Articulationes Membri Thoracici • 1. Articulatio

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ARTICULATIONES MEMBRI THORACICI

• 1. ARTICULATIO HUMERI-art. simplex, art. spheroidea (but functions as a hinge joint) movement: eq, Ru only flexion, extension is possible, in ca: rotation, abduction, adduction also between scapula (cavitas glenoidalis) and humerus (caput) Capsula articularis Recessus: cranial and caudal recesses Labrum glenoidale  Ligg. glenohumeralia (eq, ca)- tickened part of the capsule (capsular ligament) in the med. and lat. walls in ca, and cranially in eq  Lig. coracohumerale (eq, Ru)- capsular ligament between scapula (tub. supraglenoidale) and humerus (tub. majus, minus)  No collateral ligaments! Instead of them: laterally m. infraspinatus (1), medially m. subscapularis (5) ca: part of the joint capsule surrounds the tendon of m. biceps brachii (9) and forms vagina synovialis intertubercularis eq, bo: bursa intertubercularis (=bursa bicipitalis) under the tendor of the m. biceps brachii (may communicate with the joint cavity of the shoulder joint in horse)

• 2.ARTICULATIO CUBITI-art. composita, ginglymus (hinge joint) movement: extension and flexion between humerus (condyle), radius (caput), ulna (insisura trochlearis) Articulatio humeroulnaris Articulatio humeroradialis Capsula articularis Recessus: recessus cranialis, large recessus caudalis  Lig. collaterale cubiti mediale- from epicondylus med. to radius (in ca also to ulna)  Lig. collaterale cubiti laterale- from epicondylus lat. to radius (in ca, Ru also to ulna)  Lig. olecrani (ca)- capsular ligament from fossa olecrani of humerus to olecranon

•3. ARTICULATIO RADIOULNARIS PROXIMALIS- art. simplex, art. trochoidea movement: ca: rotational movements are possible (pronatio, supinatio) eq, Ru: no movement! between radius (circumferentia articularis radii) and ulna (incisura radialis ulnae)  Lig. anulare radii (ca)- encircles the head of the radius, running under the collateral ligaments Membrana interossea antebrachii (ca) (in eq, Ru it is ossified)

• 4. ARTICULATIO RADIOULNARIS DISTALIS- art. simplex, art. trochoidea ca: the joint exists; eq: ulna is missing, Ru: ossified radius and ulna movement: ca: rotational movements are possible (pronatio, supinatio) between radius (incisura ulnaris radii) and ulna (circumferentia articularis ulnae) Capsula articularis  Lig. radioulnare (ca)- capsular ligament at the distal ends of radius and ulna, cranially

FASCIAL STRUCTURES  fascia axillaris  fascia brachii  fascia antebrachii

FLEXORS OF THE SHOULDER (Ca) m. deltoideus (pars acromialis et scapularis) m. infraspinatus m. teres minor m. triceps brachii caput longum m. teres major m. subscapularis

1. M. infraspinatus o Origin: fossa infraspinata, spina scapulae, margo caudalis scapulae o Insertion: facies m. infraspinati of humerus o Action: acts as a lateral collateral ligament for shoulder joint; flexor of shoulder joint

2. M. teres minor o Origin: distally on margo caudalis scapulae, tuberculum infraglenoidale o Insertion: teres minor tuberosity of humerus (laterally) o Action: flexor of shoulder joint

4. M. deltoideus o Origin: 4a. scapular part: caudal edge of spina scapulae, 4b. acromial part: from acromion o Insertion: tuberositas deltoidea of humerus o Action: flexor of shoulder joint

5. M. subscapularis o Origin: fossa subscapularis o Insertion: tuberculum minus of humerus o Action: its wide tendon acts as a medial collateral ligament for shoulder joint; extends shoulder joint, but also helps maintaining flexion

6. M. teres major o Origin: proximally on margo caudalis scapulae and angulus caudalis scapulae o Insertion: teres major tuberosity of humerus (together with m. latissimus dorsi) o Action: flexor of shoulder joint

(7. M. latissimus dorsi o Origin: superficial layer of thoracolumbar fascia (from spinous processes of the last 7-8 thoracic and lumbar vertebrae); also muscular attachment proximally to the last few ribs o Insertion: on teres major tuberosity (together with m. teres major) o Action: draws free limb caudally; together with m. teres major flexes shoulder)

EXTENSORS OF THE SHOULDER (Ca) m. supraspinatus m. biceps brachii m. coracobrachialis m. subscapularis

8. M. supraspinatus o Origin: fossa supraspinata, spine and cranial border of scapula o Insertion: greater tubercle of the humerus (tuberculum majus) o Action: extends and stabilizes shoulder joint

9. M. biceps brachii o Origin: tuberculum supraglenoidale of scapule; a retinaculum transversum fixes its tendon in the intertubercular groove (between tuberculum majus and minus). Tendon in vagina synovialis intertubercularis. o Insertion: tuberositas radii and tuberositas ulnae (proc. coronoideus medialis) o Action: extends shoulder joint and flexes elbow joint

10. M. coracobrachialis o Origin: coracoid process of supraglenoid tubercle, o Insertion: crest of minor tubercle on humerus (behind attachment of m. triceps brachii caput mediale) o Action: extensor of shoulder joint

FLEXORS OF THE ELBOW (Ca) m. biceps brachii , m. brachialis 9. M. biceps brachii o Origin: tuberculum supraglenoidale of scapule; a retinaculum transversum fixes its tendon in the intertubercular groove (between tuberculum majus and minus) o Insertion: tuberositas radii and tuberositas ulnae (proc. coronoideus medialis) o Action: extends shoulder joint and flexes elbow joint

11. M. brachialis o Origin: caudally on neck of humerus; (then it will twist laterally, then cranio-medially in sulcus m. brachialis towards antebrachium) o Insertion: tuberositas radii and tuberositas ulnae (proc. coronoideus medialis) o Action: flexes elbow joint

EXTENSORS OF THE ELBOW (Ca) m. triceps brachii (caput longum, laterale, mediale, accessorium) m. anconeus m. tensor fasciae antebrachii

M. triceps brachii In dogs it has four heads: caput longum, laterale, mediale and accessorium o 3. Caput longum o Origin: distal 2/3 of margo caudalis scapulae o Insertion: tuber olecrani o Action: flexor of shoulder joint and extensor of elbow joint o 12. Caput laterale o Origin: linea m. tricipitis o Insertion: tuber olecrani o Action: extend elbow joint o 13. Caput mediale o Origin: proximal medial surface of humerus (near teres major tuberosity) o Insertion: tuber olecrani o Action: extend elbow joint o 14. Caput accessorium o Origin: caudally from neck of humerus o Insertion: tuber olecrani o Action: extend elbow joint Bursa between skin and olecranon (1. bursa subcutanea olecrani), between tendons of caput mediale and caput longum (2. bursa intratendinea olecrani) and between olecranon and tendons (3.bursa subtendinea m. tricipitis brachii).

15. M. anconeus o Origin: lateral epicondylar (supracondylar) crest, and around fossa olecrani o Insertion: latero-proximally on olecranon (tuber olecrani, proc. anconeus) o Action: extends elbow joint

16. M. tensor fasciae antebrachii o Origin: detaching from m. latissimus dorsi o Insertion: medially on tuber olecrani, then radiates into antebrachial fascia o Action: tenses antebrachial fascia and extends elbow joint

MUSCLES THAT CONNECTS THE FORELIMB WITH THE TRUNK AND ARE ATTACHED TO THE SCAPULA: a. M. trapezius o Origin: between C3-Th9 region. - pars cervicalis: from raphe of neck - pars thoracica: from supraspinous ligament o Insertion: cervical part inserts on proximal ¾ of scapular spine (distally there is the omotransversarius muscle); thoracic part inserts on proximal third of scapular spine o Action: supports trunk, elevates (lifts) forelimb, draws it cranially

b. M. rhomboideus o Origin: nuchal crest of occipital bone (pars capitis); from raphe of neck to spinous processes of Th1-3 vertebrae (pars cervicis); and from processus spinosus of Th4-7 vertebrae (pars thoracis) o Insertion: dorsomedial border of scapula o Action: elevates limb and pulls base of scapula against trunk forwards or backwards (depending on which part will contract more)

c. M. serratus ventralis o Origin: cervical part from proc. trans. of C2-7, thoracic part from middle of ribs 1-8. o Insertion: facies serrata on scapula (medially) o Action: supports trunk, helps at inspiration, carries shoulder cranial or caudal with respect to position of forelimb d. M. omotransversarius o Origin: distal part of scapular spine, then runs under m. sternocleidomastoideus o Insertion: caudal border of ala atlantis o Action: if limb is free: draws shoulder cranially; if limb is fixed: flexes neck laterally

MUSCLES THAT CONNECTS THE FORELIMB WITH THE TRUNK AND ARE ATTACHED TO THE HUMERUS: e. Pectoral muscles M. pectoralis superficialis It has two parts: m. pectoralis descendens and transversus o Origin: m. pectoralis descendens from manubrium sterni, m. pectoralis transversus from 1-3rd sternebrae o Insertion: crest of greater tubercle of humerus (crista tuberculi majoris), upper part of crista humeri o Action: ventral connection to forelimb, adduction, draws limb cranially or caudally depending its position M. pectoralis profundus Also called: m. pectoralis ascendens

6 o Origin: all sternebrae of sternum and costal cartilages of true ribs o Insertion: main part inserts on minor tubercle of humerus (and just a small aponeurosis joins to major tubercle) o Action: supports trunk, behaving as a strong retractor (draws limb caudally) and adductor of forelimb

M. sternocleidomastoideus  M. sternocephalicus  f. M. brachiocephalicus- From humerus to head and neck o m. cleidobrachialis: o Origin distal cranial surface of humerus and crista humeri, o Insertion: on clavicular intersection o m. cleidocephalicus: o Origin: on clavicular intersection o Insertion: m. cleidomastoideus: mastoid part of temporal bone m. cleidocervicalis: dorsal midline (raphe cervicis) over cranial half of neck o Action: If forelimb is fixed: unilateral contraction of the muscle moves head into the lateral direction, bilateral contraction fixes head and neck (or bends downward). If limb is free (it’s in an elevated position), it will move forelimb cranially.

INTERSPECIES DIFFERENCES EQ  m. deltoideus- no acromial part  m supraspinatus- inserts also on tuberculum minus (not just majus), between the inserting tendons runs the tendon of m. biceps brachii (that’s why retinaculum transversum is not needed)  m. biceps brachii- at the origin under its tendon there is a bursa bicipitalis(!), retinaculum transversum is missing (instead of that two tendons of m. supraspinatus fixes it), lacertus fibrosus (fibrous connection between m. biceps brachii and m. extensor carpi radialis, which is part of the passive stay apparatus) is especially developed.  m. triceps brachii- caput accessorium is missing  m. subclavius (also in su, Ru)- Origin: 1-4. costal cartilage, sternum, Insertion: bends with m. supraspinatus and shoulder fascia, Action: suspension of the trunk

m. subclavius

ARTICULATIONES MANUS EQ • ARTICULATIO CARPI- art. composita movement: flexion, extension common fibrosal layer, but synovial layer inserts on all carpal rows, forming separate joints  Lig. collaterale carpi laterale- between proc. styloideus lat. and os carpi ulnare, also os carpale IV and metacarpus  Lig. collaterale carpi mediale- between proc. styloideus med. to os carpi radiale, also os carpale II and metacarpus • 1. Articulatio antebrachiocarpea (=articulatio radiocarpea) joint between the trochlea radii and proximal row of carpus movement: flexion, extension mainly, little side movement is possible if the joint is flexed, 90 degree of flexion is allowed Capsula articularis –very spacious Recessus lateropalmaris  no dorsal ligament! (Lig. radiocarpeum dorsale is not present)  Lig. radiocarpeum palmare (from crista transversa of radius to os carpi radiale) • 2. Articulatio mediocarpea joint between proximal and distal row of carpal bones movement: extension, flexion, 45 degree of flexion is allowed Capsula articularis- less spacious Communication between art. mediocarpea and art. carpometacarpea (between os carpale III and os carpale IV+V)!  Lig. carpi radiatum- palmar fibers diverging from os carpale III. (Previous nomenclature: lig. carpi palmare prof=lig. radiocarpeum palmare+ lig. carpi radiatum) • 3. Articulationes carpometacarpeae- amphiarthrosis joints between distal carpal bones and basis of metacarpal bones movement: very limited movements possible Capsulae articulares- tight  Ligg. carpometacarpea dorsalia  Ligg. carpometacarpea palmaria • Articulationes intercarpeae-joints between carpal bones  Ligg. intercarpea dorsalia  Ligg. intercarpea palmaria  Ligg. intercarpea interossea •Articulatio ossis carpi accessorii- joints between os carpi accessorium and other bones Capsula articularis  Lig. accessorioulnare- from os carpi accessorium to radius (processus styloideus lateralis)  Lig. accessoriocarpoulnare- from os carpi accessorium to os carpi ulnare  Lig. accessorioquartale- from os carpi accessorium to os carpale IV+V  Lig. accessoriometacarpeum- from os carpi accessorium to metacarpus

• ARTICULATIONES METACARPOPHALANGEAE=FETLOCK JOINT- art. composita, hinge joint joints between metacarpal bone and proximal phalanx and proximal sesamoid bones movement: flexion and extension mainly, minimal side movement when in extreme flexion HYPEREXTENSIO! Capsulae articulares Recessus: recessus dorsalis, recessus palmaris  Ligg. collateralia (mediale/laterale)  Sesamoid ligaments (arrangement of the sesamoid ligaments function as a suspensory or stay apparatus for the fetlock joint during hyperextension)  PROXIMAL SESAMOID LIGAMENT:  1. M. interosseus medius- fully tendinous, comes from the basis of the metacarpal bones inserts on the proximal sesamoid bones, giving tractus appositus toward m. extensor digitorum communis, the tractus appositus is a part of the passive stay apparatus o 2. Lig. metacarpointersesamoideum- between lig. palmare and os MCIII  MIDDLE SESAMOID LIGAMENT: o 3. Ligg. palmaria- transverse fibers between the proximal sesamoid bones, but extends beyond them in Un o 4. Ligg. sesamoidea collateralia- connects each proximal sesamoid bones to metacarpus, and Ph1  DISTAL SESAMOID LIGAMENT: o 5. Lig. sesamoideum rectum- from proximal sesamoid bones to the Ph2 (5a. superficial band) and to Ph1 (5b. deep band), also called Y ligament o 6. Ligg. sesamoidea obliqua- from proximal sesamoid bones to Ph1, also called V ligament o 7. Ligg. sesamoidea brevia- from the distal border of the sesamoid bone to Ph1 o 8. Ligg. sesamoidea cruciata- crossing fibers from the distal border of the sesamoid bones to Ph1, also called X ligament

•ARTICULATIONES INTERPHALANGEAE PROXIMALES MANUS=PASTERN JOINT- articulatio sellaris (saddle joint) joint between proximal and middle phalanges movement: extension, flexion mainly, minimal rotation and side movements Capsulae articulares Recessus: recessus dorsalis, recessus palmaris  Ligg. collateralia  Ligg. palmaria • ARTICULATIONES INTERPHALANGEAE DISTALES MANUS=COFFIN JOINT- articulatio composita, articulatio sellaris (saddle joint) joint between middle and distal phalanges, distal sesamoid bone movement: extension, flexion mainly, minimal side movements Capsulae articulares Recessus: recessus dorsalis, recessus palmaris Bursa podotrochlearis (!)- between os sesamoidea distale and tendon of m. flexor dig. profundus  Ligg. collateralia  Ligg. dorsalia  Sesamoid ligaments: o 1. Ligg. sesamoidea collateralia o 2. Lig. sesamoideum distale impar [=lig. naviculare distale]- connects os sesamoideum distale and Ph3  Ligaments of the cartilago ungularis: o Ligg. chondrocompedalia o Ligg. chondrocoronalia o Ligg. chondrosesamoidea o Ligg. chondroungularia collateralia o Ligg. chondroungularia cruciata

ARTICULATIONES MANUS BO

 1. Lig. intersesamoideum interdigitale- between the axial sesamoid bones  2. Lig. phalangosesamoideum interdigitale- between Ph1 of one digit and the axial sesamoid bone of the other  3. Lig. interdigitale proximale-between proximal phalanges of digit III and IV.  4. Lig. interdigitale distale- between Ph2 of one digit and os sesamoideum distale of the other

FASCIAL STRUCTURE (all species)  fascia carpi o Retinaculum flexorium- thickening of the deep carpal fascia palmarly, it’s fibers are running transversally to fix the flexor muscle tendons o Retinaculum extensorium- thickening of the deep carpal fascia dorsally, it’s fibers are running transversally to fix the extensor muscle tendons o Canalis carpi- canal between the proximal row of carpal bones and retinaculum flexorium. Through the carpal canal run the tendons of the digital flexors (within the vagina synovialis communis musculi flexorii), vessels, nerves  fascia digiti

CARPAL EXTENSORS (Ca) m. extensor carpi radialis m. extensor carpi ulnaris

17. M. extensor carpi radialis o Origin: lateral epicondylar (supracondylar) crest of humerus o Insertion: Mc. II-III. (dorsal surface of metacarpals’ bases) o Action: strongest extensor of carpal joint

18. M. extensor carpi ulnaris It’s also called m. ulnaris lateralis o Origin: lateral epicondyle of humerus, behind collateral ligament o Insertion: lateral aspect of Mc. V. base, and also attaches with a short and strong tendon to accessory carpal bone o Action: supports carpus when extended to bear weight, also helps in flexion, abduction and lateral rotation of carpal joint since its attachment to os carpi accessorium

CARPAL FLEXORS (Ca) m. flexor carpi radialis m. flexor carpi ulnaris (caput humerale et ulnare)

19. M. flexor carpi radialis o Origin: medial epicondyle of humerus, behind collateral lig. o Insertion: Mc. II-III. (palmar surface of metacarpals’ bases) o Action: flexes carpus

20. M. flexor carpi ulnaris o Origin: its 20a.caput humerale starts medial epicondyle of humerus, 20b. caput ulnare from proximal end of ulna (humeral head is muscular, ulnar head is thinner and more tendinous) o Insertion: accessory carpal bone o Action: flexes carpus

DIGITAL EXTENSORS OF THE FORELIMB (Ca) m. extensor digitorum communis, m. extensor digitorum lateralis m. extensor digiti I. et II. m. abductor digiti I. [pollicis] longus 21. M. extensor digitorum communis o Origin: lateral epicondyle of humerus o Insertion: proc. extensorius of distal phalanx of digits II-V. o Action: extends carpus and joints of digits II-V.

22. M. extensor digitorum lateralis o Origin: lateral humeral epicondyle, lig. collaterale laterale o Insertion: goes to digits III-V., at the level of first digit it unites with tendons from common digital extensor and interosseous muscles, inserts on distal phalanx (proc. ext.) o Action: extends carpus and joints of digits III-V.

23. M. extensor digiti I. et II. [pollicis et indicis] o Origin: middle third of ulna (laterally) (adjacent to m. abductor digiti I. longus) o Insertion: pollicis: head of Mc. I., indicis: unites with common digital extensor, thus together are inserting on distal phalanx of digit II. o Action: extends digits I-II., indicis adducts dew claw (which is not in contact with the ground)

24. M. abductor digiti I. [pollicis] longus o Origin: adjacent lateral surface of radius and ulna, and from interosseous membrane o Insertion: Mc. I. base (medially) o Action: extends and abducts digit I.

DIGITAL FLEXORS OF THE FORELIMB (Ca) m. flexor digitorum superficialis m. flexor digitorum profundus (caput humerale, radiale et ulnare)

25. M. flexor digitorum superficialis o Origin: medial epicondyle of humerus o Insertion: middle phalanx of digits II-V. (palmar surface) o Action: flexes carpus and affected joints of digits II-V.

26. M. flexor digitorum profundus o Origin: 26a. caput humerale from medial epicondyle of humerus, 26b. caput radiale proximo-medially from radius, and 26c. caput ulnare proximo-caudally from ulna o Insertion: distal phalanx of digits I-V. (palmar surface, on the last phalanges’ flexor tubercle) o Action: flexes carpus and joints of digits I-V. Vagina synovialis communis mm. flexorium- around the flexor tendons, at the level of the carpus 13

PRONATORS OF THE FORELIMB (Ca) movement: rotating the limb inward m. pronator teres m. pronator quadratus

27. M. pronator teres o Origin: medial epicondyle of humerus o Insertion: craniomedial surface of radius’ upper part o Action: pronates forearm (rotates arm medially)

28. M. pronator quadratus o Origin and insertion: connects apposed surfaces of radius and ulna, fills interosseous space (medially) o Action: pronates forearm (rotates arm medially)

SUPINATORS OF THE FORELIMB (Ca) movement: rotating the limb outwards m. supinator m. brachioradialis

29. M. supinator It’s also called m. supinator brevis o Origin: lateral epicondyle of humerus, lateral collateral ligament o Insertion: cranial surface on proximal part of radius o Action: supinates forearm and forefoot (rotates arm laterally)

30. M. brachioradialis It’s also called m. supinator longus. Just about 33% of the dogs have it o Origin: lateral supracondylar crest, above m. ext. carpi radialis o Insertion: distally and medially on radius o Action: supinates forearm and forefoot (rotates arm laterally)

INTERSPECIES DIFFERENCES; EQ

 m. flexor carpi ulnaris- not divided, two heads unite  m. pronator teres, m. pronator quadratus, m. brachioradialis, m. supinator- not present  m extensor digitorum communis- has a caput accessorium (formely it was called muscle of Thiernesse)  m. extensor digitorum lateralis- has a caput accessorium (formely it was called muscle of Phillips)  m. flexor digitorum superficialis- there is ligamentum accessorium(!) (or proximal check ligament) coming from the distal portion of radius to m. flexor dig. superficialis, the ligament is a part of the passive stay apparatus  m. flexor digitorum profundus- caput ulnare is mostly tendinous, there is ligamentum accessorium(!) (or distal check ligament) joining to m. flexor dig. profundus, which is the fibrous continuation of the palmar carpal ligament and a part of the passive stay apparatus  the two digital flexor tendons are surrounded by vagina synovialis communis musculi flexorii proximalis at the carpal joint, and vagina synovialis communis musculi flexorii distalis at the fetlock joint  m. interosseus medius- fully tendinosus, next to metacarpal bone, it gives tractus appositus towards the tendon of m. extensor dig. communis

Three fibrocartilaginous surfaces providing gliding surface for the digital flexor tendons:  Scutum proximale- fibrocartilaginous surface of lig. palmare for the digital flexor tendons  Scutum medium- fibrocartilaginous surface at Ph2 palmar, proximal side for the digital flexor tendons  Scutum distale- fibrocartilaginous surface at the distal sesamoid bone on the palmar side for the deep digital flexor tendon

Elements of passive stay apparatus: The passive stay apparatus is a group of ligaments, tendons and muscles which "lock" major joints in the limbs of the horse. It is best known as the mechanism by which horses can enter a light sleep while still standing up.  lacertus fibrosus  m. interosseous medius + tractus appositus  supf. + deep dig. flexor with lig. accessorium (proximal, distal check ligaments)  suspensory apparatus (fetlock)

Three transversal palmar ligaments hold the flexor tendons in place:  Ligamentum anulare palmare  Ligamentum anulare digitale proximale  Ligamentum anulare digitale distale