PECTORAL APPENDICULAR MUSCLES Pectoral Muscle Complex Pectoralis Superficialis Muscle: - Pectoralis Descendens Muscle: o Origin: from cranial

end of sternum o Insertion: on antebrachial fascia of antebrachium o Function: adducts humerus toward the chest and retracts it Pectoralis Transversus Muscle: o Origin: from cranial end of sternum o Insertion: along humeral crest on distal end of humerus o Function: adducts humerus toward the chest and retracts it

Pectoralis Profundus Muscle: - Origin: from caudal 2/3 or from full length of sternum - Insertion: on greater & lesser tubercles of humerus, and to some extent, along humeral crest - Function: adducts humerus toward the chest and retracts it Xiphihumeral Muscle distinct narrow band formed by caudal muscle fibers of pectoralis profundus muscle Trapezius & Sternocleidomastoid Muscle Complexes Trapezius Muscle Complex: - Cleidocervical Muscle (clavotrapezius muscle): o Origin: from nuchal crest of skull and middorsal line of cranial part of neck o Insertion: on the clavicle o Function: together with cleidobrachial muscle, it protracts the arm Cervical Trapezius Muscle lies cranial to thoracic trapezius muscle o Origin: from middorsal line of front of thorax & neck and from aponeurosis between cervical trapezius muscles o Insertion: on ventral portion of scapular spine and its metacromion o Function: adducts scapular toward middorsal line, as well as protracts & retracts it Thoracic Trapezius Muscle: o Origin: from middorsal line of thorax o Insertion: on dorsal portion of scapular spine o Function: adducts scapular toward middorsal line, as well as protracts & retracts it

Sternocleidomastoid Complex: - Sternomastoid Muscle: o Origin: from manubrium of sternum o Insertion: on mastoid region of skull o Function: turns head side-to-side and flexes it downward Sterno-occipital Muscle: o Origin: from manubrium of the sternum o Insertion: on occipital region of the sternum o Function: Cleidomastoid Muscle lies deep to wise sternomastoid & cleidocervical muscles o Origin: from clavicle o Insertion: on mastoid region of skull o Function: pulls head laterally and pulls clavicle cranially; turns head

REMAINING SUPERFICIAL MUSCLES OF SHOULDER Omotransversarius Muscle (levator scapulae ventralis muscle) caudal end lies on side of neck between cleidocervical and cervical trapezius muscles - Origin: from metacromion of scapula - Insertion: onto transverse process of atlas and to basiooccipital bone of skull - Function: protracts the scapula cranially and assists in protraction of entire limb o In stationary limb, assists in bending the head sideways Deltoid Muscle Complex lies caudal and ventral to scapular attachment omotransversaris muscle - Cleidobrachial Muscle (clavodeltoid muscle) covers front of shoulder & part of pectoralis transversus o Origin: from clavicle o Insertion: on the ulna o Function: protracts the arm Acromiodeltoid Muscle lies dorsal and caudal to cleidobrachial muscle o Origin: from acromion of scapula near attachment of omotransversaris muscle o Insertion: on deltoid tuberosity of humeral body o Function: retracts & abducts the humerus Scapulodeltoid Muscle lies along caudal border of scapula o Origin: from scapular spine o Insertion: on deltoid tuberosity of humerus o Function: retracts and adducts the humerus

Latissmus Dorsi Muscle: - Origin: from thoracolumbar fascia and from spinous processes of last thoracic vertebrae - Insertion: on proximal end of humerus - Function: retracts the humerus DEEPER MUSCLES OF THE SHOULDER Supraspinatus Muscle: - Origin: from supraspinous fossa of scapula - Insertion: on greater tubercle of humerus - Function: extends the shoulder joint Infraspinatus Muscle: - Origin: from infraspinous fossa - Insertion: on greater tubercle of humerus - Function: assists in flexion or extension of shoulder joint and assists in supination of humerus Teres Major Muscle: - Origin: from caudal border of scapula caudoventral to infraspinatus muscle - Insertion: on teres major tubercle beneath lesser tubercle of humerus - Function: flexes the shoulder joint Teres Minor Muscle very small, triangular muscle - Origin: by tendon from middle of caudal border of scapula - Insertion: on greater tubercle of humerus - Function: assists interspinatus muscle in rotating the humerus outward

Rhomboideus Muscle Complex: - Rhomboideus Cervicis et Thoracis Muscle: o Origin: from spinous processes of posterior cervical & anterior thoracic vertebrae o Insertion: along dorsal border of scapula o Function: Rhomboideus Capitus Muscle most cranial muscle bundle of complex o Origin: from dorsal edge of scapula o Insertion: on back of the skull o Function: pulls the scapula toward the vertebral column, helps hold it in place, and assists in its protraction & retraction

Serratus Ventralis Muscle: - Origin: by slips from ribs (dorsal to junction of bony ribs and costal cartilages) and from transverse processes of the caudal cervical vertebrae - Insertion: on dorsal border of scapula ventral to insertion of rhomboideus muscle - Function: together with pectoral muscle, it forms a muscular sling that transfers much of the weight of the body to the pectoral girdle and appendages Subscapular Muscle: - Origin: from subscapular fossa - Insertion: on lesser tubercle of humerus - Function: adducts the humerus

MUSCLES OF BRACHIUM Extensor Muscles Tensor Fasciae Antebrachii Muscle (dorsoepitrochlear muscle): - Origin: from lateral surface of latissimus dorsi muscle - Insertion: on tendon of triceps branchii muscle and on antebrachial fascia - Function: extends forearm Triceps Brachii Muscle large muscle that covers caudal surface and most of medial & lateral surfaces of humerus - Long Head lies on caudal surface of humerus o Origin: from distal 2/3 of caudal border of scapula o Insertion: on olecranon of ulna o Function: acts on shoulder & elbow joint and extends forearm Lateral Head covers much of lateral surface of humerus o Origin: from proximal end of humerus o Insertion: on olecranon of ulna o Function: extends forearm Medial Head lies on medial surface of humerus deep to several nerves & blood vessels o Origin: from most of body of humerus o Insertion: o Function: extends forearm Accessory Head long, narrow muscle that is largely fused with medial head o Origin: from caudal surface of humerus o Insertion: o Function: extends forearm Short Head: o Origin: from medial surface of distal end of humerus (cranial to supracondylar foramen) o Insertion: o Function: extends forearm

Anconeus Muscle: - Origin: from distal end of lateral side of humerus - Insertion: on olecranon next to insertion of triceps branchii muscle - Function: extends forearm Flexor Muscles Brachial Muscle covers craniolateral surface of humerus - Origin: from body of humerus - Insertion: on proximal end of ulna - Function: flexes the forearm Biceps Brachii Muscle lies on craniomedial side of humerus - Origin: by a single tendon from dorsal border of glenoid cavity o the scapula - Insertion: by a tendon on radial tuberosity - Function: supinates the forearm; major flexors of elbow joint Coracobrachial Muscle: - Origin: from coracoid process - Insertion: on proximal end of humerus - Function: assists in adduction of humerus

MUSCLES OF ANTEBRACHIUM Extensor Muscles Brachioradial Muscle: - Origin: proximally from humerus - Insertion: on the styloid process of radius - Function: extends the paw at the wrist & assists supinator muscle in supinating the paw Extensor Carpi Radialis Muscle Complex: - Extensor Carpi Radialis Longus Muscle lies more lateral & cranial; not subdivided o Origin: near lateral epicondyle of humerus o Insertion: on proximal end of 2nd metacarpal o Function: extends the paw at the wrist Extensor Carpi Radialis Brevis Muscle lies more superficial & caudal o Origin: near lateral epicondyle of humerus o Insertion: on proximal end of 3nd metacarpal o Function: extends the paw at the wrist

Extensor Carpi Ulnaris Muscle lies on ulnar side of forearm - Origin: near lateral epicondyle of humerus - Insertion: on base of 5th metacarpal - Function: FLEXES & abducts the wrist Extensor Digitorum Communis Muscle: - Origin: from lateral epicondyle of humerus - Insertion: on terminal phalanges - Function: extend the wrist and the 2nd to 5th digits Extensor Digitorum Lateralis Muscle: - Origin: fom humerus near origin of extensor digitorum communis muscle - Insertion: merge with counterparts of digitorum communis muscle near distal end of proximal phalanges - Function: extend the wrist and the 2nd to 5th digits Extensor Pollicis Muscle lies deep to extensor carpi ulnaris muscle - Origin: from proximal of lateral surface of ulna - Insertion: tendons merge with those of long extensor muscle at mid-length of digits - Function: contributes to extension of first 2 digits Extensor Indicis Muscle - lies deep to extensor carpi ulnaris muscle - Origin: from proximal of lateral surface of ulna - Insertion: tendons merge with those of long extensor muscle at mid-length of digits - Function: contributes to extension of first 2 digits Abductor Pollicis Longus Muscle: - Origin: from lateral surface of ulna & adjacent part of radius - Insertion: tendons insert upon radial side of 1st metacarpal - Function: abducts the thumb Supinator Muscle crosses obliquely over proximal half of radius underneath belly of extensor digitorum communis muscle and proximal to the belly of abductor pollicis longus muscle - Origin: from lateral epicondyle of humerus and elbow ligaments - Insertion: upon radius - Function: powerful supinator of the forepaw

Flexor Muscles Pronator Teres Muscle: - Origin: from medial epicondyle of humerus - Insertion: onto medial border of radius - Function: pronates forearm and forepaw Flexor Carpi Radialis Muscle: - Origin: near medial epicondyle of the humerus - Insertion: on proximal ends of 2nd and 3rd metacarpals - Function: flex the paw at the wrist Flexor Carpi Ulnaris Muscle on ulnar side of the forearm - Origin: Humeral Head from medial epicondyle Ulnar Head from caudomedial side of ulnar olecranon - Insertion: on pisiform bone of carpus - Function: flex the paw at the wrist Flexor Digitorum Superficialis Muscle lies between 2 carpal flexor muscles - Origin: from medial epicondyle of humerus and from surface of the flexor digitorum profundus muscle - Insertion: on middle phalanx of each digit - Function: flexes the wrist and digits up to their middle phalanges * 3 Heads of Flexor Digitorum Superficialis Muscle: o Medial Head: Forms a strong tendon, which splits into 4 relatively thick superficial tendons to digits 1 to 4 o Lateral Head smaller than medial head Splits into 2 thin, deeper tendons to digits 3 and 4 o Deep Head: Arises from surface of underlying flexor digitorum profundus muscle Sends 3 thin tendons to digits 2 to 4 Flexor Digitorum Profundus Muscle: - Origin: Ulnar Head from length of outer edge of ulna Radial Head from interosseus ligament (middle 1/3 of radius) between radius and ulna 3 Humeral Heads from the medial epicondyle of the humerus - Insertion: common deep flexor tendon on terminal phalanges of digits - Function: flexes the wrist and all segments of the digits Pronator Quadratus Muscle: - Origin: from distal 1/3 of ulna - Insertion: on outer edge of radius - Function: pronates the forepaw Lumbrical Muscles small intrinsic muscles of the paw - Origin: superficially from common deep flexor tendon - Insertion: on joints of proximal phalanges of digits 2 to 5 - Function: flex the proximal phalanges Abductor Muscle of 5th Digit small, powerful bulbous muscle - Origin: distal to flexor carpi ulnaris muscle on the pisiform and 5th metacarpal bones - Insertion: by a long tendon on proximal phalanx of digit 5 - Function: abducts the thumb