Muscles of the Boundaries

Question 1

True or false: Only the pec major is a boundary for the ax

Answer 1

False, both pec minor and major serve as boundaries

Question 2

Subscap muscle: Origin and insertion

Answer 2

Origin: Arises from subscap fossa of scapula
Passes directly IN FRONT of shoulder joint and fuses with its capsule
Insertion: Lesser tubercle of humerus

Question 3

Subscap muscle: Action

Answer 3

Medial rotator of arm

Question 4

Subscap muscle: Innervation and blood supply

Answer 4

Upper and Lower subscap nerves

Subscap vessels

Question 5

Teres Major: Origin and Insertion

Answer 5

Origin: Inferior angle andadjacent axillary border of the scapula
Passes anterior to the long head of the triceps brachii muscle and anatomical neck of humerus
Insertion: lesser tbular ridge

Question 6

Teres major: Action

Answer 6

Adductor and medial rotator of arm

Question 7

Teres major: Innervation and blood supply

Answer 7

Innervation: Lower scapular nerve

Blood Supply: Subscapular Vessels

Question 8

Lat Dorsi: Pathway

Answer 8

Crosses inferior angle of scapula and the origin of the teres major, then turns under the same muscle to reach its anterior position

Question 9

Serratus Anterior: Origin and Insertion

Answer 9

Origin: Upper 8 Ribs
Insertion: Vertebral border of scapula

Question 10

Serratus Anterior: Action

Answer 10

Prevents retraction of the scapula and shoulder; when lower fibers contract, it can assist the trapezius muscle in trating the scapula or shoulder

Question 11

What is “Winged Scapula”?

Answer 11

When the serratus anterior loses innervation