Changes

==Common structures of the Proximal Forelimb and Shoulder==

==Common structures of the Proximal Forelimb and Shoulder==

:The spine:

:The spine:

::defines '''Infraspinous''' and '''Supraspinous''' '''Fossae''', inhabited by muscles accordingly

::defines '''Infraspinous''' and '''Supraspinous''' '''Fossae''', inhabited by muscles accordingly

:serves as a point of attachment for the '''trapezius''' muscle

::serves as a point of attachment for the '''trapezius''' muscle

:culminates in the '''acromion''' in all but the horse and pig

::culminates in the '''acromion''' in all but the horse and pig

Medial muscle attachment consist mostly of the '''subscapularis''', with the '''serratus ventralis''' attaching dorsally. The Scapula articulates with the humerus at the '''glenoid cavity'''.

Medial muscle attachment consist mostly of the '''subscapularis''', with the '''serratus ventralis''' attaching dorsally. The Scapula articulates with the humerus at the '''glenoid cavity'''.

====Muscles of the Shoulder====

====Muscles of the Shoulder====

These muscles are grouped:

These muscles are grouped:

*Lateral:'''Supraspinatus ''' and '''Infraspinatus''', Suprascapular n. of the brachial plexus

 

**Origin: the fossae of the scapula

Lateral:'''Supraspinatus ''' and '''Infraspinatus''',  

**Insertion: both tubercles of the humerus

:Innervated by: Suprascapular n. of the brachial plexus

**Action: brace the shoulder  

:Origin: the fossae of the scapula

**Clinical significance: bursa between the tendon of the infraspinatus and lateral tubercle of the humerus can be the site of inflammation

:Insertion: both tubercles of the humerus

*Medial:

:Action: brace the shoulder  

**'''Supscapularis''': Subscapular n. from the brachial plexus

:Clinical significance: bursa between the tendon of the infraspinatus and lateral tubercle of the humerus can be the site of inflammation

***Origin: Deep surface of the scapula

 

***Insertion: medial tubercle of the humerus

Medial:

***Action: braces medial shoulder joint, potential adductor

:Innervated by: '''Supscapularis''': Subscapular n. from the brachial plexus

**'''Coracobrachialis''': Musculocutaneous n. of the brachial plexus

:Origin: Deep surface of the scapula

***Origin: medial supraglenoid tubercle

:Insertion: medial tubercle of the humerus

***Insertion: proximal shaft of the humerus

:Action: braces medial shoulder joint, potential adductor

***Action: fixator

 

*Caudal (Flexors): Axillary n. of the brachial plexus

'''Coracobrachialis''':

**'''Deltoids'''

:Innervated by: Musculocutaneous n. of the brachial plexus

***Origin: caudal border and spine of the scapula

:Origin: medial supraglenoid tubercle

****One head in the horse and two in species with an acromion (site of second origin)

:Insertion: proximal shaft of the humerus

***Insertion: deltoid tuberosity on the humerus

:Action: fixator

**'''Teres Major'''

 

***Origin: dorsal part of the caudal scapula  

Caudal (Flexors):

***Insertion: teres tuberosity midway down humerus

:Innervated by: Axillary n. of the brachial plexus

**'''Teres Minor'''

:'''Deltoids'''

*There are no defined extensors of the shoulder.  Those involved (brachiocephalic m., biceps brachii, supraspinatus, and ascending pectorals) have other, more primary roles.

::Origin: caudal border and spine of the scapula, one head in the horse and two in species with an acromion (site of second origin)

::Insertion: deltoid tuberosity on the humerus

:'''Teres Major'''

::Origin: dorsal part of the caudal scapula  

::Insertion: teres tuberosity midway down humerus

:'''Teres Minor'''

 

 

There are no defined extensors of the shoulder.  Those involved (brachiocephalic m., biceps brachii, supraspinatus, and ascending pectorals) have other, more primary roles.

====Muscles of the Elbow====

====Muscles of the Elbow====