Muscles Of The Shoulder And Back

Front 1

Cat: Clavodeltoid, Acrominodeltoid, Spinodeltoid

Human: Deltoid (anterior, lateral and posterior fibers)

Back 1

Origin: Clavicle, acromion of scapula, spine of scapula

Insertion: Deltoid tuberosity of humerus

Function: Abduction, flexion, extension and rotation of humerus at shoulder

Front 2

Cat: Clavotrapezius, Acromiotrapezius, Spinotrapezius

Human: Trapezius (superior, middle, and inferior fibers)

Back 2

Origin: Occipital bone, ligamentium nuchae, last cervical vertebrae and all spinous process of all thoracic vertebrae

Insertion: Clavicle and scapula (spine and acromion)

Function: Elevate, rotate, depress, and retract (adducts) scapula
Also, lateral flexion, extension, and hyperextension of neck

Front 3

Cat: Levator scapulae ventralis

Human: Levator scapulae

Back 3

Origin: Transverse process of C1-C4

Insertion: Medial border of scapula

Function: Elevates and adducts scapula; lateral flexion of neck

Front 4

Cat: Supraspinatus

Human: Supraspinatus

Back 4

Origin: Supraspinous fossa of scapula

Insertion: Greater tubercle of humerus

Function: Abduction of humerus

Front 5

Cat: Infraspinatus

Human: Infraspinatus

Back 5

Origin: Infraspinous fossa of scapula

Insertion: Greater tubercle of humerus

Function: Extension and lateral rotation of humerus

Front 6

Cat: Latissimus Dorsi

Human: Latissimus Dorsi

Back 6

Origin: The lumbodorsal fascia (connects to: spinous process of last 6 thoracic vertebrae, lumbar vertebrae, and lower ribs) and inferior angle of scapula

Insertion: Intertubercular groove of humerus

Function: Extends and adducts humerus; rotation of humerus

Front 7

Cat: Rhomboideus (Rhomboid Capitis, Rhomboid Minor, Rhomboid Major)

Human: Rhomboid Major, Rhomboid Minor

Back 7

Origin: Spinous processes of the last cervical and first thoracic vertebrae (C7 and T1-T5)

Insertion: Medial border of the scapula

Function: Medial retraction and elevates scapula

Front 8

Cat: Splenius

Human: Splenius

Back 8

Origin: Spinous processes of cervical and upper thoracic vertebrae (C7-T6)

Insertion: Mastoid process of occipital bone and transverse process of C2-C4

Function: Extend head; lateral flexion of head

Front 9

Cat: Teres Major

Human: Teres Major

Back 9

Origin: Posterior inferior angle of scapula

Insertion: Intertubercular groove of humerus

Function: Extends and hyperexten humerus; adducts humerus; medial rotation of humerus

Front 10

Cat: Subscapularis

Human: Subscapularis

Back 10

Origin: Subscapular fossa

Insertion: Lesser tubercle of humerus

Function: Medial rotation of humerus