Back Muscles - Extrinsic Flashcards Preview

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Flashcards in Back Muscles - Extrinsic Deck (10)
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1
Q

Trapezius

Origin (Proximal)

Insertion (Distal)

Action

A

Origin:

  • Medial 3rd of sup. nuchal line
  • Ext. occip. protuberance
  • Nuchal lig.
  • SP of C7-T12

Insertion:

  • Lateral 3rd of clavicle
  • Acromion & spine of scapula

Action:

  • Descending: elevates shoulder complex
  • Middle: retracts scapula
  • Ascending: depresses shoulder complex
2
Q

Latissimus Dorsi

Origin (Proximal)

Insertion (Distal)

Action

A

Origin:

  • SP of T7/T8-T12
  • Thoracolumbar fascia
  • Iliac crest
  • Inf. 3/4 ribs

Insertion:
-Floor of inter tubercular sulcus of humerus (anterior side)

Action:

  • Extends/adducts/medially rotates humerus
  • Raises body to arm while climbing
3
Q

Levator Scapulae

Origin (Proximal)

Insertion (Distal)

Action

A

Origin:
-Posterior tubercles of TP of C1-C4

Insertion:
-Medial border of scapular spine superior to root of scapular spine

Action:

  • Elevates scapula
  • Tilts glenoid cavity inferiorly by rotating scapula
4
Q

Rhomboid Minor

Origin (Proximal)

Insertion (Distal)

Action

A

Origin:

  • Nuchal lig.
  • SP of C7-T1

Insertion:
-Smooth triangular area at medial end of scapular spine

Action:

  • Retract scapula
  • Rotate scapula to depress glenoid cavity [like levator scap.]
  • Fixes scapula to thoracic wall
5
Q

Rhomboid Major

Origin (Proximal)

Insertion (Distal)

Action

A

Origin:
-SP of T2-T5

Insertion:
-Medial border of scapula from spine to inferior angle

Action:

  • Retract scapula
  • Rotate scapula to depress glenoid cavity [like levator scap.]
  • Fixes scapula to thoracic wall
6
Q

Serratus Posterior Superior

Origin (Proximal)

Insertion (Distal)

Action

A

Origin:
-Nuchal lig. & SP of C7-T3

Insertion:
-Sup. borders of ribs 2-4

Action:

  • Proprioception
  • Elevate/depress ribs
7
Q

Serratus Posterior Inferior

Origin (Proximal)

Insertion (Distal)

Action

A

Origin:
-SP of T11-L2

Insertion:
-Inf. borders of ribs 8-12 near angles

Action:

  • Proprioception
  • Elevate/depress ribs
8
Q

What is the trapezius innervated by?

A

Cranial nerve XI: the spinal accessory nerve

9
Q

What is the latissimus dorsi innervated by?

A

Thoracodorsal nerve (beneath teres major)

10
Q

What are the rhomboids/levator scapulae innervated by?

A

Dorsal scapular nerve (between scapula and thoracic wall)