NERVES OF THORACIC LIMB OF THE OSTRICH (STRUTHIO CAMELUS L.)

Norbert Pospieszny¹, Paulina Pachulska², Katarzyna Paździor², Jerzy Wustinger^2
1 Department of Biostructure and Animal Physiology, Wrocław University of Environmental and Life Sciences, Poland
² Institute of Anatomy and Histology, Wrocław University of Environmental and Life Sciences, Poland

ABSTRACT

The objective of the study was to analyze nerves of the wing of the ostrich. The investigation was conducted on 8 wings of two-day old chicks of the ostrich. The situation of the nerves of the brachial plexus was described and shown on the schemes, on which they were projected on bones of the adult bird using Adobe Photoshop CS. The analysis was documented by photographs.

Key words: ostrich, brachial plexus, nerves.

INTRODUCTION

Anatomy of the ostrich is not well known and there is lack of professional studies of the issue. So that our knowledge is based on books [1,2,3,4]. Increasing interesting in the ostrich as a breeding animal makes need knowledge of morphologic elements its nervous system. The object of the study was route of nerves of the wing. The study contains the schemes and the photographs of nerves. Involution of nerves in connection with reduction musculature of wing and patagium was also described.

MATERIAL AND METHODS

The investigation was conducted on 8 wings of two-day old ostrich chicks. Material was fixed in 4% solution of formic aldehyde. During investigation a magnifying glass (7x) was used. The scale in photographs was established exact to 0.1 mm on the base of measurements using an electronic slide caliper.

EXAMINATION RESULTS

The direction of the study was to describe situation and to observe division of  the individual nerves of  the two-day old ostrich chick's wing. The function of ostrich's wings is not flying, but many others not connected with transportation, for example mating rituals. Reduction of the function entailed involution some muscles and patagium and also many contents of brachial plexus (rami musculares, propatagiales, metapatagiales).

Brachial plexus is the source of wing's nerves. It is descended from the roots of plexus (radices plexus), which are ventral branches of spinal nerves last cervical and first thoracic segments of the spinal medulla. These roots gains together to form trunks of plexus (trunci plexus) and then divides into plexus fasciculi (fasciculi plexus). The dorsal fasciculus (fasciculus dorsalis) divides into the tricipital nerve (n. tricipitalis), the axillary nerve (n. axillaris) and the radial nerve (n.  radialis) (Figs. 1, 2).

Fig. 1. Nerves of the wing of the ostrich – skeletotopy. The upper side

Fig. 2. Brachial plexus of the ostrich

A – n. radialis

The best developed is the radial nerve, it is located on the bottom side of the wing (where is also the brachial plexus situated) and it passes the cranial border as it goes to the upper side of the wing. Here it divides into many branches leading to skin and muscles of the upper side of the wing:

1. muscular branches (rami musculares)

2. dorsal cutaneous brachial nerve (n.  cutaneus brachialis dorsalis)
   dorsal cutaneous antebrachial nerve (n.  cutaneus antebrachialis dorsalis).

Near the elbow joint the radial nerve divides into the superficial branch (ramus superficialis) and the deep branch (ramus profundus). The superficial branch gives rise to the lateral radial nerve (n.  radialis lateralis) and medial radial nerve (n.  radialis medialis), they are located on the appropriate sides of the forearm. The deep branch supply: the wrist giving the dorsal carpal branches (rami carpales dorsales), the alula giving the alular branch (ramus alularis) and the metacarpus giving the dorsal metacarpal nerves (nn. metacarpales dorsales). These last nerves give rise to the digital branches (rami digitales), supplying the third and fourth finger.

The ventral fasciculus (fasciculus ventralis) divides into the ventral cutaneous brachial nerve (n. cutaneus brachialis ventralis), the bicipital nerve (n. bicipitalis), the medianoulnar nerve (n.  medianoulnaris) and the pectoral nerve (n.  pectoralis) (Figs. 3, 4).

Fig. 3. Nerves of the wing of the ostrich – skeletotopy. The bottom side

Fig. 4. Brachial plexus of the ostrich

A – n. medianoulnaris B – n. radialis C – n. cutaneus brachialis ventralis

The ventral cutaneous brachial nerve supplies skin on the bottom side of the wing. The bicipital nerve, just like the tricipital nerve on the upper side, supplies appropriate (reduced) muscles. The pectoral nerve wasn't found, partly because of its poor size (highly advanced reduction) connected with involution of pectoral muscles and partly because the material was very small.

The medianoulnar nerve is quite large when we compare it with the little wing of two-day old chick. On the internal side of the elbow joint it divides into the ulnar nerve (n.  ulnaris) which  is located laterally and the median nerve (n. medianus) located medially.

Median nerve in the wrist area gives rise to the ventral carpal branches (rami carpales ventrales); one of these branches extends into the alular branch (r. alularis) and the other extends into the ventral metacarpal branch (r. metacarpalis ventralis).

The ulnar nerve gives rise to the cubital cutaneous branch (r. cutaneus cubiti) and then divides into the cranial branch (r. cranialis) and the caudal branch (r.  caudalis). These branches extend into ventral metacarpal branches (rr. metacarpales ventrales) and these – into the digital branches (rr. digitales).

DISCUSSION

The study was based on the literature concerning the nervous system of the wing of domestic hen. It was assumed that the main route of nerves on the limb of the ostrich chicks is similar to the adult one. This assumption allowed us to create a skeletotopy using photogpaphs taken from an adult ostrich's skeleton (present in the museum in the Institute of Anatomy and Histology AU in Wrocław).

During preparation we noticed that the nerves of the brachial plexus are surprisingly big sized comparing to very poor developed muscles. The main route of the nerves is clear and easy to observe and susceptible to morphologic analysis. The main nervous branches are similar to these described in domestic hen [1].

CONCLUSIONS

These conclusions were formulated basis of investigation and morphologic analysis:

1. The ostrich has only brachial plexus (plexus brachialis), there is no accessory brachial plexus (plexus brachialis accessorius), present in many other birds.

2. The main nerves are strongly developed in such a young bird.

3. Reduction of the musculature entailed limitation of number of muscular branches.

4. Involution of patagium contributed to atrophy of propatagial, metapatagial, postpatagial branches (rr. propatagiales, metapatagiales, postpatagiales).

REFERENCES

1. Komarek V., Malinowsky L., Lemez L., 1982. Anatomia ptaków domowych i embriologia kury [Anatomy and Embryology of the Domestic Birds]. PWRiL, Warszawa [in Polish].

2. Kobryń H., Kobryńczuk F., 2004. Anatomia Zwierząt t. 3 [Animal Anatomy, vol. 3]. Wydawnictwo Naukowe PWN, Warszawa [in Polish].

3. Baumel J.J., 1993. Handbook of Avian anatomy\Nomina Anatomica Avium. Cambridge Massachusetts.

4. Nickel R., Schummer A., Seiferle E., 1973. Lehrbuch der Anatomie der Haustiere, Bd.V: Anatomie der Hausvogel [Textbook of the Domestic Animals Anatomy, Vol. 5: Anatomy of the Domestic Birds]. Parey Verlag, Stuttgart [in German].

Accepted for print: 1.10.2009

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Norbert Pospieszny
Department of Biostructure and Animal Physiology,
Wrocław University of Environmental and Life Sciences, Poland
Kożuchowska 1/3, 51-631 Wrocław, Poland

Paulina Pachulska
Institute of Anatomy and Histology,
Wrocław University of Environmental and Life Sciences, Poland
Kożuchowska 1-3, 51-631 Wrocław, Poland

Katarzyna Paździor
Institute of Anatomy and Histology,
Wrocław University of Environmental and Life Sciences, Poland
Kożuchowska 1-3, 51-631 Wrocław, Poland

Jerzy Wustinger
Institute of Anatomy and Histology,
Wrocław University of Environmental and Life Sciences, Poland
Kożuchowska 1-3; 51-631 Wrocław, Poland
phone: +48+71 32 05 746
email: jotwu@gen.ar.wroc.pl

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Responses to this article, comments are invited and should be submitted within three months of the publication of the article. If accepted for publication, they will be published in the chapter headed 'Discussions' and hyperlinked to the article.

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