List the structures found on the left side of the horse's neck.
a) Longus colli muscle, esophagus, trachea, left subclavian artery, costocervical trunk, deep cervical artery, vertebral artery, internal thoracic artery, superficial cervical artery, brachiocephalic trunk, bicarotid trunk, left and right carotid arteries, aorta, sympathetic trunk, vertebral nerve, recurrent laryngeal nerve, vagus nerve, phrenic nerve, middle cervical ganglion, cervicothoracic ganglion
b) Esophagus, trachea, left subclavian artery, costocervical trunk, deep cervical artery, vertebral artery, internal thoracic artery, superficial cervical artery, brachiocephalic trunk, bicarotid trunk, left and right carotid arteries, aorta, sympathetic trunk, vertebral nerve, recurrent laryngeal nerve, vagus nerve, phrenic nerve, middle cervical ganglion, cervicothoracic ganglion
c) Longus colli muscle, trachea, left subclavian artery, costocervical trunk, deep cervical artery, vertebral artery, internal thoracic artery, superficial cervical artery, brachiocephalic trunk, bicarotid trunk, left and right carotid arteries, aorta, sympathetic trunk, vertebral nerve, recurrent laryngeal nerve, vagus nerve, phrenic nerve, middle cervical ganglion, cervicothoracic ganglion
d) Longus colli muscle, esophagus, right subclavian artery, costocervical trunk, deep cervical artery, vertebral artery, internal thoracic artery, superficial cervical artery, brachiocephalic trunk, bicarotid trunk, left and right carotid arteries, aorta, sympathetic trunk, vertebral nerve, recurrent laryngeal nerve, vagus nerve, phrenic nerve, middle cervical ganglion, cervicothoracic ganglion