Equine Skeletal System

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Equine Skeletal System
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• Axial Skeleton contains bones in the trunk area.
• Skull
• Spine (Vertebral column)
• Ribs
• Breastbone (Chest cavity)
• Pelvis
• Tail

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• Skull bones flat, irregular in shape
• Forms framework for the brain, mouth, eyes
  nasal cavity.
• Vertebral column flexible column of small bones
  (vertebrae)
• Hip bones two large flat bones attached to the
  spine and sacrum that forms the pelvis or pelvic
  girdle
• Ribs Breastbone (Sternum) along with thoracic
  vertebrae form the chest cavity

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• Appendicular Skeleton forelegs and hindlegs
  used for locomotion, grooming, defense and
  feeding
• Forelegs connected to axial skeleton by
  muscles, not skeletal attachments
• Hindlegs attached to pelvis at the hip joint

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• Articulations (joints) the union of two or more
  bones or cartilages held together by ligaments,
  tendons, or a tough fibrous capsule
• Joints classified by structure and move ability
• Free moving joints contain a joint cavity between
  the two surfaces, bones covered with smooth
  cartilage and held together by ligaments

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Equine Muscular System
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• - Only in heart
• Muscles red, lean meat, composes 50 of total
  body weight. Stimulated to contract or change
  shape by nerve impulses from the brain, then
  sends nerve impulses back to brain indicating the
  degree of contraction so movement is smooth.

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Three Basic Muscle Types

• 1. Smooth muscles (involuntary)
• Visceral muscle
• Location Digestion system Uterus
• Prolonged activity w/o fatigue

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• 2. Cardiac Muscle (Involuntary Striated)
• - Contractions require no nerve stimulus
• - Rhythmic contractions with no conscious
  control

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• 3. Striated, Skeletal Muscles attached to bones
  of skeletal system either directly or by tendons
  and act voluntarily.
• A. Bones serve as levers and muscles move the
  body voluntary.
• B. Arranged in opposite sets one set of
  muscles bend the limb (flexor muscle), one set
  straightens the limb (extensor muscle)
• C. Voluntary muscles become fatigued need
  short rest periods.

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• Tendons eliminate undue friction, allows muscle
  to move freely.
• A. Tendon sheath is a synovial sac through
  which a tendon passes. Synovial lubricates
  the surrounding tendon.
• B. Tendon bursa is a synovial sac interposed
  between the tendon and the surface over which it
  comes in contact which lubricates and cushions
  the tendon.
• C. Both found near joints

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Tendons are fibrous cords of connective tissue
attaching muscle to bone, cartilage or other
muscle. Tendons insert into bone or cartilage by
means of small spikes known as Sharpeys
fibres.
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Functional Anatomy

• Flexors bend the limb
• Decrease angle of a joint
• Examples Teres major (front leg), Iliacus (hind
  leg)

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Functional Anatomy

• Extensors straighten the limb
• Increase the angle of a joint
• Examples Brachiocephalicus (front leg),
  Gluteus medius (hind leg)

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Functional Anatomy

• Abductors
• Move a limb away from the center plane of the
  equine
• Example Deltoid (front leg)

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Functional Anatomy

• Adductors
• Pulls a limb toward the center plane of the
  equine
• Example Pectoral muscles (front leg)

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Digestive System

• Digestive system converts feed into a form to use
  for maintenance, growth and reproduction. Parts
  mouth, pharynx, esophagus, stomach, intestines,
  anus, liver, teeth, pancreas and salivary glands
• A. Rate of feed passage through stomach (30
  minutes to 2 hours) Feed passes through S. I.
  Rapidly. Feed not digested and absorbed in the
  S. I. passes into the cecum (colon) w/n 2 to 4
  hours

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• B. Grinding decreases feed size
• Increases rate of passage, decreases absorption
  of nutrients
• C. Large amounts of concentrates, overwhelming
  the digestive capacity of the stomach and S.I.,
  can ferment and produce gas or lactic acid
  causing colic or founder if they pass through the
  cecum

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• Mouth extends from lips to the pharynx. Bounded
  on the sides by cheeks, above by hard palate and
  below by tongue
• Pharynx is muscular, funnel like tube from back
  of mouth to esophagus directs food and serves as
  air passage.
• Esophagus extends from the pharynx down left side
  of neck through thoracic cavity and diaphragm to
  stomach at an angle which makes regurgitation
  impossible

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• Stomach U-shaped muscular sac at front of
  abdominal cavity. Makes up less than 10 of
  total digestive capacity for the adult
• Small Intestine 2 in diameter tube. Site of
  most nutrient absorption. 30 of total digestive
  capacity.

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(1) Anus. (2) Rectum. (3) Base of caecum. (4)
Small intestine. (5) Kidney. (6) Liver. (7)
Diaphragm. (8) Oesophagus. (9) Large colon. (10)
Caecum. (11) Small colon
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• Large Intestine consist of cecum, large colon,
  small colon, rectum and anus
• Cecum Colon 65 of digestive capacity.
  Enlarged to allow bacteria time to break down
  large quantities of cellulose
• Small colon extends from large colon to the
  rectum. Place where balls of dung formed.
  Moisture is reabsorbed in L. I. Creating solid
  contents