. Anatomy, descriptive and applied. Anatomy. TRANSVERSE AURICULAR MUSCLE iFiG. 839.—The cartilage of the right pinna, isolated, with the muscles, viewed from the inside. (Spalteholz.) Where the helix turns downward a small tubercle, tubercle of Darwin (hiberculum auriculae 'IDarwiniJ), is frequently seen. This tubercle is very evident about the sixth month of fetal life; at this stage the human pinna has a close resemblance to that of some of the adult monkeys. The cranial surface of the pinna presents elevations which correspond to the depressions on its outer surface and after which they are
. Anatomy, descriptive and applied. Anatomy. TRANSVERSE AURICULAR MUSCLE iFiG. 839.—The cartilage of the right pinna, isolated, with the muscles, viewed from the inside. (Spalteholz.) Where the helix turns downward a small tubercle, tubercle of Darwin (hiberculum auriculae 'IDarwiniJ), is frequently seen. This tubercle is very evident about the sixth month of fetal life; at this stage the human pinna has a close resemblance to that of some of the adult monkeys. The cranial surface of the pinna presents elevations which correspond to the depressions on its outer surface and after which they are named, e. g., 'eminentia conchae, eminentia fossae triangularis, etc. Structure.—The pinna is composed of a thin plate of yellow fibrocartilage, covered with integument and connected to the surrounding parts by the extrinsic ligaments and muscles, and to the com- mencement of the external auditory ?canal by fibrous tissue. The integument is thin, closely ad- herent to the cartilage, and covered with hairs furnished with sebaceous glands which are most numerous in. the concha and scaphoid fossa. The hairs are most numerous and largest on the tragus and antitragus. The cartilage of the pinna (cartilago ?auriculae) (Fig. 840) consists of one single piece; it gives form to this part of thS ear, and upon its surface are found all the eminences and depressions above described. It does not enter into the construction of all parts of the pinna; thus, it does not form a constituent part of the lobule; it is deficient also between the lamina of the tragus and beginning of the crus helix, the notch between them (incisura ferminalis auris) being filled up by dense fibrous tissue. At the front part of the pinna, where the helix bends upward, is a small projection of cartilage, called the spine of the helix (spina helicis), while the lower part of the helix is prolonged downward as a tail-like process, the Cauda helicis; this is separated from the antihelix by a fissure, the fissura ant
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1913
