Difference between revisions of "Shoulder Muscles - Horse Anatomy"
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'''''Supraspinatus ''''' | '''''Supraspinatus ''''' | ||
:'''Innervation''':Suprascapular n. of the brachial plexus | :'''Innervation''':Suprascapular n. of the brachial plexus | ||
− | :'''Origin''': Supraspinous fossa of the [[Bones and Cartilages - Horse Anatomy|scapula]] | + | :'''Origin''': Supraspinous fossa of the [[Bones and Cartilages - Horse Anatomy#Scapula|scapula]] |
− | :'''Insertion''': Lesser and greater tubercles of the [[Bones and Cartilages - Horse Anatomy|humerus]] | + | :'''Insertion''': Lesser and greater tubercles of the [[Bones and Cartilages - Horse Anatomy#Humerus|humerus]] |
:'''Action''': Extends and braces the shoulder | :'''Action''': Extends and braces the shoulder | ||
'''''Infraspinatus''''' | '''''Infraspinatus''''' | ||
:'''Innervation''':Suprascapular n. of the brachial plexus | :'''Innervation''':Suprascapular n. of the brachial plexus | ||
− | :'''Origin''': Supraspinatous fossa and spine of the [[Bones and Cartilages - Horse Anatomy|scapula]] | + | :'''Origin''': Supraspinatous fossa and spine of the [[Bones and Cartilages - Horse Anatomy#Scapula|scapula]] |
:'''Insertion''': Tendon of insertion bifurcates into a deep part and a superficial part. | :'''Insertion''': Tendon of insertion bifurcates into a deep part and a superficial part. | ||
− | :: Deep - Greater tubercle of the [[Bones and Cartilages - Horse Anatomy|humerus]] | + | :: Deep - Greater tubercle of the [[Bones and Cartilages - Horse Anatomy#Humerus|humerus]] |
− | :: Superficial - Lateral [[Bones and Cartilages - Horse Anatomy|humerus]], distal to the greater tubercle | + | :: Superficial - Lateral [[Bones and Cartilages - Horse Anatomy#Humerus|humerus]], distal to the greater tubercle |
:'''Action''': Brace the shoulder, supporting flexion or extension. | :'''Action''': Brace the shoulder, supporting flexion or extension. | ||
− | :'''Clinical significance''': The bursa between the superficial tendon of the infraspinatus, and the lateral tubercle of the [[Bones and Cartilages - Horse Anatomy|humerus]] can be the site of inflammation (bursitis). | + | :'''Clinical significance''': The bursa between the superficial tendon of the infraspinatus, and the lateral tubercle of the [[Bones and Cartilages - Horse Anatomy#Humerus|humerus]] can be the site of inflammation (bursitis). |
=='''Medial'''== | =='''Medial'''== |
Revision as of 10:27, 31 October 2012
The muscles of the shoulder are grouped:
Lateral
Supraspinatus
- Innervation:Suprascapular n. of the brachial plexus
- Origin: Supraspinous fossa of the scapula
- Insertion: Lesser and greater tubercles of the humerus
- Action: Extends and braces the shoulder
Infraspinatus
- Innervation:Suprascapular n. of the brachial plexus
- Origin: Supraspinatous fossa and spine of the scapula
- Insertion: Tendon of insertion bifurcates into a deep part and a superficial part.
- Action: Brace the shoulder, supporting flexion or extension.
- Clinical significance: The bursa between the superficial tendon of the infraspinatus, and the lateral tubercle of the humerus can be the site of inflammation (bursitis).
Medial
Supscapularis
- Innervation: Subscapular n. from the brachial plexus
- Origin: Deep surface of the scapula
- Insertion: Lesser tubercle of the humerus
- Action: Braces medial shoulder joint. Primarily acts as an extensor of the shoulder, but can contribute to maintaining flecion.
Coracobrachialis
- Innervation: Musculocutaneous n. of the brachial plexus
- Origin: Coracoid process of scapula
- Insertion: Proximal shaft of the humerus
- Action: Fixator
Caudal (Flexors)
Deltoid
- Innervation: Axillary n. of the brachial plexus
- Origin: Caudal border and spine of the scapula. One head in the horse, compared with two in species with an acromion (site of second origin.
- Insertion: Deltoid tuberosity of humerus
- Action: Flexes shoulder
- In the horse, the aponeurosis of the deltoid is partially fused to the infraspinatus.
Teres Major
- Innervation: Axillary n. of the brachial plexus
- Origin: Dorsal part of the caudal scapula
- Insertion: Teres major tuberosity midway down the humerus
- Action: Flexes the shoulder, supports adduction.
Teres Minor
- Innervation: Axillary n. of the brachial plexus
- Origin: Distal third of scapula, deep to the deltoid
- Insertion: Teres minor tuberosity midway down the humerus
- Action: Flexes the shoulder
NB// There are no defined extensors of the shoulder. Those involved (brachiocephalic m., biceps brachii, supraspinatus, and ascending pectorals) have other, more primary roles.