This is a slender muscle with only one head.
Origin - The bottom part of the muscle splits into two tendons. These tendons insert next to each other
on the inside of the radius and the ulna just underneath the elbow joint.
Insertion - On the bony piece on the front of the lower end of the scapula
Action - Flexes elbow joint and extends shoulder joint
Deltoid muscle, O, I, A
This muscle is a superficial muscle that has two portions. The front portion which is
wider and arises from the scapulars spine and the acromial portion which is smaller and
tapers at both ends.
Origin - Acromial - acromion at the bottom end of the scapulars spine.
Spinal – scapulars spine
Insertion - On the outside of the humerus a third of the way down.
Action - Makes shoulder joint flex and pulls the foreleg away from the dog’s body
Infraspinatus muscle O, I, A
Contributes to the shoulders Form and shape.
Origin - outer top part of the scapula (infraspinous fossa).
Insertion - Into the outer side of the greater tubericle of the humerus.
Action - extend or flex shoulder joint, abduct shoulder, rotate arm laterally
and stabilize the shoulder joint.
Supraspinatus muscle O, I, A
Creates the form of the front shoulder
Origin - Top outer part of scapula
Insertion - with a thick tendon on greater tubericle of humerus
Action - Extends and stabilises shoulder joint
Brachiocephalicus muscle O, I, A
Has one insertion but hen splits into two thereafter.
Origin - Cleidocerphalicus - middle of the back of the front half of the neck
Cleidomastoid - Bottom of the skull behind the ear hole.
Instertion - Verticaly on the front of the humerus and its lower half.
Action - Pulls head forwards and neck and head down and to one side.
Splenius Muscle O, I, A
Adds to fleshy part of the dogs neck
Origin - Nuchal ligaments cord and tops of the spines of V3, V4, V5
Insertion - 5 points
1. Back of the skull (middle and top to mastoid process)
Action - both muscles together move neck up and head forward
One muscle moves neck to one side.
Sternocephalicus muscle O, I, A
Both sides fo body
Origin - manubrium (sternum)
Insertion - upper edge of the back end of the skull.
Bottom of the skull behind the mastoid process
Action and function - Muscles together move head up and down in a nod. One at a time move head to one side.
Rhomboideus muscle O, I, A
Thick muscle that has four sides and a very pointy front end.
Has two parts (neck and Chest) but is one muscle
Origin - V2, T6 and back of the skull.
Insertion - upper edge of the shoulderblade
Action - pulls top of shoulder up forwards and towards the body.
When shoulder is still it can lift the neck.
Omotransversarius muscle O, I, A
Thick full muscle that begins in the neck.
Origin - lower end and side of V1
Insertion - Bottom of scapulars spine and deltoids surface.
Action - when limb is fixed and still pulls neck to the side. When neck is fixed and still pulls limb forward.
Triceps Brachii muscle
This muscle is a big fleshy superficial muscle that has three heads, two long
heads and one lateral head.
Origin - Long head – on the rear edge of the scapula from the lower part until two thirds up.
Lateral Head – on the humerus’s curved ridge on upper and outer surface.
Insetion - At the humerus on the top and side of the olecranon (elbows point)
Action - Long Head – Flexes the shoulder joint and extends the elbow joint
Lateral Head – only extends the elbow joint
Latissimus Dorsi muscle O, I, A
A superficial muscle. It is a large thin muscle that is
triangular in shape.
Origin - On the Top of the spines muscles starting at the top of the shoulder to the tips of the lumbar
vertebrae as well as from the last two or three ribs.
Insertion - On the nearest middle part of the humerus.
Action - pulls leg backwards
Pectoralis Descendens muscle O, I, A
Origin - On the sternums front end
Insertion - In the middle of the front of the humerus, it inserts on the short vertical line.
Action - Advances forelimb and pulls the forelimb to the center of the body
Pectoralis Transversus Muscle O, I, A
Is a flat and rectangular shaped muscle.
Origin - It starts at the front portion of the sternum and goes down to the level where the fourth rib is.
Insertion - It inserts in a line that runs down most of the front of the humerus.
Action - Pulls forelimb towards the middle line of the body
Pectoralis Profundus O, I, A
Origin - On the majority of the sternum (not the front tip) and from the surface of the front part of the abdomen where the xiphoid process is.
Insertion - On the top inside surface of the humerus, and vertically from the upper third till the upper half of the front of the humerus.
Action - adducts foreleg and moves it backwards with movement
Trapezius Muscle O, I, A
triangular shaped superficial muscle. It is divided into two smaller triangular shaped muscles by a by a thin tendinous area
Origin - On the Middle of the bottom section of the back of the neck and the front section of the thorax starting at the third neck vertebra and ending at the ninth thoracic vertebra.
Insertion - Neck - top three fourths of the scapulars spine
Thoracic – top one third of the scapulars spine
Action - Draws scapula up, backward and forward and lifts neck
Longissimus Dorsi Muscle O,I,A
it is the biggest and longest muscle in spine
Origin - On the inside of the deep surface of the ilium’s pelvic wing and its crest, also on the top bonny bits of the spinous process in the lumbar vertebrae.
Insertion - On the upper ends of all the ribs, the sides of all the thoracic and all the lumbar vertebrae, and on the side of the sixth neck vertebrae.
Action - Stretches and straightens back and loins, lateral flexion
Serratus Ventralis Muscle O, I, A
A deep layer muscle that is divided into two portions The Neck portion and the Chest portion.
Origin - Neck - On the sides of third or the fourth vertebrae down to the seventh vertebrae.
Chest – On the sides of the lower parts of the first eight or nine ribs of the dog.
Insertion - Deep surface of the top half of the scapula.
Action - Pulls the top of the shoulder blade forwards, lifts and bends (neck)
Pulls shoulder blade back and down and rotates the blade (chest)
Normal canine shoulder landmarks
Right= lateral rad
Left = caudocranial
Normal canine shoulder with attachment sites. What are the 2 ligaments and 1 tendon?
Lateral rad- note margin of joint capsule
Normal canine should with attachment sites for muscles and tendons
Dog body references
thorax carriage muscles