ANATOMICAL, HYSTOLOGICAL STRUCTURE AND BIOMECHANICS OF THE COCKPIT
ANATOMICAL STRUCTURE OF THE HORSE FACE
The bony base of the finger is made up of the puto, corona, hoof, shuttle and two sesamoid bones.
The sesamoid bones of the I phalanx, located on the back of the prosthetic joint, form a wide trough, along which tendon flexors of the finger (surface and deep) slip.
The bones of the horse's finger form three joints: pivot, coronal and ungulate. Each of them has its own joint capsule and a number of auxiliary ligaments that fix the bones in one or another position (Figure 1.1).
In the process of historical development there was a transformation of the paw, it began to rise above the ground. At the same time, the reduction of the paw rays, not participating in supporting to the ground, occurred. Thus, in the horse, the pastern (plyus) and the first two phalanges of the third finger were elevated above the ground and formed a unified structure of the free limb, supporting
Fig. 1.1. Sagittal section of the horse's hoof:
/- II phalanx; 2 - the shuttle bone; 3 - III phalanx; 4 - the subcutaneous layer; 5 - the basis of the skin; b - extensor tendon; 7 - capsule of the ungulate joint; 8 - the base of the skin of the border with papillae; 9 - the subcutaneous layer of the border and corolla; 10 - the base of the skin of the corolla; 11 - the basis of the skin of the wall; 12 - leaves of the skin; 13 - periosteum; 14 - The horn wall of the horn; 15 - white line; 16 - horn sole; 17 - the base of the leather soles; 18 - horn arrow; 19 - shuttle-hoofed bundle; 20 - subcutaneous layer of crumb; 21 - base of crumb skin with papillae; 22 - the shuttle bursa; 23 - tendon sheath; 24 - tendon of the deep flexor of the finger; 25 - a direct ligament of the sesamoid bones
The body, as an addition, an elongating limb that allows you to capture more space while moving, and, therefore, contributes to the speed and ease of running.
The horse is characterized by one more formation, which is absent in other animals - these are crumby cartilages; they cover the crumbs from the sides and soften the blows when hooves rest on the ground.
ANATOMY OF FINGER BONES
Putative bone (I phalanx, os phalangis primae). It lies between the metacarpal and two sesamoid and coronary bones, it is directed from the top down, forming an angle of 130 ... 140 ° on the thoracic bone and 150 ° on the hind limbs. It distinguishes two ends - proximal and distal, and two surfaces - dorsal and palmar, passing without sharp boundaries to the lateral edges.
At the proximal end is a slightly deepened articular area, divided by a groove in the sagittal direction for articulation with the metacarpal (metatarsal) bone; palmarno protrude the mounds for attaching ligaments.
The distal end is a cushion with a groove almost in the middle for articulation with the coronoid; Side are the ligamentous tubercles and ligamentous fossae. Dorsal surface convex and smooth; The palmar (plantar) is almost flat, with a triangular rough surface for attaching the tangles of the joint. Towards the distal end, the putative bone becomes thinner.
Venous bone (II phalanx, os phalangis secundae). It is located between the stump, hoofed and shuttle bones and has the same direction with the correct position of the phalanx.
The proximal part of the coronary bone is broader than the distal and considerably protrudes posteriorly. This ledge, covered from the palmar side with fibrous cartilage, is a roller for sliding the tendon of the deep flexor of the finger. On the articular surface of the proximal end there are two pitlike areas for articulation with the platen of the prostrate bone.
The distal end in front is at the border with the upper edge of the horny capsule; behind, from the side of the palmar surface, the coronoid is almost half hidden in the horn capsule. The distal end joins with the hoofed and shuttling bones (Figure 1.2).
Hoof bone (III phalanx, os phalangis tertiae, os ungulae). Entirely enclosed in a horny shoe. It is divided into three surfaces: dorsal, or wall (facies dorsalis); proximal, or articular (facies articularis); and the distal or plantar (facies solearis) (Figure 1.3).
Fig. 1.2. Bones of a horse's finger:
a - dorsal surface; b is a palmar (plantar) surface: 1 - a putative bone; 2 - coronary; 3 - Hoof bone
The hoof bone corresponds to the shape of the hoof. It looks like a truncated cone turned by a broad base to the ground, somewhat elongated posteriorly, with an obliquely cut deep facies articularis, which is in contact with the ridge of the distal end of the coronary bone.
The anterior dorsal contour of the coffin bone is a continuation along the straight line of the contour of the coronoid bone. The hoof bone is entirely hidden inside the horn capsule, with most of it located in the region of the anterior half of the hoof. Behind the cone bone cone is supplemented by two processes - ungulate bone branches (rami ungulae), located inside the lower lateral parts of the horn capsule and serving as the basis for fixing the cartilage cartilages. The latter are, as it were, the extension of the branches of the hoof bone up and back.
Thus, the branches of the hoof bone together with the cartilage form two lateral walls of the rear part of the hoof with a rather wide
Fig. 1.3. Hoof bone:
a - lateral and dorsal surfaces:/- extensor process; 2 - articular surface; 3 - branch; b - sole surface:/- bending surface
kim and deep space between them, this space is filled with the shuttle bone, ligaments, the shuttle bursa, the end of the tendon of the deep flexor of the finger and crumb, forming the back contour of the hoof.
The articular surface is covered with hyaline cartilage, it is a small depression with a sagittal crest dividing this depression into a medial, somewhat larger, part and lateral - smaller. At the anterior margin of the articular surface there is an extensor, or coronary processus (processus extensorius, processus coronarius), serving as a kind of splash that prevents excessive unbending of the hoof joint forward, and the attachment point of the tendon of the common extensor of the finger on the thoracic limb and the tendon of the long extensor of the finger on the pelvic.
The wall surface of the hoof bone is porous, with a large number of holes for passage of blood vessels and nerves. In normal ungulates, the outer (lateral) part of the wall surface is more inclined, and the inner (medial) bone is more steep. This feature, as well as a more pronounced depression on the medial side of the articular surface, makes it possible to distinguish the ungual bone of the right limb from the same bone of the left limb.
The plantar surface is broad, divided by a
Shuttle bone (Sesamian bone III phalanx, os naviculare, os sesamoideium phalangis tertiae). Has a flat oblong shape, reminiscent of the shape of a weaving shuttle, and why it got its name. It is placed between the branches of the ungulate bone on the posterior surface of the distal end of the coronary bone, with which it joins.
On the palmar (plantar) surface of the shuttle bone there is the subcortical synovial bursa (bursa podotrochlearis), above which the tendon of the deep flexor of the finger passes. These three anatomical elements (shuttlebone, bursa and tendon) form a shuttle block through which the deep flexor tendon slides.
The front surface of the shuttle bone is covered with cartilage, slightly concave and complements the articular surface of the hooves -
of the bone. To the upper rough edge of the shuttle bone is attached the shuttle-putt , or hanging , ligamentum Suspensorium, going to the lateral surfaces of the marrow.
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