht 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 stabilize the scapula.
These muscle are responsible for joining tht 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 stabilize the scapula.
'''''Trapezius'''''
'''''Trapezius''''': Accessory n.
*Origin: mid-dorsal raphe and supraspinous ligament
*Origin: mid-dorsal raphe and supraspinous ligament
*Insertion: spine of the scapula
*Insertion: spine of the scapula
*Body: two parts, cervical and thoracic separated by aponeurosis
*Body: two parts, cervical and thoracic separated by aponeurosis
*Action: raises scapula against the trunk and swings cranially to advance the limb
*Action: raises scapula against the trunk and swings cranially to advance the limb
'''''Brachiocephalic m.'''''
'''''Brachiocephalic m.''''': Accessory n.
*Two parts separated by the clavicle where it exists
*Two parts separated by the clavicle where it exists
*Origin: clavicle or vestigial fibrous intersection
*Origin: clavicle or vestigial fibrous intersection
**advances the limb and extends the shoulder joint when limb is in motion
**advances the limb and extends the shoulder joint when limb is in motion
**draws head and neck ventrally when limb is fixed
**draws head and neck ventrally when limb is fixed
'''''Omotransversarius'''''
'''''Omotransversarius''''': Accessory n.
*Origin: transverse processes of the atlas
*Origin: transverse processes of the atlas
*Insertion: acromion and adjacent scapula
*Insertion: acromion and adjacent scapula
*Action: advancing the limb
*Action: advancing the limb
*Innervation: accessory n.
*Innervation
'''''Latissimus dorsi'''''
'''''Latissimus dorsi''''': local branch of brachial plexus
*The '''broadest muscle of the back'''
*The '''broadest muscle of the back'''
*Origin: thoracolumbar fascia
*Origin: thoracolumbar fascia
**retracts free limb and flexes shoulder joint
**retracts free limb and flexes shoulder joint
**draws trunk forward over the fixed limb
**draws trunk forward over the fixed limb
'''''Pectoral mm.'''''
'''''Pectoral mm.''''': brachial plexus
*Two superficial parts, cranial and caudal
*Two superficial parts, cranial and caudal
**Origin: cranial sternum
**Origin: cranial sternum
***may also retract free limbs
***may also retract free limbs
***draw trunk forward when limb is fixed
***draw trunk forward when limb is fixed
'''''Serratis ventralis'''''
'''''Serratis ventralis''''': branch of brachial plexus
*Origin: C4 to 10th rib
*Origin: C4 to 10th rib
*Insertion: medial scapula and scapular cartilage
*Insertion: medial scapula and scapular cartilage
**cervical portion can retract the limb
**cervical portion can retract the limb
**caudal portion can advance the limb
**caudal portion can advance the limb
'''''Rhomboids'''''
'''''Rhomboids''''': brachial plexus, although in some species, dorsal spinal nerves can innervate
*Origin: median connective tissue from poll to withers, lying deep to the trapezius
*Origin: median connective tissue from poll to withers, lying deep to the trapezius
*Insertion: dorsal border and adjacent scapula
*Insertion: dorsal border and adjacent scapula
*Action: retracting the limb, may also raise limb
*Action: retracting the limb, may also raise limb
===Intrinsic Musculature===
===Intrinsic Musculature===