Lateral group

MUSCLES OF SHOULDER - MUSCLES ON THE LATERAL ASPECT

Lateral group (View image)

  • Deltoideus  
  • Supraspinatus
  • Infraspinatus
  • Teres minor

Deltoideus

    • This muscle lies at the scapulo-humoral angle, partly on the triceps and partly on the infraspinatus. It consists of two parts, acromial and scapular, which are placed one above the other and are separated by an interval
    • Origin:
      • Acromial part - Acromion process and scapular fascia
      • Scapular part - The posterior border of the scapula
    • Insertion: To the deltoid tuberosity of the humerus. The scapular part is mostly inserted to the fascia covering the triceps
    • Action: To flex the shoulder and abduct the arm (view image)
    • Blood supply: Posterior circumflex artery
    • Nerve supply: Axillary nerve

Supraspinatus (View flash animation)

    • This muscle not only fills up the supraspinous fossa but also extends beyond it and is in contact with the subscapularis
    • Origin: The supraspinous fossa(view image)
    • Insertion: The muscle divides below the level of the acromion process into two divisions - medial and lateral. The lateral is inserted to the summit of the tuberosity and medial to the anterior division of the medial tuberosity of the humerus
    • Action: To extend the shoulder (view image)
    • Blood supply: Suprascapular artery
    • Nerve supply: Suprascapular nerve

Infraspinatus

    • This muscle covers most of the infraspinous fossa and extends beyond it posteriorly
    • Origin: Infraspinous fossa (view image)
    • Insertion: Two insertions as
    • A wide flat tendon to the circular rough area below the summit of the lateral tuberosity of the humerus
    • Medial surface of the convexity of the lateral tuberosity of the humerus
    • Action: To abduct the scapula and rotate it outwards (view image)
    • Blood supply: Subscapular and suprascapular arteries
    • Nerve supply: Suprascapular nerve

Teres minor

    • This is a small-elongated muscle under the deltoideus, infraspinatus and lies mostly on the triceps brachii
    • Origin: The rough lines at the distal part of the infraspinous fossa and the posterior border of the scapula(view image)
    • Insertion: To the deltoid tuberosity and a small rough area above it
    • Action: To flex the shoulder joint and abduct the arm and rotate it outwards (view image)
    • Blood supply: Subscapular and suprascapular arteries
    • Nerve supply: Axillary nerve
Last modified: Thursday, 13 October 2011, 10:10 AM