Lab #1: Pectoral Girdle, Superficial/ Intermediate back muscles

Trapezius: upper fibers

-trapezius is very superficial!! goes all the way from back of head and all way down to lower back!!

Proximal Attachment/Origin:

-external occipital protuberance

-spinous process of c7 vertebra

-medial 1/3 of superior nuchal line

-ligamentum nuchae

Distal Attachment/ Insertion:

-lateral 1/3 of clavicle

-Acromion process of scapula

Innervation:

-(spinal) accessory CN XI

-C3, C4 nerves

Action: (fixed origin)

1. elevate scapula

-fibers travel upward from scapula to insert into cervical vertebra

2. rotate glenoid cavity superiorly

Action: (fixed insertion)

1. extension, lateral flexion, and contralateral rotation of head and cervical spine

-acting bilaterally trapezius extends neck

Trapezius: middle fibers

-trapezius is very superficial!! goes all the way from back of head and all way down to lower back!!

Proximal Attachment/ Origin:

-spinous process of T1-T5 vertebrae

(T is for TRAP, middle goes to first half of thoracic)

Distal Attachment/ Insertion:

-medial margin of the acromion process of the scapula

-superior lip of spine of scapula

Innervation:

-Spinal Accessory nerve CN XI

-C3, C4 spinal nerves

Action: (fixed origin)

1. retraction of scapula (pulling back of shoulders)

Action: (fixed insertion)

1. extension, lateral flexion, and contralateral rotation of head and cervical spine

-acting bilaterally trapezius extends neck

Trapezius: lower fibers

-trapezius is very superficial!! goes all the way from back of head and all way down to lower back!!

Proximal Attachment/ Origin:

-spinous process of T6-T12

(T is for TRAP, lower goes to other half of thoracic)

Distal Attachment/ Insertion:

-tubercle at the apex of spine of scapula

Innervation:

-spinal accessory nerve CN XI

-C3, C4 spinal nerves

Action: (fixed origin)

1. depression of scapula (pull shoulders down)

2. rotate glenoid cavity superiorly

Action: (fixed insertion)

1. extension, lateral flexion, and contralateral rotation of head and cervical spine

-acting bilaterally trapezius extends neck

Latissimus Dorsi

-aka: lower back

Proximal Attachment/ Origin:

-spinous process of T6-T12

(same as lower trap)

-thoracolumbar fascia (attaches to a lot of CT)

-posterior lip of iliac crest

-ribs 9 to 12

-tiny bit of inferior angle of scapula

Distal Attachment/ Insertion:

-floor of intertubercular groove of humerus

(ANTERIOR INSERTION!! = goes under armpit!!)

Innervation:

-thoracodorsal nerve, C6, C7, C8

Action: (fixed origin)

1. adducts shoulder

2.internal rotation of shoulder

3. extends shoulder

-with continued contraction, it can depress scapula and laterally flex the trunk

4. hyperextends vertebral column

-when acting bilaterally

Action: (fixed insertion)

5. anteriorly/ laterally tilts pelvis

-when acting bilaterally

Rhomboid Major

-larger and inferior to rhomboid minor

Proximal Attachment/ Origin:

-spinous process of T2-T5

Distal Attachment/ Insertion:

-medial border of scapula

(between the level of the scapular spine and the inferior angle)

Innervation:

-dorsal scapular nerve, C5

Action:

1. retracts scapula (adduction)

2. elevates scapula

3. downward rotation of scapula

Rhomboid Minor

-smaller and superior to rhomboid major

Proximal Attachment/ Origin:

-nuchal ligament

-spinous process of C7-T1

(deep to upper and middle trap)

Distal Attachment/ Insertion:

-medial border at the root of spine of scapula

Innervation:

-dorsal scapular nerve, C5

Action:

1. retracts scapula

2. downward rotation of scapula

-pulls at top of scapula to cause anterior tilt

Serratus Posterior Superior

Proximal Attachment/ Origin:

-Spinous Process of T1-T3 vertebrae

Distal Attachment/ Insertion:

-upper borders of ribs 2-5

Innervation:

-intercostal nerves T2-T5

Action:

-elevates ribs

Serratus Posterior Inferior

Proximal Attachment/ Origin:

-spinous process of T11-L2 vertebrae

Distal Attachment/ Insertion:

-inferior border of ribs 9-12

Innervation:

-intercostal nerves T9-T12

Action:

-depress ribs

Levator Scapulae

-above the scapula

-find the superior angle of scapula to locate it

-muscle fibers are very vertical

Proximal Attachment/ Origin:

-posterior tubercles of transverse processes of C1-C4 vertebrae

Distal Attachment/ Insertion:

-medial border of scapula

(between superior angle and root of scapula spine)

Innervation:

-dorsal scapular nerve, C4, C5

-cervical spinal nerve C3, C4

Action: (fixed origin)

-elevates scapula

-downward rotation of scapula

Action: (fixed insertion working UNILATERALLY)

-lateral flexion and ipsilateral rotation of cervical spine

Action: (fixed insertion working BILATERALLY)

-extension of cervical spine

Major Regions and Bony Landmarks: Sternum

1. manubrium

-clavicular notch (two)

-jugular notch (one)

2. body of sternum

3. xiphoid process

-tip at bottom

Major Regions and Bony Landmarks: Clavicle

1. sternal end with facet

-rounded, sharp cut-off end

-medial end

2. acromial end with facet

-taper off into flat end

-lateral end

3. superior surface

-"smooth" superior

4. inferior surface

-bumpy

5. conoid tubercle

-on posterior- inferior side

-near acromial/lateral end

6. trapezoid line

-on posterior-inferior side

-near acromial/lateral end

-extends from conoid tubercle to acromial end

7. subclavian groove

-on inferior surface

8. shaft

-body of clavicle

HOW TO SIDE:

1. superior vs. inferior

-smooth superior

-conoid tubercle is inferior

2. posterior vs. anterior

-anterior sticks out

-should form crossbow when put together

3. lateral vs. medial end

-sternal (sharp cut off) end= medial

-acromial (flat/ tapers off) end= lateral

Major Regions and Bony Landmarks: Scapula

1. Dorsal/ posterior surface

-has the spine

2. Costal/ anterior surface

3. medial (vertebral) border

4. lateral (axillary) border

-near glenoid cavity

5. superior angle

6. inferior angle

7. spine of scapula

8. supraspinous fossa

-above the spine

9. infraspinous fossa

-below the spine

10. subscapular fossa

-on anterior side

11. acromion

-found laterally and posteriorly

-at end of spine, looks like hook

12. coracoid process

-found laterally and anteriorly

13. suprascapular notch

-at base of coracoid process

14. glenoid cavity

-most lateral

-circular depression

15. supraglenoid tubercle

-above glenoid cavity

16. infraglenoid tubercle

-below glenoid cavity

HOW TO SIDE:

1. lateral vs. medial

-acromion, coracoid process, and glenoid cavity are lateral

2. anterior/ costal vs. dorsal surface

-spine of scapula is posterior

-subscapular fossa is anterior

Major Regions and Bony Landmarks: Humerus (proximal)

1. head of humerus

-big ball

-it is medial

2. anatomical neck

-ridge that lines head

3. surgical neck

-thinning of bone below head

4. greater tubercle

-lateral

5. crest of greater tubercle

-ridge that extends from greater tubercle

6. lesser tubercle

-most anterior

7. crest of lesser tubercle

-ridge that extends from lesser tubercle

8. intertubercular sulcus

-groover between the two tubercles

9. deltoid tuberosity

-bump on lateral side about halfway down

10. radial groove

-faint diagonal line originating in the posterior

HOW TO SIDE:

1. medial vs. lateral

-head is medial

-deltoid tuberosity is lateral

2. anterior vs. posterior

-lesser tubercle is anterior