Anatomic investigation of the lumbosacral plexus of the helmeted guinea fowl (Numida meleagris)

The study was conducted for the determination of the main nerves of the lumbosacral plexus in the helmeted guineafowl. Five helmeted guineafowls were used. Fowls were anaesthetised and the a. carotis communis was cut for blood drainage. Body cavities were revealed and were fixated with 10% formaldehyde. Nerves forming the lumbosacral plexus were dissected and photographed. Results were named according to the Nomina Anatomica Avium. It was determined that the lumbosacral plexus forms by 8 synsacral ventral rami from the ventrolateral side of synsacrum which include (2–9) synsacral spinal nerves. It was seen that the lumbar plexus was formed by the ventral rami of the 2nd, 3rd and 4th spinal nerves, and the sacral plexus was formed by the ventral rami of the 5th, 6th, 7th, 8th and 9th synsacral spinal nerves. It was observed that following nerves of n. pubicus (ilioinguinalis), r. cutaneous femoris lateralis, r. cutaneous femoris medialis (n. saphenus), n. femoralis and n. obturatorius originate from the lumbar plexus, and following nerves of n. ischiadicus, the common branch of n. fibularis and n. tibialis originate from the sacral plexus. It was determined that the n. ischiadicus was formed by the truncus cranialis, medianus and caudalis. In conclusion, it was determined that there are macro anatomical differences between different avian species in the quantity, thickness and distribution of the spinal nerves that form the lumbosacral plexus, and in formations of the plexus, and in separations of nerve branches.     

The lumbosacral Plexus of the Barn Owl (tyto alba): Formation,branches and distribution

The aim of the present study is to reveal the anatomical structure of lumbosacral plexus of barn owl. Six barn owls were included in the study. Nerves originating from plexus were dissected individually, and findings of innervation areas of nerves were determined. Lumbosacral plexus of barn owl was observed to be formed by ventral rami of ten synsacral spinal nerves. It was found that while the r. cutaneus femoris lateralis, the n. obturatorius, the n. coxalis cranialis, the r. cutaneus femoris medialis, the n. cutaneus femoris cranialis and the n. femoralis originated from the lumbar plexus, the n. isciofemoralis, the n. cutaneus femoris caudalis, the n. coxalis caudalis and the n. ischiadicus originated from the sacral plexus. Consequently, when the results of the study were compared with information of different avian species, it was observed that differences focused on the formation of the lumbar and sacral plexuses and innervation level of digits.     

Macroanatomical Aspects of the Lumbar Plexus and its Branches in the Sparrowhawk

This study examined the plexus lumbalis and its branches in the sparrowhawk (Accipiter nisus). Fifteen sparrowhawks were used in this study. After administering an anaesthetic to the birds, the body cavities were opened. The birds were fixed with formaldehyde after draining of the blood. The nerves of the plexus lumbalis were dissected separately and photographed. The plexus lumbalis was formed by the union of the branches of the synsacral spinal nerves, which left from the ventrolaterale of os lumbosacrale. The plexus consisted of three (2nd, 3rd and 4th) synsacral spinal nerves. The cranial and caudal nerves originating from the plexus lumbalis were the nervus cutaneous femoris, nervus coxalis cranialis, nervus femoralis, nervus saphenus and nervus obturatorius. The general macroanatomical shape of the plexus lumbalis and the distribution of the nerves originating from this plexus were similar to those of other bird species.     

Gross morphological features of plexus brachialis in the chinchilla (Chinchilla lanigera)

This study documents the detailed features of the morphological structure and the innervation areas of the plexus brachialis in the chinchilla (Chinchilla lanigera). The animals (5 female and 5 male) were euthanased with ketamine hydrocloride and xylazine hydrocloride combination, 60 mg/kg and 6 mg/kg, respectively. Skin, muscles and nerves were dissected under a stereo-microscope. The brachial plexus of the chinchilla is formed by rami ventrales of C5-C8, T1 and T2, and possesses a single truncus. The subscapular nerve is formed by the rami of the spinal nerves originating from C6 (one thin ramus) and C7 (one thick and 2 thin rami). These nerves innervate the subscapular and teres minor muscles. The long thoracic nerve, before joining with the brachial plexus, obtains branches from C6 and C7 in 5 cadavers (3 male, 2 female), from C7 in 4 cadavers (2 male, 2 female) and from C6-C8 in only 1 female cadaver. These nerves disperse in variable combinations to form the extrinsic and intrinstic named, nerves of the thoracic limb. An undefined nerve branch originates from the rami ventrales of C7, C8 and T1 spinal nerves enter the coracobrachial muscle.     

Origin and distribution of the brachial plexus of the Van cats

Knowing the structure and variations of the plexus brachialis is important in neck and shoulder surgery. The knowledge of the brachial plexus reduces the injury rate of the nerves in surgical interventions to the axillary region. The major nerve trunks of the thoracic limb were the suprascapular, subscapular, axillary, radial, musculocutaneous, median and ulnar nerves. In Van cats, the brachial plexus was formed by the ventral branches of the spinal nerves, C6-C7-C8 and T1. The 7th cervical nerve was quite thick compared to the others. The subscapular nerve was the thinnest (on the right side, the average length was 6.55 ± 0.60 mm and on the left side was 6.50 ± 0.60 mm), and the radial nerve was the thickest (the average length on the right side was 28.48 ± 0.44 mm and on the left side was 29.11 ± 0.55 mm). The suprascapular nerve was formed by the ventral branch of the 6th cervical nerve. The subscapular nerves were formed by a branch originating from the 6th cervical nerve and the two medial and caudal branches originating from the 7th cervical nerve. No communicating branch between the ulnar nerve and the median nerve was observed in the palmar region. The axillary nerve was formed by the ventral branches of the 7th nerve, the musculocutaneous nerve was formed by ventral branches of the 6th and 7th cervical nerves, and the ulnar nerve was formed by ventral branches of the 8th cervical and the 1st thoracic nerves. The radial nerve was the thickest branch in the brachial plexus. In Van cats, the origin and distribution of nerves were similar to those reported in the literature for other species of cats, with the exception of the suprascapular, subscapular and axillary nerves.     

Morphology,ultrasonographic and computed tomography configuration of the dog pelvis and perineum

The current study used topographic anatomy, distribution of arteries and nerves, sectional anatomy of the pelvis, computed tomography (CT) and ultrasonography examination to describe the canine pelvis and its organs. This study was conducted on twenty male and female baladi dogs, weighing 30–35 kg and aged between 1.5 and 2 years. The pelvis dorsal boundary appeared long and reached to the level of the third caudal vertebra. The vesicogenital pouch in the female extended further caudally than the rectogenital pouch while in the male the two pouches were at the same level and extended to the level of the first sacral vertebra. The plexus lumbosacralis formed from the ventral branches of the last three lumbar nerves and the first three sacral nerves. The obturator nerve arose from the ventral branches of the fifth and sixth lumbar nerves. We developed an anatomical atlas of the pelvis of both sexes of the dog using CT scans compared to anatomical sections. Our study is the first research on the pelvis in both sexes of the dog to compare sagittal CT scan data to sagittal anatomical sections. In the CT slices, the prostate appeared homogenous, relatively hypodense presenting with a soft tissue density. It appeared oval in the longitudinal sections and elliptical to round at the cross sections. It was situated on the floor of the pelvic cavity or the pelvic brim depending on its size. The present study is also the first to describe the fascia diaphragmatic pelvis.     

Anatomical description of the origin and distribution of the lumbosacral plexus in one puma (Puma concolor)

Wild felids often suffer spinal and limb disorders; however, their nervous system anatomy is poorly studied. Herein, the lumbosacral plexus (Plexus lumbosacralis) of an adult puma and the motor and sensitive innervation of the pelvic limb is described. We found anatomical similarities to other felids, but also some differences. Branches L4-S3 form the lumbosacral plexus (Plexus lumbosacralis) in the puma. The femoral nerve (N. femoris) arises from the union of L4-L5, while in other felids, it is formed by L5-L6. Unlike in the cat, the sartorius muscle receives branches from the saphenous (N. saphenous) and femoral nerves (N. femoris), and the lateral head of the gastrocnemius and superficial digital flexor muscles are innervated by a branch of the soleus muscle.     

Gross Anatomy of the Brachial Plexus in the Giant Anteater (Myrmecophaga tridactyla)

Ten forelimbs of five Myrmecophaga tridactyla were examined to study the anatomy of the brachial plexus. The brachial plexuses of the M. tridactyla observed in the present study were formed by the ventral rami of the last four cervical spinal nerves, C5 through C8, and the first thoracic spinal nerve, T1. These primary roots joined to form two trunks: a cranial trunk comprising ventral rami from C5‐C7 and a caudal trunk receiving ventral rami from C8‐T1. The nerves originated from these trunks and their most constant arrangement were as follows: suprascapular (C5‐C7), subscapular (C5‐C7), cranial pectoral (C5‐C8), caudal pectoral (C8‐T1), axillary (C5‐C7), musculocutaneous (C5‐C7), radial (C5‐T1), median (C5‐T1), ulnar (C5‐T1), thoracodorsal (C5‐C8), lateral thoracic (C7‐T1) and long thoracic (C6‐C7). In general, the brachial plexus in the M. tridactyla is similar to the plexuses in mammals, but the number of rami contributing to the formation of each nerve in the M. tridactyla was found to be larger than those of most mammals. This feature may be related to the very distinctive anatomical specializations of the forelimb of the anteaters.     

Corneal innervation in mesocephalic and brachycephalic dogs and cats: assessment using in vivo confocal microscopy

Objective To determine the density of the canine and feline corneal neural network in healthy dogs and cats using in vivo confocal microscopy (IVCM). Animals examined A total of 16 adult dogs (9 Mesocephalic breeds, 7 Brachycephalic breeds) and 15 cats (9 Domestic Short-haired cats (DSH), 6 Persian cats) underwent IVCM. Procedure Animals were examined with a confocal corneal microscope (HRTII/RCM; Heidelberg Retina Tomograph II/Rostock Cornea Module^®, Heidelberg Engineering, Dossenheim, Germany). The investigations focused on the distribution of the corneal nerves and quantification of central subepithelial and subbasal nerve plexus. Results The corneal stromal nerve trunks, subepithelial and subbasal nerve plexus were observed. The nerve fiber density (NFD) quantified in nerve fiber length in mesocephalic dogs were 12.39 ± 5.25 mm/mm² in the subepithelial nerve plexus and 14.87 ± 3.08 mm/mm² in the subbasal nerve plexus. The NFD of the subepithelial nerve plexus in DSH cats was 15.49 ± 2.7 and 18.4 ± 3.84 mm/mm² in the subbasal nerve plexus. The subbasal NFD of DSH cats was significantly higher than in mesocephalic dogs (P = 0.037). The subepithelial NFD in brachycephalic dogs, and Persian cats were 10.34 ± 4.71 and 9.50 ± 2.3 mm/mm², respectively. The subbasal NFD measured 11.80 ± 3.73 mm/mm² in brachycephalic dogs, and 12.28 ± 4.3 mm/mm² NFD in Persian cats, respectively. The subepithelial and subbasal NFD in Persian cats were significantly lower than in DSH cats (P = 0.028, respectively, P = 0.031), in contrast to brachycephalic vs. mesocephalic dogs. Conclusion The noninvasive IVCM accurately detects corneal innervation and provides a reliable quantification of central corneal nerves.     

Observations on the Equine Hypophysial Portal System

The blood supply to the equine pituitary gland, with special attention to its portal system, was studied by the aid of vascular injections and histological serial sections. The primary capillary plexus of the median eminence was supplied by the rostroventral and rostrodorsal infundibular arteries, which were branches of the internal carotid arteries and the ramus communicans caudalis, respectively. The neural lobe was supplied by the caudal infundibular arteries, which originated from the arteria intercarotica caudalis. Dorsal and ventral groups of the portal vessels were described. Their regional distribution into the sinusoidal capillaries of the pars distalis was discussed. Results of this investigation indicated that the portal vessels were the sole supply to the equine pars distalis. No direct arterial supply to this part of the adenohypophysis was observed.     

Function of the ramus communicans of the medial and lateral palmar nerves of the horse

Reasons for performing study: The role of the communicating branch between the medial and lateral palmar nerves of horses (i.e. the ramus communicans) in conveying sensory impulses proximally should be determined to avoid errors in interpreting diagnostic anaesthesia of the palmar nerves. Hypothesis: Sensory nerve fibres in the ramus communicans of horses pass proximally from the lateral palmar nerve to merge with the medial palmar nerve, but not vice versa. Objective: To determine the direction of sensory impulses through the ramus communicans between lateral and medial palmar nerves. Methods: Pain in a thoracic foot was created with set‐screw pressure applied to either the medial or lateral aspect of the sole of each forelimb of 6 horses. The palmar nerve on the side of the sole in which pain was created was anaesthetised proximal to the ramus communicans with local anaesthetic. Lameness was evaluated objectively by using a wireless, inertial, sensor‐based, motion analysis system (Lameness Locator). Lameness was also evaluated subjectively by using a graded scoring system. Local anaesthetic was then administered adjacent to the ramus communicans to determine the effect of anaesthesia of the ramus communicans on residual lameness. Results: When pain originated from the medial or the lateral aspect of the sole, anaesthesia of the ipsilateral palmar nerve proximal to the ramus communicans did not entirely resolve lameness. Anaesthesia of the ramus communicans further attenuated or resolved lameness. Conclusions: Sensory fibres pass in both directions in the ramus communicans to connect the medial and lateral palmar nerves. Potential relevance: When administering a low palmar nerve block, both palmar nerves should be anaesthetised distal to the ramus communicans to avoid leaving nondesensitised sensory nerve fibres passing through this neural connection. Alternatively, local anaesthetic could also be deposited adjacent to the ramus communicans when anaesthetising the palmar nerves.     

Anatomical Structure of the Brachial Plexus in the Merlin (Falco columbarius)

This study aimed to document the detailed features of the morphological structure and the innervation areas of the brachial plexus in Merlin (Falco columbarius). The skin and muscles of five adult male Merlins were dissected under the stereo microscope. The Merlin had two plexus trunks. The accessory brachial plexus consisted of ventral rami C10 and C11. C11 was divided into two branches: the cranial and caudal. The brachial plexus was composed of a rather complex network involving the ventral rami of C11‐C13, T1 and T2. In addition, a thin branch from the last two cervical sympathetic nerves participated in the plexus formation. C12, C13 and T1 had rather thick trunk. C12, C13 and T1 were also involved in the formation of the brachial plexus emerging after 1 cm from the foramen inter‐vertebrale as three trunk roots.     

The macroanatomy of coronary arteries in donkeys (Equus asinus L.)

The aim of this study was to define the arteries that supply the cardiac muscle in donkeys with regard to their course and possible variations. Six hearts belonging to donkeys of different age and sex constituted the material of the study. Following exposition of the arteries by means of injection of latex coloured with Rotring ink to a. coronaria sinistra and a. coronaria dextra, dissection was performed. The arterial vascularization of the heart in donkeys was determined to be supplied by a. coronaria sinistra and a. coronaria dextra which originate from the aorta. A. coronaria sinistra, measured to be larger than a. coronaria dextra, was determined to have its origin at the aorta, at the level of the free border of valvula semilunaris sinistra, and to extend between truncus pulmonalis and auricula sinistra. The mentioned artery was detected to give off two branches, namely, ramus interventricularis paraconalis and ramus circumflexus sinister which extend in sulcus interventricularis paraconalis and sulcus coronarius, respectively. However, a. coronaria dextra was determined to have its origin at the beginning of the aorta, at the level of valvula semilunaris dextra, and to extend to margo ventricularis dexter between truncus pulmonalis and auricula dexter. This study has revealed ramus interventricularis subsinuosus and ramus circumflexus dexter to intercommunicate by means of anastomosis and to form a. coronaria dexter. Examination of material revealed the absence of anastomosis between r. circumflexus sinister and r. circumflexus dexter. Branches named rami septales, originating from ramus interventricularis paraconalis and ramus interventricularis subsinuosus were determined to supply septum interventriculare. Ramus proximalis atrii sinistri was determined to have its origin at ramus circumflexus sinister whereas ramus proximalis venriculi dextri was determined to stem from the beginning of a. coronaria dextra in the material of this study. However, examination of the cranial and caudal branches of ramus coni arteriosi, revealed the cranial branch to be ramus proximalis ventriculi dextri in a cadaver.     

The Morphology of the Cervico-thoracic Sympathetic System in Donkeys (Equus asinus L.)

Five adult donkeys of both sexes, used in applied anatomy classes, and perfused with formalin for teaching purposes, constituted the study material. Ganglion cervicale caudale of the examined materials has observed to exhibit individually variable situation as to extend on the left side of the median line, at the alignment of the first and second intercostal spaces and on the right side between the level of the first and third costa. The ganglion extended more caudally on the right side of median line. The lateral surface of the ganglion was determined to be covered with the m. scalenus medius. On the both sides of the median plane, the ganglion cervicale caudale was seen to be situated on the lateral surface of the m. longus colli. On the left side, the ganglion overlapped the oesophagus in two cadavers and on the right side it was situated within a groove between the m. longus colli and trachea in three cadavers. The rami communicantes received by the ganglion cervicale caudale originated from the eighth cervical and first thoracic spinal segments. The ganglion cervicale caudale was formed by the coalescence of the last cervical and first three thoracic sympathetic ganglia. The ganglion cervicale caudale gave off branches that formed the rami communicantes, plexus cardiacus, n. vertebralis and ansa subclavia. One branch extended from the ganglion to the plexus brachialis. in one specimen, two sympathetic–parasympathetic communicating branches were observed to extend from the ansa subclavia and near by the origin of the truncus sympathicus to the n. vagus. In one of the donkeys examined, a branch originating from the ganglion cervicale caudale on the left side of the median plane was determined to end on the ligamentum arteriosum. A microscopic ganglion structure suggesting the existence of the ganglion cervicale medium was determined in a donkey.     

The spinal nerves that constitute the lumbosacral plexus and their distribution in the chinchilla

In this study, the spinal nerves that constitute the lumbosacral plexus (plexus lumbosacrales) (LSP) and its distribution in Chinchilla lanigera were investigated. Ten chinchillas (6 males and 4 females) were used in this research. The spinal nerves that constitute the LSP were dissected and the distribution of pelvic limb nerves originating from the plexus was examined. The iliohypogastric nerve arose from L1 and L2, giving rise to the cranial and caudal nerves, and the ilioinguinal nerve arose from L3. The other branch of L3 gave rise to the genitofemoral nerve and 1 branch from L4 gave rise to the lateral cutaneous femoral nerve. The trunk formed by the union of L4-5 divided into medial (femoral nerve) and lateral branches (obturator nerve). It was found that the LSP was formed by all the ventral branches of L4 at L6 and S1 at S3. At the caudal part of the plexus, a thick branch, the ischiadic plexus, was formed by contributions from L5-6 and S1. This root gave rise to the nerve branches which were disseminated to the posterior limb (cranial and caudal gluteal nerves, caudal cutaneous femoral nerve and ischiadic nerve). The ischiadic nerve divided into the caudal cutaneous surae, lateral cutaneous surae, common fibular and tibial nerve. The pudendal nerve arose from S1-2 and the other branch of S2 and S3 formed the rectal caudal nerve. The results showed that the origins and distribution of spinal nerves that constitute the LSP of chinchillas were similar to those of a few rodents and other mammals.     

Innervation of the wing membrane in the bent-winged bat Miniopterus fuliginosus

The nerves that innervate the fingertips and wing membrane from the upper arm of the bent-winged bat Miniopterus fuliginosus were examined under a stereomicroscope. The radial, median, ulnar and musculocutaneous nerves were formed by the brachial plexus, which ran to the wing membrane. The two suspected axillary nerves ran to the wing membrane. The radial nerve ran to the end of the first digit, while the median nerve ran along the forearm and subsequently branched-off to run along the second to fifth digits up to the end of the phalanges. The ulnar nerve ran to the plagiopatagium on the extensor side of the elbow joint. Finally, the musculocutaneous nerve passed through the ventral side of the humerus and branched out at the elbow joint to run radially to the propatagium area. In this study, the visible nerves that were distributed from the upper arm to the fingertips of Miniopterus fuliginosus were formed by C6–T1.     

Origin and distribution of facial nerve anatomy in van cats

This study aims to reveal the morphological properties of facial nerve and the middle ear in Van cats. Study material was composed of 6 female Van cats. Dissections were performed under a Zoom Stereo Microscope. There was no plexus buccalis in Van cats. The chorda tympani was observed to pass through an opening in the tympanic cavity, emerge through a small opening just behind the retroarticular process, and join the lingual nerve. A rounded anatomical formation with a size of 2.75 ± 0.3 mm was found to be located within the mastoid process of the temporal bone between the facial nerve and the auricular branch of the vagus nerve. The stapes nerve was not present. The geniculate ganglion was very prominent and about 1.00 mm high. The deep petrosal nerve was observed to emerge from the plexus tympanicus. The bulla tympanica was 18.96 ± 0.10 mm long, 13.03 ± 0.20 mm wide and 13.16 ± 0.20 mm high. After leaving the mandibular nerve, the n.tensoris tympani coursed caudally around the a.maxillaris, formed an ansa, entered the tympanic cavity through the canalis musculotubarius and reached an end in the m. tensor tympani. Due to the scarcity of studies on the middle ears of Van cats, it is thought that this study will fill a gap in the field of veterinary anatomy.     

Gross Anatomical Study of the Nerve Supply of Genitourinary Structures in Female Mongrel Hound Dogs

Anatomical variations in lumbosacral plexus or nerves to genitourinary structures in dogs are under described, despite their importance during surgery and potential contributions to neuromuscular syndromes. Gross dissection of 16 female mongrel hound dogs showed frequent variations in lumbosacral plexus classification, sympathetic ganglia, ventral rami input to nerves innervating genitourinary structures and pudendal nerve (PdN) branching. Lumbosacral plexus classification types were mixed, rather than pure, in 13 (82%) of dogs. The genitofemoral nerve (GFN) originated from ventral ramus of L4 in 67% of nerves, differing from the expected L3. Considerable variability was seen in ventral rami origins of pelvic (PN) and Pd nerves, with new findings of L7 contributions to PN, joining S1 and S2 input (23% of sides in 11 dogs) or S1–S3 input (5%), and to PdN, joining S1–S2, unilaterally, in one dog. L7 input was confirmed using retrograde dye tracing methods. The PN also received CG1 contributions, bilaterally, in one dog. The PdN branched unusually in two dogs. Lumbosacral sympathetic ganglia had variant intra‐, inter‐ and multisegmental connectivity in 6 (38%). Thus, the anatomy of mongrel dogs had higher variability than previously described for purebred dogs. Knowledge of this variant innervation during surgery could aid in the preservation of nerves and reduce risk of urinary and sexual dysfunctions.