BOXER FOREQUARTERS AND ITS FUNCTION
By Edward M. Gilbert Jr.
Copyright © 2006 by Gilbert’s K-9 Seminars (First published in “The Boxer Ring.”)
The Boxer in 2005 dominated the AKC show ring. I consider the Boxer as the strongest breed in the Working Group in 2005. Boxers took two of the top six placings in All-Breed competition and five of the top six Working Group standings in 2005. Class competition has depth of quality. This has come about due to excellent breeders that keep the Standard in mind. Exhibitors and handlers have contributed their share by properly conditioning their dogs for the show ring. The parent club, American Boxer Club, has for some years put a strong emphasis on education – and it is, and has been paying off.
The Boxer forequarters can not be looked at in isolation, the entire dog needs to be considered. The most perfect forequarters is meaningless without a proper body and a balanced rear assembly to complement it. The forequarters of the Boxer supports 60% of the weight of the dog, this weight is primarily due to the head and neck assembly. In the show ring trot the forequarters assist in propulsion and movement.
The Boxer forequarters are attached to the body by muscle, ligaments and tendons.
The muscular system of the Boxer is composed of the muscles and their surrounding connective tissue structures, and the blood vessels, nerve endings, and lymphatic channels that supply them. The skeletal system is composed of the bones, joints and ligaments that make up the supporting and protective portions of the body that provide for rigidity and bodily movement. The skeleton represents the body frame upon which the soft tissues depend for support. In addition, the bones comprise an essential storage system for minerals such as calcium, magnesium, phosphorous and fluoride. Bone marrow, deep within the long bones, is the source of both red and white blood cells. The different components of these systems all interact with each other to various extents, to produce the functional living canine.
Canine locomotion is primarily determined by the muscles, skeleton and the nervous reflex system and their interactions. The other systems mentioned above must be in proper working condition in order for proper locomotion to occur. This discussion concentrates on the muscles and skeleton and assumes the canine is in excellent health and has no problems in the other systems that would affect the locomotion.
In discussing dogs the major bones are referred to – but bones are meaningless without the proper muscle, ligament and tendons to hold them in place and provide movement to these levers. Also the nervous reflex system is a major factor in movement. Of the 92 bones in the forequarters there are 46 bones in one leg of the Boxer forequarters. There are 16 sesamoid bones in each leg whose function is to alter the course of tendons and protect tendons in the areas where the greatest friction is developed.
The forequarters are attached to the body by muscle. To a limited extent the shoulder blade can slide in any direction more or less parallel with the rib cage. If the dog has poor muscle attachment, the forequarters may move in undesirable directions. The forequarter is made up of the shoulder blade, which articulates with the upper arm at the shoulder joint (ball and socket joint); the upper arm, which articulates with the forearm (hinge joint); the forearm consists of the radius and ulna; the wrist consisting of seven carpal bones; the front pastern consisting of five metacarpal bones; and the forefoot which consists of 12 phalange or toe bones. The forelegs which comprise the forearm and front pastern must be straight, parallel to each other when seen from the front and have strong bone.
When bone is discussed in a standard is must be realized that what is seen and felt by the hand is the total combination of bone, muscle, ligaments, tendons and fascia. Standards refer to this combination as bone.
More than 53 muscles act upon the forelimb. Each of these muscles acts in conjunction with a number of other muscles, and the direction of pull on the skeletal part is due to the sum of the forces applied by individual muscles.
The upper end of the shoulder blade is attached to the backbone (thoracic vertebrae) by a portion of the trapezius muscle. This attachment is to the third through the ninth thoracic vertebrae and the spine of the shoulder blade. The area from the first to the ninth thoracic vertebrae is called the withers. The forward portion of this muscle connects from the neck to the spine of the shoulder blade. The trapezius muscles of the dog are firmly attached at the withers and prevent the shoulder blade from sliding above the height of the withers. The action of this muscle is to raise the foreleg and pull it forward.
The highest part of the shoulder blade lies just below the level of the first and second vertebrae. The spine on the shoulder blade points to the highest part of the shoulder blade. The shoulder blade is long and sloping, close lying to the rib cage, and well attached to the body. The shoulder blade is not excessively covered with muscle, as this provides unnecessary weight which will result in a loss of endurance.
The front assembly angulation varies as a function of age, maturity, conditioning, and the height and slope of the thoracic vertebrae – particularly the first through ninth, and the rib cage assembly. In particular the amount of layback of the ribs in relation to the vertebral column affects movement.
The primary function of the shoulder blade is to oscillate (move regularly) back and forth, thus aiding the front legs to swing back and forth. For the average shoulder blade the muscles are capable of rotating the blade about 30 degrees (15 degrees in each direction from the stationary position.) The oscillation of the shoulder blade allows absorption of shock as the feet touch the ground; it assists in lifting the feet off the ground on the forward motion of the leg; it increases reach; it adds to forward propulsion.
Because of the ball and socket type shoulder joint, the front may have faults unlike the rear such as paddling, weaving and out at the elbows. Most of these faults are due to improper conditioning – either not in condition or over-conditioned.
The head of the upper arm fits into the socket, or glenoid cavity, on the lower end of the shoulder blade. The shoulder joint is of the ball and socket variety. Although the shoulder joint can move in all directions, muscles along with the form of the cavity in general restrict greater motion to the fore and aft plane. Other joints in the forequarters are of the hinge type - they more or less restrict motion to the fore and aft plane.
The upper arm is the humerus and is the largest bone in the forequarters. It is longer than the shoulder blade. The lower end of the humerus articulates with the radius and ulna, or forearm, at the elbow joint. The upper arm is longer than the shoulder blade and approaches a right angle to the shoulder blades. The elbows are not pressed too closely nor standing off too far from the chest wall. Overdeveloped or loaded shoulders will result in an out at the elbow condition.
The brisket is deep, reaching down to the elbows; the depth of the body at the lowest point of the brisket equals half the height of the dog at the withers. The ribs, extending far to the rear, are well arched but not barrel-shaped. Chest of fair width and forechest well defined, being easily visible from the side. The loins are short and muscular; the lower stomach line, lightly tucked up, blends into a graceful curve to the rear. This structure is required for a proper front assembly as it provides the proper lung and heart room for excellent Boxer movement.
The forearm, radius and ulna bones, are perpendicular, long with firm, lean muscles. Forelegs seen from the front, are straight, parallel, with strong bone. The radius is the main weight bearing bone in the forequarters. The ulna is joined along its length to the radius such that the two bones act as one. At the top of the ulna is the olecranon process which is referred to as the point of elbow. The bottom end of the forearm articulates at the wrist joint with the top row of seven carpal bones.
The carpal bones join to the top of the metacarpal bones. The five metacarpal bones comprise the front pastern. The front pasterns are strong, short and clearly defined, slightly slanting almost vertical, but standing almost perpendicular to the ground.
The lower end of the metacarpals join to the forefoot. The forefeet are small, round, compact turning neither in nor out, with well-arched toes and with thick cushioned and hard pads. The forefeet are larger than the rear feet by a ratio of 60 to 40.
The most important feature of the forequarter assembly affecting movement is its relationship to the overall balance of the Boxer. As the Standard states: “In judging the Boxer first consideration is given to general appearance and overall balance. Special attention is then devoted to the head, after which the individual body components are examined for their correct construction, and the gait evaluated for efficiency.”