Anatomy - Upper Limb Muscles

Front 1

Trapezius

Back 1

Innervation - Accessory Nerve (CN XI)

Blood Supply - Superficial branch of the transverse cervical artery

Action:
Upper - elevate shoulder
Middle - retract scapula
Lower - depress scapula
abducts arm over shoulder along with serratus anterior

Front 2

Latissimus Dorsi

Back 2

Innervation - Thoracodorsal N

Blood Supply - Thoracodorsal A/V

Action - draws arm backward and inwards; adducts and internally rotates; raises arm while climbing

Front 3

Levator Scapulae

Back 3

Innervation - Dorsal Scapular N (C5)

Blood Supply - Dorsal scapular artery

Action - Elevates Scapula

Front 4

Rhomboid major and minor

Back 4

Innervation - Dorsal Scapula N

Blood Supply - Dorsal Scapular A

Action - Retracts Scapula (with Traps)

Front 5

Serratus Anterior

Back 5

Innervation - Long Thoracic N

Blood Supply - Lateral thoracic A; thoracodorsal A

Actions - protracts scapula; rotates scapula for abduction and flexion of arm; helps in abduction of shoulder over head

Front 6

Deltoid

Back 6

Innervation - Axillary N

Blood Supply - Suprascapular A, scapular circumflex A

Actions:

Front 7

Supraspinatus

Back 7

Innervation - Suprascapular N (C4,5,6)

Blood Supply - Suprascapular A

Action - Initiates abduction of shoulder; 0-15 degrees

Front 8

Infraspinatus

Back 8

Innervation - Suprascapular N

Blood Supply - Suprascapular A, Scapular Circumflex A

Action - lateral rotation of shoulder

Front 9

Teres Minor

Back 9

Innervation - Axillary N

Blood Supply - Scapular Circumflex A

Action - Lateral rotation of shoulder

Front 10

Teres Major

Back 10

Innervation - Lower Subscapular N

Blood Supply - Thoracodorsal A

Action - adduction and medial rotation

Front 11

Subscapularis

Back 11

Innervation - Upper and Lower subscapular N

Blood Supply - Braches of subscapular A

Action - medial rotation at shoulder; adduction of arm

Front 12

Subclavius

Back 12

Innervation - Nerve to the Subclavius (C5-C6)

Blood Supply - Clavicular branch of the thoracoacromial trunk

Action - not significant; steadies clavicle

Front 13

Pectoralis Major

Back 13

Innervation: Lateral and Medial Pectoral N

Blood Supply - Pectoral branch of thoracoacromial trunk

Actions: (at shoulder)
-adduction
-medial rotation
-flexion (upper fibers)
-extension of flexed arm (lower fibers)

Front 14

Pectoralis Minor

Back 14

Innervation - Medial and Lateral Pectoral N

Blood Supply - Pectoral branch of thoracoacromial trunk

Action - steadies scapula; depresses point of shoulder; helps in forced inspiration by elevation of ribs

Front 15

What are the borders of the triangle of auscultation?

Back 15

Medial border - Trapezius

Lateral border - Teres major/scapula

Inferior border (base) - Lats

Front 16

What are the borders of the quadrangular space?

Back 16

Superior border - teres minor, subscapularis

Inferior border - teres major

Lateral border - lateral head of triceps, surgical neck of humerus

Medial border - Long head of triceps

Front 17

What are the borders of the upper triangular space?

Back 17

Lateral border - long head of triceps

Upper border - Teres minor and subscapularis

Lower border - Teres Major

Contains Circumflex scapular branch of subscapular A

Front 18

What are the borders of the lower triangular space?

Back 18

lies adjacent to humerus

medial border - long head of triceps

lateral border - shaft of humerus

superior border - teres major

contains radial nerve and profundi brachii artery