Lateral group of muscles of Shoulder region

Lateral group of muscles of Shoulder region –

Table of Contents

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
Blood supply: Posterior circumflex artery
Nerve supply: Axillary nerve

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
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
Blood supply: Suprascapular artery
Nerve supply: Suprascapular nerve

This muscle covers most of the infraspinous fossa and extends beyond it posteriorly
Origin: Infraspinous fossa
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
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
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
Blood supply: Subscapular and suprascapular arteries
Nerve supply: Axillary nerve