Subscapularis
By : Karam Alanaz
*it is one of the rotator cuff muscles , the name of it tells us that one of this muscle’s attachments is the subscapular fossa of the scapula , whereas (subscapularis) refer to subscapular fossa .
General
Supply
* It is triangle in shape .
* one of the rotator cuff muscles , that helps to hold the humeral head in
glenoid cavity.
* ATTACHMENTS :Subscapular Fossa of the Scapula and the Lesser Tubercle
of the Humerus
* works at shoulder (GH) joint .
* one of the rotator cuff muscles , that helps to hold the humeral head in
glenoid cavity.
* ATTACHMENTS :Subscapular Fossa of the Scapula and the Lesser Tubercle
of the Humerus
* works at shoulder (GH) joint .
A- INNERVATION :The Upper and Lower Subscapular Nerves (C5, C6) , from
posterior cord of brachial plexus.
B- ARTERIAL :
The Circumflex Scapular Artery (a branch of the Subscapular Artery) , the Dorsal Scapular , Suprascapular Arteries (both either direct or indirect branches of the Subclavian Artery)
and the Lateral Thoracic Artery (a branch of the Axillary Artery) .
posterior cord of brachial plexus.
B- ARTERIAL :
The Circumflex Scapular Artery (a branch of the Subscapular Artery) , the Dorsal Scapular , Suprascapular Arteries (both either direct or indirect branches of the Subclavian Artery)
and the Lateral Thoracic Artery (a branch of the Axillary Artery) .
Origin
Subscapular Fossa of the Scapula.
Inserion
Lesser Tubercle of the Humerus.
Movement(Action)
(medially rotates shoulder joint and adducts it , helps to hold humeral head in glenoid cavity )
A) Standard Mover Action :
- when the subscapularis contracts and the humeral attachment is pulled toward the scapular attachment, the anterior side of the humerus moves medially. This movement is called medial rotation of the arm at the GH joint, because the anterior side of the humerus rotates medially. Note the similarity of the direction of fibres of the subscapularis to the direction of fibres of the latissimus dorsi and teres major.
B) Reverse Mover Action :
- If the subscapularis contracts and the humerus is fixed, the subscapularis pulls the medial border of the scapula against the rib cage wall. This is called medial tilt (or lateral rotation) of the scapula and occurs relative to the humerus at the GH joint. When the scapula moves relative to the arm at the shoulder joint, it also moves relative to the rib cage at the scapulocostal joint. .
* it Stabilizes the shoulder (GH) joint and the scapula .
* Because the lower fibers of the subscapularis are below the axis of motion of
the GH joint, they may contribute to the reverse action of upward rotation of the scapula at the GH and scapulocostal joints.
A) Standard Mover Action :
- when the subscapularis contracts and the humeral attachment is pulled toward the scapular attachment, the anterior side of the humerus moves medially. This movement is called medial rotation of the arm at the GH joint, because the anterior side of the humerus rotates medially. Note the similarity of the direction of fibres of the subscapularis to the direction of fibres of the latissimus dorsi and teres major.
B) Reverse Mover Action :
- If the subscapularis contracts and the humerus is fixed, the subscapularis pulls the medial border of the scapula against the rib cage wall. This is called medial tilt (or lateral rotation) of the scapula and occurs relative to the humerus at the GH joint. When the scapula moves relative to the arm at the shoulder joint, it also moves relative to the rib cage at the scapulocostal joint. .
* it Stabilizes the shoulder (GH) joint and the scapula .
* Because the lower fibers of the subscapularis are below the axis of motion of
the GH joint, they may contribute to the reverse action of upward rotation of the scapula at the GH and scapulocostal joints.
Relation
1-From the posterior perspective, the subscapularis is deep to the scapula and superficial to the rib cage.
2-From the anterior perspective, the subscapularis is deep to the entire rib cage and superficial to the scapula.
3-The anterior wall of the subscapularis faces the serratus anterior. Both the subscapularis and the serratus anterior are located between the scapula and the rib cage.
4-From the anterior perspective, the distal tendon of the subscapularis is deep to the proximal tendons of the short head of the biceps brachii and the coracobrachialis.
5-The distal tendon of the subscapularis attaches onto the humerus directly proximal to the distal tendons of the latissimus dorsi and teres major.
The subscapularis is involved with the deep back arm line myofascial meridian.
2-From the anterior perspective, the subscapularis is deep to the entire rib cage and superficial to the scapula.
3-The anterior wall of the subscapularis faces the serratus anterior. Both the subscapularis and the serratus anterior are located between the scapula and the rib cage.
4-From the anterior perspective, the distal tendon of the subscapularis is deep to the proximal tendons of the short head of the biceps brachii and the coracobrachialis.
5-The distal tendon of the subscapularis attaches onto the humerus directly proximal to the distal tendons of the latissimus dorsi and teres major.
The subscapularis is involved with the deep back arm line myofascial meridian.
NOTES :
1. The subscapularis is one of the four rotator cuff muscles. The rotator cuff muscles are the supraspinatus, infraspinatus, teres minor, and subscapularis. Sometimes the rotator cuff muscles are called the SITS muscles; each of the four letters stands for the first letter of the four rotator cuff muscles. Subscapularis is the last S of SITS.
2. The subscapularis (along with the latissimus dorsi and teres major) is located in the posterior axillary fold of tissue, which borders the axilla (armpit) posteriorly.
3. The distal tendon of the subscapularis adheres to the capsule of the glenohumeral joint, which is deep to the subscapularis.
4. There is a bursa located between the subscapularis muscle and the scapula called the subscapular bursa.
1. The subscapularis is one of the four rotator cuff muscles. The rotator cuff muscles are the supraspinatus, infraspinatus, teres minor, and subscapularis. Sometimes the rotator cuff muscles are called the SITS muscles; each of the four letters stands for the first letter of the four rotator cuff muscles. Subscapularis is the last S of SITS.
2. The subscapularis (along with the latissimus dorsi and teres major) is located in the posterior axillary fold of tissue, which borders the axilla (armpit) posteriorly.
3. The distal tendon of the subscapularis adheres to the capsule of the glenohumeral joint, which is deep to the subscapularis.
4. There is a bursa located between the subscapularis muscle and the scapula called the subscapular bursa.
