Muscles of the upper trunk- origins, insertions, actions and antagonists.

As I said in my last post, if you want to work with the body (especially sports massage or Reciprocal Inhibition) you need to know the antagonist muscles, as well as the origins, insertions and actions of them. This is because in a classic example of poor posture you will see this.
So if you see tight muscles in one area, you can look at the antagonistic muscles to see why they may actually be over extended and loose, instead of the origin of the problem! You may just be stuck in a compensation pattern. No one is going to want to put their shoulders back if their muscles in their pecs have atrophied and are so tight that it is uncomfortable. So stretching or puffing your chest out may actually be what you need to help the muscles in your shoulders and back! If you have this common issue, and want a cheap fix, laying on a rolled up towel, or a foam roller between your shoulder blades (or scapula) may help this issue correct itself without massage, allowing gravity to do it's work for you.

So let's get into the muscles, and their antagonists. (This will be long, but fear not, you only need to get a general idea of these and their locations, most health professionals will not memorize all of this stuff. . .It is a great resource to keep in your files though. Which is the only reason I have made it!)

Erector Spinae Group

Action:

• Unilaterally: Laterally flex vertebral column to the same side
• Bilaterally: Extend the vertebral column

Origin: Common tendon that attaches to the posterior surface of sacrum, iliac crest, spinous processes of the lumbar and last two thoracic vertebrae

Insertion: Various attachments at the posterior ribs, spinous and transverse processes of thoracic and cervical vertebrae and mastoid process of temporal bone

       Antagonist: rectus abdominis muscle

Spinalis

Action: Laterally: Flex the head and neck to the same side. Bilaterally: Extend the vertebral column.

Origin:

• Spinous processes of the upper lumbar and lower thoracic vertebrae
• Ligamentum nuchae, spinous process of C-7

Insertion:

• Spinous processes of upper thoracic
• Spinous processes of cervicals, except C-1

       Antagonist: Rectus abdominis muscle

Longissiums

Action: Laterally: Flex the head and neck to the same side. Bilaterally: Extend the vertebral column.

Origin: Common tendon, transverse processes of upper five thoracic vertebrae

Insertion:

• Lower nine ribs and transverse processes of thoracic vertebrae
• Transverse processes of cervical vertebrae
• Mastoid process of temporal bone

       Antagonist: Rectus abdominis muscle

Iliocostalis

Action: Unilaterally: laterally flex the vertebral column to the same side. Bilaterally: Extend the vertebral column.

Origin: common tendon, posterior surface of ribs 1-12

Insertion:

• Transverse processes of lumbar vertebrae 1-3 and posterior surface of ribs 6-12
• Posterior surface of ribs 1-6
• Transverse processes of lower cervicals

       Antagonist: Rectus abdominis muscle

Transversospinalis Group

Multifidi and Rotatores

Action:

• Unilaterally: Rotate the vertebral column to the opposite side
• Bilaterally: Extend the vertebrae

Origin:

• Multifidi: Sacrum and transverse processes of lumbar through cervical vertebrae
• Rotatores: Transverse processes of lumbar through cervical vertebrae

Insertion: Spinous processes of lumbar vertebrae through second cervical vertebrae

• Multifidi span two to four vertebrae
• Rotatores span one to two vertebrae

Semispinalis Capitus

Action: Extend the vertebral column and head

Origin: Transverse processes of C-4 to T-5

Insertion: Between the superior and inferior nuchal lines of the occiput

       Antagonist: Sternocleidomastoid, Longus colli and capitis, Scalenus anterior, medius, and posterior

Splenius Capitis and Cervicis

Action:

• Unilaterally: Rotate the head and neck to the same side, laterally flex the head and neck to the same side
• Bilaterally: Extend the head and neck

Origin:

• Capitis: Inferior one-half of ligamentum nuchae and spinous processes of C-7 to T-4
• Cervicis: Spinous processes of T-3 to T-6

Insertion:

• Capitis: Mastoid process and lateral portion of superior nuchal line
• Cervicis: Transverse processes of C-1 to C-3

Antagonist: (Both) Sternocleidomastoid; Longus colli and capitis; Scalenus anterior, medius, and posterior. 

(When you think of the area of the neck people would chop to decapitate you, think of the two capitis's)

Quadratus Lumborum

Action:

• Unilaterally:

1. Laterally tilt the pelvis
2. Laterally flex the vertebral column to the same side
3. Assist to extend the vertebral column

• Bilaterally: Fix the last rib during forced inhalation and exhalation

Origin: Posterior iliac crest

Insertion: Last rib and transverse processes of first through fourth lumbar vertebrae

       Antagonist: Rectus abdominis, Internal oblique, External oblique

Abdominals

Rectus Abdominis

Action: Flex the vertebral column and tilt pelvis posteriorly

Origin: Pubic crest, pubic symphysis

Insertion: Cartilage of fifth, sixth, and seventh ribs and xiphoid process

       Antagonist: Erector spinae, Quadratus Lumborum

External Oblique

Action:

• Unilaterally: Laterally flex vertebral column to the same side, Rotate vertebral column to the opposite side
• Bilaterally: Flex the vertebral column, Compress abdominal contents

Origin: External surfaces of fifth to twelth ribs

Insertion: Anterior part of the iliac crest, abdominal aponeurosis to linea alba

       Antagonist: Erector spinae, Quadratus Lumborum

Internal Oblique

Action:

• Unilaterally: Laterally flex vertebral column to the same side, Rotate vertebral column to the same side
• Bilaterally: Flex the vertebral column, Compress abdominal contents

Origin: Lateral inguinal ligament, iliac crest and thoracolumbar fascia

Insertion: Internal surface of lower three ribs, abdominal aponeurosis to linea alba

       Antagonist: Erector spinae, Quadratus Lumborum

Transverse Abdominis

Action: Compress abdominal contents

Origin: Lateral inguinal ligament, iliac crest, thoracolumbar fascia and internal surface of lower six ribs

Insertion: Abdominal aponeurosis to linea alba

       Antagonist:  erector spinae

Diaphragm

Action: Draw down the central tendon of the diaphragm, Increase the volume of the thoracic cavity during inhalation

Origin:

• Costal attachment: Inner surface of lower six ribs
• Lumbar attachment: Upper two or three lumbar vertebrae
• Sternal attachment: Inner part of xiphoid process

Insertion: Central tendon

Intercostals

External and Internal Intercostals

Action:

• External: Draw the ribs superiorly to assist with inhalation
• Internal: Draw the ribs inferiorly to assist with exhalation

Origin: Inferior border of the rib above

Insertion: Superior border of the rib below

       Antagonist: External intercostal muscles

Serratus Posterior Superior

Action: Elevate the ribs during inhalation

Origin: Spinous processes of C-7 to T-3

Insertion: Posterior surface of second through fifth ribs

Antagonist: Serratus posterior superior, Transversus abdominis

Serratus Posterior Inferior

Action: Depress the ribs during exhalation

Origin: Spinous processes of T-12 to L-3

Insertion: Posterior surface of ninth through twelfth ribs

       Antagonist: Serratus posterior superior, Levatores costarum brevis and longi

Intertransversarii

Action:

• Unilaterally: Laterally flex the vertebral column to the same side
• Bilaterally: Extend the vertebral column

Origin and Insertion:

• Cervical: Spanning the transverse processes of vertevrae C-2 to C-7
• Lumbar: Spanning the transverse processes of vertebrae L-1 to L-5

Interspinalis

Action: Extend the vertebral column

Origin and Insertion:

• Cervical: Spanning the spinous processes of C-2 to T-3
• Lumbar: Spanning the spinous processes of T-12 to L-5

Subclavius (or under the clavicle)
Origin=the first rib right at the junction with the costal cartilage.
Insertion=the groove for the subclavius muscle, called the subclavian groove

Action=depresses the clavicle inferiorly and anteriorly

Antagonist=sternocleidomastoid or SCM muscle

Rhomboid major
 origin= spinous process of upper thoracic vertebrae
 insertion= vertebral border of scapula
 action = rotates and retracts scapula

While retracting-Antagonists: Serratus Anterior, Pectoralis Minor
While rotating-Antagonists: Trapezius (upper fibers), Trapezius (lower fibers), Serratus anterior (lower fibers)


Rhomboid minor
Origin= spinous process of lower cervical and upper thoracic vertebrae
 Insertion= vertebral border of scapula action= rotates and retracts scapula
Antagonist= Trapezius






Levetor scapulae
Origin= transverse processes of cervical vertebrae
 Insertion= vertebral border of scapula
 Action= elevates scapula,
Antagonist=serratus anterior and the lower fibers of the trapezius

Pectoralis minor
Origin= anterior surface of upper-middle ribs

Insertion= coracoid process of scapula
Action= depresses, protracts, and rotates scapula
Antagonist=rhomboid muscles


Pectoralis major
 Origin= clavicle, sternum, and costal cartilages of upper ribs
 Insertion= greater tubercle of humerus
 Action= flexes, adducts, and medially rotates arm

Antagonist to sterno section= romboid and trapezius muscles
antagonist to the rest are supraspinatus and deltoid muscles

Supraspinatus
 Origin= supraspinous fossa of scapula
 Insertion= greater tubercle of humerus
Action= abducts arm (part of Rotator cuff)
Antagonist=Pectoralis major lower fibers, latissimus dorsi, teres major

Infraspinatus
 Origin= infraspinous fossa of scapula
 Insertion= greater tubercle of humerus
Action= laterally rotates arm (part of rotator cuff)
Antagonist=subscapularisteres Major, lats, pec major, anterior deltoid

     Teres major
 Origin= inferior angle of scapula

 Insertion= lesser tubercle of humerus
 Action= adducts, extends and medially rotates arm
 Antagonist=deltoid, infraspinatus, and teres minor.





Teres minor
 Origin= On the dorsal surface of the middle half of the lateral border of the scapula.
Insertion=The lowest of the three facets of the greater tubercle of the humerus
Action=Externally rotates the arm
Antagonist= Deltoid


Subscapularis
Origin=Subscapular fossa of the scapula.
Insertion=Lesser tubercle of humerus.
Action=medial rotation of the arm at the shoulder joint
Antagonist= infraspinatus.

Trapezius

Action: 

Upper Fibers: elevate and upwardly rotate scapula. Extends neck.

Middle Fibers: Adducts scapula

Lower Fibers: to depress and help upper fibers upwardly rotate scapula

Origin: 
Upper part: External occipital proturberance, medial third of the superior nuchal line, the ligamentum nuchae, and the spinous process of C7

Medial Part: Spinous processes of T1 to T5.

Lower Part: Spinous processes of T6 to T12

Insertion: 
Upper Part: Lateral third of the clavicle and the medial aspect of the acromion process of the scapula

Middle Part: Medial edge of the superior surface of the acromion process of the scapula and the superior edge of the scapular spine.

Lower Part: Tubercles of the apex of the scapular spine.

And that's all folks! (For now at least. . .)