Horse (equid) characteristics: One digit per foot ending in symmetrical, horny hoof. Walks on very tip of toe. Elongated skull; large lower jaw. Large upper and lower incisors. In side view, neck widens as it approaches shoulder (elongated triangular shape). Mane present, upright on wild species. Tuft of hair often present on forehead ("forelock"). Rear profile of neck straight or arched. Pointed, upright ears. Long, slender limbs. Humerus and femur short; lower portion of limb long, especially forefoot and hind foot (adaptation for speed by shifting weight of muscles mass upward, close to the body). Ulna and fibula reduced. | 112 HORSE ANATOMY Horse equid characteristics One digit per foot ending in symmetrical horny hoof. Walks on very tip of toe. Elongated skull large lower jaw. Large upper and lower incisors. In side view neck widens as it approaches shoulder elongated triangular shape . Mane present upright on wild species. Tuft of hair often present on forehead forelock . Rear profile of neck straight or arched. Pointed upright ears. Long slender limbs. Humerus and femur short lower portion of limb long especially forefoot and hind foot adaptation for speed by shifting weight of muscles mass upward close to the body . Ulna and fibula reduced and fused to adjacent weight-supporting bones. Femur has projecting third trochanter on outer side of shaft for attachment of the gluteus superficialis muscle. Barrel-like trunk. Long hair on tail. In same group as tapirs and rhinoceroses. AbDIL Abductor digit I longus Adduc Adductor AT Achilles tendon Bicep Biceps brachii BiFemLH Biceps femoris long head BiFemSH Biceps femoris short head Brach Brachialis Brcph Brachiocephalicus Bucc Buccinator Canin Caninus Coccy Coccygeus DelRe Deltoid rear portion DelSp Deltoid spinal portion Digas Digastric DLaMn Depressor labii mandibularis ECR Extensor carpi radialis EDC Extensor digitorum communis EDLat Extensor digitorum lateralis EDLon Extensor digitorum longus ExAbO External abdominal oblique FCR Flexor ANATOMICAL DRAWINGS AFTER ELLENBERGER ASHDOWN FROM DISSECTIONS carpi radialis FCU Flexor carpi ulnaris FDP Flexor digitorum profundus FDS Flexor digitorum superficialis GasLa Gastrocnemius lateral head GluMe Gluteus medius - GluSu Gluteus superficialis Grac Gracilis Iliac lliacus I Hoc lliocostalis InAbO Internal abdominal oblique Infra Infraspinatus LAOM Levator anguli oculi medialis LatDo Latissimus dorsi LatNa Lateralis nasi LeNas Levator nasolabi-alis LLaMx Levator labii maxillaris LngCa Longus capitis LonAt Longissimus atlantis LonCa Longissimus capitis Longi Longissimus Malar Malaris Mass .
