Horse sagittal half-head

This horse half-head shows a superficial dissection on the right lateral aspect and a median sagittal section on the medial aspect.
On the lateral side the skin has been removed, except on the nostrils, lips and external ear. In the rostral part of the dissection are the muscles of facial expression: the levator nasolabialis, caninus, levator labii superioris, zygomaticus, buccinator (buccal portion) and depressor labii inferioris muscles. The caudal part of the dissection is occupied by the masseter muscle, covered by the masseteric fascia from the facial crest of the maxillary bone. On its surface the muscle shows the course of the dorsal and ventral buccal branches of the facial nerve, which end rostrally as buccolabial branches. In the notch of the facial vessels, the facial artery and vein are located together with the parotid duct. In the dorsal and caudal part of the masseter muscle, the transverse facial artery and vein are located together with the auriculotemporal nerve. The parotidoauricularis muscle, the parotid gland and the maxillary and linguofacial veins are located at the cervicofacial junction.
In the median sagittal section, the nasal cavity is occupied by the ventral, dorsal and middle nasal conchae, separated by the dorsal, middle and ventral nasal meatuses. The perpendicular plate of the ethmoid bone is located in the caudal area of the nasal cavity; this bone is the rostral limit of the cerebral fossa. The cerebellar fossa lies caudal to it. The vomer bounds the choanae, the passage to the nasopharynx, where the pharyngeal opening of the auditory tube is located. The oral cavity is bounded dorsally by the hard palate, which continues caudally as the soft palate. The sagittal section of the tongue shows the proper lingual muscle as well as the genioglossus and geniohyoid muscles. The oropharynx is occupied by the root of the tongue and the soft palate. The epiglottis, arytenoid cartilage and cricoid cartilage bound the laryngeal cavity with the lateral ventricle, vocal fold and infraglottic cavity. The laryngopharynx is occupied by the oesophageal vestibule. The oesophagus lies dorsal to the trachea and ventral to the longus colli and longus capitis muscles. The mandibular lymph nodes lie in the intermandibular space.