The Human Posterior Cricoarytenoid (PCA) Muscle and Diaphragm: A Histochemical Comparison as a Basis for Reinnervation Attempts

Abstract

Brøndbo K, Dahl HA, Teig E, Gujord KM. The human PCA muscle and diaphragm. A histochemical comparison as a basis for reinnervation attempts. Acta Otolaryngol (Stockh) 1986; 102: 474–481.

PCA (posterior cricoarytenoid) muscles and biopsies from the SCM (sterno-cleidomastoid) muscles as well as the diaphragm were serially sectioned and incubated for myofibrillar ATPase and selected metabolic enzymes. The three main fibre types were present in all muscles, although some PCA muscles seemed to lack IIB fibres. The mean fibre type pattern of the PCA muscle was 57% type I, 36% type IIA and 7% type ILB, as compared with 42% type I, 42% type IIA and 16% type IIB in the diaphragm. AU fibre types of the PCA muscle and the diaphragm were significantly more oxidative and less glycolytic than the corresponding SCM muscle fibres. Most striking was the finding of high 3-HBDH activity in the PCA and diaphragm muscle fibres, especially in type I.

Key Words:

• posterior cricoarytenoid muscle
• diaphragm
• muscle histochemistry
• human laryngeal muscle
• respiratory muscles