FRONTAL AND ORBITAL REGION. 15 



bottom of this canal, which separates the external from 

 the middle ear. 



The muscles of the pinna require a patient dissection ; indeed, they 

 are not always to be found, being only rudimentary in man. The 

 integument covering them is very thin and delicate. 



The intrinsic muscles of the ear are five in number. 



The major helicis consists of vertical fibres, to be found 

 on the anterior border of the helix, just above the tragus. 



The minor helicis is placed upon that part of the helix 

 which extends into the concha; its fibres are arranged 

 obliquely. 



The tragicus is a vertical bundle of fibres situated on the 

 outer surface of the tragus. 



The anti-tragicus arises from the outer part of the anti- 

 tragus, and its fibres converge to be inserted into the 

 pointed extremity of the anti-helix. 



The transversus auriculae is found on the posterior aspect 

 of the ear, stretching transversely across the depression 

 between the helix and the concha. 



On removing all the integument, the pinna of the ear 

 will be found to consist of a single cartilage, presenting 

 the general outlines of the ear ; it does not extend into the 

 lobule, and its continuity is broken by notches and fissures. 

 It is firmly attached to the processus auditorius of the 

 temporal bone by a cartilaginous tube called the vneatus 

 auditorius externus. In the subcutaneous cellular tissue of 

 the meatus are the ceruminous glands, which secrete the 

 wax of the ear. 



FRONTAL AND ORBITAL REGION. 



To dissect the occipito-frontalis muscle, make an incision from the 

 root of the nose backward to the occiput ; this should be met at the 

 vertex by an incision made from the ear at right angles to it ; another 

 must be carried along the eyebrow, from the root of the nos-e outward. 

 The flap is to be lifted from the nasal angle, and with great care ; for the 

 fibres are traced with difficulty, and the thin plane which they con- 

 stitute is very adherent to the integument and liable to be cut through 

 or dissected up from the bone upon which it lies ; the aponeurotic 

 tendon which expands over the vertex of the skull can hardly fail 

 of being disfigured by " button-holes." 



The OCCIPITO-FRONTALIS MUSCLE consists of two portions, 

 a frontal and an occipital ; the two being connected b}' an 

 iiponeurosis, which expands over the vertex of the cranium. 

 It may therefore be described as arising from the external 



