Anatomy of the Horse: with Aaron Horowitz and Rolf Berg

Product Information

The medial pterygoid m. (deep ) runs from the pterygoid process to the ramus and condylar process of the mandible and causes side to side movements of the jaw. The masseter (unilaterally) and medial pterygoid mm. act to cause lateral movements in the jaw. During the Lower Pliocene period 10 million years ago, Pliohippus, a fully hoofed animal three times the size of the original Eohippus, emerged and, by the time Homo sapiens had evolved, it had become Equus, a recognisable horse. Equus appears to have originally come from North America and then migrated southwards and then spread into Asia, Africa and Europe. It became extinct in the Americas 8000 years ago and the different species of Equus developed in Asia, Africa and Europe as a result of the different climates and terrains. Near the caudal edge of the BOVINE skull is the cornual process which projects from the frontal bone and forms the bony part of each horn. (Figs. 14B-3, 4) Figure 14B-4 Goat skull, lateral view. (The specimen is rotated so that the horns appear asymmetric.) cp, cornual process arising from the frontal bone; 1, coronoid process of the mandible; 2, paracondylar process; 3, occipital condyle; 4, nasal bone; 5, maxilla; 6, infraorbital foramen. Note the close proximity of the cornual process to the orbit. On the right side the cornual process is covered with a horn. Figure 18-36 Dissection of the orbit; the zygomatic arch and periorbita have been removed. 1, Lacrimal gland; 2, periorbita; 3, lateral rectus; 4, maxillary artery (a.); 5, supraorbital a.; 6, lacrimal a.; 7, muscular branch of external ophthalmic a.; 8, malar a.; 9, infraorbital a.; 10, major palatine a.; 11, buccal a.; 12, supraorbital nerve ( frontal n.); 13, lacrimal n.; 14, trochlear n.; 15, zygomatic n.; 16, oculomotor n.; 17, rostral branches of maxillary n.; 18, buccal n.; 19, lingual n.; 20, inferior alveolar n.; 21, masticatory n.; 22, auriculotemporal n.; 23, CN VII facial n.; 24, auriculopalpebral n.; 25, guttural pouch.

Throatlatch [5] [6] [7] [8] [9] [10] (also, throttle, throatlash [ citation needed], throat [11]): the point at which the windpipe meets the head at the underside of the jaw, [3] corresponding to where the eponymous part of a bridle goes. [12] The mandibular salivary glands are also very prominent (especially in BOVINE, Fig. 25.2), and are near the mandibular lymph nodes. Figure 18-8 Deep dissection of the equine head. 1, Infraorbital nerve; 1′, levator labii superioris; 2, dorsal buccal branch of facial nerve; 3, mental nerve; 3′, depressor labii inferioris; 4, facial vein; 5, deep facial vein; 6, buccal vein (5 & 6 are part of the venous sinuses); 7, buccinator; 8, masseter; 9, occipitomandibularis; 10, sternocephalicus; 11, external jugular vein; 12, mandibular salivary gland; 13, linguofacial vein; 14, maxillary vein. Figures above (left) Bovine: needle placement for desensitizing the cornual n. bovine. The cornual n. follows the temporal ling/ridge to the base of the horn. (right) Caprine (goat): A, Needle placement for desensitizing the cornual branch of the lacrimal n. B, Needle placement for desensitizing the cornual branch of the infratrochlear n. (Modified from Muir WW III, Hubbell JAE, Bednarski RM, Skarda RT: Veterinary anesthesia, 4th ed. St. Louis, Mosby, 2000.)Pavord, Tony; Pavord, Marcy (2007). Complete Equine Veterinary Manual. David & Charles. ISBN 978-0715318836.

The respiratory system of a horse consists of the lungs as well as the large and small airways. As a horse breathes in, the air travels down the trachea, divides into tubes called the right and left bronchi, down small airways called the bronchioles and then into the lungs. Rostral to the infraorbital foramen find the palpable nasoincisive notch, between the incisive and nasal bones at the rostrum (i.e., nose area). Cornelisse CJ, Rosenstein DS, Derksen FJ, Holcombe SJ. Computed tomographic study of the effect of a tongue-tie on hyoid apparatus position and nasopharyngeal dimensions in anaesthetised horses. American journal of veterinary research. 2001 Dec 1;62(12):1865-9. The mandibular symphysis (on the midline) is the fibrous connection of the right and left hemi-mandibles. Either type of infection can cause damage to adjacent vessels or nerves, leading to hemorrhaging or dysphagia and/or Horner’s syndrome.

' + letter + '

Joints: where bones come together. Joints help a horse to have motion and can allow for rotation, bending, straightening or may not move at all. Withers: the highest point of the thoracic vertebrae, the point just above the tops of the shoulder blades, seen best with horse standing square and head slightly lowered; the height of the horse is measured at the withers.

A medial retropharyngeal lymph node is found on the ventral surface of the pouch (note image above with abscess of the lymph node).

Figure 14B-12 Sagittal section through a central incisor tooth (I1) of a young horse showing the internal structure of the tooth. 1, pulp cavity (in life filled with vessels, nerves and connective tissue); 1′, secondary dentine (receding pulp cavity fills in with dark dentine, note that it is located on the labial (lip) side with respect to the infundibulum); 2, dentine; 3, enamel; * cementum in the infundibulum, stippling on portions of the outside of I2 represent cementum as well (often the soft cementum is worn away); A, transection of tooth showing dental star (1′) and cup filled with dark debris; B, transection of tooth showing dental star (1′) and cementum filling the bottom of cup. The central and second incisors are in wear (flat occlusal surface) but I3 is newly erupted and not yet in wear, so the horse is near 5 years old. The dental star is flattened in young horses as in the above figure but more round in older horses after the tooth is worn down past the enamel spot.