Introducing 

Prezi AI.

Your new presentation assistant.

Refine, enhance, and tailor your content, source relevant images, and edit visuals quicker than ever before.

Loading…
Transcript

Scapulohumeral Muscles

The scapulohumeral muscles all originate on the scapula and insert somewhere on the humerus to act on the glenohumeral joint. Four of the six comprise the rotator cuff muscles (supraspinatus, infraspinatus, teres minor, and subscapularis).

Posterior

Anterior

Supraspinatus

Supraspinatus

ROTATOR CUFF MUSCLE

The supraspinatus muscle initiates arm abduction and can accomplish the first 15 degrees of abduction.

Supraspinatus

  • Origin: Supraspinous fossa
  • Insertion: Greater tubercle of humerus
  • Innervation: Suprascapular nerve
  • Blood Supply: Suprascapular artery
  • Actions: Abducts arm initial 15 degrees

Infraspinatus

Infraspinatus

ROTATOR CUFF MUSCLE

The infaspinatus muscle, along with the other rotator cuff muscles, helps to stabilize the glenohumeral joint.

  • Origin: Infraspinous fossa
  • Insertion: Greater tubercle of humerus
  • Innervation: Suprascapular nerve
  • Blood Supply: Suprascapular artery
  • Actions: Laterally rotates the arm

Teres minor

Teres minor

ROTATOR CUFF MUSCLE

The teres minor muscle lies inferior to the infraspinatus muscle and can be difficult to distinguish from that muscle.

  • Origin: Lateral border of the scapula
  • Insertion: Greater tubercle of the humerus
  • Innervation: Axillary nerve
  • Blood Supply: Circumflex scapular and posterior circumflex humeral arteries
  • Actions: Laterally rotates the arm

Subscapularis

Subscapularis

ROTATOR CUFF MUSCLE

The subscapularis muscle is a triangular-shaped muscle. Unlike the other rotator cuff muscles, this muscle originates on the anterior scapula and inserts on the lesser tubercle of the humerus.

  • Origin: Subscapular fossa
  • Insertion: Lesser tubercle of the humerus
  • Innervation: Upper and lower subscapular nerves
  • Blood Supply: Subscapular artery
  • Actions: Medially rotates the arm

Deltoid

Deltoid

The deltoid muscle covers the shoulder, giving it its rounded appearance. It has anterior, middle, and posterior parts and thus has several functions at the glenohumeral joint.

Posterior deltoid

  • Origin: Anterior: Clavicle, Middle: Acromion, Posterior: Scapular spine
  • Insertion: Deltoid tuberosity of humerus
  • Innervation: Axillary nerve
  • Blood Supply: Thoracoacromial and anterior & posterior humeral circumflex arteries
  • Actions: Anterior: Flexes and medially rotates arm, Middle: Abducts arm (15-90 degrees), Posterior: Extends and laterally rotates arm

Middle deltoid

Anterior deltoid

Teres

major

Teres major

The teres major muscle is not part of the rotator cuff. Instead, the teres major functions in conjunction with the latissimus dorsi muscle.

  • Origin: Inferior angle of the scapula
  • Insertion: Medial proximal humerus
  • Innervation: Lower subscapular nerve
  • Blood Supply: Circumflex scapular and subscapular arteries
  • Actions: Adducts and medially rotates the arm
Learn more about creating dynamic, engaging presentations with Prezi