Sagittal CT image
The respiratory system develops from the primitive pharynx. When the embryo is 3.5 weeks old, the laryngotracheal sulcus develops in front of primitive larynx which ultimately forms larynx, trachea and esophagus. By 28 weeks of gestation, the larynx develops entirely . Soon after birth, larynx displaces down and attains its normal position [1, 2]. There is no definite criteria regarding the level of displacement of larynx to be called as laryngoptosis. Few reported cases stated laryngoptosis whenever the tracheal rings are not palpable. The larynx may be present just above the manubrium sterni or even behind it[1, 3] .
The exact pathophysiology of congenital laryngoptosis is still unknown. Reported cases shows some significant anatomical changes. Dayal and Singh , Tucker , Jackson  and Muslow  all have reported the displacement of the hyoid bone a lower position with short thyrohyoid membrane. Majority of reported cases had tracheal deviation towards left side and no tracheal rings were palpable. Anatomical variation could be either short sternohyoid muscle  or a fibrotic band pulling this muscle causing hoarseness of voice.
Congenital laryngoptosis is a developmental anomaly. There is no evidence of any known predisposing factors. Acquired laryngoptosis may be a sign of pulmonary emphysema which is associated with downward displacement of diaphragm together with the connected mediastinal structures such as tracheal and larynx . Congenital laryngoptosis doesn’t require corrective surgery until it is symptomatic which is caused by shortening of hyoid muscles. Tracheostomy may be needed for the patients with laryngoptosis who have breathing difficulty.
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 Congenital laryngoptosis. A case report Journal: Ann Otol Rhinol Laryngol, 1971, 80(2):244-5.. Author: Dayal D, Singh AP
 Essential otolaryngology, head and neck surgery. Journal: Embryology of clefts and pouches, 1999, 7:237-68. Author: Lee KJ, Drake AF.
 Laryngoptosis. An unusual cause of hoarseness. Journal: Arch Otolaryngol, 1973, 98(5):356-357.. Author: Stewart KC, Smith R, Tohme SM.
 Laryngoptosis. Journal: Arch Otolaryngol, 1937, 98(5):356-357.. Author: Tucker G.
 Anamolies of the larynx. Journal: Otolaryngology, 1971, 4(22):34-6. Author: Jackson C.
 Laryngoptosis. Journal: Ann Otol, 1939, 48:779.. Author: Muslow JE.
 Laryngoptosis, an easily detectable sign of pulmonary emphysema. Journal: Diseases of the chest., 1954, 26(6):705-8.. Author: Raab W.