muscles for tbl 1

Question 1

Describe the function, origin, insertion, and innervation of the serratus anterior

Answer 1

The serratus anterior attaches to lateral portions of the first eight ribs proximally and to the medial border of the scapula distally. It slides the scapula laterally on the posterior thoracic wall (protraction of scapula) when reaching for something. The serratus anterior also works synergistically with the descending and ascending parts of the trapezius to rotate the scapula upward thus allowing the deltoid to fully abduct the upper limb from the horizontal plane. Long thoracic nerve innervates the serratus anterior

Question 2

Describe the function, origin, insertion, and innervation of the pectoralis major

Answer 2

Proximally, the large sternocostal head of the pectoralis major attaches to the sternum and superior six costal cartilages and its smaller clavicular head attaches to the clavicle.Note both heads attach to the humerus distally; thus, deduce together the heads synergistically adduct the upper limb with the latissimus dorsi and synergistically rotate the arm medially with the subscapularis and teres major.

Question 3

Describe the function, origin, insertion, and innervation of the pectoralis minor

Answer 3

The pectoralis minor, which is deep to the pectoralis major, attaches to the 3rd, 4th and 5th ribs proximally and to the coracoid process of the scapula distally. Envision it stabilizes the scapula against the posterior thoracic wall during protraction. Lateral pectoral nerve innervates the clavicular head of the pectoralis major and the medial pectoral nerve innervates the sternocostal head and the pectoralis minor.