Thoracic Limb Muscles PDF

Shoulder and arm  Fascia of the thoracic limb Superficial fascia: insert in cutaneous muscle of trunk Deep fascia: 1. axillary f 2. brachial f 3. antebrachial f 4. fascia of manus: dorsal and palmar deep fascia (extensor/flexor) 5. digital f (annular ligament) ...

Shoulder and arm  Fascia of the thoracic limb Superficial fascia: insert in cutaneous muscle of trunk Deep fascia: 1. axillary f 2. brachial f 3. antebrachial f 4. fascia of manus: dorsal and palmar deep fascia (extensor/flexor) 5. digital f (annular ligament)  AXILLARY FASCIA it lines the medial aspect of the scapula, separating it from the axillary interstitium and the thoracic wall in the axillary interstitium pass the axillary vessels and nerve branches of the brachial plexus at the cranial edge, it extends and involves the supraspinatus m., ending at the scapular spine. it continues at this level with the omobrachial fascia. at the caudal border it has the same behavior, this time involving the infraspinatus muscle  BRACHIAL FASCIA completely envelops the arm muscles and delegates deep leaflets that sheath them individually continues with the axillary and forearm fascia  ANTEBRACHIAL FASCIA Corresponds to the continuation of the brachial fascia It ́s a strong fascia that covers the extensor and flexor muscles of the elbow and digit in the forearm region. It is fused to the periostium of the humerus and the olecranon and also to the colateral ligaments of the elbow joint and the accessory ligament of the deep digital flexor tendon. Is reforced by: the terminal aponeurosis of the tensor muscle of the antebrachial fascia and by the transverse pectoral muscle; Lacertus fibrosus of the brachial biceps m. (mainly in the horses) It will become to fascia of the manus, at the levels of the carpus. üThe fascia of the manus divided into a dorsal and a palmar part.  FASCIA OF THE MANUS Constitute an extension of the antebrachial fascia is reenforced in the articular regions ➜ present tendons sheaths, synovial bursae and synovial tendon sheaths Allows a better conduction of the tendons of antebrachial muscles to the phalanges Divided into a dorsal and a palmar fascia The palmar fascia are more developed in the ungulates ➜ important role in the support of the metacarpophalangeal region  FASCIA OF THE MANUS Dorsal deep fascia – Extensor retinaculum In a dorsolateral position, at the level of the carpus Support the extensor tendons üExtension of the fascia of the manus, in the carpal region that form a ringlike structure; Strengthens the carpal joint Surrounds the tendons of the carpus and the digital tendons Palmar deep fascia – Flexor retinaculum In a medial position, at the level of the carpus Support the flexor tendons üLimits the carpal canal Extension of the fascia of the manus, in the carpal region that form a ringlike structure; Strenghtens the carpal joint Surrounds the tendons of the carpus and the digital tendons Medial view - Horse Palmar view Konig, Carpal canal FASCIA OF THE MANUS Contains the flexor tendons (superficial and deep in the horse; just the deep flexor tendon in the other species), arteries, veins and nerves (median n.). Limited by: Dorsally - Palmar surface of the carpal bones and palmar carpal ligament Laterally -accessory carpal bone Palmar – Flexor retinaculum The structures are surrounded by a synovial bursae.  Digital fascia (anular ligaments) Three transverse ligaments: Palmar anular ligament in the palmar surface of the metacarpophalangeal joint Adherent to the superficial digital flexor tendon Digital anular ligament Proximal digital anular ligament Middle of the first phalanx Horse: arranged in a cruciate pattern; middle part is fused with the superficial digital flexor tendon Distal digital anular ligament Distal to the proximal interphalangeal joint  THORACIC LIMB MUSCLES grouped around the shoulder girdle and thoracic limb four large groups: shoulder arm forearm manus the muscles of each of these segments act on the next those of the hand allow the fingers to move with each other  MOVEMENTS Supination and pronation – rotational movements which occurs at the superior radioulnar joint Supination: rotation of the thoracic limb so the dorsum of the manus is turned laterally; (outward rotation) Pronation: rotation of the thoracic limb so the dorsum of the manus is turned medially; (inward rotation) Extension and Flexion – movements in one plane üExtension: increase the angle formed by a joint Flexion: decrease the angle formed by a joint Abduction and Adduction – movements regarding the median plane of the body Abduction: move the limb away from the body (midline) üAdduction: move the limb toward the body (midline)  Muscles of the shoulder (joint) Lateral scapular region supraspinatus muscle [m.supraspinatus] infraspinatus muscle [m. infraspinatus] deltoid muscle [m. deltoideus] minor teres muscle [m. teres minor] Medial scapular region major teres muscle [m. teres major] articular muscle of the shoulder joint [m. articularis humeri] subscapular muscle [m. subscapularis] coracobrachial muscle [m. coracobrachialis] axillary fascia  Lateral scapular region supraspinatus muscle [m.supraspinatus] Origin: arises from and fills the supraspinous fossa of the scapula, beyond which it extends cranially and to part of the scapular cartilage in ungulates Attachment: by one strong tendon on the greater tubercle of the humerus (CARN & PIGS) by two tendons on the lesser and greater tubercles (HORSES & RUM) Anatomical relationship: partly blends with the joint capsule of the shoulder joint ucovered by the subclavian muscle in horses and pigs ulaterally covered by the trapezius, omotransverse and brachiocephalic muscles udelimits, with the subscapularis m., the interstitium where the suprascapular nerve and vessels pass its termination is related with the proximal tendon of the biceps brachii (which is framed by its two tendons in HORSES & RUM) and with the infraspinatus m. Blood supply: suprascapular a cranial circumflex humeral a Nerve: suprascapular n Function: stabilization and extension of shoulder joint during weight bearing supports arm abduction and rotation  Lateral scapular region Infraspinous muscle Origin: infraspinous fossa and the scapular spine Attachment: by tendon on the greater tubercle, over a synovial bursa EQ & RUM - it splits into a deep part, which inserts on the greater tubercle of the humerus, and a stronger superficial part, which inserts distal to the greater tubercle on the lateral aspect of the humerus uWINES - as if it had been divided by the strong retroversion of the scapular spine, the muscle has an elongated accessory head on the cranial side of the latter, covered by the corresponding expansion of the deltoid muscle, which ends in a tendon slightly in front of the main part. It is sometimes described as an accessory supraspinatus muscle Anatomical relationship: covered by an aponeurosis that joins the aponeurosis of the deltoid m. (UNG) the tendon functions as a lateral collateral ligament of the shoulder it is caudally related to the teres minor m., which separates it from the long head of the triceps brachii m. Blood supply: suprascapular a cranial circumflex humeral a Nerve: suprascapular n Function: flexor of the shoulder joint supports arm abduction and rotation Fixation of the shoulder joint  Lateral scapular region Deltoid muscle Origin: flat, triangular muscle, composed of two parts: scapular and acromial spine of the scapula with an aponeurosis (pars scapularis) ü acromion (pars acromialis) (EQ; SU) Attachment: both parts end by a tendon on the deltoid tuberosity, in the humerus minor teres tubercle) Anatomical relationship: lies directly under the skin covers the infraspinatus m., minor teres m. and proximal part of the triceps brachii m. Blood supply: suprascapular a cranial circumflex humeral a Nerve: axillary n Function: flexor of the shoulder joint supports arm abduction and rotation  Lateral scapular region Minor teres muscle Origin: distal third of the caudal margin of the scapula and proximally to the infraglenoid tubercle Attachment: by a tendon on the lateral surface of the humeral proximal epiphysis, in its own tubercle (minor teres tubercle) Anatomical relationship: lies deep to the infraspinous m. at its insertion, to which it adheres, and to the deltoid m. covers the origin of the long head of the triceps brachii muscle and, in ungulates, part of the lateral head Blood supply: cranial circumflex humeral a Nerve: axillary n Function: flexor of the shoulder joint Rotates the shoulder laterally, preventing medial rotation when weight bearing  Medial scapular region Major teres muscle Origin: caudal angle of the scapula and adjacent part of the caudal border Attachment: ends on the humeral major teres tuberosity, together with the latissimus dorsi muscle Anatomical relationship: the medial aspect is related to the ventral thoracic serrate and pectoralis ascendens muscles, to the termination of the cutaneous muscle of the trunk, as well as to several branches of the brachial plexus ü the tendon is covered by the termination of the coracobrachial m. in ungulates ü the cranial border delimits with the subscapularis m., the interstice already described Blood supply: subscapular a. thoracodorsal a. Nerve: axillary n Function: flexor of the shoulder joint upports adduction of the limb  Medial scapular region Articular muscle of the shoulder Origin: caudal angle of the scapula and adjacent part of the caudal border only exists in horses, pigs and cats weak muscular bundle in the caudal region of the scapulohumeral angle scapular neck : Attachment caudal part of the neck of humerus Anatomical relationship: it is covered by the origin of the long head of the triceps brachii m. and, at the termination, penetrates between the fibers of the biceps brachii m. Nerve: axillary n Function: It adheres to the joint capsule, which it tenses  Medial scapular region Corabrachial muscle Origin: tendon of origin emerges form the coracoid process of the scapula, where it is protected by a synovial bursa Attachment: terminates by tendon around the teres major tuberosity of the humerus as well as further distal on the medial aspect of the humeral dyaphisis in horses and ruminants (sometimes in the cat), this tendon it is divided into two unequal parts [one medial (long branch), the other lateral (short branch], which embrace the distal tendon of the teres major muscle Anatomical relationship: the tendon of origin emerges between the supraspinatus and subscapularis muscle the fleshy body responds laterally to the humerus, to the tendons of the teres major and latissimus dorsi muscles, and to the origin of the medial head of the triceps brachii m. the medial side is related to the termination of the pectoralis ascendans muscle the caudal border is related to the brachial plexus when the muscle is bifid, the musculocutaneous nerve and the cranial humeral circumflex vessels pass between the two parts Blood supply: scranial circumflex humeral a Nerve: muscuocutaneous n Function: addution of the arm ü external rotation od the limb  Medial scapular region Subscapular muscle Origin: occupies the subscapular fossa of the scapula Attachment: inserts, deep to the coracobrachial muscle, on the lesser tubercle of the humerus Anatomical relationship: the tendon functions as a medial collateral ligament of the shoulder joint it is caudally related to the long head of the triceps brachii and to the teres major m. with the latter, it delimits an interstice in the region of the joint where the subscapular and circumflex vessels of the shoulder pass, as well as the axillary nerve the medial aspect is related to the ventral thoracic serrate m. between the two lies the connective tissue of the axillary interstitium, as well as several branches of the brachial plexus the cranial border joins the supraspinatus m. in its dorsal part, separating distally to form with it an interstitium where the suprascapular a.v. and n. pass as well as the tendon of the coraco-brachial m Blood supply: subscapular a. suprascapular a Nerve: subscapular n Function: primarily acts as an extensor of the joint, but it can also contribute to maintaining flexion ü adductor and internal rotation of the arm  Muscles of the arm and elbow joint Cranial region of the arm flexor muscles of the forearm: brachial muscle [m. brachialis] biceps brachii muscle [m. biceps brachii] Caudal region of the arm extensor muscles of the forearm: triceps muscle of the forearm [m.triceps brachii] (3 or 4 heads) anconeus muscle [m. anconeus] tensor muscle of the antebrachial fascia [m. tensor fasciae antebrachii] arise either from the scapula or the humerus and insert on the proximal part of the ulna or radius they either bridge both the shoulder and the elbow joint or only this last one  Cranial region of the arm Flexor m of the forearm: brachial m Origin: origin on the caudal surface of the proximal humerus, under the humeral neck and occupies the brachial groove of the humerus (coiled muscle) Attachment: by tendon on the medial side of the proximal ulna uin horses and ruminants it delegates an extension that ends at the radius tuberosity, mixing with the termination of the m. biceps brachii Anatomical relationship: in horses, pigs and cats, the scapular articular m. insinuates at its origin it is related to the teres minor and deltoid muscles and to the lateral and long heads of the triceps brachii the radial nerve and satellite vessels are related to its caudolateral border distally it passes between the biceps brachii and the humerus in horses it is covered by the lacertus fibrosus Blood supply: caudal circumflex humeral a. radial colateral a. deep brachial a. Nerve: musculocutaneous n Function: flexor of the elbow ü external rotator of the limb  Cranial region of the arm Flexor m of the forearm: biceps braquii m Origin: single tendon, in the supraglenoid tubercle of the scapula, which then lodges in the inter-tubercular groove of the humerus (contained by the transverse humeral ligament) Attachment: by tendon in the tuberosity of the radius (medial side of the proximal epiphysis) at the level where the terminal tendon is formed, another fibrous structure stands out (lacertus fibrosus or aponevrosis of the brachial biceps m.) which moves laterally and joins the antebrachial fascia, on the surface of the radial extensor muscle of the carpus it is particularly developed in equines, where it is involved in the equine stay apparatus in pigs and carnivores, the tendon delegates another extension that runs around the medial border of the radius and towards the olecranon of the ulna in horses, the fleshy part of the muscle has tendon intersections; a true fibrous cord also develops that extends the proximal tendon, accompanies the whole muscle, joins the distal tendon and the lacertus fibrosus, and seals the joint angles of the shoulder and elbow  Cranial region of the arm Flexor m of the forearm: biceps braquii m Anatomical relationship: the proximal tendon descends to the cranial aspect of the scapulohumeral joint in horses and ruminants, it remains separated from the joint capsule by a cushion of adipose connective tissue an intertubercular bursa [bursa intertubercularis] and is covered by the terminal tendons of the supraspinatus, passing between them in pigs, it is included within the joint, being covered by the articular capsule on its cranial side in carnivores it has an intermediate disposition, where the muscle invaginates the capsule of the shoulder joint cranially, thus forming a synovial sheath in the region of the intertubercular groove it is related to the insertions of the brachial and superficial pectorals superficialis muscles, and the termination of the ascending pectoralis m. it covers the cranial aspect of the humerus, the corresponding border of the coracobrachial m., the cranial humeral circumflex vessels, and the musculocutaneous n. laterally it is related to the brachial m., which also lies under the lacertus fibrosus in equines the terminal tendon insinuates itself between the radial extensor muscle of the carpus and the pronator teres muscle or the fibrous structures that take their place in ungulates in horses, it adheres to the dorsal membrane of the elbow and is related to the medial collateral ligament Blood supply: cranial circumflex humeral a. bicipital a Nerve: musculocutaneous n Function: extensor of the shoulder joint ü flexor of the elbow joint ü seals the joint angles of the shoulder and elbow (+ horses)  Cranial region of the arm Extensor m of forearm: triceps brachii m fills the triangle between the caudal border of the scapula, the humerus and the olecranon, clearly visible under the skin in the live animal ü possesses three heads of origin (a long, a lateral and a medial) ü dogs, pigs and small ruminants present a fourth head - accessory head ü ends with a strong tendon in the olecranon tuberosity ü a synovial bursa [bursa subtendinea m. tricipitis brachii] is interposed between the tendon and the olecranon the largest and longest of the heads ü side-flattened triangular shape ü in dogs and pigs it seems to be divided into two parts  Cranial region of the arm Extensor m of forearm: triceps brachii m  Cranial region of the arm Extensor m of forearm: triceps brachii m Origin: caudal margin of the scapula Attachment: Laterally - deltoid and teres minor mm. and the lateral head ü Medially - teres major, latissimus dorsi, tensor fascia of the forearm muscles, the medial head and scapular vessels ü Cranially - scapula, shoulder joint and eventually m. articular muscle of the scapula, brachial m., radial n. and caudal humeral caudal circumflex and deep brachial vessels, and to medial and accessory heads ü Caudallly border is edged medially by the tensor m. of the antebrachial fascia Blood supply: cranial circumflex humeral a. caudal circumflex humeral a. deep brachial a Nerve: radial n Function: chief extensor of the elbow ü stabilizes the elbow joint ü long head - + flexion of the shoulder joint  Cranial region of the arm Extensor m of forearm: anconeus m Origin: short, flat, but strong muscle ü in cats one can isolate lateral anchoneus m. and one medial anchoneus m outline of the olecranon fossa and supracondylar crest Attachment: lateral aspect of the ulnar olecranon Anatomical relationship: situated deep to the triceps muscle of the forearm ü it blends with the its lateral head in the horse and ox Blood supply: Ulnar collateral a. Deep brachial a. Nerve: radial n Function: extensor elbow  Cranial region of the arm Extensor m of forearm: tensor m of antebrachial fascia Origin: flat, broad, straplike muscle ü detaching from ventral border of latissimus dorsi m., directly or by aponevrosis, and extending through medial region of triceps m. to olecranon distal termination of the latissimus dorsi m. ü ungulates present another aponevrotic lamina that inserts into the caudal edge of the scapula Attachment: terminates by aponeurosis on the medial aspect of the tendon of the m. triceps brachii and over the antebrachial fascia Anatomical relationship: laterally it is related to the triceps muscle long head, the medial epicondyle of the humerus and origin of the palmar forearm muscles ü medially it is related to the teres major and latissimus dorsi muscles and to the axillary interstitium Blood supply: caudal humeral circumflex a. ulnar collateral a. ü deep brachial a. Nerve: radial n Function: It supports the action of the m. triceps brachii – extension of the elbow ü chief tensor of the antebrachial fascia ANTEBRACHIAL AND HAND Forearm (antebrachial) muscles - craniolateral and dorsal surface of the forearm Superficial muscles Braquioradial muscle (M. brachioradialis) Radial extensor muscle of the carpus (M. extensor carpi radialis) Common digital extensor muscle (M. extensor digitorum communis) Lateral digital extensor muscle (M. extensor digitorum lateralis) Profound muscles Supinator muscle (M. supinator) Extensor carpi obliquus muscle or long abductor muscle of the first digit (M. extensor carpi obliquus or M. abductor digiti I longus) Extensor muscle of the first and second digit (M. extensor digiti I and II) Forearm (antebrachial) muscles – caudomedial and palmar surface of the forearm Superficial muscles Ulnar extensor muscle of the carpus (M. extensor carpi ulnaris) or M. ulnaris lateralis Ulnar flexor muscle of the carpus (M. flexor carpi ulnaris) Superficial digital flexor muscle (M. flexor digitalis superficialis) [carnivores] Radial flexor muscle of the carpus (M. flexor carpi radialis) Round pronador muscle (M. pronator teres) Profound muscles Superficial digital flexor muscle (M. flexor digitalis superficialis) [ungulates] Deep digital flexor muscle (M. flexor digitalis profundus) Quadrate pronator muscle (M. pronator quadratus)  Forearm (antebrachial) muscles - craniolateral and dorsal surface of the forearm Superficial m: braquioradial m Origin: much reduced, is a long, narrow muscle in the flexor angle of the elbow joint. ü Exists in Cats, inconstant in Dogs. Absent in Rabbit and Ungulates ü This muscle has also been called the long supinator m. epicondylar crest (or lateral supracondilar crest) of the humerus Attachment: Above the radial styloid process (in the distal third of the radius) Anatomical relationship: Insert in the the cranial portion of the antebrachial fascia Superficial to the radial extensor muscle of the carpus; Is lateral to the brachial muscle Nerve: radial n Function: Supination - auxiliar role in the supination and flexion of the elbow  Forearm (antebrachial) muscles - craniolateral and dorsal surface of the forearm Superficial m: radial extensor m of carpus Origin: largest and the most cranial extensor muscle in the lateral surface. ü long and fusiform shape with a long tendon Cat – the muscle splits into two muscle bellies (long and a short portion) Dog (Rabbit) – tendon is double Ungulates (horse and ruminants) – muscle belly has strong aponeurosis insertions epicondylar crest (or lateral supracondilar crest) and lateral epicondyle of the humerus ü distal to the insertion of the brachioradial m. and over the lateral colateral ligament of the elbow Attachment: proximal extremity (dorsal tubercule) of the second and third metacarpal bones (carn) or third metacarpal bone (Ung) ü Cat: Long portion ends in the dorsal tubercule of the second metacarpal bone and the short portion attaches the third metacarpal bone. Anatomical relationship: The muscle receive the lacertus fibrosus (extension of the tendon of the biceps muscle of the forearm, that unites to the tendon of the radial extensor muscle of the carpus (and to the antebrachial fascia) Related with the humerus, the deep branch of the radial nerve and blood vessels. Distally: Pass through the groove for the radial extensor muscle of the carpus (radius) ü Extensor carpi obliquus muscle pass dorsally Covered by the extensor retinaculum Blood supply: Dorsal (cranial) interosseous a. and collateral radial artery Nerve: deep ramus of radial n Function: extension carpal joint and flexion elbow  Forearm (antebrachial) muscles - craniolateral and dorsal surface of the forearm Superficial m: common digital extensor m Long and fusiform muscle In the lateral surface of the forearm, caudolateral to the radial extensor m. of the carpus Carn: just one belly muscle with a tendon divided into 4, one for each digit (with exceptionof the first digit) Ungulates: more than one belly, each one with its own tendon Swine: three heads Medial extensor digit m. (II + III) ü Lateral extensor digit m. (IV + V) ü Median extensor digit m. (III+IV) Ruminants: two heads Medial extensor digit muscle (III) Common (Lateral) digital extensor muscle (III+IV) Horse: one head Dorsal extensor digit muscle (III) Vestigial muscle of the II and IV digit (Philips m.)  Forearm (antebrachial) muscles - craniolateral and dorsal surface of the forearm Superficial m: common digital extensor m Origin: Lateral epicondyle of the humerus (or in the distal extremity of the supracondilar crest), lateral collateral ligament of the elbow joint and ulna. Carn.: lateral humeral epicondyle Horse: lateral epicondyle of the humerus, lateral tuberosity of the radius and lateral collateral ligament of the elbow Attachment: Long tendon of insertion on the extensor process of the distal phalanx of each functional digit Pass dorsal to the carpus and metacarpus The tendons of the common digital extensor muscle receive the termination of the interosseous muscle The tendons pass through the groove for the common digital extensor muscle (radius) Are cover by the extensor retinaculum Blood supply: borsal interosseous a. and collateral radial artery Nerve: radial n Function: Extension of the carpal and digital joints. Extension of the distal phalanx (over the middle phalanx) Extension of the hand (over the forearm) Stabilizes the carpal joints (especially in the ungulates) Forearm (antebrachial) muscles - craniolateral and dorsal surface of the forearm Superficial m: lateral digital extensor m Origin: Long and fusiform muscle. Smaller than the common digital extensor m. Caudal to the common digital extensor muscle of the lateral surface of the antebrachium (in the ulnar border). Depending of the species the muscle is divided into one (horse and rum.), two (dog and pig) or three bellies (cat) The tendon ends in the most lateral digits Lateral humeral epicondyle (pig, horse), lateral supracondilar crest (cat), lateral collateral ligament of the elbow joint (dog, pig, horse), lateral tuberosity of the radius (dog, horse) and in the ulna (laterally; horse) Attachment: In the dorsal surface of the proximal (horse), middle or distal phalynx: Horse: Dorsolateral surface of the proximal phalynx (III digit) Rum: dorsolateral surface of the middle phalynx (IV digit) Swine: dorsal surface of the middle and distal phalages (IV and V digit) Cat: Unite to the common digital extensor tendons in the proximal phalages (II, III, IV and V digit) Dog: Unite to the common digital extensor tendons in the proximal phalanges (III, IV and V digit) Blood supply: Dorsal interosseous a. and collateral radial artery Nerve: radial n Function: Extension of the carpal and phalangeal joints of the lateral digits in carnivores and the pig; Extension of the carpal and metacarpal joints of the fourth digit in ruminants; Extension of the carpal joint in the horse.  Forearm (antebrachial) muscles - craniolateral and dorsal surface of the forearm Profundos m: extensor carpi oblique m or long abductor m Origin: middle third of the lateral border of the radius and ulna (in the interosseus ligament) Attachment: Proximal epiphysis of the metacarpal bone: I (Carn); II (Swine, Horse) Medial surface of the metacarpal bone: III (Rum.) Anatomical relationship: Covers the craniolateral aspect of the antebrachium. Runs deep to the digital extensor tendons Oriented in a oblique way over the radius and the ulna, from the lateral surface of the radius to the medial surface of the carpus. Blood supply: Dorsal interosseous a. Nerve: Deep branch of the radial nerve Function: Extension of the carpus. Carn – deviates the paw medially (supination). Abduction and extension of the first digit  Forearm (antebrachial) muscles - craniolateral and dorsal surface of the forearm Profundos m: extensor m of first and second Origin: In the same plane and in the same orietation of the oblique extensor of the carpus (1), but distally Deep to the rest of the extensor muscles of the carpus and the digits. Present in Carnivores Other species – is fused to the common digital extensor muscle Horses – vestigial muscle – Thierness m. Craniolateral border of ulna – in the interosseous ligament (carn) Attachment: Two tendons: ü Dorsal surface of the metacarpus of the digit I; ü Join to the tendon of comum digital extensor m. to digit II Blood supply: Dorsal interosseous a. Nerve: Deep branch of the radial nerve Function: Extension of the first and second digits and adduction of the first digit  Forearm (antebrachial) muscles - palmar and medial surface of the forearm Superficial m: Ulnar extensor m of carpus Origin: Long and fusiform shaped Ends in a double tendon Lateral epicondyle of the humerus Attachment: Lateral carpal (accessory bone) and metacarpal bones Accessory bone: Lateral surface – Carn. Proximal border – Ung. (main portion) Proximal epiphysis of the metacarpal bones: ü V–Carn,Sw IV – Rum., Horse (weak portion) Anatomical relationship: Caudolateral surface of the forearm, caudal to the lateral digital extensor m. Cranial and parallel to the Ulnar flexor muscle of the carpus Carn: lateral surface (extensor functions) Rum., Horse: palmar region of the forearm (flexor functions) Swine and Rabbit: intermediate position Tendons are cover by the extensor and flexor retinaculum Blood supply: MUlnar a. and interosseous a. Nerve: radial n Function: Carn. – Flexion of the carpal joints; Supports the extension of the carpus when is already in a extended position. Abduction of the hand Other species – Flexion of the carpal joint  Forearm (antebrachial) muscles - palmar and medial surface of the forearm Superficial m: Ulnar flexor m carpus Origin: Long and fusiform shaped ü Present two heads: ü Humeral head (caput humerale) – in ung. present several tendinous intersections and is more developped. ü Ulnar head (caput ulnare) ü Both portion end in a common tendon. Humeral head: medial epicondyle of the humerus Ulnar head: Olecranon (caudomedial surface) Attachment: Accessory carpal bone (proximal border) Anatomical relationship: The most caudal of the flexors muscles ü Parallel to the ulnar extensor muscle of the carpus ü Humeral head (4) is superficial to the Superficial digital flexor muscle (5) - except in Carn. Blood supply: colateral ulanr a and median a Nerve: ulnar n Function: flexion hand, carni: supination limb  Forearm (antebrachial) muscles - palmar and medial surface of the forearm Superficial m: superficial digital extensor Origin: Long and fusiform muscle; Strong muscle ü Presents tendons that divides into several branches to reach all the digits, except the digit ü In pigs and rum. the muscle presente two bellies, a superficial (smaller) and a deep belly (stronger) Medial epicondyle of the humerus Attachment: Proximal region of the palmar surface of the middle phalanx of the digits ü Dog: all the digits except the digit I ü Swine and Rum.: digit III and IV ü Horse: digit III Anatomical relationship: Medial surface of the forearm ü Carn. lies directly beneath the skin, between the ulnar flexor m. of the carpus and the radial flexor m. of the carpus muscles ü Ungulates – in a more profound position beneath the ulnar flexor muscle of the carpus (4) and the m. ulnaris lateralis (7) ü Rum and pig – superficial part cross the flexor retinaculum and the deep portion pass benetah it. ü Horse – cover the deep digital flexor muscle with which is partially fused. Blood supply: ulnar and median a Nerve: ulnar and median n Function: flexion hand and middle phalanx  Forearm (antebrachial) muscles - palmar and medial surface of the forearm Superficial m: radial flexor m carpus Origin: Long and fusiform ü The most medial of the flexor muscles medial epcondyle humerus Attachment: Metacarpal bones: ü Carn. II and III metacarpal bone ü Sw. and Rum.: III metacarpal bone ü Horse: II metacarpal bone Anatomical relationship: In the medial surface and caudal to the round pronator m. Blood supply: Median a. Nerve: median n Function: flexion carpal joint  Forearm (antebrachial) muscles - palmar and medial surface of the forearm Superficial m: round pronador m Origin: Short muscle in the medial surface of the forearm, cranial to the Digital flexor muscles ü Present in the Carnivores ü Other species – inconstant and vestigial Medial epicondyle of the humerus, cranial to the insertion of the radial flexor muscle of the carpus Attachment: Medial border of the radius (in the proximal region) Anatomical relationship: Covers the medial colateral ligament of the elbow ü The median nerve and artery pass between the muscle and the radius Blood supply: Median a. Nerve: median n Function: pronation  Forearm (antebrachial) muscles - palmar and medial surface of the forearm Superficial m: quadrate pronador m Origin: Present only in the Carnivores. ü It bridges the media aspect of the interosseous space of the forearm Palmar surface of the ulna (medial border) Attachment: Palmar surface of the radio Anatomical relationship: Covers the palmar surface of the radius, the interosseous membrane of the forearm and the caudal interosseous vessels; ü Deep to the digital flexor muscles Blood supply: Caudal interosseous a. Nerve: median n Function: pronation  Forearm (antebrachial) muscles - palmar and medial surface of the forearm Profund m: deep digital flexor m Origin: Humeral head – Medial epicondyle of the humerus ü The most developed. ü Radial head – Distal third of the radius, in the palmar surface ü Ulnar head: ü Ung.: Caudal border of the olecranon (ulna) ü Carn: Caudal border of the ulna, extending from the olecranon to the distal third Attachment: Flexor tubercule of the distal phalanx of each digitt ü Horses: ends in the semi-lunar line of the flexor tubercule of the distal phalanx Blood supply: Caudal interosseous a. Ulnar a. ü Median a. Nerve: median n, ulnar n Function: Flexion of the carpal joint and of the distal falanges of the hand, and thereby promotes the flexion in the whole hand.  Forearm (antebrachial) muscles - palmar and medial surface of the forearm Profund m: Superificial digital flexor m Origin: Flat, oblique and short muscle. Short supinator m. Present in the carnivores and in the pig lateral epicondyle of the humerus Attachment: proximal third of the radius, in the dorsal and medial border Anatomical relationship: Covered by the extensor muscles - Covered by the radial extensor m. of the carpus and by the common digital extensor m. ü The termination contacts with the round pronator m. ü Covers the lateral part of the elbow joint and the dorsal surface of the proximal extremity of the radius ü Covers the deep ramus of the radial nerve Blood supply: Median a. or radial artery depending of the species Nerve: radial n Function: supination  Forearm (antebrachial) muscles - palmar and medial surface of the forearm Profund m: Superificial digital flexor m Origin: Flat, oblique and short muscle. Short supinator m. Present in the carnivores and in the pig lateral epicondyle of the humerus Attachment: proximal third of the radius, in the dorsal and medial border Anatomical relationship: Covered by the extensor muscles - Covered by the radial extensor m. of the carpus and by the common digital extensor m. ü The termination contacts with the round pronator m. ü Covers the lateral part of the elbow joint and the dorsal surface of the proximal extremity of the radius ü Covers the deep ramus of the radial nerve Blood supply: Median a. or radial artery depending of the species Nerve: radial n Function: supination  Forearm (antebrachial) muscles - palmar and medial surface of the forearm Profund m: Superificial digital flexor m Origin: Flat, oblique and short muscle. Short supinator m. Present in the carnivores and in the pig lateral epicondyle of the humerus Attachment: proximal third of the radius, in the dorsal and medial border Anatomical relationship: Covered by the extensor muscles - Covered by the radial extensor m. of the carpus and by the common digital extensor m. ü The termination contacts with the round pronator m. ü Covers the lateral part of the elbow joint and the dorsal surface of the proximal extremity of the radius ü Covers the deep ramus of the radial nerve Blood supply: Median a. or radial artery depending of the species Nerve: radial n Function: supination  THORACIC LIMB MUSCLES Digital muscles Long digital muscles belong to theantebrachial muscles Their origin is proximal to the elbow joint from the humerus or forearm and run with long tendons over carpus to insert on diferent parts of the digits Extensors muscles: Common digital extensor muscle Lateral digital extensor muscle Long abductor muscle of the first digit/ Oblique extensor muscle of the carpus Extensor muscle of the first and second digit Flexor muscles: Superficial digital flexor muscle Deep digital flexor muscle Interflexor muscles Short digital muscles Interosseous muscles (m. interossei) Lumbrical muscles (m. lumbricales) Short digital flexor muscle (m. flexor digitorum brevis) Proper digital muscles  Long digital muscles Flexor muscles: Interflexor muscles Short muscles or tendons Located between the digital flexor muscles (surperficial and deep) Located in the palmar surface, at the level of the carpus and metacarpus Absent in the Horses Carnivores – present a distal interflexor muscle Sw., Rum – present a proximal and a distal interflexor muscle Nerve: Median nerve Function: Assist the digital flexor muscles  Short digital muscles Interosseous muscles (m. interossei) Located deeply to the tendon of the deep digital flexor m. ü In the palmar surface of the metacarpal bone ü Carn., sw.: present muscle bellies, in number of 4 (for all the metacarpus, except the first) ü Rum, horse: tendinous ü Ruminants - single origin that divides into 5 branches at the distal metacarpus ü Horses – three interosseus m. ü Lateral and medial – very small and with no functional importance ü Middle interosseous muscle – also term the fetlock suspensory ligament ü The interosseous m. ends in the proximal sesamoid bones or ends fusing with the corresponding extensor digital tendon Origin: Proximal epiphysis of the corresponding metacarpal bone and the joint capsule of the carpus (in the palmar ligament of the carpus) Attachment: Proximal sesamoid bones Blood supply: Palmar metacarpal artery Nerve: Deep branch of the ulnar nerve Function: Flexion of the metacarpophalangeal joints ü Fetlock suspensory ligament – Provide the proximal support to the fetlock. ü Belongs to the suspensory apparatus – Prevent the overextension of the fetlock joint ü Fetlock suspensory apparatus – composed by the interosseous m./tendon, proximal sesamoid bones and distal sesamoidean ligaments.  Short digital muscles Lumbrical muscles (m. lumbricales) Origin: Small muscles that are placed between the digital flexor tendons, on the palmar surface of the metacarpal region. ü Absent in the ruminants and swine; Branches of the deep digital flexor tendon (perfurating tendon) Attachment: Proximal phalanx of the third to fifth digit ü Carn. – 3 muscles that end in the proximal falanges of the third, fourth and fifth digit ü Horse – 2 muscles that lie on either side of the digital flexor tendon Nerve: Deep branch of the ulnar nerve Function: Flexion of the metacarpophalangeal joints ü Assist the digital flexor muscles and suport the ergot in the horse  Short digital muscles Proper digital muscles Exclusively in the carnivores (more developed in cat) ü Correspond to small muscles that assist in the extension, flexion, abdiction, adduction and rotation of the digits. ü Muscles of the first digit: ü Abductor m. of the first digit (M. abductor digit I brevis) ü Flexor m. of the first digit (M. flexor digit I brevis) ü Addutor of the first digit (M. adductor digit I) ü Muscles of the second digit: ü Addutor of the second digit (M. adductor digit II) ü The most developed (usually is the only refered in the literature) ü Abductor m. of the second digit (M. abductor digit II) ü Flexor m. of the second digit (M. flexor digit II) ü Muscles of the fifth digit: ü Abductor m. of the fifth digit (M. abductor digit V) ü Flexor m. of the fifth digit (M. flexor digit V) ü Addutor of the fifth digit (M. adductor digit V)