Muscles of the upper limb
Muscles of the Muscles of the
pectoral girdle movable part
Muscles of the pectoral girdle
1. Deltoid m.
Origin: scapula, clavicle
Insertion: deltoid tuberosity of humerus
Action: abducts arm
2. Subscapularis m.
Origin: anterior surface of scapula in subscapular fossa
Insertion: lesser tubercle of humerus
Action:
▪ adducts arm – chief medial rotator of humerus
▪ Assisted by pectoralis major
▪ Helps to hold head of humerus in glenoid cavity – stabilizes shoulder joint
o Forms part of posterior wall of axilla
o Tendon of insertion passes in front of shoulder joint
o Rotator cuff m. (deep m.)
o Nerve – subscapular nerves (C5 – C7)
3. Supraspinatus m.
Origin: supraspinatus fossa
Insertion: sup. part of greater tubercle of humerus
Action: abducts arm
Stabilizes shoulder joint; helps to prevent downward dislocation of humerus (like
when carrying a heavy suitcase)
Located on posterior aspect of scapula
, Deep to trapezius
Rotator cuff m.
Nerve – suprascapular nerve
On the posterior surface of the scapula, there is a spine that divides it into supraspinatus
and infraspinatus fossa
4. Infraspinatus m.
Origin: infraspinatus fossa
Insertion: greater tubercle of humerus (post. to insertion of supraspinatus)
Action: adducts arm – rotates humerus laterally
Helps to hold head of humerus in glenoid cavity – stabilizes shoulder joint
Partially covered by deltoid, trapezius
Rotator cuff m.
Nerve – suprascapular nerve
5. Teres major m.
Origin: inferior angle of the scapula
Insertion: humerus
Action: adducts arm
6. Teres minor m.
Origin: scapula
Insertion: greater tubercle of humerus (inf. to insertion of infraspinatus)
Action: adducts arm – rotates humerus laterally
Helps to hold head of humerus in glenoid cavity – stabilizes shoulder joint
Small, elongated m.
Inferior to infraspinatus, may be inseparable from infraspinatus
Nerve – axillary nerve
Muscles of the Muscles of the
pectoral girdle movable part
Muscles of the pectoral girdle
1. Deltoid m.
Origin: scapula, clavicle
Insertion: deltoid tuberosity of humerus
Action: abducts arm
2. Subscapularis m.
Origin: anterior surface of scapula in subscapular fossa
Insertion: lesser tubercle of humerus
Action:
▪ adducts arm – chief medial rotator of humerus
▪ Assisted by pectoralis major
▪ Helps to hold head of humerus in glenoid cavity – stabilizes shoulder joint
o Forms part of posterior wall of axilla
o Tendon of insertion passes in front of shoulder joint
o Rotator cuff m. (deep m.)
o Nerve – subscapular nerves (C5 – C7)
3. Supraspinatus m.
Origin: supraspinatus fossa
Insertion: sup. part of greater tubercle of humerus
Action: abducts arm
Stabilizes shoulder joint; helps to prevent downward dislocation of humerus (like
when carrying a heavy suitcase)
Located on posterior aspect of scapula
, Deep to trapezius
Rotator cuff m.
Nerve – suprascapular nerve
On the posterior surface of the scapula, there is a spine that divides it into supraspinatus
and infraspinatus fossa
4. Infraspinatus m.
Origin: infraspinatus fossa
Insertion: greater tubercle of humerus (post. to insertion of supraspinatus)
Action: adducts arm – rotates humerus laterally
Helps to hold head of humerus in glenoid cavity – stabilizes shoulder joint
Partially covered by deltoid, trapezius
Rotator cuff m.
Nerve – suprascapular nerve
5. Teres major m.
Origin: inferior angle of the scapula
Insertion: humerus
Action: adducts arm
6. Teres minor m.
Origin: scapula
Insertion: greater tubercle of humerus (inf. to insertion of infraspinatus)
Action: adducts arm – rotates humerus laterally
Helps to hold head of humerus in glenoid cavity – stabilizes shoulder joint
Small, elongated m.
Inferior to infraspinatus, may be inseparable from infraspinatus
Nerve – axillary nerve
