The following conditions must be met to become a great Tenor Singer
(1) The thyroid cartilage must be wide
(2)The width of the larynx is larger compared to the width of the cervical spine
(3)It is wide between the thyrohyoid bones, and also the thyrohyoid membrane displays flexibility
(4)The cricothyroid articulation moves with ease
(5)The cricothyroid muscle is a larger/fat shape
(6)There is enough space between the thyroid cartilage and the cervical spine
(7)The pharyngeal cavity is big surrounding the hyoid bone
(8) The suprahyoid muscles move smoothly
(9)The muscle tendon junction of the hyoid bone is flexible
(10) The lateral pterygoid muscle moves smoothly
Of course, innate size or shape (based on the above conditions being met) can always make and show improvements to some porportions. Those methods to achieve improvements could be by exercising, and/or proper care or throat treatment by a voice care specialist or trainer.
Please make a great throat by being mindful of the mechanics and statuses of the throat. The more you understand the throat, the easier it will be to gain strong vocal control which will put you on the right path to becoming great tenor singer.
Note:Vocalization is the same with sports. With sports ‘exercise’ is required to get flexible and strong muscles – it is the same process and applied circumstances with vocalization.