ns 3 9090 013 413 154 Wsbstsr Family Library of Veterinary Medicine Cumm.ings School of Veterinary Medicine at Tufts University 200 Wsstboro Road Mnrthf^raftnn. MA01538 Ligaments and Muscles = OF THE HORSE. BY S. SISSON, V.S., Demonstrator of Anatomy, Ontario Veterinary College, Toronto, Canada. Toronto: J. A. CARVETH & CO. 1895.' Entered according 1 o -Act of Parliament of Canada, in the year one thousand eight hundred and ninety-four, by J. A. Carveth, at the Department of Agriculture, Ottawa. PREFACE. Q (^ Q Q In the following pages an attempt is made to gi\'e the principal ligaments and skeletal muscles of the horse in a condensed and sim- plified form. Consequently, the smaller ligaments of the complex joints have been entirely omitted. The muscles of the eye, ear, larnyx, etc., have also been omitted, as belonging more properly to the description of the special organs with which they are connected. INDEX ® d d e LlUAMENTS : PAG^E 1.5 " of elbow " of fetlock " of hock 14 16 22 Antero-lateral of coffin-joint Arciform Astragalo-metatarsal 18 15 23 11 23 Capsular, chondro-stemal 13 hip 20 21 ■' inter-transverse lumbar 10 " intervertebral 9 14 •' sacro-iliac. 19 12 Chondro-xiphoid. 13 Costo-transverse 12, 13 12 Cotyloid .... 20 Crucial 21 Inferior common " sacro-iliac " sesamoidean 9 19 17 12 Interoaseus, of coffin -joint.. .. . . 18 " radio-ulnar ' ' tibio-fibular . Intersesamoidean 14 22 17 Interspinous 10 Intertransverse Intervertebral substance Lateral of elbow femoro-patellar femoro-tibial , 9 9 14 21 20 of fetlock . 16 " of knee , 15 '' of pastern sesamoidean ' ' of hock Ligamentum nuchae " teres Occipito-atloid 17 17 22 10 20 11 Patellar. 21 Posterior, femoro-tibial , 21 22 ** of knee. ... lo ' ' temporo-m axillary Postero-lateral of coffin-joint ............ 18 Pubio-femoral 20 VI INDEX, Ligaments — Continued. page Round 20 Sacro-Sciatic 19 Stellate 12 Straight, patellar 21 Styloid 11 Subcarpal, (or check) ' 15 Subflava 10 Subtarsal, (or check) 23 Superior, common 9 " Sacro-iliac 19 " Sesamoidean 16, 17 Supraspinous 10 Suspensory 16, 17. Tarsometatarsal 23 Transverse, (of hip) 20 Muscles : Adductor brevis 52 longus 52 *' magnus 51 Anconeus 44 Antea spinatus . . : 42 Anterior deep pectoral 37 " superficial pectoral 37 Biceiw rotator tibialis 51 Buccinator 33 Caput magnum 44 " medium 44 ' ' parvum 44 Complexus 27 Compressor coccygis 32 Coraco-humeralis 43 Coraco-radialis . . 43 Curvator coccygis 32 Deltoid 42 Depressor labii inferioris 33 " labii superioris 34 " coccygis 32 Diaphragm 31 Digastricus 35 Dilatator naris inferior. 34 ' ' naris lateralis 34 " naris superior 34 ' ' naris transversalis 34 Erector coccygis .... 32 Extensor metacarpi magnus '. . . . 45 " *' obliquus 45 " pedis (fore-limb) 45 " " (hind-limb) 53 " " brevis 56 " suffraginis 46 INDEX. Vll Muscles — Continued. page External intercostal 38 " pterygoid 35 Flexor metacarpi externus 46 " " " internus 46 " " medius 46 " metatarsi 54 " pedis accessorius 56 " pedis perforans, (fore-limb) 47 (hind-limb) 55 " perforatus, (fore-limb) 47 (hind-limb) . Gastrocnemius 55 Gemellus ^ 53 Genio-hyoideus 36 Glutei , 49 Gracilis 52 Humeralis obliquus 43 Hyoideus parvus 36 Hyoideus transversus 37 Iliacus 30 Internal intercostal 38 " pterygoid 35 Interossei 48 Intertransversales colli 26 " lumborum 30 Ischio-f emoralis .' 52 Lateralis sterni 39 Latissimus dorsi 28 Levatores costarum 39 Levator humeri 24 " labii superioris alaeque nasi 33 " " " proprius 33 " menti 33 Longissimus dorsi 29 Longus colli 26 Lumbrici 48 Masseter 34 Mylo-hyoideus 36 Oil luus abdominis externus ... 40 " " internus 40 ' ' capitis anticus 27 " *• posticus 28 Obturator externus 52 ' ' internus 53 Occipito-styloideus 36 Orbicularis oris 32 Panniculus 24 Pectineus 52 Peroneus 54 Popliteus 55 Vlll INDEX. Muscles -Continued. pa6e Postea-spinatiis 42 Posterior, deep pectoral 08 " superficial pectoral 37 Psoas magnus. ... 30 " parvus 30 Pyriformis ;")3 Quadratus luniljorum 30 Rectus abdominis 40 " capitis anticus major 25 ** " " minor 25 " " lateralis 25 " ' ' posticus major 28 " " " minor 28 '' femoris . . ; 50 ■ ' parvus 50 Retractor costse 41 RhomboideuR 2(i Sartorius 51 Scalenus 25 Scapulohumeralis posticus 43 Scapulo-ulnaris 44 Semimembranosus 51 Semitendinosus 51 Serratus anticus 29 ' ' maernus 38 ' ' posticus 2J> Soleus 55 Spinalis colli 27 Splenius -7 Sterno-maxjllaris 25 Sterno-thyro-hyoideus 25 Stylo-hyoideus 3H Stylo-maxillaris 35 Subscapularis - 43 Subscapulo-hyoideus 25 Superfic alis costarum 29 Temporalis 35 Tensor fascia latae 49 Teres major 43 minor 42 Trachelo-mastoideus .... 27 Transversalis abdominis 41 ' ' costarum 29 Trapezius cervicalis 26 '* dorsalis 28 Triangularis sterni 39 Triceps abductor femoris 51 " cruralis 50 " e.xtensor brachii 44 Vastus extemus. 50 " internus 50 Zygomaticus 33 LIGAMENTS AND MUSCLES OF THE HORSE- PART I. LIGAMENTS. VERTEBRAL LIGAMENTS. A. Ligaments of the Bodies. L Superior Common.— This ligament is riband-like, and is at- tached to the superior surface of the bodies of the vertebnis from the axis to the sacrum. It is widened where it passes over the intervertebral discs, to which it is attached, and narrowest over the middle of the vertebral bodies. 2. Inferior Co/w/uon. — Is attached to the under surface of the bodies of the vertebrae, from the 6th dorsal to the sacrum. At first cord like, it gradually expands and becomes c n- tinuous with the pelvic ligaments. 3. Intervertebral Discs.— These are placed between the extrem- ities of the bodies of adjacent vertebr^^, and are comi^osed of fibrous tissue and fibro-cartilage. They are thinnest in the dorsal region, and that between the last lumbar and the sacrum is the thickest. B. Ligaments of the Oblique Processes. Capsular.— These are attached round the diarthrodial facets of adjacent processes, and are yellow-elastic in the cervical region, white-fibrous in the dorsal and lumbar regions. 10 LIGAMENTS AND MUSCLES OF THE HORSE. C. Ligaments of the Transverse Processes. 1. Inter-Transverse. — Extend between the borders of the trans- verse processes of adjacent vertebrae. 2. Capsular. — These surround the joints formed by the facets on the transverse processes of the 4th and 5th, and 5th and 6th lumbar, and between the last and the l)ase of t^e sacrum. D. Ligaments of the Spinous Processes. 1. Suj^rasfAnous. — Composed of two portions : — {a) Ligamentum nucha? (yellow elastic). Cordiform portion, attached to the first three dorsal spines and to the occipital tuberosity. Lamellar portion, its tibres are attached above to the first three dorsal spines and to the cordiform portion, below to the spinous processes of the ]ast six cervical vertebrae. {h) Dorso Lumbar. — (White fibrous).— Extends along vertebral spines from 4th dorsal to sacrum. 2. Inttrsinnous. — Extend between the borders of the spinous processes of adjacent vertebne. ( Yellow elastic in the cervical region.) E. Ligaments of the Arches. Ligamenta suhflava. — Extend Ijetween the arches of adjacent vertebrae. (Yellow elastic in the cervical region.) Sacro-coccygeal and Inter-coccygeal.— These are connected by 1. It ter vertebral Discs. — Small and biconcave. 2. Fibrous *>/i«rt^/<6\ — Which may be considered to represent the superior and inferior common ligaments of the back and loins. Synovial Membranes. These are found lining the capsular ligaments of the joints formed by the oblique processes ; also surrounding the jrnnts formed by the transverse processes of the 4th and LIGAMENTS AND MUSCLES OF THE HORSE. 11 5th, and 5th and 6th, lumbar vertebra? ; and between the last and the sacrum. In old subjects, however, these latter joints have frequent- ly become anchylosed. Movements. These are flexion, extension, lateral inclination and rotation. They are best seen in the cervical region. Rotation is ab- sent in the lumbar region, and very slight in the dorsal region. OCCIPITO-ATLOID. 1. Capsular. — Attached around the condyles of the occiput and the anterior border of the atlas. 2. Cruciform.— Formed by the superior fiV)res of the capsular which intercross. 3. Styloid. — Lateral thickenings of the capsular, attached to the styloid processes of the occipital. Synovial Membranes. There are two of these, each belonging to an occipital condyle and its corresponding cavity, on the anterior part of the atlas. Each is related on its inner side to the dura mater and odontoid ligament, and on its outer side to the capsu- lar ligament. Movements. These are flexion and extension (nodding of the head). Atlo-axoid. 1. Capsidar — A membranous ligament connecting the articu- lar surfaces, having superior, inferior, and lateral thick- enings. 2. Odontoid. — Flat and triangular in shape, is attached behind to the depression on the upper surface of the odontoid process, in front to the floor of the atlas, and to the lateral edges of the foramen magnum. 12 LIGAMENTS AND MUSCLES OF THE HORSE, Synovial Membrane. There is a single synovial sac for this joint. Movements. Rotation, in which the axis remains fixed, and the atlas rotates around the odontoid process, carrying the head with it. Temporo-maxillary Articulation. Ligaments. Capsular.— This is membranous, and is attached above, around the articular surface of the temporal bone ; below, around the condyle of the inferior maxilla. Thickenings of the capsular are sometimes designated pos- terior and external ligaments. Inter-articular fibro-cartilage.— A disc of fibro-caitilage inter- posed between the joint surfaces. Synovial Membranes. Two in number, one above, the other below the cartilage. Movements. Depression, elevation, protraction, retraction and lateral move- ment of the inferior maxilla. Ligaments of the Ribs. A. Costo-Vertebral. (a) Costo-Central. L Inter articular. — Attached in the groove on the head of each rib, and to the upper border of the intervertebral disc, meeting the ligament of the opposite side at the median line. 2. Stellate.— Atis^ohed to the rib just below the head, to the bodies of the vertebrae in front and behind, and to the intermediate disc. {h) Costo-transverse. Anterior. LIGAMENTS AND MUSCLES OF THE HORSE. 13 Posterior. — Bands stretching across the joint before and behind, being attached to the neck of the rib and the transverse process. B. Chondro-costal.— Continuity of the periosteum and perichon- drium. C. Chondro-sternal. Capsular. Superior and l7iferior — Merely thickenings of the capsular above and below. Cartilage of the 9th rib. — Attached to the preceding cartilage by fibrous bands, also to the ensiform cartilage of the sternum, by the chondro-xiphoid ligament. The succeed- ing cartilages are attached each to the posterior edge of the cartilage in front by fibro-elastic bands. Synovial Membranes. In the costo-central joint there are two sacs, separated by the interarticular ligament, except in the first, which has a single sac. In the costo-trans verse joint there is a single sac. But in the last two or three there is no separate sac, as the two joint cavities are continuous. In the 8 chondro-costal joints there are synovial sacs, the first pair having a common sac. Movement. Rotation. In inspiration, the rib moves forwards and outwards, in expiration, it returns to its former position. Note. — There are no movable joints in the sternum of the horse, the segments being united by persisting cartilage. There are, however, two fibrous cords (suprasternal ligaments) on the lateral borders of its upper surface. 14 LIGAMENTS AND MUSCLES OF THE HORSE. ANTERIOR LIMB. Shoulder Joint. (Scapulo-hiimeral.) Ligament. Cwpsular. — This is the only ligament of this joint. It is at- tached around the glenoid cavity of the scapula above, and the head of the humerus below. It is a loose sac and comparatively thin, except in front, where it is reinforced by fibres passing from the coracoid process to the inner and outer lips of the bicipital groove. Synovial Membrane. This is single, and lines the capsular ligament. Movements. Extension, flexion, adduction, abduction, circumduction, and rotation. Note. — The absence- of binding ligaments is fully compensated for by the numerous tendons and muscles surrounding the joint. These are the antea-spinatus, postea-spinatus, flexor brachii, teres minor, caput magnum, and the subscapularis. Atmospheric pressure is of undoubted assistance also. ELBOW JOINT. A. Humero-radial. 1. Anteiior. — Membranous, being attached above to the hum- erus, below, to the radius. 2. Internal lateral. — Attached above to a small eminence on the inner side of the distal extremity of the hunjerus, be- low, to the radius just below the bicipital tuberosity. 3. External lateral.— Y'lKed. above to a depression on the outer side of the lower extremity of the humerus, below, to the external tuberosity of the radius. B. Radioulnar. 1. liiternsseus. — Those below the radio-uhiar arch being ossified in the adult. LIGAMENTS AND MUSCLES OF THE HORSE. 15 2. Arciform. — These pass from the lateral surfaces of the ulna to blend with the lateral ligaments. Synovial Membrane. There is a single synovial membrane. It is supported in front by the anterior ligament, and laterally by the lateral liga- ments, but posteriorly it is in relation to the anconeus muscle. It sends a process upwards into the olecranon fossa, and two downwards to lubricate the small facets be- tween the radius and ulna. Movements. Flexion and extension. (Movement between the radius and ulna is inappreciable.) In flexion, the forearm deviates a little outwards. Exten- sion is limited by the beak of the olecranon and by the tension of the lateral ligaments. KNEE JOINT. 1. Anterior Co/?i»>ton.— Membranous.— Attached above to the radius, below, to the metacarpal, blending laterally with the lateral ligaments. 2. Posterior Common.— yinch thicker than preceding. At- tached in a similar way, its anterior surface being intim- ately united to the carpal bones. 3. Internal Za^em^.— Attached above to the internal eminence of the radius, below, to the large and small metacarpals, giving slips to the bones over which it passes 4. External Lat^.ral. — Attached above to the external eminence, of the radius, below, to the external small metacarpal, giv ing slips to the cuneiform and unciform. {Check Liyunent.— This is a strong fibrous band, and is a con- tinuation of the posterior common ligament of the carpus. It joins the tendon of the flexor pedis perforans near the middle of the metacarpus.) 16 LIGAMENTS AND MUSCLES OF THE HORSE. Synovial Membranes. These are three in number : — (a ) Radio-carpal. — Which lubricates the joint between the radius and the upper row of carpal bones, also descending between the latter. (6.) Intrr-carpal. — Which lubricates the joint between the two rows, and has prolongations upwards and downwards be- tween the bones. It communicates with the (c.) Carpo-meiacaipal. — Which lubricates the joint between the lower row and the heads of the metacarpals, sending pouches down for the facets on tlie large and small meta c irpals. Movements. riexi >n and extension. When the limb is flexed, also abduc- tion and adduction. The movement is principally at the r-sciatic ligament. It transmits the great sciatic nerve, and gluteal vessels and nerves. 2. Lesser Sacro-sciatic. — Is formed by the lower border of the sacro-sciatic ligament, and the external border of the is- chium ; transmits the common tendon of the obturator in- ternus and pyriformis muscles. Synovial Membrane. This is rudimentary. Movement. Scarcely appreciable. 20 LIGAMEXTS AXD MUSCLES OF THE HORSE. HIP-JOINT. 1. Capsular. — Attached above to the rim of the cotyloid cavity, and to the cotyloid ligament ; below, around the head of the femur. '2. Cotyloid. — Consists of a ring of tibro-cartilage attached around the rim of the cotyloid cavity, which it deepens. 3. Traisverse. —Is that part of the preceding which bridges over the cotyloid notch. 4. I'lihiojemoral. —Attached in the sulcus on the head of the femur ; it passes inwards in the sub-pubic groove, blending with the prepubic tendon and its fellow of the opposite side (the fibres intercrossing). 5. Round {llgamentiun teres \. — Attached below to the sulcus on the head of the femur, above, to the rough depression of the cotyloid cavity (non-articular portion). Synovial Membrane. This completely lines the capsular ligament, and is also reflected on the pubio-femoral and round ligaments. Movements. This joint admits of more extensive movements than any other in the limbs. These are flexion, extension, abduction, ad- duction, circumduction, and rotation. Abduction is re- stricted by the pubio-femoral ligament, which is absent in the other domesticated animals. STIFLEJOINT. A. Femoro-tibial Ligaments. 1. Lateral. — {a) Internal. — Attached above to a tubercle on the internal condyle of the femur, below, to the internal tuberosity of the tibia. lb) External. — Attached above to a depression on the external condyle of the femur, below, to the head of the fibula. LIGAMENTS AND MUSCLES OF THE HORSE. 21 2. Pos^eWor.— Membranous. Attached above to the posterior surface of the femur above the condyles, below, to the tibia just below its articular surface, blending laterally with the lateral ligaments. 3. Cmcm/.— These are two fibrous cords crossing each other, named anterior and posterior. The anterior is attached above in the intercondyloid groove, below, to the tibial spine ; the posterior, also attached above in the groove, passes downwards and backwards, to be inserted to a tubercle on the posterior border of the tibial articular sur- face. {Semihinar Cartilayes.— These are crescent- shaped, each having a flat, inferior surface, resting on the tibial facet, a con- cave upper surface, related to the condyle of the femur, a convex, thick, outer border, and a concave, thin, inner border, embracing the tibial spine The inner one is held in position by two bands, the outer by three, constituting the so-called coronary ligaments. ) B. Femoro-patellar. 1. Capsular.— Attached around the articular surface of the patella and the trochlea of the femur. 2. Lateral— Thickenings of the capsular ligament on each side. C. Patellar. 1. Internal Straight.— Attached to the internal border of the patella and inner side of anterior tuberosity of the tibia. This ligament has a fibro- cartilaginous thickening which enlarges the articular surface of the patella. 2. Middle Straight— Attached to apex of patella and a groove on the anterior tuberosity of the tibia. 3. External Straight - Attached to external border of patella and outer side of anterior tuberosity of the tibia. Note.— These may properly be considered continuations of the triceps crural is. 22 LIGAMENTS AND MUSCLES OF THE HORSE. TiBio-FiBULAK Joint.— United by 1. Peri/Jierrd Fibres. — Surrounding the joint. 2. Interosseous Fibres. — Extending across the tibio-fibular arch. Synovial ^Iembranes. These are three in number. The tirst lubricates the joint be- tween the femoral trochlea and the patella. It lines the capsular ligament and protrudes upwards undei- the triceps. Below it touches and sometimes communicates with the synovial membranes of the femoro-tibial joint. The other two membranes lubricate the femoro-tibial joint. They are separated by the crucial ligament, and a quantity of fat separates them from the straight patellar ligaments. The external sac also pouches downwards, investing the tendon of origin of the popliteus, and the common tendon of the flexor metatarsi and extensor pedis muscles. Movements (of the joint as a whole. ) These are flexion and extension, with slight lateral movement and rotation when the joint is flexed HOCK-JOINT. 1. Anterior (membranous). —Attached above to the tibia, below, to the astragulas, cuneiform magnum and medium, and the astragalo-metatarsal ligament, blending laterally with the lateral ligaments. 2. Posterior {membranons). —Attached above to the tibia, below, to the astragalus and oscalcis, blending laterally wdth the lateral ligaments. 3. Internal /a^emZ.— Attached above to the internal malleolus of the tibia, below, to the large and inner small metatarsals, and to the bones it passes over. 4. External /a^emZ. —Attached above to the external malleolus of the tibia, below, to the large and outer small metatarsals, and the bones over which it passes. LIGAMENTS AND MUSCLES OF THE HORSE. 23 4. Astragal 0-metatarsal. - Attached above to a tubercle on the inner side of the astragalus, and, widening below, is attached to the cuneiform magnum and medium, and large metatar- sal bones. 5. Tarso-metatarsal. - Is a thick mass of fibrous tissue covering the posterior surface of the hock, blending inwardly with the lateral ligament, outwardly with the calcaneo-cuboid ligament. Below, it is continued to form the check-ligament. 6. Calcaneo-cuboid (or C alcaiieo-metatarsal). —Atta^ched to the posterior border of the oscalcis, the cuboid, and the outer small metatarsal. J^ote. This ligament is affected in curb. Synovial Membranes. These are three in number. The first (and most important) lubricates the joint between the tibia and astragalus. It is supported by the anterior, posterior, and lateral liga- ments. When distended (as in bog-spavin), it causes the anterior ligament to bulge out at the antero-intemal part of the joint. The second lubricates the joint between the astragalus and OS calcis above, and the cuneiform magnum and cuboid below. It has prolongations above, in front, and below. The third supplies the joint formed between the cuboid, cuneiform medium and parvum aV)Ove, and the three meta- tarsals below. It descends to supply the facets of the large and small metatarsals. Movements. Flexion and extension. ]\Tofe. — For a detailed description of the synovial apparatus, the student is referred to Chauveau. 24 LIGAMENTS AXD MUSCLES OF THE HORSE- PART TT. riYOLOQY. Subcutaneous Region. Panniculus Carnosus. The facial portion consists of scattered bundles of fibres, best developed over the masseter muscles, being continued into the submaxillary space and over the parotid gland. Other fibres reach the angle of the mouth, which they retract. The cervical portion is attached below, to the cariniform cartil- age of the sternum. Here it is a thick band, but becomes thin anteriorly and superiorly! The thoracic portion consists of fibres running in a vertical dir- ection, covering the scapular region. The abdominal portion reaches from the groin to the elbow muscles, where it sends a tendon to be attached to the inner tuberosity of the humerus. The action of this muscle is to shake the skin, thus removing ofiending insects. INFERIOR CERVICAL REGION. 1. Levator Humeri. 6. Rectus capitis anticus minor- 2. Sterno maxillaris. 7. Rectus capitis lateralis. 3. S'erno-thyro-hyoifpAis. 8. Scalenus. 4. Snhscapulo hyoideus. 9. Longus colli. 5. Rectus capitis anticus major. 10. Intertransversales colli. 1. Levator Humerl Origin. — From the mastoid proc^ess, occipital crest, wing of the atlas and transverse processes of 2nd, 3rd, and 4th cervical vertebra^. LIGAMENTS AND MUSCLES OF THE HORSE. 25 Insertio7i. — To the deltoid ridge. ^c^ion. — Extension and inward rotation of shoulder joint ; if the limb is fixed, it bends the neck laterally. 2. Sterno-maxillaris. Origin.— Yrom the cariniform cartilage of the sternum. Insertion.— To the angle of inferior maxilla. Action. — Tog^iher they depress the head, singly, flex it laterally. 3. Sterno-thyro-hyoideus. Origin. — From the cariniform cartilage of sternum. Insertion.— To the thyroid cartilage of the larynx, and the body of hyoid bone. Action.— To depress the hyoid bone and larynx. 4. SUBSCAPULO-HYOIDEUS. Origin.— 'Fvom the fascia of the subscapularis muscle. Insertion. — To the body of the hyoid bone. Action. — To depress the hyoid bone. 5. Rectus Capitis Anticus Major. Origin. — From the transverse processes of the 3rd, 4th and 5th cervical vertebrae. Insertion. — To the tubercles at the junction of basilar process of occipital, and body of sphenoid. Action.— To^Qihev they depress the head, singly, flex it laterally. 6. Rectus Capitis Anticus Minor. Origin.— Yvom the lower part of the anterior border of atlas. Insertion. — with preceding muscle. Action. — ^3imQ as preceding muscle. 7. Rectus Capitis Lateralis. Origin. — From the atlas external to pseceding. Insertion.— To the styloid process of the occipital. Action. — Same as preceding muscle. 8. Scalenus. Origin. From the transverse processes of the last 4 cervical vertebrae. B 26 LIGAMENTS AND MUSCLES OF THE HORSE. Insertion. — To tlie external surface and anterior border of 1st rib, by two slips. Action. — To draw forward or fix the first rib, thus aiding in inspiration ; or, if the rib is fixed, to flex the neck or incline it to one side, according as the muscles act together or singly. 9. LoNGUs Colli Origin.— ^vom the bodies of the fii-st 6 dorsal vertebra?, and from the bodies and transverse processes of the last 6 cer- vical vertebn^. Insertion. — To the tubercle of the atlas. Action. — To bend the neck downwards. 10. Intertransvejisales Colll Consists of six bundles, each having Origin. — From the oblique piocess of one vertebra. Insertion. — To the transverse process of preceding vertebra. Action. — Lateral bending of the neck. SUPERIOR CERVICAL REGION. 1. Trapezius cei'vicalis, 6. Spinalis colli. '1. Rliomhoideus Loyigus. 1 . Ohliquus capitis anticus. 3. Spknius. 8. Obliquus capjitis posticus. 4 Cornple.rus (major). 9. Rectus ccqntis posticus major. 5. Trachelomastoideus. 10. Rectus capitis posticus tniiior. 1. Trapezius Cervicalis. Origin. — From the funicular portion of the ligamentum nuchae, as far forward as the 3rd cervical vertebra. Insertion. — To the tubercle on the spine of the scapula. Action. — It draws the scaj^ula forwards and upwards. 2. Rhomboideus Longus. Origin. — From the funicular portion of the ligamentum nuchae, as far forward as the axis. LIGAMENTS AND MUSCLES OF THE HORSE. 27 Insertion — To the antero-internal surface of the cartilage of prolongation. Action. — Draws scapula upwards and forwards. 3. Splenius. Origin. — From the funicular portion of the ligamentum nuchae and from the 2nd, 3rd, and 4th dorsal spines. Insertion. — To the mastoid crest, wing of the atlas and trans- verse processes of 2nd, 3rd, 4th and 5th cervical vertebrae. Action.— Acting together they elevate head and neck, singly, they incline these to one side. 4. COMPLEXUS. Origi7L. — From the spines of tlie 2nd, 3rd and 4th dorsal ver- tebrae, transverse processes of 1st six dorsal vertebne, and oblique processes of last six cervical vertebra^. Insertion. — To the occipital bone on each side of the tuberosity. Action. — Together, they extend the head ; singly, also turn it slightly to one side. 5. Trachelo-mastoideus. Origin. — From the transverse processes of the hrst two dorsal vertebne, and oljlique processes of last six cervical vertebrae. Inseition. — To the mastoid crest and to the w^ing of the atlas. Action. — Together, they extend the head ; singly, bend the neck laterally. 6. Spinalis Colli. Consists of live bundles. Origin. — From the oblique processes of the last live cervical vertebrae. Insertion. — To the spines of all the cei'vical except the fii'st and last. Action. — Together, they extend the neck; acting singly, they incline the neck to the opposite side. 7. Obliquus Capitis Anticus. Origin. — From the edge of the wing of the atlas. 28 LIGAMEN'TS AND MUSCLES OF TflE HORSE. Insertion. — To the mastoid crest, and styloid process of the occipital. Action. — To extend the head on the atlas. 8. Obliquus Capitis Posticus. Origin. — From the side of the spine of the dentata. Insertion. — To the superior surface of wing of atlas. Action. — To rotate the head around the odontoid process. 9. Rectus Capitis Posticus Major. Origin. — From the spine of the dentata. Insertion. — To the occipital bone beneath the complexus. Action. — To extend the head. 10. Rectus Capitis Posticus Minor. Origin. — Upper surface of the ring of the atlas. Insertion. — To the occipital bone beneath the preceding. Action. — Same as the preceding muscle. DORSO-LUMBAR REGION. 1. Trapezius dorsalis. 2. latissimiis dorsi. 3. Strratus anticios. ~\ . n u ^- f Super ficialis cos f arum. 4. >Se7'7rUus posticus. J ^ "^ 5. Longissinms dorsi. 6. Transversalis costaruni. 1. Trapezius Dorsalis. Origin. — From the summits of the 3rd to the 10th dorsal spines. hisertion. — To the tubercle on the spine of the scapula. Action. — It pulls the scapula upwards and backwards. 2. Latissimus Dorst. Origi7i. — From the supraspinous ligament, from the 4th dorsal to the last lumbar vertebra. Insertion. — To the internal tubercle of the humerus. Action. — Flexion and inward rotation of the shoulder joint. LIGAMENTS AND MUSCLES OF THE HORSE. 29 3. Serratus Anticus. Origin.— From the dorsal spines, 2n(] to 13th inclusive. Insertion.— To the anterior border and external surface of the nine ribs posterior to the 4 th. Action. — It assists in inspiration, by drawing the ribs forwards. 4. Serratus Posticus. Origin.— Yvom the last seven dorsal spines, and first two lum- bar. Insertion. — To the posterior border and external surface of last nine ribs. Action. — It assists in expiration. Note. — The two preceding muscles constitute the superficialis costarum of Strangeways. 5. LONGISSIMUS DoRSi. Origin. — From the inferior surface of the ilium anterir>r to the sacro- iliac articulation, first two bones of sacrum, dorsal and lumbar spines and supraspinous ligament Insertion. — To the transverse and oblique processes of the lum- bar, transverse processes of the dorsal, transverse and spinous processes of last four cervical, and external surface of last sixteen ribs. Action. — -Acting together, they are the great extensors of the vertebral column ; acting singly, it inclines the spine to the side of the acting muscle. It may also assist in expiration. 6. Transversalis Costarum. Origin.— 'Fyovh the transverse processes of the first two lumbar vertebrae, and from the anterior border of the ribs, near their angles. Insertion. — To the posterior border of the ribs, anterior to Ihe 14th, and to the last cervical transverse process. Action. — It draws the ribs backwards, thus assisting in expira- tion. 30 LIGAMENT>S AND MUSCLES OF THE HORSE. SUBLUMBAR REGION. 1. Psoas ma gnus. 4. Quadratus lumborum. 2. Psoas pai'viis. 5. Intertransversales lumborum. 3. Iliac lis. 1. Psoas Magxus. Origin. — From the inferior surface of the bodies of the last two dorsal vertebrae, last two ribs and transverse processes of lumbar, except the last. Insertion. — To the internal trochanter of the femur. Actio7i. — Flexion, and outward rotation of hip joint. If hind limb is fixed, both muscles will arch the loins ; or singly, incline the trunk to one side. 2. Psoas Parvus. Origin. — From the bodies of last four dorsal and all the lumbar vertebra^. Insert'* on — To the ilio-pectineal line. Action. — Both muscles flex the pelvis on the loins ; singly, cause lateral motion. 3. Iliacus. Ori^i?^.— From the venter surface and external angle of the ilium and sacro-iliac ligament. Insertion. — To the internal trochanter of femur. Action — Similar to Psoas Magnus. 4. QuADRATus Lumborum. Attachments. — To the tips of the transverse processes of the lumbar vertebrae, last three ribs, and sacro-iliac ligament. Action. — 'Sf it\\ muscles fix the last ribs and thus assist the diaphragm. Singly, lateral bending of the loins is pro- duced. T). Intertransversales Lumborum. These connect adjacent transverse processes, and assist preceding muscle. ]JGAMENTS AND MUSCLES OF THE HORSE. 31 The Diaphragm Consists of (a.) A tendinous centre. {h.) A fleshy rim. (c.) Two crara or pillars. The rim is attached to the ensiform cartilage of the sternum, and the cartilages of the false ribs (anteriorly), or to the rib above the chondro costal joint (posteriorly). The right crus (much the largest), is attached to the lumbar vertebra?, (blending with the inferior common ligament), and joins the tendinous centre. The left crus is smaller, and is attached to the first two lumbar vertebnv in a similar manner. The tendinous centre is composed of white glistening tibres which interlace. Foramina of Diaphragm. (a.) Hiatus Aorticus.^A notch between the two pillars, giving passage to the posterior aorta, vena azygos, and thoracic duct. {}>.) Foramen De,rtruui.-^it\xs.tQ& slightly to the right of the median plane, about the middle of the tendinous centre. It gives passage to the posterior vena cava, which is ad- herent to its margin. (c ) Foramen Sinistrum.-^h:^ is a slit in the fibres of the right crus, a little to the left of the median plane. Through it pass the oesophagus, oesophageal branches of the pneurao- gastric nerve, and the pleural artery. The sympathetic and splanchnic nerves pass to the abdomen above the crura, and underneath the psoas parvus muscles. Action of Diaphragm. -It is the principal muscle of inspiration, increasing the antero-posterior diameter of the Thorax. COCCYGEAL REGIOIS. 1. Erector coccygis. 3. Curvator coccygis. ^ '2. Depressor coceijgis. 4. Compressor coccygh. 32 LIGAMENTS AND MUSCLES OF THE HORSE. 1. Erector Coccygis. Origin. —From the sides and summits of the sacral spines. Insertion. — To the upper surface of the coccygeal vertebra?. Actio7i.— -Both elevate the tail ; acting separately, incline it to one side, and also elevate it. 2. Depressor Coccygis. Origin. — From the inferior surface of the sacrum as far forward as the 3rd foraDien. Insertion — To the inferior surface of the coccygeal vertebrae. Action. —Depression or lateral movement of tail. 3. CuRvAToR Coccygis. Origin. — From the last two lumbar spines and sacral spines. Insertion.— To the sides of the coccygeal bones. Action. — Lateral inclination of the tail. 4. Compressor Coccygis. 07'igin.— From the sacro-sciatic ligament and ischiatic ridge. l7isertion.— To the last sacral and first two coccygeal bones. Action. — It depresses the tail. FACIAL REGION. 1. Orbicularis oris. 7. Levator labii superioris alaegue 2. Zygomaticus. nasi. 3. Levator labii superioris 8. Dilatator naris lateralis, propius (nasalis longus.) 9. " " superior i. Depressor labii inferioris. 10. " " transversal is. 5. Levator menti. 11. " " inferior. 6. Buccinator. 12. Dej^ressor lahii superioris. Orbicularis Oris. This muscle is arranged in the form of a sphincter, its fibres circumscribing the opening of the mouth in an elliptical manner. Action — To close the lips. LIGAMENTS AND MUSCLES OF THE HORSE. 33 Zygoma Ticus. Origin. — From the surface of the masseter muscle. Insertion. — To the buccinator muscle just above the angle of the mouth. Action. — To raise the angle of the mouth. Levator Labii Superioris Proprius (nasalis longus.) Origin. — From the malar and superior maxillary bones below the orbit. Insertion. — To the upper lip. Action. — Together, they elevate the lip ; separately, raise and draw it to the side of the muscle acting. Depressor Labii Inferioris. Origin. — Yroxn. the edge of ramus of inferior maxilla behind last molar tooth. Insertion. — To the lower lip. Action. — To retract lower lip. Levator Menti (Levator labii inferioris.) Origin. —From the inferior maxilla below the intermediate and corner incisors, and as far back as the canine. Insertion.— \t mixes with orbicularis oris, and forms the pro- minence of the chin. Action. —To raise the lower lip. Buccinator. Attachments. — To the superior maxilla from the alveolus of the canine tooth, back to the alveolar tuberosity ; in a similar manner to the inferior maxilla ; anteriorily blending its fibres with those of the orbicularis oris. Action. — Principally to press the food between the teeth : but it may also retract the angle of the mouth. Levator Labii Superioris Al.eque Nasi. Origin. — From the frontal and nasal bones. I insertion. — To the nostril and upper lip. Action. — To dilate the nostril and raise the upper lip. 34 LIGAMENTS AND MUSCLES OF THE HORSE. 8. Dilatator Naris Lateralis. Origin.— From, the superior maxilki. Insei'tion. — To the nostril (broad part of alar cai'tilage) Action — To dilate the nostril. 9. Dilator Naris Superior. This muscle is composed of a few fibres arising from the extre- mity of the septum nasi, and terminating on the wall of the false nostril, and on the extremity of the superior tur- binated bo]ie. Action. — To dilate the false nostril. 10. Dilatator Naris Transveksalis. Composed of fi))res passing across transversely, to be attached on each side on the wide part of the alar cartilages. It dilates the nostrils. 11. Dilatator Naris Inferior. Orirjin. — From the nasal process of pi'emaxilla, and edge of superior maxilla adjacent. Insertion. — To the wall of the false nostril and the cartilaginous prolongation of the inferior turbinated bone. Action — To dilate the false nostril. 12. T)epressor Labii Superioris. Origin. — From the premaxilla above the interdental space. Insertion. — To the upper lip. Action. — To depress the upper lip. TEMPORO-MAXILLARY REGION. 1. Masseter. 4. Fterygoidens externns. 2. Temjjoralis. 5. Digastricus. 3. Fterygoidens internus. G. StyJo-nKc.rillaris. 1 . Masseter. Origin. — From the zygomatic ridge of the superior maxilla and malar. LIGAMENTS AND MUSCLES OF THE HORSE. 35 Insertion. — To the external surface of the ramus of the inferior maxilla. Action.— To raise the lower jaw, thus bringing the teeth strongly together. Temporalis. Origin. — Yvom the temporal fossa. Insertion. -To the coronoid process of the inferior maxilla. Action.— Chiefly to elevate the lower jaw ; or to oppose pro- trusion action of the external pterygoid. Also to cause lateral motion. Pterygoideus Internus. Origin.— From a rough crest formed by the palatine bone and the pterygoid process of the sphenoid. Insertion.— To the excavated internal sui-face of the ramus of the inferior maxilla, ^c^zon.— Together, they elevate the lower jaw ; singly, produce lateral movement. PTERYCiOIDEUS ExTERNUS. Oricjhi.—YYom the wing and pterygoid pi-ocess of the sphenoid. Insertion.— To the neck below the condyle of the inferior maxilla. Action.— A.cth\^ together, they protrude the lower jaw ; acting singly, the lower jaw is carried to the side opposite to the muscle acting. DiGASTRICUS. Oriyin.—¥vom the styloid process of the occipital, in common with the stylo-maxillaris. Insertion.— 'i'o the ramus of the inferior maxilla, near the sym- physis. Action.— To depress the lower jaw, and open the mouth. Stylo-maxillaris. Origin.— Fvom the styloid process of the occipital bone. Insertion.— To the angle of the inferior maxilla. Aciion.-To depress the lower jaw and open the mouth. 36 LIGAMENTS AND MUSCLES OF THE HORSE. HYOIDEAL REGION. 1. Mylo-hyokleus. 2. Genio-hyoideus. 3. Stylo-hyoideus (hyoideiis magnus). 4. Kerato-hyoideus (hyoideus parvus). 5. Occipi^o- stylo ideus (stylo-hyoideus). 6. Hyoideus transverstvs. 1 . Mylo-hyoideus. Origin. — From a line on tlic inner surface of tlie inferior maxilla near the alveoli. Inseriion.— To the body and spur process of the hyoid bone, and to a median fibrous raphe. Actio7i, — The two muscles form a sling for the tongue, which they raise in contracting. 2. Genio-hyoideus. Origin. — From the inner surface of the inferior maxilla, near the symphysis. Insertion. — To the spur process of the hyoid bone. Action. — To draw the hyoid bone forward. 3. Stylo-hyoideus. Origi7i. — From the posterior part of the great cornu of the hyoid bone. Insertion. — To the heel process of the hyoid bone. Action. — To elevate the base of the tongue and the larynx. 4. Kerato-hyoideus (or hyoideus parvus). Origin. — From the posterior edge of the small cornu, and the adjacent part of the great cornu of the hyoid bone. Insertio7i.-~ To the upper edge of the heel process. Action. — To elevate the larynx. 5. Occipito-styloideus. Origin. — From the styloid process of the occipital bone. LIGAMENTS AND MU8CLES OF THE HOUSE. 87 Insertion. — To the posterior extremity of the great cornu of hyoid bone. Action.— To retract the hyoid bone and attached structures. {Note. — This muscle covers the guttural pouch, and is perfor- ated in opening the pouch). 6. Hyoideus Transversus. An unpaired muscle stretching across the mediam line be- tween the small cornua of the hyoid bone, to which it is attached. Action. — To raise the root of the tongue. PECTORAL REGION. 1. Anterior superficial iw,ctoTal. 3. Anterior deep fector at. 2. Posterior superficial pectoral. 4. Posterior deep pectoral. 1. Anterior Superficial Pectoral (pectoralis anticus). Origin. — From the cariniform cartilage, and first two or three inches of inferior border of the sternum. Insertion. — To the deltoid ridge of the humerus. Action. — Adduction. 2. Posterior Superficial Pectoral (pectoralis transversus). Origin. — From the inferior border of the sternum, from within an inch of its anterior extremity back to the sixth costal cartilage. Insertion. — { Principally) to the fascia on the inner surface of the fore-arm, and by a small band to the deltoid ridge of the humerus. Action. — It adducts the fore-limb, and also tenses the fascia of the fore-arm. 3. Anterior Deep Pectoral (pectoralis parvus). Origin. — From the cartilages of the first four ribs, and the ad- jacent lateral surface of the sternum. Insertion. — To the fascia of the antea-spinatus muscle. Action. —To draw the scapula backwards and downwards. 38 LIGAMENTS AND MUSCLES OF THE HORSE. 4. Posterior Deep Pectoral (pectoralis magnus). Origin. — From the cartilages of 5th to 8th ribs (inchisive), and from the adjacent lateral surface of the sternum : also from the abdominal tunic. Insertiun. — To the inner trochanter of the humerus. Action. — To draw the shoulder joint and fore-limb backwards. COSTAL REGION. 1. Serratus AJaynns. 4, Levatores Costarum (17). 2. Exte7mal Inter Gostalsill). 5. Triangularis 8ter7ii. 3. Internal Intercostah (17). 6. Lateralis Sterrii. 1. Serratus Magnus. , Origin — From the outer surface of the eight true ribs, and from the transverse processes of the last five cervical vertebra. Insertion. — To two rough triangular surfaces on the upper part of the internal surface of the scapula. Action. — The two muscles form a sling to support the trunk. In contracting, it draws the upper extremity of the scapula downwards and backwards ; or, if the limb is fixed, it may act as a muscle of inspiration. 2. External Intercostals. Each of these occupies an intercostal space, the fibres arising from the anterio*' I'ib, and passing downwards and back- wards to be attached to the posterior rib. Action. — To draw the ribs forwards and upwards, assisting in inspiration. 3. Internal Intercostals. The fibres of these arise from the posterior rib, and pass down- wards and forwards to be attached to the anterior rib. Action. — Opposed to the preceding, and thus muscles of expira- tion. LIUAMEXTS AND ML'SCLES OF THE HORSE. 39 Xote. — The internal intercostal muscles diifer from the ex- ternal set in being continued down to occupy the spaces between the costal cartilages, while in the extreme upper part of the intercostal spaces, they are either absent or thin and aponeurotic. This inter-cartilaginous portion is insi^iratory. 4. Levatokes Costarum. Origin.— Yrom the transverse processes of the dorsal vertebrae. Insertion. — To the outer surfaces of the ribs, posterior to origin. Action. — To draw the ribs forward and assist in inspiration. 5. Triangularis 8terni. Origin.— Yvom the borders of the upper surface of the sternum, extending from opposite to the 2nd costal cartilage, to the ensiform cartilage. Insertion. — To the costal cartilages, 2nd to 8th inclusive. Action. — To assist in expiration, G. Lateralis Sterxi. Origin. — Outer surface of 1st rib above its cartilage. Insertion. — To the side