Set 1 Flashcards
Sternocleidomastoid (SCM)
Innervation
CN XI (SA nv.) + C2-3
SCM
Primary Open Chain Action
Both working together: flexion of the cervical spine
Individual muscle working alone: rotation of head to opposite side
PRIMARY NECK FLEXOR**
SCM
Secondary Open Chain Action
Ipsilateral lateral flexion (side bending)
Scalenes (ant., middle, post.)
Innervation
Cervical nerves VPR C1-8
Scalenes (ant., middle, post.)
Primary Open Chain Action
Ipsilateral flexion and rotation of the neck to opposite side
Scalenes (ant., middle, post.)
Secondary Open Chain Action
Neck flexion
Trapezius
Innervation
CN XI (SA nv.) + C3,4
Trapezius
Primary Open Chain Action
Upper fibers:
- Scapula elevation, adduction, upward rotation
- PRIMARY SHOULDER GIRDLE ELEVATOR***
Middle fibers:
- Scapula adduction
- PRIMARY SHOULDER GIRDLE RETRACTOR***
Lower fibers:
- Scapula depression, upward rotation
- PRIMARY SHOULDER GIRDLE DEPRESSOR***
Trapezius
Secondary Open Chain Action
Unilateral:
- rotation of head to opposite side
- lateral flexion of head to same side
Bilateral: head and neck extension
Levator Scapulae
Innervation
C3,4 + Dorsal Scapular (C5) to lower fibers
Levator Scapulae
Primary Open Chain Action
Elevation, adduction, and downward rotation of scapula
Serratus Anterior
Innervation
Long Thoracic n. (C5-7)
Serratus Anterior
Primary Open Chain Action
- Scapular abduction (Protraction and upward rotation)
- Holds the medial border of the scapula firmly against the thorax
Serratus Anterior
Secondary Open Chain Action
- Stabilizes the scapula for shoulder muscles
- Scapular depression
Pectoralis Major
Innervation
Medial + Lateral Pectoral n. (C5-8T1)
Pectoralis Major
Primary Open Chain Action
Clavicular fibers:
-IR, flexion, horizontal adduction
Stern all fibers:
- Adducts arm toward opposite iliac crest
- PRIMARY ARM ADDUCTOR***
Pectoralis Major
Secondary Open Chain Action
- Extends arm if flexed
- Depression of the shoulder girdle via the arm
Pectoralis Minor
Innervation
Medial Pectoral n. (C8T1)
Pectoralis Minor
Primary Open Chain Action
- Depression of the shoulder girdle
- Scapular downward rotation
Pectoralis Minor
Secondary Open Chain Action
- Fixes scapula against upward movements, depressing tip of shoulder joint
- Weak shoulder abduction
Deltoideus
Innervation
Axillary n. (C5,6)
Deltoideus
Primary Open Chain Action
All actions of the arm (shoulder)
Anterior fibers:
-flexion (PRIMARY***)
Middle fibers:
-abduction (PRIMARY***)
Posterior fibers:
- Horizontal abduction (PRIMARY***)
- Hyperextension
Deltoideus
Secondary Open Chain Action
Anterior + middle fibers:
-shoulder “scpation” (arm elevation in the plane of the scapula)
Anterior fibers:
- from abducted position, horizontal adduction
- from ER position, IR
Posterior fibers:
- from flexed position, extension
- from IR position, ER
Coracobrachialis
Innervation
Musculocutaneous n. (C6-7)
Coracobrachialis
Primary Open Chain Action
Flexion, adduction, horizontal adduction of arm (shoulder)
Coracobrachialis
Secondary Open Chain Action
Shoulder IR
Supraspinatus
Innervation
Suprascapular n. (C5)
Supraspinatus
Primary Open Chain Action
Arm (shoulder) abduction
Supraspinatus
Secondary Open Chain Action
- Holds head of humerus in glenoid fossa, preventing subluxation
- Shoulder scaption
- Shoulder ER
Infraspinatus
Innervation
Suprascapular n. (C5,6)
Infraspinatus
Primary Open Chain Action
- Arm (shoulder) ER
- PRIMARY ARM ER***
Infraspinatus
Secondary Open Chain Action
- Depresses head of humerus in glenoid fossa to allow for abduction
- Holds head of humerus in glenoid fossa preventing subluxation
Teres Minor
Innervation
Axillary n. (C5[,6])
Teres Minor
Primary Open Chain Action
Arm (shoulder) ER
Teres Minor
Secondary Open Chain Action
- Depresses head of humerus in glenoid fossa, allowing for abduction
- Holds head of humerus in glenoid fossa, preventing subluxation
- Assists in shoulder adduction
Subscapularis
Innervation
Upper + Lower Subscapular n. (C5,6)
Subscapularis
Primary Open Chain Action
- Arm (shoulder) IR
- PRIMARY ARM IR***
Subscapularis
Secondary Open Chain Action
- Depresses head of humerus in glenoid fossa to allow for arm abduction
- Holds head of humerus in glenoid fossa, preventing subluxation
Latissimus Dorsi
Innervation
Thoracodorsal (C6-8)
Latissimus Dorsi
Primary Open Chain Action
Arm extension, Hyperextension, adduction, and IR
Latissimus Dorsi
Secondary Open Chain Action
- Assists with forceful exhalation (ex. coughing, sneezing)
- Assists with scapula depression
Teres Major
Innervation
Lower Subscapular n. (C5,6)
Teres Major
Primary Open Chain Action
Arm extension, hyperextension, adduction, and IR
Rhomboideus Major
Innervation
Dorsal Scapular n. (C5)
Rhomboideus Major
Primary Open Chain Action
Scapular elevation, adduction, downward rotation
Rhomboideus Minor
Innervation
Dorsal Scapular n. (C5)
What is the PRIMARY NECK FLEXOR?
SCM
What is the PRIMARY SHOULDER GIRDLE ELEVATOR?
Upper fibers of the Trapezius.
What is the PRIMARY SHOULDER GIRDLE RETRACTOR?
Middle fibers of the Trapezius.
What is the PRIMARY SHOULDER GIRDLE DEPRESSOR?
Lower fibers of the Trapezius.
What is the PRIMARY ARM ADDUCTOR?
Pectoralis Major
What is the PRIMARY ARM EXTERNAL ROTATOR?
Infraspinatus
What is the PRIMARY ARM INTERNAL ROTATOR?
Subscapularis
Rhomboideus Minor
Primary Open Chain Action
Adduction, downward rotation, and elevation of scapula