BIOD 151 Lab 6 Study Guide
Muscles that act on scapula:
● We will focus on the appendicular skeleton meaning muscles that act on our arms, legs,
shoulder blades or any muscles that act on pectoral or pelvic girdle that is considered to be part
of the appendicular skeleton
● Trapezius muscle
○ Very large fan-shaped muscle
○ Action: elevate, depress shoulders, stabilizes scapula when arm is doing the movements,
works with other muscles to rotate and retract scapula
○ Performs mobility role and stabilization role
○
Innervation: accessory nerve
● Serratus anterior
○ Action: protraction of scapula
■ So completes any forward pushing
■ When it works with pectoralis minor, it helps draw the scapula laterally and
forward around chest wall
■ Stabilizes the scapula as well
, ○
● Pectoralis minor
○ Action: when working with serratus anterior draws the scapula laterally and forward
around chest wall
○ One of the accessory muscles to breathing; during labored breathing, it will help expand
thoracic cavity to allow for more air to come into lungs
○ Innervation: medial and lateral pectoral nerves
● Muscles that act on humerus (upper arm bones)
○ Pectoralis major
■ Large chest muscle
■ Very superficial muscle
■ Action: flex, adduct, and medial rotate humerus
■ Innervation: medial and lateral pectoral nerves (same as pectoralis minor)
■
■ ^^^its the big chest muscle that has nipple on it
○ Latissimus dorsi
, ■ Action: adduct, medial rotate the humerus, extension of shoulder, backward
swing of the arms
■
■ It is number 4
■ Insertion: is humerus and that is how it moves humerus
○ Deltoid
■ Large muscle on top of humerus
■ Made up of 3 components: anterior fibers, lateral fibers, posterior fibers
● Each component responsible for a diff job
○ Anterior fibers: flex and medially rotate shoulders
○ Lateral fibers: abduct arms
○ Posterior fibers- extend and laterally rotate the shoulders
■ Innervation: axillary nerve
■
Muscles that act on scapula:
● We will focus on the appendicular skeleton meaning muscles that act on our arms, legs,
shoulder blades or any muscles that act on pectoral or pelvic girdle that is considered to be part
of the appendicular skeleton
● Trapezius muscle
○ Very large fan-shaped muscle
○ Action: elevate, depress shoulders, stabilizes scapula when arm is doing the movements,
works with other muscles to rotate and retract scapula
○ Performs mobility role and stabilization role
○
Innervation: accessory nerve
● Serratus anterior
○ Action: protraction of scapula
■ So completes any forward pushing
■ When it works with pectoralis minor, it helps draw the scapula laterally and
forward around chest wall
■ Stabilizes the scapula as well
, ○
● Pectoralis minor
○ Action: when working with serratus anterior draws the scapula laterally and forward
around chest wall
○ One of the accessory muscles to breathing; during labored breathing, it will help expand
thoracic cavity to allow for more air to come into lungs
○ Innervation: medial and lateral pectoral nerves
● Muscles that act on humerus (upper arm bones)
○ Pectoralis major
■ Large chest muscle
■ Very superficial muscle
■ Action: flex, adduct, and medial rotate humerus
■ Innervation: medial and lateral pectoral nerves (same as pectoralis minor)
■
■ ^^^its the big chest muscle that has nipple on it
○ Latissimus dorsi
, ■ Action: adduct, medial rotate the humerus, extension of shoulder, backward
swing of the arms
■
■ It is number 4
■ Insertion: is humerus and that is how it moves humerus
○ Deltoid
■ Large muscle on top of humerus
■ Made up of 3 components: anterior fibers, lateral fibers, posterior fibers
● Each component responsible for a diff job
○ Anterior fibers: flex and medially rotate shoulders
○ Lateral fibers: abduct arms
○ Posterior fibers- extend and laterally rotate the shoulders
■ Innervation: axillary nerve
■
