Equine Anatomy and Physiology
Expert-defined terms from the Certificate Programme in Equine Therapy for Meditation course at LearnUNI. Free to read, free to share, paired with a globally recognised certification pathway.
Acetabulum #
The socket part of the hip joint where the head of the femur fits. It is formed by the fusion of three pelvic bones: the ilium, ischium, and pubis.
Adipose Tissue #
A type of connective tissue that stores energy in the form of fat. It provides insulation and cushioning for organs and structures in the body.
Agonist #
A muscle that contracts to produce a specific movement at a joint. It is also known as the prime mover.
Alveolus #
The small sacs in the lungs where gas exchange occurs. Oxygen is absorbed into the bloodstream, and carbon dioxide is released from the bloodstream into the alveoli to be exhaled.
Aorta #
The largest artery in the body that carries oxygenated blood from the heart to the rest of the body. It originates from the left ventricle of the heart.
Articular Cartilage #
The smooth, white tissue that covers the ends of bones where they meet to form joints. It helps reduce friction and absorb shock during movement.
Atlas #
The first cervical vertebra (C1) in the spine, which supports the skull and allows for nodding movements of the head.
Autonomic Nervous System #
The part of the nervous system that controls involuntary functions such as heart rate, digestion, and respiration. It is divided into the sympathetic and parasympathetic divisions.
Axial Skeleton #
The part of the skeleton that includes the skull, vertebral column, ribs, and sternum. It provides support and protection for the vital organs of the body.
Biceps #
A muscle located on the front of the upper arm that flexes the elbow joint and supinates the forearm.
Calcaneus #
The largest bone in the foot, commonly known as the heel bone. It provides attachment for several muscles and ligaments involved in movement and stability of the foot.
Canine Teeth #
The pointed teeth located between the incisors and premolars in the mouth of horses. They are used for tearing and cutting food.
Cardiovascular System #
The organ system responsible for transporting nutrients, oxygen, hormones, and waste products throughout the body. It includes the heart, blood vessels, and blood.
Carotid Artery #
The major artery located on each side of the neck that supplies blood to the brain, face, and neck. It is a common site for pulse measurement.
Cartilage #
A tough, flexible connective tissue found in various parts of the body, such as the joints, ears, and nose. It provides cushioning and support for bones and other structures.
Caudal #
Refers to the tail end or rear portion of the body. It is the opposite of cranial, which refers to the head end or front portion of the body.
Cecum #
A pouch-like structure located at the beginning of the large intestine in horses. It plays a role in digesting fibrous plant material through fermentation by bacteria.
Cervical Vertebrae #
The seven vertebrae of the neck region that support the head and allow for a wide range of motion. They are numbered C1 to C7, with C1 being the atlas and C2 being the axis.
Chondrocyte #
A cell found in cartilage tissue that produces and maintains the extracellular matrix. It plays a vital role in cartilage growth, repair, and maintenance.
Clavicle #
A long bone located in the shoulder region that connects the scapula to the sternum. It provides support and mobility for the shoulder joint.
Coccyx #
The small, triangular bone at the base of the spine, also known as the tailbone. It is made up of fused vertebrae and provides attachment for various muscles and ligaments.
Common Digital Extensor Tendon #
A tendon that extends the fetlock, pastern, and coffin joints in the front limb of horses. It runs along the dorsal surface of the limb and helps support weight-bearing.
Coronary Band #
The junction between the skin and hoof of a horse where the hoof wall begins to grow. It is a critical area for hoof health and growth.
Cranial #
Refers to the head end or front portion of the body. It is the opposite of caudal, which refers to the tail end or rear portion of the body.
Cremaster Muscle #
A thin layer of muscle that covers the spermatic cord in males and aids in temperature regulation of the testes. It contracts to bring the testes closer to the body for warmth or relaxes to move them away for cooling.
Cricoid Cartilage #
A ring-shaped cartilage located at the base of the larynx or voice box in the throat. It provides structural support and protection for the vocal cords.
Cruciate Ligaments #
A pair of ligaments in the stifle joint that cross over each other to provide stability and support. The cranial cruciate ligament (CCL) and caudal cruciate ligament (CrCL) prevent excessive movement of the femur on the tibia.
Deltoid Muscle #
A large muscle located on the shoulder that helps to abduct, flex, and extend the arm at the shoulder joint. It is divided into three parts: anterior, middle, and posterior deltoid.
Dental Pad #
A thick, flat structure made of firm connective tissue located on the upper jaw of some herbivores, such as horses and cattle. It is used to grind and chew fibrous plant material.
Diatomaceous Earth #
A naturally occurring sedimentary rock made up of fossilized diatoms, a type of algae. It is commonly used as an insecticide or dewormer for horses due to its abrasive properties.
Digestive System #
The organ system responsible for processing food, extracting nutrients, and eliminating waste from the body. It includes the mouth, esophagus, stomach, intestines, liver, and pancreas.
Digital Cushion #
A specialized structure located in the hoof of a horse that provides shock absorption and support for the coffin bone. It helps distribute weight evenly and reduce stress on the joints.
Dorsal #
Refers to the upper or back side of the body. It is the opposite of ventral, which refers to the lower or front side of the body.
Endocrine System #
The system of glands that produce hormones to regulate various bodily functions, such as metabolism, growth, and reproduction. It includes the pituitary, thyroid, adrenal, and pancreas glands.
Endothelium #
The thin layer of cells that lines the interior surface of blood vessels, lymphatic vessels, and the heart. It plays a crucial role in regulating blood flow, immune response, and nutrient exchange.
Epaxial Muscles #
The group of muscles located on the dorsal or back side of the body that extend and stabilize the vertebral column. They include the longissimus, iliocostalis, and spinalis muscles.
Epiglottis #
A flap of cartilage located at the base of the tongue that covers the entrance to the trachea during swallowing to prevent food from entering the airway. It is an essential structure for proper breathing and swallowing.
Equine #
Refers to horses or members of the horse family, including domesticated horses, donkeys, and zebras. It is commonly used in veterinary and equestrian contexts.
Esophagus #
The muscular tube that connects the mouth to the stomach and carries food and liquids to be digested. It uses peristaltic contractions to move contents down to the stomach.
Extensor Carpi Radialis Muscle #
A muscle located on the front of the forearm that extends and abducts the wrist joint. It helps support weight-bearing and stabilizes the carpus during movement.
External Intercostal Muscles #
The muscles located between the ribs that help expand the chest cavity during inhalation. They assist in breathing by lifting the ribs and increasing lung volume.
Fascia #
A band or sheet of connective tissue that surrounds muscles, organs, and other structures in the body. It provides support, protection, and allows for movement between structures.
Femoral Artery #
The major artery in the thigh that supplies blood to the lower extremities. It is a common site for pulse measurement in horses and other animals.
Femur #
The long bone located in the thigh that connects the hip joint to the knee joint. It is the largest and strongest bone in the body and plays a crucial role in weight-bearing and movement.
Fetlock Joint #
The joint located between the cannon bone and pastern in the lower limb of a horse. It allows for flexion and extension of the limb and provides shock absorption during movement.
Fibula #
The smaller of the two bones in the lower leg, located on the outside of the tibia. It provides muscle attachment and support for the ankle joint.
Flexor Digitorum Profundus Muscle #
A muscle located on the back of the forearm that flexes the fingers or digits of the hand. It helps grip objects and perform fine motor movements.
Frontal Sinus #
A pair of air-filled cavities located in the frontal bone of the skull. They help reduce the weight of the skull and provide resonance for vocalization.
Gait #
The pattern of movement of a horse's legs during locomotion, such as walking, trotting, cantering, and galloping. Each gait has a specific footfall sequence and rhythm.
Gall Bladder #
A small organ located under the liver that stores and concentrates bile produced by the liver. It releases bile into the small intestine to aid in digestion and absorption of fats.
Gastrocnemius Muscle #
A muscle located on the back of the lower leg that flexes the knee joint and extends the ankle joint. It is commonly known as the calf muscle.
Gastrointestinal Tract #
The series of organs that make up the digestive system, including the mouth, esophagus, stomach, small intestine, and large intestine. It is responsible for processing food and absorbing nutrients.
Glottis #
The opening between the vocal cords in the larynx that allows air to pass into the trachea during breathing and sound production. It can close to prevent food and liquids from entering the airway.
Hard Palate #
The bony structure that forms the roof of the mouth and separates the oral and nasal cavities. It plays a role in chewing, swallowing, and speech production.
Heart #
The muscular organ that pumps blood throughout the body to deliver oxygen and nutrients to tissues and organs. It consists of four chambers: the left and right atria and ventricles.
Hematopoiesis #
The process of blood cell formation that occurs in the bone marrow. It produces red blood cells, white blood cells, and platelets to maintain proper blood function.
Hepatic Portal System #
The system of veins that carries nutrient-rich blood from the intestines to the liver for processing and detoxification. It plays a crucial role in metabolic functions and nutrient distribution.
Hindgut Fermentation #
The process of microbial digestion that occurs in the cecum and colon of horses. It breaks down fibrous plant material into volatile fatty acids for energy production.
Hock Joint #
The joint located in the hind limb of a horse between the tibia, fibula, and tarsal bones. It allows for flexion and extension of the limb and provides support during weight-bearing.
Humerus #
The long bone located in the upper arm that connects the shoulder joint to the elbow joint. It provides attachment for muscles that move the shoulder and elbow.
Hyoid Bone #
A U-shaped bone located in the neck that supports the tongue and larynx. It plays a role in swallowing, speech production, and head movement.
Ileum #
The final portion of the small intestine that connects to the large intestine. It absorbs nutrients and water from digested food before passing waste to the colon.
Ilium #
The largest and most superior pelvic bone that forms the hip joint with the femur. It provides attachment for muscles and supports the weight of the body during movement.
Inferior Vena Cava #
The large vein that returns deoxygenated blood from the lower body to the right atrium of the heart. It plays a crucial role in circulation and oxygen delivery.
Inguinal Canal #
A passage in the abdominal wall that allows structures such as blood vessels and nerves to pass between the abdomen and the groin. It is a common site for hernias in horses.
Innervation #
The supply of nerves to a specific organ or structure in the body. It allows for communication between the central nervous system and peripheral tissues.
Integumentary System #
The organ system that includes the skin, hair, hooves, and glands. It provides protection, regulation of body temperature, and sensory perception.
Internal Intercostal Muscles #
The muscles located between the ribs that help compress the chest cavity during exhalation. They assist in breathing by lowering the ribs and reducing lung volume.
Iris #
The colored part of the eye that surrounds the pupil and controls the amount of light entering the eye. It adjusts the size of the pupil to regulate light intensity.
Ischium #
The lower and posterior pelvic bone that forms part of the hip joint with the femur. It provides attachment for muscles and supports the weight of the body during movement.
Jejunum #
The middle portion of the small intestine located between the duodenum and ileum. It plays a significant role in nutrient absorption and digestion.
Kidney #
The pair of organs located in the abdominal cavity that filter blood to remove waste and regulate fluid balance. They produce urine, maintain electrolyte balance, and control blood pressure.
Lacrimal Gland #
The gland located in the eye socket that produces tears to lubricate and protect the surface of the eye. It helps maintain moisture and clarity for vision.
Larynx #
The cartilaginous structure located in the throat that houses the vocal cords and controls airflow during breathing and sound production. It plays a crucial role in speech and swallowing.
Large Intestine #
The final portion of the digestive tract that includes the cecum, colon, and rectum. It absorbs water and electrolytes from undigested food before eliminating waste as feces.
Lateral Collateral Ligament #
A ligament located on the outside of the stifle joint that provides stability and support. It prevents excessive abduction or adduction of the tibia on the femur.
Ligament #
A band of fibrous connective tissue that connects bones and supports joints. It provides stability, limits movement, and prevents dislocation of bones during movement.
Liver #
The largest internal organ located in the abdomen that performs various functions, including detoxification, metabolism, and nutrient storage. It produces bile to aid in digestion and filter blood.
Lumbar Vertebrae #
The five vertebrae of the lower back that support the weight of the body and allow for bending and twisting movements. They are numbered L1 to L5.
Lung #
The pair of organs located in the chest that facilitate gas exchange between air and blood. They bring oxygen into the body and remove carbon dioxide as waste.
Lymphatic System #
The network of vessels, nodes, and organs that help maintain fluid balance, remove waste, and fight infection. It includes the spleen, thymus, and lymph nodes.
Mandible #
The lower jawbone that forms part of the skull and supports the teeth. It allows for chewing, speaking, and facial expressions.
Masseter Muscle #
A muscle located on the side of the face that elevates and closes the jaw during chewing. It is one of the primary muscles involved in mastication.
Medial Collateral Ligament #
A ligament located on the inside of the stifle joint that provides stability and support. It prevents excessive abduction or adduction of the tibia on the femur.
Medulla Oblongata #
The lower part of the brainstem that controls vital functions such as respiration, heart rate, and blood pressure. It serves as a relay station between the brain and spinal cord.
Mesentery #
A double layer of peritoneum that attaches the intestines to the abdominal wall and provides support and stability. It contains blood vessels, nerves, and lymphatic vessels.
Metacarpus #
The region of the forelimb between the carpus (knee) and the phalanges (hoof). It consists of five metacarpal bones that support the weight of the body.
Metatarsus #
The region of the hind limb between the tarsus (hock) and the phalanges (hoof). It consists of six metatarsal bones that support the weight of the body.
Mitochondria #
The organelles in cells that produce energy in the form of adenosine triphosphate (ATP) through cellular respiration. They are known as the powerhouse of the cell.
Muscle #
A contractile tissue that generates force and movement in the body. It is composed of muscle fibers that work together to produce coordinated movements.
Myofibril #
The thread-like structures within muscle fibers that contain contractile proteins, actin, and myosin. They slide past each other during muscle contraction to generate force.
Myosin #
A thick filament protein found in muscle fibers that interacts with actin to generate muscle contraction. It forms cross-bridges with actin during muscle contractions.
Nephron #
The functional unit of the kidney responsible for filtering blood and producing urine. It consists of a glomerulus, proximal tubule, loop of Henle, distal tubule, and collecting duct.
Nervous System #
The complex network of cells, tissues, and organs that regulate