Pectoralis profundus Pectoralis minor Dog And Feline

• Origin: Most of the sternum (except its front tip) and from the surface of the front end of the abdomen (in the region of the xiphoid process).

• Insertion: Upper inner surface of the humerus, and onto a vertical line on the upper third to upper half of the front of the humerus.

• Structure: The pectoralis profundus is seen on the side of the lower portion of the chest, its upper edge directed toward the shoulder joint. In the feline, the portion at the outer edge of the muscle forms a separate division called the xiphihumeratis. Its inserting end passes deep to the remainder of the muscle (see diagram in "Pectoralis transversus," page 61) and ultimately inserts onto the upper portion of the humerus.

Pectoralis Transversus Horse

PECIOSAL IS ASCENDENS

Extensor Caudae Lateralis Muscle

INTE RT RAN SV E RSARII OORSALIS CAUDAE (Î)

SAC ROC All DAL IS DO RSA LI S MEOtALIS(l)

SACROCAUDALIS DORSALIS LATERALIS (21

INTERTRANSVERSARII VENTRALIS

PELVIS

Dog Pelvis

COCCYGEUS

LEFT SIDE VIEW FRONT

TAIL

INTERTRANSVERSARIt DORSALIS C AU DAE

SACROCAUDALIS DORSALIS LATERALIS

SACROCAUDALIS DORSALIS MEDIAL!S

SACROCAUDALIS VENTRALIS LATERALIS (S)

Canine Coccygeus

TOP VIEW

COCCYGEUS

INTE RT RAN SV E RSARII OORSALIS CAUDAE (Î)

PELVIS

SACROCAUDALIS VENTRALIS LATERALIS

SAC ROC All DAL IS DO RSA LI S MEOtALIS(l)

SACROCAUDALIS DORSALIS LATERALIS (21

SACRUM

COCCYGEUS

PELVIS

LEFT SIDE VIEW FRONT

TAIL

INTERTRANSVERSARII VENTRALIS

TOP VIEW

INTERTRANSVERSARIt DORSALIS C AU DAE

SACROCAUDALIS DORSALIS LATERALIS

SACROCAUDALIS DORSALIS MEDIAL!S

SACROCAUDALIS DORSALIS MEDIAL!S

SACROCAUDALIS DORSALIS LATERALIS

INTERTRANSVERSARII CAUDAE

SACROCAUDALIS VENTRALIS LATERALIS (S)

COCCYGEUS

Tail muscles

The entire tail is surrounded by a total of twelve muscles—six per side of the body—that pass longitudinally and get thinner as they pass along its length. On one side of the body, they can be divided into three groups. Each group has a primary function—two elevators above, which extend the tail upward, the sacrocaudalis dorsalis medialis and lateralis; two lateral flexors on the side, which bend the tail to the side, the intertrans-versarii dorsales and ventrales caudae, and two depressors below which flex the tail downward, the sacrocaudalis ventralis medialis and lateralis. The two upper elevators are a continuation of the spinal muscles of the back. The two lateral flexors, which begin on the sacrum and the tail vertebrae, taper as they pass along the side of the tail. In the dog, the upper lateral flexor (intertransversarii dorsalis caudae) is especially thick where it begins at the sacrum and ends shortly on the side of the tail. In the horse and the ox, the lateral flexors tend to be segmented between the transverse processes of the tail vertebrae. The lateral flexors are incompletely divided into upper and lower bundles in the ox. The two depressors begin on the bottom of the lumbar vertebrae and sacrum. The lateral depressor is larger than the medial one.

Coccygeus (Coccygeus lateralis; Feline: Abductor caudae internus)

• Origin: The inner surface of the midsection of the pelvis (above the level of the hip socket) in the ox, the dog, and the feline; also from the broad sacrotuberal ligament in the ox; only from the broad sacrotuberal ligament in the region of the hip socket in the horse.

• Insertion: Sides of the tail vertebrae at the base of the tail (tail vertebrae 1-4 in the horse, 1-3 in the ox, and 2-5 in the dog and the feline)

• Action: Both sides of the body together: Pull the base of the tail downward. One side only: Pulls the tail to that side.

• Structure: The coccygeus is a small, flat muscle connecting the pelvis to the base of the tail. Basically triangular, it originates narrow at the pelvis and fans out as it approaches the tail. It lies deep to the sacrotuberal ligament. Although inconspicuous, it may create a curved transition between the top of the rear portion of the pelvis and the base of the tail. Its curved rear edge is most likely to be seen directly when the tail is raised.

Cutaneous Muscle

CUTANEOUS MUSCLE

Facial portion (PLATiSMAJ

Sternal portion

Sternal porlior

Cutaneous muscle (Panniculus carnosus, Cutaneous maximus)

HORSE

The cutaneous muscle, or skin muscle, Is a thin, blanketing sheet of muscle that covers a large part, but not all, of the body. It has very little attachment directly to the skeleton, and is divisible into several portions. The cutaneous muscle and the overlying skin soften the definition of the underlying muscles and other structures. One of its functions is to twitch the skin to get rid of flies. Portions that affect surface form are described below.

On the front of the chest, the sternal portion, a part of the neck portion, thickens into a muscular band that can be seen on the surface as a distinct ovoid bulge. It attaches directly to the tip of the sternum, where it is thickest, and then thins and widens as it ascends upward and outward. It passes diagonally over the brachiocephalicus.

The large trunk portion covers the side of the trunk. As it approaches the upper arm, it gets considerably thicker and can obscure some of the definition of the underlying latissimus dorsi, serratus ven-tralis, and pectoralis ascendens. It ultimately inserts into the humerus along with the latissimus dorsi and the pectoralis ascendens. In front of the knee region, along with the skin, it creates the triangular fold of the flank, or stifle fold. This flap spans from the side of the abdomen to the front of the thigh. The muscular fibers of the trunk portion begin on the side of the chest and abdomen on a line directed variably from the top of the shoulder or the middle of the back to the front of the knee. The lower portion of this line of origin, convex forward, coincides with a distinct line that appears prominently on the surface of the animal in life. This line is seen only in the horse.

A division of the facial portion separates into a unit that attaches to the comer of the mouth, called the platysma. When it contracts, it retracts the corner of the mouth, altering its shape.

In the ox, the cutaneous muscle is generally reduced and can be seen directly only at the fold of the flank. This fold is larger and descends lower in the ox than in the horse, reaching below the knee to the shin of the lower leg.

DOG AND FELINE

The cutaneous muscle is seen where it forms the fold of the flank. It varies in where it attaches to the leg, ranging from the upper end of the thigh down to the knee, depending on the species and breed.

Left Leg Anatomy Thigh

ALL LEFT FRONT LIMB

SUP RAS PI NAT US

Split Knee Cartilage

SUP RAS PI NAT US

ALL LEFT FRONT LIMB

FRONTVIEW OUTSIDE VIEW OUTSIDEVIEW

HORSE DOG

Supraspinatus HORSE AND OX

• Origin: Outer surface of the front portion of the scapula and the adjacent cartilage.

• Insertion: Inner and outer front corners of the top of the humerus.

• Action: Extends the shoulder joint, advancing the limb.

• Structure: The belly of the supraspinatus is thin where it begins, on the outside of the top of the shoulder blade; it twists to face forward at the front of the shoulder joint, and then splits before inserting into the two areas of insertion on the humerus. In the ox it is completely covered by thin muscles. In the horse a small piece of the middle of the belly comes to the surface, and the subclavius muscle (attached to the front of the supraspinatus) and the supraspinatus together create the rounded front edge of the shoulder form (located at the base of the side of the neck). In the ox, however, the supraspinatus alone creates the front of the shoulder form (the subclavius is deep). DOG AND FELINE

• Origin: Same as in the horse and the ox, except no scapular cartilage is present.

• Insertion: Single area of insertion on top of the humerus. Belly doesn't twist or split before inserting.

• Structure: Although it is mostly covered by thin muscle, the supraspinatus creates the front form of the shoulder.

Infraspinatus Muscle Horse

OUTSIDE VIEW < FRONT

OUTSIDE VIEW FRONT

HORSE OX DOG

Infraspinatus

HORSE AND OX

• Origin: Outer surface of the rear portion of the scapula and the adjacent cartilage.

• Insertion: Outer side of the top of the humerus.

• Action: Rotates the arm outward; pulls the limb away from the body.

• Structure: The infraspinatus lies on the outer surface of the rear portion of the shoulder blade. Its flat belly (lying on the flat surface of the scapula) contributes to the planar quality of the shoulder region.

The trapezius and latissimus dorsi cover the upper portion of the muscle, and the deltoid belly and its wide tendon cover the lower portion. Only a small part of the infraspinatus reaches the surface, although the portion covered by the wide tendon of the deltoid also directly creates surface form.

DOG AND FELINE

• Origin: Same as in the horse and ox, except there is no scapular cartilage.

Horse Cartilage

OUTSIDE VIEW FRONT

Pectoralis Cat

LION

LION

Teres major DOG AND FELINE

• Origin: Upper third of the rear edge of the shoulder blade. Feline: Also the adjacent surface of the infraspinatus muscle.

• Insertion: Short vertical line on the inner surface of the humerus approximately one fourth of the way down the bone. The teres major and latissimus dorsi insert together via a common tendon on the humerus.

• Action: Flexes the shoulder joint.

• Structure: The teres major is a narrow, slightly flattened muscle that comes to the surface only in the feline. In the other species, it is covered by the latissimus dorsi and the triceps. As it descends, it dives under the long head of the triceps. It can be seen directly where it is not covered by muscle, or indirectly through the latissimus dorsi, which is thin enough to reveal its form. The triceps is too thick to let the teres major show through. In the dog, the elongated form of the teres major may be evident on the surface under cover of the latissimus dorsi when it is strongly contracted while pulling the arm backward. Because the thick triceps muscle begins high on the scapula in the horse and the ox, the teres major remains hidden from view (the triceps originates lower down, on the rear edge of the scapula in the dog and the feline).

WIDE TENDON

Teres Minor Dog

Spinal portion Rear portion

WIDE TENDON

Spinal portion Rear portion

WIDE TENDON

Rear Deltoid Insertion

DELTOID Sea putar portion Acromial portion

WIDE TENDON

DELTOID Sea putar portion Acromial portion

WIDE TENDON

ALL LEFT FRONT LIMB

Deltoid Canine

ALL LEFT FRONT LIMB

WIDE TENDON

DELTOID Spinal portion portion

OUTSIDE VIEW OUTSIDE VIEW OUTSIDEVIEW

FRONT -4 FRONT FRONT

HORSE OX DOG

Deltoid

HORSE

• Origin: Spinal portion: Spine of the scapula and surface of the underlying infraspinatus muscle via a wide tendon. Rear portion: Upper back corner of the bony scapula

• Insertion: Into the outside of the humerus, one third of the way down the bone.

• Action: Flexes the shoulder joint and pulls the forelimb away from the body.

• Structure: The deltoid consists of two portions. The wider spinal (front) portion arises from the spine of the scapula and the surface of the infraspinatus as a wide, flat tendon before becoming fleshy. The more prominent rear portion is entirely fleshy, and it tapers at both ends.

• Origin: Acromial portion: Acromion at the lower end of the spine of the scapula and along the spine for a short distance. Scapular portion: Spine of the scapula via a wide tendon, and partly into the rear edge of the bony scapula one fourth of the way down the bone.

• Insertion: One third of the way down on the outside of the humerus. The scapular portion also inserts onto the surface of the lateral head of the triceps.

• Structure: The acromial portion originates from the acromion, as well as from the lower end of the spine. The scapular portion is quite flat and is made up of a wide front portion, which originates via a wide tendon, and a narrower rear portion, which originates directly from the rear edge of the scapula by fleshy fibers. Because the scapular portion inserts, in part, onto the surface of the triceps, the lower end of the deltoid is wider than in the other species where it tapers almost to a point.

DOG AND FELINE

• Origin: Acromial portion: Acromion at the lower end of the spine of the scapula. Spinal portion: Spine of the scapula. In the feline, the spinal portion originates from the lower two thirds of the spine.

• Insertion: One third of the way down, on the outside of the humerus.

• Structure: The larger spinal portion dives under the acromial portion toward the point of their common insertion. The spinal portion may begin as a fleshy belly directly at the scapular spine or as a wide flat tendon of varying size.

Extensor Carpi Radialis Horse

HORSE

BICEPS BRACH)I

LONG TENDON OF THE BICEPS

TENDON OF EXTENSOR CARPI RADIALIS

Flexor Carpi Ulnaris Horse

ALL LEFT FRONT LIMB

FRONT VIEW OUTSIDE ►

HORSE

BICEPS BRACH)I

LONG TENDON OF THE BICEPS

TENDON OF EXTENSOR CARPI RADIALIS

BICEPS BRACHII

ALL LEFT FRONT LIMB

BICEPS BRACHII

Biceps Tendon Insertion Shoulder

INSIDE VIEW FRONT ►

FRONT VIEW OUTSIDE ►

INSIDE VIEW FRONT ►

Biceps brachii

HORSE

• Origin: Bony prominence on the front of the lower end of the scapula.

• Insertion: 1. Inner front corner of the top of the radius. 2. Ligament on the inside of the elbow. 3. By a special long tendinous extension, into the tendon of the extensor carpi radialis muscle (and therefore indirectly into the front of the metacarpal bone).

• Action: Flexes the elbow joint; extends the shoulder joint (and locks the shoulder in place when the animal is in the standing position).

• Structure: The biceps brachii begins as a very strong, flattened tendon at its origin. After passing through a bony groove at the top of the humerus, it develops into a thick, fleshy belly, tapered at both ends. The lower end splits and inserts into the radius and the inner elbow ligament. Strong tendinous fibers running through the entire length of the belly, beginning at the tendon of origin above, emerge at the bottom of the muscle and form the long tendon of the biceps (lacerta fibrosus). The long tendon passes down the surface of the extensor carpi radialis muscle and soon joins its tendon, thereby gaining insertion into the metacarpal bone. This strong "cable," stretching from the shoulder blade to the wrist, prevents the shoulder from flexing when the animal is standing, reducing the muscular energy necessary to maintain that position. The muscular mass of the biceps brachii does not come to the surface in the horse, but rather adds muscle mass onto the front of the humerus.

• Structure: Similar to that in the horse, but the long tendon is less developed.

• Insertion: The lower end of the muscle splits into two tendons that insert into adjacent areas on the inside of the radius and ulna, just below the elbow joint.

• Structure: The biceps is slender, and the long tendon is not present. The lower end of the belly comes to the surface on the inside front of the elbow region.

FELINE

• Insertion: Into the radius only, just below the elbow joint. When the forearm is pronated, with the palm facing backward, the insertion area is on the rear side of the bone. As the forearm is supinated (with the palm rotating forward), the radius rotates, bringing the insertion area around toward the front.

• Action: Flexes the elbow joint; supinates the forearm, rotating the palm forward (or upward, depending on the position of the forearm).

In four-legged animals, only one head of the biceps is present. In primates, a second head is present, descending from the coracoid process of the scapula and inserting into the inside of the humerus.

Tensor Fasciae Antebrachii

OUTSIDE VIEW < FRONT

Veterinary Anatomy Elbow

ALL LEFT FRONT LIMB

OUTSIDE VIEW < FRONT

Brachialis

HORSE

• Origin: Upper third of the rear surface of the humerus.

• Insertion: Inner side of the radius near its top, slightly below and to the inside of the insertion of the biceps muscle.

• Action: Flexes the elbow joint.

• Structure: Beginning on the back of the humerus, the belly curves around the outside of the bone, passes in front of the elbow joint, and ends on the inside of the elbow region. Only a small piece of the outer side of the brachialis comes to the surface in front of the elbow joint.

• Insertion: Same as in the horse. In some small ruminants, the lower end of the brachialis splits and also inserts into an adjacent area on the ulna. DOG

• Origin: Upper half of the back of the humerus.

• Insertion: Inner side of the ulna, just below the elbow joint. Some fibers attach to the inserting end of the biceps tendon, thereby inserting indirectly into the radius.

FELINE

• Origin: From most of the length of the back of the humerus.

• Insertion: Inner side of the ulna, just below the elbow joint (not into the radius at all).

The brachialis is exclusively a flexor of the forearm. In animals that rotate the forearm (pronation and supination), like felines and primates, the brachialis inserts only into the ulna, and not into the radius (in these animals, supination is produced by the biceps brachii pulling on the radius). Animals that do not rotate the forearm, such as the horse and the ox, have a reduced ulna, and the brachialis inserts into the radius, producing only flexion at the elbow joint.

Tensor Fasciae Antebrachii

TRICEPS BRACH It Long head Lateral head

OUTSIDE VIEW FRONT

OUTSIDE VIEW -« FRONT

OUTSIDE VIEW ■4 FRONT

TRICEPS BRACH It Long head Lateral head

Triceps brachii HORSE AND OX

• Origin: Long head: Most or all of the rear border of the scapula. Lateral head: Curved ridge on upper outer surface of the humerus.

• Insertion: Side and top of the olecranon of the humerus (point of the elbow).

• Action: Long head: Both extends the elbow joint and flexes the shoulder joint. Lateral head: Extends the elbow joint only.

• Structure: Large fleshy muscle consisting of three or more heads. Only the long and lateral heads are visible; the medial head lies deep to the lateral head. The lateral head has a flattened, somewhat rectangular form. The long head is triangular. When the muscle is tensed, the rear edge straightens. When relaxed, the soft muscle mass drops down and produces a bulging form above (and separate from) the olecranon.

DOG AND FELINE

• Origin: Long head: Dog: Lower half to two thirds of the rear edge of the scapula. Feline: Lower one third to one half of the rear edge of the scapula.

• Structure: The long head separates into two forms—a higher, more forward part, and a lower, more posterior part. The two parts are separated by a furrow. In the dog, when the arm is stretched forward the medial head of the triceps, which originates from the inside of the shaft of the humerus, may be seen on the inside of the elbow region, directed toward its insertion on the olecranon.

The tensor fasciae antebrachii (dorso-epitrochlearis, scapulo-ulnaris)

is a wide, flat, thin muscle that lies deep to the triceps. It originates from the tendon of insertion of the latissimus dorsi muscle, and often from the upper end of the rear border of the bony scapula as well. It inserts into the inner side of the olecranon. Its action is to assist in extending the elbow joint. Only a narrow strip of the muscle may be visible past the rear edge of the long head of the triceps, usually most evident in the ox.

OUTSIDE VIEW FRONT

HORSE

OUTSIDE VIEW -« FRONT

OUTSIDE VIEW ■4 FRONT

Anconeus Proces

Anconeus DOG AND FELINE

• Origin: A line on the rear surface and outer back edge of the lower third of the humerus.

• Insertion: A line on the outer surface of the upper end of the ulna.

• Action: Extends the elbow joint.

• Structure: The anconeus is a short, strong, triangular muscle. The upper portion is covered by the lateral head of the triceps. The lower, exposed portion creates a small, simple, flat plane between the humerus and the ulna, below the bulging lateral head of the triceps.

In the horse and the ox, this muscle is completely covered by the lateral head of the triceps.

Anconeus Muscle Horse

Brachioradialis (Supinator longus) DOG AND FELINE

• Origin: A short line on the outer surface of the humerus, below the halfway point.

• Insertion: In the dog, three fourths of the way down the radius, on its inner front edge. In the feline, it inserts further down, into the top of the bony prominence on the inside of the lower end of the radius.

• Action: Flexes the elbow joint; supinates the forearm in the feline, rotating the palm inward then forward (the dog forearm does not supinate).

• Structure: This long, thin, flat muscle is developed in felines (and primates), reduced or absent in dogs, and absent in the horse and the ox. It begins on the outside of the humerus and descends downward and slightly inward on the front of the forearm, to end on the inner surface of the radius, above the wrist. Its upper end is covered by the lateral head of the triceps. In the domestic cat, there is a gap between the upper ends of the brachioradialis and the extensor carpi radialis.

Dog Left Lateral Carpus

OUTSIDE VIEW ■4 FRONT

FRONT VIEW OUTSIDE ►

ALL LEFT FRONT

Anumals Tendon Anatomy

OUTSIDE VIEW FRONT VIEW

ALL LEFT FRONT

OUTSIDE VIEW FRONT VIEW

HORSE

OUTSIDE VIEW ■4 FRONT

FRONT VIEW OUTSIDE ►

Extensor carpi radialis (Extensor metacarpi magnus)

HORSE AND OX

• Origin: Bony ridge on the outside lower third of the humerus.

• Insertion: Top of the front surface of the metacarpal bone (cannon bone of the horse).

• Action: Extends and locks the wrist joint; flexes the elbow joint.

• Structure: The extensor carpi radialis is the largest of the extensor muscles on the forearm. This powerful muscle lies on the front of the radius. Its fleshy belly begins flattened and faces outward at its origin, then shifts to the front of the limb, becoming oval in cross section. Two thirds of the way down the radius it develops into a wide flat tendon, which is joined by the long tendon of the biceps brachii from the front of the upper arm. The upper end of the muscle is covered by the lateral head of the triceps.

DOG AND FELINE

• Insertion: Upper ends of the front of the second and third metacarpal bones.

• Structure: In the dog and feline, the extensor carpi radialis is more slender than in the horse and the ox. In the dog, the lower end separates into two tendons, corresponding to the extensor carpi radialis longus and brevis. In the feline, the entire muscle is divisible into separate longus and brevis muscles.

Extensor Digitorum Communis Muscle

Extensor digitorum communis (Extensor pedis)

HORSE

• Origin: Extensive area from the outer front portion and outer ridge at the lower end of the humerus, the vertical ligament connecting the outer side of the humerus to the ulna (at the elbow), and the outer edge of the upper third of the radius.

• Insertion: Upper edge of the front of all three toe bones, primarily into the last one.

• Action: Extends the wrist joint and all three toe joints.

• Structure: The extensor digitorum communis travels from the elbow to the toe. Its muscle belly, tapered at both ends, often shows a groove down its length. It becomes tendinous two thirds of the way down the radius. A small tendon that branches off this tendon at the level of the bottom of the radius passes downward and outward to join the tendon of the extensor digitorum lateralis (shown here in side view). A deep head originates from an area on the outside of the ulna and adjacent radius; it is not visible on the surface.

• Insertion: Ultimately into the upper edge of the front of the last toe bone on both toes.

• Structure: The muscle consists of two distinct, parallel narrow bellies. The more forward belly sends a single tendon to the inner toe. The tendon of the other belly splits at its lower end and inserts into both toes.

DOG AND FELINE

• Origin: Outer side of the lower end of the humerus. In the feline, the origin continues upward for a short distance on the outer bony ridge of the humerus.

• Insertion: Last toe bone of the four outer toes.

• Structure: The single belly becomes tendinous two thirds of the way down the radius. In front of the wrist, the tendons diverge toward their insertions. The first and second digits have their own extensor muscle, the extensor digiti I & II, separate from the extensor digitorum communis (the second digit therefore receives two tendons). The belly of the extensor digiti I & II is located deep in the forearm under other muscles, but its very thin tendons come to the surface (see page 134). This muscle is typically found in species where first and second digits are present.

Supinator Muscle Dog

FRONT VIEW OUTSIDE ►

OUTSIDE VIEW FRONT

OUTSIDE VIEW < FRONT

FRONT VIEW OUTSIDE ►

FRONT VIEW OUTSIDE ►

OUTSIDE VIEW FRONT

OUTSIDE VIEW < FRONT

FRONT VIEW OUTSIDE ►

Extensor digitorum lateralis (Extensor suffraginis)

HORSE

• Origin: Upper fourth of the outer surface of the radius, part of the elbow ligament above, and an adjacent area on the ulna.

• Insertion: Upper edge on the front of the upper toe bone.

• Action: Extends the first toe joint.

• Structure: This is a narrow muscle lying on the outside of the forearm. Its belly becomes tendinous two thirds of the way down the forelimb. After passing over the outside of the wrist, the tendon descends diagonally toward the front of the limb, not quite reaching the midline. Below the wrist it receives a small tendon from the extensor digitorum communis. The lower portion of the belly is more visible on the surface than the upper part.

• Origin: Similar to the horse, but additionally from the lower end of the humerus, and less so from the shaft of the radius.

• Insertion: Upper edge of the front of the two lower toe bones of the outer digit.

• Action: Extends all the outer toe joints; flexes the elbow joint.

• Structure: The muscle belly is wider than in the horse, and it is visible throughout its length.

• Origin: Front edge of the vertical ligament on the outside of the elbow joint, and the upper end of the outer surface of the radius.

• Insertion: The three tendons of the extensor digitorum lateralis unite with the tendons of the extensor digitorum communis to ultimately insert into the last toe bone of the three outer digits (toes 3,4, and 5).

• Action: Extends all the joints of the three outer toes; extends the wrist joint.

• Structure: The elongated belly becomes tendinous two thirds of the way down the forearm, and then passes over the front of the wrist, toward the outside. It splits into two tendons; then the inner tendon splits again, forming three tendons in total.

FELINE

• Origin: The lower end of the bony ridge on the outside of the humerus (no attachment to the radius).

• Insertion: Same as in the dog, but into the outer four digits (toes 2-4).

• Structure: Lower end of the muscle belly separates into four tendons.

In the anatomy literature, among the different animal species, the extensor digitorum lateralis is described as inserting in various combinations into the top edges of the upper, middle, and terminal toe bones, as well as fusing into the sides of the tendons of the extensor digitorum communis of the outer toes.

Comic Legs Rear View

OUTSIDE VIEW REAR VIEW

OUTSIDE VIEW REAR VIEW

Ulnaris lateralis (Flexor metacarpi extern us)

HORSE

• Origin: Outer surface of the lower end of the humerus, behind the elbow joint ligament.

• Insertion: Top and outer surface of the accessory carpal (pisiform) bone of the wrist; upper end of the outer splint bone.

• Action: Flexes the wrist joint; extends the elbow joint. Although technically a part of the extensor group of the forearm, this muscle is functionally a flexor of the wrist joint because its main tendon inserts behind the wrist joint. It is therefore called the ulnaris lateralis rather than the extensor carpi ulnaris.

• Structure: Elongated, flattened muscle that lies on the outside of the forearm toward the rear. It begins on the outside of the elbow and, as it descends, inclines toward the midline on the back of the wrist. The muscle belly partially overlaps the extensor digitorum lateralis in front of it. Below, it separates into two tendons—a short, broad tendon to the accessory carpal bone, and a longer, thinner, rounded tendon to the splint bone. On the back of the wrist, its tendon to the accessory carpal bone is fused to the tendon of the flexor carpi ulnaris.

Accessory Carpal Bone DogFeline Carpal Bones

OUTSIDE VIEW REAR VIEW

• Insertion: Also into the top of the outer surface of the single metacarpal bone.

• Structure: Wider than in the horse, and less tapered at its ends. The lower portion of the muscle belly fuses with the belly of the flexor carpi ulnaris on the back of the forearm. They insert together as a single tendon into the accessory carpal bone.

Extensor carpi ulnaris

DOG AND FELINE

• Insertion: Top of the outer surface of the fifth, or outer, metacarpal bone. There is no insertion into the accessory carpal bone.

• Action: Extends the wrist joint.

• Structure: Elongated muscle, followed by a strong, broad tendon, which passes down the outside of the forearm and ends on the outside of the wrist.

ABDUCTOR DIGITI I LONGUS

Dog Accesory Carpal Bone

ABDUCTOR DIGITI I LONGUS

OUTSIDE VIEW ■4 FRONT

abductor digiti i longus i

FRONT VIEW OUTSIDE ►

OUTSIDE VIEW ■4 FRONT

FRONT VIEW OUTSIDE ►

HORSE

ABDUCTOR DIGITI I LONGUS

ALL LEFT FRONT LIMB

INSIDE VIEW FRONT ►

FRONT VIEW OUTSIDE ►

Abductor digit! I (pollicis) longus (Extensor carpi obliquus)

HORSE

• Origin: Middle section of the outer surface of the radius.

• Insertion: Head of the inner splint bone.

• Action: Extends the carpal joint.

• Structure: The flat, triangular muscle belly begins on the outside of the forearm, then curves down, around, and to the inside of the wrist, ending as a tendon. It emerges from under the extensor digitorum communis and then passes over the tendon of the extensor carpi radialis. It may produce a very subtle effect on the surface.

• Origin: Lower half of the outer surface of the radius and an adjacent area on the ulna.

• Insertion: Inner side of the upper end of the metacarpal bone. DOG AND FELINE

• Origin: Outer surface of the middle portion of the radius and the ulna.

• Insertion: Inner surface of the upper end of the first (inner) metacarpal bone.

• Action: Pulls the first digit away from the paw and extends it.

• Structure: More developed deep in the forearm in the feline than in the dog. Surface exposure is about the same in both.

Cat Anatomy Pronator Teres

Pronator teres DOG AND FELINE

• Origin: Inner surface of the lower end of the humerus. It is the forward-most attachment of all the flexor muscles.

• Insertion: Inner front edge of the radius, approximately a third to halfway down the bone.

• Action: Pronates the forearm, rotating it so the palm Is directed backward. It also flexes the elbow joint. Pronation is minor in the dog, because there is very little movement of the radius rotating around the ulna. In the feline, however, movement is fairly extensive because there is full pronation and supination of the forearm, and the muscle is therefore more developed.

• Structure: The pronator teres is the first muscle of the flexor muscles. Its cylindrical belly, passing downward and forward, lies on the upper third of the inside of the forearm.

The pronator teres is not present in the horse. In the ox, it is a weak, fibrous band, occasionally containing a few muscular fibers. It does not create surface form.

Dog Drawing Back Vieuw

INSIDE VIEW FRONT ►

REAR VIEW OUTSIDE

INSIDE VIEW FRONT ►

REAR VIEW < OUTSIDE

INSIDE VIEW FRONT ►

REAR VIEW OUTSIDE

HORSE

INSIDE VIEW FRONT ►

REAR VIEW < OUTSIDE

Flexor carpi radialis (Flexor metacarpi internus)

HORSE

• Origin: Lower end of the inner surface of the humerus.

• Insertion: Upper end of the rear surface of the inner splint bone.

• Action: Flexes the wrist joint; extends the elbow joint.

• Structure: Long, slightly flattened muscle belly becomes tendinous three fourths of the way down the forearm. The entire front edge lies up against the exposed radius.

• Insertion: Upper inner corner of the metacarpal bone. DOG AND FELINE

• Insertion: Upper end of the rear surface of the second and third metacarpals.

• Structure: The short, thick belly becomes tendinous halfway down the forearm; its tendon splits at the back of the wrist. The flexor carpi radialis is quite narrow in the feline.

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Responses

  • bisrat
    What is the action of the pectoralis profundus?
    7 years ago
  • jay
    How does the Pectoralis profundus (major) in a cat relate to a humans Pectoralis profundus (major)?
    7 years ago
  • Mathias
    What is the sacrocaudalis?
    7 years ago
  • mason
    Where is the triangular muscle in a dog?
    5 years ago
  • bella
    How to stretch dog tail ligament to straighten?
    5 years ago
  • Piia
    Where does the flexor digitorum profundus insert on a horse?
    5 years ago
  • giada
    What is the extensor carpi radialis in a dogs front leg?
    5 years ago
  • SAMUEL
    Where are tendons in dog front legs?
    5 years ago
  • Violetta
    Where is the pectoral muscle located on an animal?
    5 years ago
  • Luis Robertson
    Is it a muscle or tendon that is on the inside of dog flank?
    5 years ago
  • Muhammad
    What pectoralis inserts on the humerus?
    4 years ago
  • berta
    Where would the pectoralisprofundus be on a dog?
    3 years ago
  • CEDIVAR
    What are the main cutaneous muscles?
    5 months ago

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