Muscles of the upper limb Flashcards
Pectoralis major - insertion
- The distal attachment of both heads is into the intertubercular sulcus of the humerus.
Pec major - origin
Clavicular head – originates from the anterior surface of the medial clavicle.
Sternocostal head – originates from the anterior surface of the sternum, the superior six costal cartilages and the aponeurosis of the external oblique muscle.
Pec major - function
Adducts and medially rotates the upper limb, and draws the scapula anteroinferiorly. The clavicular head also acts individually to flex the upper limb.
Innervation of pec major
- Lateral and medial pectoral nerves
Pec minor - insertion
- Coracoid process of the scapula
Pec minor - origin
- 3rd-5th ribs
Pec minor - function
Stabilised the scapula by drawing it anteroinferiorly against the thoracic wall
Pec minor - innervation
- Medial pectoral nerve
Serratus anterior - insertion
They attach to the costal (rib facing) surface of the medial border of the scapula.
Serratus anterior - origin
The muscle consists of several strips, which originate from the lateral aspects of ribs 1-8
Serratus anterior - function
Rotates the scapula, allowing the arm to be raised over 90 degrees. It also holds the scapula against the ribcage.
What are the rotator cuff muscles
The rotator cuff muscles are a group of four muscles that originate from the scapula and attach to the humeral head
The rotator cuff muscles are supraspinatus, infraspinatus, subscapsularis and teres minor
Supraspinatus - origin
- Originates from the supraspinous fossa of the scapula
Supraspinatus - insertion
- Attaches to the greater tubercle of the humerus
Supraspinatus - innervation
- Suprascapular nerve
Supraspinatus - action
- Abducts the arm 0-15 degrees, and assists deltoid for 15-90 degrees
Infraspinatus - origin
- Originates from the infraspinous fossa of the scapula
Infraspinatus - insertion
- Attaches to the greater tubercle of the humerus
Infraspinatus - innervation
- Suprascapular nerve
Infraspinatus - action
- Lateral rotation of the arm
Subscapularis - origin
- Originates from the subscapular fossa, on the costal surface of the scapula
Subscapularis - insertion
- It attaches to the lesser tubercle of the humerus
Subscapularis - innervation
- Upper and lower subscapular nerves
Subscapularis - action
- Medial rotation of the arm
Teres minor - origin
- Originates from the posterior surface of the scapula, adjacent to its lateral border
Teres minor - insertion
- It attaches to the greater tubercle of the humerus
Teres minor - innervation
- Axillary nerve
Teres minor - action
- Lateral rotation of the arm
Teres major - origin
- Originates from the posterior surface of the inferior angle of the scapula
Teres major - insertion
- It attaches to the medial lip of the intertubercular groove of the humerus
Teres major - innervation
- Lower subscapular nerve
Teres major - action
- Adducts at the shoulder and medially rotates the arm