Okay Anatomy Anatomy I: Lesson 11 Myologia Part II Objective: Students will examine the muscles of a canine in order to identify the musculature of the body.
Practical Tasks: 6) carpal flexors, pronators of the radioulnar joint 7) digital flexors of the forelimb, pronators of the radioulnar joint 8) carpal extensors, supinator of the radioulnar joint 9) digital extensors of the foreimb, supinator of the radioulnar joint 10) m. sternocleidomastoideus, m. omotransversarius
Carpal flexors Practical Task 6 Pronators of the radioulnar joint Copyright, O.K. Anatomy School
Muscles of the Carpal Joint 3) M. flexor carpi radialis : strong, fleshy muscle covering caudomedial aspect of the radius. Epicondylus medialis humeri caudal to the Ligamentum collaterale mediale of the elbow s : on palmar aspect of proximal end of metacarpus Eq Ca Su Bo Mc 2 Mc 2 and Mc 3 Innervated by N. medianus from the brachial plexus flexing the carpal joint Mc 3 Mc 3
4) M. flexor carpi ulnaris : a fibrous, flattened muscle covering the caudal aspects of the long flexors of the digits; in Ca it is on caudolateral aspect of the antebrachium Body : with two (2) heads caput humerale (powerful) caput ulnare (weaker) (absent in Su) caput humerale Epicondylus medialis humeri caput ulnare Olecranon on accessory bone Innervations N. ulnaris from the brachial plexus flex carpal joint, in Ca: also to supinate it to some degree. Muscles of the Carpal Joint
2) Long flexors of the digits: Muscles of the Digits Long muscles Flexors of the digits Their muscle bellie are on caudal aspect of the forearm between the flexors and the carpal joint. Their strong tendons divide into several branches ending in 2 nd or 3 rd phalanx of corresponding digits. These muscles are of considerable static significance as they help in bearing the body weight, especially in large ungulates, thus they can also be frequently overstressed or strained in horses. They include the following two (2) muscles:
Muscles of the Digits Long muscles Flexors of the digits 1) M. flexor digitalis superficialis : is the weaker one of thes two ones, with differences in different species; Body one (1) belly in Ca and Eq, and two (2) in Su and Bo medial epicondyle of humerus tendon divided into following branches: Each tendon branchs is inserted by means of two limbs on the 2 nd phalanx after being perforated by the corresponding tendon of the deep digital flexor at the level of the 1 st phalanx flex the first two joints of the digits activate several joints help in flexing entire limb helps in bearing the body's weight when fetlock (= metacarpophalangeal joint) is extended Ca: cat Ca: dog Su, Bo Eq 5 4 2 1 (undivided)
2) M. flexor digitalis profundus : Body consisting of three (3) heads: caput humerale divided into 3 distinct bellies caput radiale caput ulnare caput humerale: medial epicondyle of humerus caput radiale: middle third of radius caput ulnare: medial aspect of olecranon Muscles of the Digits Long muscles Flexors of the digits
2) M. flexor digitalis profundus : Muscles of the Digits Long muscles Flexors of the digits all five muscle bellies form one single tendon = deep flexor tendon runnng distally on caudal surface of metacarpus and dividing into a number of branches corresponding to the number of digits: each tendon branch ending on the palmar aspect of 3 rd phalanx of corresponding digits flex all joints of the forefoot including distal interphalangeal joints except the dew-claw in Bo. Also helps fixing the fetlock joint esp. in ungulates. Number of branches Ca Su Bo Eq 5 4 2 1 (undivided)
Muscles of the Radioulnar Joints 1) M. pronator teres : in Ca, Su, Bo, rudimentary in Eq medial epicondyle of the humerus dorsal surface and medial border of radius Innervated by N. medianus from the brachial plexus pronate the forearm and forefoot Pronators
Muscles of the Radioulnar Joints Pronators 2) M. pronator quadratus : an elongated, rectangular muscle only in Ca (and man) palmar surface of radius and interosseous ligament interosseous border of the ulna Innervated by N. medianus from the brachial plexus pronate the forearm and paw
Practical Task 7 Digital flexors of the forelimb Pronators of the radioulnar joint
Muscles of the Digits Long muscles Flexors of the digits 1) M. flexor digitalis superficialis : is the weaker one of thes two ones, with differences in different species; Body one (1) belly in Ca and Eq, and two (2) in Su and Bo medial epicondyle of humerus tendon divided into following branches: Each tendon branchs is inserted by means of two limbs on the 2 nd phalanx after being perforated by the corresponding tendon of the deep digital flexor at the level of the 1 st phalanx flex the first two joints of the digits activate several joints help in flexing entire limb helps in bearing the body's weight when fetlock (= metacarpophalangeal joint) is extended Ca: cat Ca: dog Su, Bo Eq 5 4 2 1 (undivided)
2) M. flexor digitalis profundus : Body consisting of three (3) heads: caput humerale divided into 3 distinct bellies caput radiale caput ulnare caput humerale: medial epicondyle of humerus caput radiale: middle third of radius caput ulnare: medial aspect of olecranon Muscles of the Digits Long muscles Flexors of the digits
Muscles of the Radioulnar Joints 1) M. pronator teres : in Ca, Su, Bo, rudimentary in Eq medial epicondyle of the humerus dorsal surface and medial border of radius Innervated by N. medianus from the brachial plexus pronate the forearm and forefoot Pronators
Muscles of the Radioulnar Joints Pronators 2) M. pronator quadratus : an elongated, rectangular muscle only in Ca (and man) palmar surface of radius and interosseous ligament interosseous border of the ulna Innervated by N. medianus from the brachial plexus pronate the forearm and paw
Carpal extensors Practical Task 8 Supinator of the radioulnar joint
Muscles of the Carpal Joint 1) M. extensor carpi radialis : Strongest extensor of the forearm. Runs in cranial surface of the radius. Body divided in the cat (slightly in the dog) into two (2) parts: - longus, and - brevis extend and fix carpal joint lateral epicondylar crest (Crista supracondylaris lateralis), or directly from lateral epicondyle of humerus proximal extremities of either: Metacarpus 3, or Mc 2 and Mc 3 Innervated by N. radialis from the brachial plexus
Muscles of the Carpal Joint 2) M. extensor carpi ulnaris = M. ulnaris lateralis: Of the carpal extensors this one is situated the furthest caudolaterally; in most species it is a flexor; Epicondylus lateralis humeri caudal to the Ligamentum collaterale laterale of the elbow the accessory carpal bone, in Ca: laterally on proximal end of Mc 5 Innervated by N. radialis from the brachial plexus in Ca: abduct and flex the, in Herbivores: to flex carpal joint.
Muscles of the Digits Long muscles Long muscels of the digits: they always activate several joints. Usually with stout muscle bellies in region of the antebrachium. These muscles can be divided into: (long) extensors, and (long) flexors The bellies of the extensors are craniolaterally and the flexors caudally on the antebrachium. As on the medial aspect of the antebrachial skeleton there are no muscles, this is termed: planum cutaneum. e 1) Long extensors of the digits: The origin of their muscle bellies is partly on the humerus and partly on antebrachial skeleton. They include the following four (4) muscles:
Muscles of the Digits Long muscles Extensors of the digits 1) M. extensor digitis communis: a powerful muscle immediately lateral to M. extensor carpi lateralis, with a long, spindle-shaped belly that is divided differently in different animals: lateral epicondyle of humerus, or lateral ligament of elbow joint 3 rd phalanx of each digit (except the first one) Ca Su Bo Eq divided into: 4 3 2 1 (undivided) extend digits of carpal joint
1) M. brachioradialis : a long, narrow band of muscle between the superficial and deep fascia of the forearm, only in Ca, but often lacking or poorly developed in the dog on crest of lateral epicondyle on the distal extremity of the medial aspect of the radius Innervated by N. radialis from the brachial plexus supinate forearm and paw. Muscles of the Radioulnar Joints Supinators
Muscles of the Radioulnar Joints Supinators 2) M. supinator : a brad, flattened muscle on flexor aspect of elbow, covered by the extensor muscle; only in Ca, Su, best developed in cat, least in Su the lateral collateral ligament of the elbow joint and also the lateral epicondyle of the humerus and the annular ligament of the radius at the proximal quarter of the medial radius Innervated by N. radialis from the brachial plexus supinate the forearm and foot.
Practical Task 9 Digital extensors of the forelimb Supinator of the radioulnar joint
Muscles of the Digits Long muscles Extensors of the digits 1) M. extensor digitis communis: a powerful muscle immediately lateral to M. extensor carpi lateralis, with a long, spindle-shaped belly that is divided differently in different animals: lateral epicondyle of humerus, or lateral ligament of elbow joint 3 rd phalanx of each digit (except the first one) Ca Su Bo Eq divided into: 4 3 2 1 (undivided) extend digits of carpal joint
Muscles of the Digits Long muscles Extensors of the digits 1) M. extensor digitis communis: a powerful muscle immediately lateral to M. extensor carpi lateralis, with a long, spindle-shaped belly that is divided differently in different animals: lateral epicondyle of humerus, or lateral ligament of elbow joint 3 rd phalanx of each digit (except the first one) Ca Su Bo Eq divided into: 4 3 2 1 (undivided) extend digits of carpal joint
Muscles of the Digits Long muscles Extensors of the digits 2) M. extensor digitalis lateralis : on lateral aspect of antebrachium Body variable number of bellies and of tendons of insertion in different species: lateral collateral ligament of elbow and laterally from proximal extremities of radius and ulna Muscle bellies Tendons of insertion Ca: cat Ca: dog 3 2 2 separate muscles Su Bo Eq 1 1 4 3 2 1 1
s Ca: cat Ca: dog Su Bo Eq on 3 rd phalanx of 2 nd to 5t h digits, there uniting with tendon of common extensor Muscles of the Digits Long muscles Extensors of the digits 2) M. extensor digitalis lateralis : on lateral aspect of antebrachium : extend joints of the inserted digits: 3 rd to 5t h digits 4 th to 5 th digits 2 nd phalanx of 4 th digit proximal phalanx of 3 rd digit extended joints of digits.. Ca: cat Ca: dog Su Bo Eq 2 nd to 5t h digits 3 rd to 5t h digits 1 st and 2 nd joints of 4 th to 5 th digits 1 st and 2 nd joints of 4 th digit 1st joint of 3 rd digit
Muscles of the Digits Long muscles 3) M. extensor pollicis longus et indicis : only in Ca, but rudimentary in the dog; in other domestic mammals represented as: M.extensor indicis which is virtually completely fused with the common extensor; from craniolateral border of the ulna beside the long abductor distally on Mc 1 (dew-claw) and uniting with 2 nd digital branch of the common extensor tendon extend 1st and 2nd digits, in dog also to abduct the dew-claw
Muscles of the Digits Long muscles Extensors of the digits 4) M. abductor pollicis longus : a flat, semipennate muscle, in lateral groove between radius and ulna, largely covered by the digital extensor muscle; caudolaterally on ulna, on lateral border of radius and on the interosseous membrane extend and abduct 1st digit (in Ca), and extend carpal joint of other domestic mammals. s at Ca Bo Su, Eq base of 1 st Mc 3 rd Mc base of 2 nd Mc
1) M. brachioradialis : a long, narrow band of muscle between the superficial and deep fascia of the forearm, only in Ca, but often lacking or poorly developed in the dog on crest of lateral epicondyle on the distal extremity of the medial aspect of the radius Innervated by N. radialis from the brachial plexus supinate forearm and paw. Muscles of the Radioulnar Joints Supinators
Muscles of the Radioulnar Joints Supinators 2) M. supinator : a brad, flattened muscle on flexor aspect of elbow, covered by the extensor muscle; only in Ca, Su, best developed in cat, least in Su the lateral collateral ligament of the elbow joint and also the lateral epicondyle of the humerus and the annular ligament of the radius at the proximal quarter of the medial radius Innervated by N. radialis from the brachial plexus supinate the forearm and foot.
Practical Task 10 M. sternocleidomastoideus M. omotransversarius
Musculature of the Pectoral Girdle Extrinsic = Superficial Musculature 2) M. sternocleidomastoideus : ally (in man): the middle of the neck the sternum (M. sternomastoideus of man = M. sternocephalicus in domestic mammals) Extra In domestic mammals with quite a variation, made up by two (2) independent muscles: 2a) M. sternocephalicus and 2b) M. brachiocephalicus and the clavicle (M. cleidomastoideus fusion of the human M.cleidobrachialis and M. cleidocephalicus => M. brachiocephalicus in domestic mammals) Processus mastoideus of Os temporalis
Musculature of the Pectoral Girdle Ad 2a) M. sternocephalicus : strap-like, strong muscle the manubrium of the sternum (or even: the 1st rib) caudal border of mandible and/or mastoid process and/or nuchal crest of Os occipitalis of skull Innervation accessori n. and ventral branches of cervical spinal nn. draw the head and neck to the side Extrinsic = Superficial Musculature
3) M. omotransversarius : a powerful muscle band extending under (= one plane deeper than) the brachiocephalic m. transverse processes (wings) of the atlas or of axis (2nd cervical vert.) acromion and distal spine of the scapula accessory n. Musculature of the Pectoral Girdle Innervated by advancing the limb (lift it forward) or flex the neck laterally Extrinsic = Superficial Musculature