Muscles

Question 1

Pectoralis Major

Answer 1

> upper part of anterior surface of thoracic wall 9superficial to pec minor + forming anterior fold of axilla)
Origin: clavicular head: medial 1/3 of clavicle
: sternocostal head: manubrium
: sternal body
: costal cartilages
Insertion: lateral lip of intertubercular groove
Action: Adduction
: Medial rotation
: Clav head: flexion of shoulder
: Sterno head: extension
Innervation: Medial and Lateral pectoral nerves C5-8

Question 2

Latissimus Dorsi

Answer 2

> Position: Superficial muscle of lower back from bottom of rib cage to superior iliac crest + sacrum
Origin: Thoracolumbar fascia to spinous processes of T6 to all sacral vertebrae(+supraspinous and interspinous ligaments)/iliac crest/lower four ribs/inferior angle of scapula
Insertion: Floor of intertubercular groove
Action: Extension
: Adduction
: Medial Rotation
Innervation: Thoracodorsal nerve C6-8

Question 3

Deltoid

Answer 3

> Position: superficial muscle on lateral upper arm giving contour to shoulder
Origin: Lateral 1/3 of clavicle (ant.)
: Lateral border of acromion (mid)
: Lat 1/3 of spine of scapula
Insertion: Deltoid tuberosity on mid-shaft of humerus
Action: ant: flexion
: medial rotation
: middle: abduction
: post: extension
: lateral rotation
Innervation: Axillary Nerve C5-6

Question 4

Coracobrachialis

Answer 4

> Position: antero-medial aspect of upper arm, medial to biceps brachii
Origin; Coracoid process of scapula
Insertion: medial aspect of mid-shaft of humerus
Action: assists flexion
: assists adduction
Innervation: Musculocutaneous nerve C5-6

Question 5

Teres major

Answer 5

> Origin: Inferior angle of scapula
Insertion: Medial lip of intertubercular sulcus
Action: Adduction
: Medial rotation
: assists extension of a flexed arm
Innervation: Lower Scapula Nerve C5-6

Question 6

Biceps Brachii

Answer 6

> Position: Anterior portion of upper arm giving it its contour
Origin: long head: supra-glenoid tubercle
: short head: coracoid process
Insertion: radial tuberosity (+bicipital aponeurosis to soft tissue of forearm)
Action: assists flexion of shoulder
: flexes elbow
: supinates forearm
innervation: Musculocutaneous nerve C5-6

Question 7

Triceps Brachii

Answer 7

> Position: Upper part of posterior arm, giving it its contour
Origin: Long: Infraglenoid tubercle
Lateral: upper part of posterior humerus
Medial: lower part of posterior humerus
Insertion: Posterior surface of olecranon of ulna
Action: long head: assists extension of shoulder
: assists adduction of shoulder
: extends elbow
Innervation: Radial nerve C6-8

Question 8

Muscles of rotator cuff

Answer 8

> Supraspinatus
infraspinatus
teres minor
subscapularis
- tendons blend with capsule to prevent unwanted slide/glide
- steers joint during physiological movement
- work in force couples (sup + teres = coronal plane)
(inf+subscap= horizontal plane)

Question 9

Supraspinatus

Answer 9

> Origin: Supraspinous fossa
Insertion: uppermost facet of greater tubercle
Action: abduction (initiates)
Innervation: Suprascapular nerve C5-6

Question 10

Infraspinatus

Answer 10

> Origin: Infraspinous fossa 
> Insertion: middle facet of greater tubercle 
> Action: Lateral rotation
              : assists adduction
> Innervation: Suprascapular nerve C5-6

Question 11

Teres Minor

Answer 11

> Origin: upper part of Lateral border of scapula
Insertion: lowermost facet of greater tubercle
Action: adduction
: extension
: lateral rotation
Innervation: Axillary nerve C5-6

Question 12

Subscapularis

Answer 12

> Origin: Subscapular fossa
Insertion: Lesser tubercle of humerus
Action: medial rotation
Innervation: Upper and lower scapular nerves C5-7