The British Journal of Surgery Vol. 66 :No. 1 :January 1979 Br. J. Surg. Vol. 66 (1979) 1-2
A curious occipital polyp M. GABER* SUMMARY
Muscles which lose their attachments are uncommon. During development this normally occurs in certain muscles, e.g. the muscles of the face and epicranius; these muscles lose their skeletal connections before migration. In the case presented here a muscle in the occipital region had lost its attachment and formed a peculiar swelling. Case report A 6-year-old girl presented with an occipital pedunculated swelling 5 cm long (Fig. 1) which moved up and down during mastication (Fig. 2). No other movements of the face, neck o r the tongue caused such a movement. The swelling was present at birth and continued to grow slowly with the child. The swelling was excised. During dissection a muscle was seen attached to the external occipital protuberance. On section the muscle was found to be inserted into the skin a t the apex of the swelling, causing corrugations of the skin (Fig. 3). Histological section showed striated muscle with a tendinous end in the centre of fibro-fatty tissue. Nerve fibres were also seen (Fig. 4).
Fig. 2. Showing the movement of the swelling on mastication.
Fig. 3. Excised swelling; the muscle is marked with a thread. Fig. 1. The patient with the head shaved to show the swelling.
* Senior Lecturer, Azhar University, Cairo. Correspondence to: Charing Cross Hospital, London.
M. Gaber of the population. It takes origin from the external occipital protuberance and frequently is inserted with the auricularis posterior muscle. It is supplied by the occipital division of the posterior auricular branch of the facial nerve. The muscle in this case may have had a common innervation with the buccinator muscle, which is also supplied by the facial nerve. If so, this would explain the movement of the swelling during mas ticat ion. Muscles of the tongue develop in the occipital region before migration; the possibility of the muscle mentioned in this case being a detached part of this group of muscles is remote. Bibliography (1974) Deuelopniental Anatomy, 7th ed. Philadelphia, Saunders, p. 234. Gray’s Textbook of Anaiorny (1972) 34th ed. London, Longmans, p. 593.
AREY L. B.
Fig. 4. Histological section showing the muscle. (HE. x 60.)
Discussion The muscle mentioned in this case could be the transversus nuchae muscle, which is present in 25 per cent
Paper accepted 30 June 1978.