Extrinsic Back Muscles.txt

• (1st Layer)
• Trapezius
• Latissimus Dorsi

• (2nd Layer)
• Levator Scapulae
• Rhomboid Minor
• Rhomboid Major

Upper Limb - appendicular skeleton

• Serratus Posterior Superior
• Serratus Posterior Inferior

Ribs

• External Occipital Protuberance
• Medial 1/3 Superior Nuchal Line
• Nuchal Ligament (to C7)
• Spinous Processes C7-T12

• Spine of the Scapula
• Acromion (medial edge)
• Lateral 1/3 of clavicle

• Spinal Accessory Nerve (CN XI) for motor.
• C3, C4 spinal nerves for pain (sensory) and procioceptive fibers

Transverse Cervical A. (superficial branch)

(additional contributions from acromial branch of suprascapular a. and dorsal branches of posterior intercostal arteries)

• Descending elevates scapula
• Middle retracts scapula
• Ascending depresses scapula

Descending and Ascending combined rotates glenoid cavity superiorly

• T7 - T12 spinous processes
• Thoracolumbar fascia
• Iliac crest
• Ribs 9 - 12 (inferior 3 or 4 ribs)

Floor of intertubercular sulcus (bicipital groove) of humerus medial to the insertion of pectoralis major

• Thoracodorsal N. (C6, C7, C8)
• (originates from posterior cord of brachial plexus, sometimes called middle scapular nerve)

• Thoracodorsal A.
• (branch of subscapular a.)

Extends, adducts, and medially rotates humerus.

Raises body toward arms during climbing.

Spinous processes of C7 - T1

Root of scapular spine (medial end)

Dorsal Scapular nerve (C4, C5)

Transverse Cervical A. (deep branch)

Note: sometimes called dorsal scapular a. but not very accurate

• Retracts scapula
• Elevates scapula

With other muscles it rotates scapula to depress gleniod cavity.

Spinous processes of T2-T5 vertebrae

Medial border of scapula (inferior to root of scapular spine)

Dorsal Scapular nerve (C4, C5)

Transverse Cervical A. (deep branch)

Note: sometimes called dorsal scapular a. but not very accurate

• Retracts scapula
• Elevates scapula

With other muscles it rotates scapula to depress gleniod cavity.

C1 - C4 transverse processes (posterior tubercles)

Medial border of scapula (superior to root of scapular spine)

• Anterior Rami (C3, C4)
• Dorsal Scapular N. (C4, C5)

Transverse Cervical A. (deep branch)

Elevates scapula and tilts its glenoid cavity inferiorly by rotating scapula

Extends or laterally flexes neck when scapula are fixed

• Lower part of ligamentum nuchae
• C7 - T3 spinous processes

Ribs 2 - 4 (superior border)

• Anterior Rami!!!
• (T2 - T5 intercostal nerves)

Intercostal arteries

• Proprioreception
• Elevate upper ribs (forced respiration)

T11 - L2 spinous processes

Ribs 8 - 12 (inferior border)

• Anterior Rami!!!
• (T9 - T11 intercostal nerves; T12 subcostal n.)

Intercostal arteries

• Proprioreception
• Stabilize lower ribs against diaphragm contraction