In Ibn Sa'd's "al-Tabaqat al-Kabir" book, there are numerous verbal descriptions of Sayedna Muhammad. One description sourced to Ali ibn Abi Talib is as follows:
May Allah bless him, is neither too short nor too tall. His hairs are neither curly nor straight, but a mixture of the two. He is a man of black hair and large skull. His complexion has a tinge of redness. His shoulder bones are broad and his palms and feet are fleshy. He has long al-masrubah which means hair growing from neck to navel. He is of long eye-lashes, close eye-brows, smooth and shining fore-head and long space between two shoulders. When he walks he walks inclining as if coming down from a height. I never saw a man like him before him or after him.
Salla Allah 3alyh wa Salam.