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Object: There is insufficient information in the neurosurgical literature regarding the long thoracic nerve (LTN). Many neurosurgical procedures necessitate a thorough understanding of this nerve's anatomy, for example, brachial plexus exploration/repair, passes for ventriculoperitoneal shunt placement, pleural placement of a ventriculopleural shunt, and scalenotomy. In the present study the authors seek to elucidate further the surgical anatomy of this structure., Methods: Eighteen cadaveric sides were dissected of the LTN, anatomical relationships were observed, and measurements were obtained between it and surrounding osseous landmarks. The LTN had a mean length of 27 +/- 4.5 cm (mean +/- standard deviation) and a mean diameter of 3 +/- 2.5 mm. The distance from the angle of the mandible to the most proximal portion of the LTN was a mean of 6 +/- 1.1 cm. The distance from this proximal portion of the LTN to the carotid tubercle was a mean of 3.3 +/- 2 cm. The LTN was located a mean 2.8 cm posterior to the clavicle. In 61% of all sides the C-7 component of the LTN joined the C-5 and C-6 components of the LTN at the level of the second rib posterior to the axillary artery. In one right-sided specimen the C-5 component directly innervated the upper two digitations of the serratus anterior muscle rather than joining the C-6 and C-7 parts of this nerve. The LTN traveled posterior to the axillary vessels and trunks of the brachial plexus in all specimens. It lay between the middle and posterior scalene muscles in 56% of sides. In 11% of sides the C-5 and C-6 components of the LTN traveled through the middle scalene muscle and then combined with the C-7 contribution. In two sides, all contributions to the LTN were situated between the middle scalene muscle and brachial plexus and thus did not travel through any muscle. The C-7 contribution to the LTN was always located anterior to the middle scalene muscle. In all specimens the LTN was found within the axillary sheath superior to the clavicle. Distally, the LTN lay a mean of 15 +/- 3.4 cm lateral to the jugular notch and a mean of 22 +/- 4.2 cm lateral to the xiphoid process of the sternum., Conclusions: The neurosurgeon should have knowledge of the topography of the LTN. The results of the present study will allow the surgeon to better localize this structure superior and inferior to the clavicle and decrease morbidity following invasive procedures.

An accessory middle cerebral artery is one variation of the intracranial vasculature that may be a source of misinterpretation by clinicians dealing with cerebrovascular diseases. We report a case of an elderly female found to have bilateral accessory middle cerebral arteries, who presented with the rupture of an aneurysm of the anterior part of the circle of Willis. Accessory middle cerebral arteries are rare anatomical findings and the bilateral occurrence is exceedingly rare. We believe this to be the first report of bilateral accessory middle cerebral arteries associated with an aneurysm of the anterior cerebral-anterior communicating arteries. The anatomical and clinical relevance of this variation is described.

During routine cadaveric dissection of the upper extremity an unusual muscle was discovered arising from the tendon of the flexor carpi ulnaris and inserting into the muscle belly of the flexor digiti minimi. The muscle's course was superficial to the ulnar nerve and artery in Guyon's canal. We review the literature regarding such muscle variations and discuss the potential for compression of the ulnar nerve by such muscles.

Object: An anomalous vertebral artery (VA) position can jeopardize an otherwise successful procedure, such as a posterior cranial fossa decompression for hindbrain herniation, and may increase the propensity for VA occlusion., Methods: The authors describe the detailed anatomy of the entrance site of the VA in adult human crania in which there is occipitalization of the atlas. They found that if the atlantal posterior arch or hemiarch was fused to the occiput one should anticipate encountering an anomalous osseous pathway as the VA enters into the cranium, as evidenced by this finding in 80% of their specimens. An anomalous entry pathway was present in all but one left-sided specimen in which the left posterior hemiarch was not fused to the occiput and one right-sided specimen in which there was an unfused and rudimentary posterior arch of the atlas., Conclusions: The clinician should consider the possibility that the VA takes anomalous routes into the skull in cases in which there is occipitalization of the atlas.

Since 1975, only approximately 60 saphenous vein graft aneurysms have been reported in the medical literature. We now report this unusual finding in a male cadaver who had undergone a recent coronary artery bypass grafting procedure. Although aneurysm formation is an unusual complication of saphenous vein graft surgery, the diagnosis must be suspected particularly in the face of a mediastinal mass on chest radiography in patients who have undergone coronary artery bypass grafting. Needle biopsy in these cases may prove lethal. We believe this to be the first description of this complication in a cadaver.

Cervical ribs are uncommon and occur in approximately 0.5-1% of the population. The authors describe a cadaver found to have a cervical rib with further compression by the dorsal scapular artery. This vessel originated from the third portion of the subclavian artery. No other anomalies were found in this specimen. The authors speculate that some cases of symptomatic cervical rib may have an additional vector of compression from a dorsal scapular artery when it arises from the third portion of the subclavian artery. Additional studies aimed at the vascular system may be useful in diagnosis and operative planning for symptomatic patients.

Object: Descriptions of the marginal venous sinus are lacking in the extant medical literature. The aim of this study was to characterize the anatomy of this intracranial venous sinus., Methods: The authors examined the marginal sinuses in 15 adult cadavers following the injection of latex into the intracranial venous system. The maximal vertical height of the sinuses, which ranged from 7 to 15 mm (mean 10 mm), was located at the lateral aspect of the foramen magnum at or near the region at which the spinal accessory nerve crossed en route to the jugular foramen. In all specimens the sinus tapered as it traveled both anteriorly and posteriorly. Ninety-three percent of the specimens demonstrated significant drainage into the veins of the hypoglossal canal. The hypoglossal nerve rootlets pierced the sinus and its tributaries in 11 (73%) of 15 specimens. The marginal sinus communicated with the basilar venous plexus in 12 (80%) of 15 specimens and with the occipital sinus in all specimens (100%). There was venous communication with the sigmoid sinus in all specimens. The vertebral artery coursed through the marginal sinus as it pierced the posterior atlantooccipital membrane in all left sides and in 87% of the right sides., Conclusions: These quantitative data will be useful to the neurosurgeon who operates in the region of the marginal sinus.

During the routine dissection of the head and neck of an adult male cadaver complete ossification of the falx cerebri was noted. Anomalous ossification was not found in any other dural component or other parts of the body. The brain appeared grossly normal. Histological sections showed normal ossification processes involving the falx cerebri. In addition, rare scattered deposits of metastatic poorly differentiated carcinoma within the trabecular spaces were seen. Reports of isolated islands of ossification involving primarily the most anterior part of the falx cerebri in man are found in the literature. Our case report represents to our knowledge, the first report of complete ossification of this dural partition. Whether this is simply an anomalous configuration or due to the few metastatic cells found within this region remains unclear.

Anomalies of the cervical spine are intriguing anatomically and often come to clinical attention. Fusion of one or more cervical vertebral segments, the Klippel- Feil anomaly (KFA), often causes increased motion at the vertebral segments superior to and inferior to the fused level with a resultant premature wear of these joints. We report an adult male skeleton with fusion of his C6 and C7 vertebral bodies (Type II KFA). A remnant of the intervertebral disc space was noted and bilateral rudimentary cervical ribs were observed emanating from the C7 vertebrae. Excessive joint degeneration was noted between the vertebral bodies of C5 and C6. Following our review of the literature and case report, it appears that there is an increased incidence of the presence of cervical ribs in KFA. We review the literature for coexistent KFA and cervical ribs and discuss their dysembryology.

There is a paucity of information in the extant literature regarding the detailed anatomy of the subanconeus (articularis cubiti) muscle. Our current study seeks to elucidate further the presence, morphology, and potential function of this muscle. Eighteen cadaveric upper extremities underwent dissection of their posterior elbow joint capsule with special attention to any fibres attaching to it from the triceps brachii muscle. We found that all specimens had various amounts of muscular attachment of the medial head of the triceps into the posterior joint capsule. It was noted that the highest concentration of fibres was into the joint capsule near the groove for the ulnar nerve. No specimen was found to have a distinct muscle belly associated with these connections to the joint capsule. On all sides these fibres were simply deeper attachments of the medial head of the triceps brachii muscle. Following tension on these deeper fibres retraction of the joint capsule was not noted but rather compression of the capsule. We would speculate on the basis of our study that these fibres of the medial head of the triceps brachii muscle do not represent a separate muscle per se and do not retract the posterior elbow joint capsule with extension of the forearm as has been theorised. It is possible that compression of the posterior elbow joint capsule from these deeply placed fibres of the triceps brachii restricts the elbow fat pad from being displaced and allows it to cushion the contact made between the olecranon process and the olecranon fossa.

Some have included the ganglion of Ribes (Francois Ribes, 1765-1845), lying on the anterior communicating artery, as the most superior ganglion of the sympathetic nervous system. To verify the presence of this structure, the anterior communicating artery was harvested from 40 fresh adult cadavers and histological analysis and immunochemistry performed. Grossly and with magnification, no ganglion-like structures were found in or around the anterior communicating artery in any specimen. However, scattered neuronal cell bodies were found in the adventitia of the anterior communicating artery with histological immunochemical analysis. Based on the lack of vasoactive intestinal peptide staining and the positive reaction to tyrosine hydroxylase, these neurons are most likely sympathetic in nature. Based on our findings, a grossly visible ganglion of Ribes does not exist. However, neuronal cell bodies were found in the adventitia of the anterior communicating artery although the function of such cells remains speculative.

This study describes the seemingly rare occurrence of bone formation within the proximal superior aspect of Meckel's cave thus forming a bony foramen for the proximal trigeminal nerve to traverse. The anatomy of Meckel's cave is reviewed and the clinical potential for nerve compression from this bony anomaly discussed., (Copyright 2005 Wiley-Liss, Inc.)

Object: The spinal accessory nerve (SAN) within the posterior cervical triangle (PCT) is the most commonly iatrogenically injured nerve in the body. Nevertheless, there is a paucity of published information regarding superficial landmarks for the SAN in this region. Additional identifiable landmarks of this nerve may assist the surgeon in identifying it for repair, use of it in peripheral nerve neurotization, or avoiding it as in proximal brachial plexus repair. The present study was undertaken to provide reliable superficial landmarks for the identification of the SAN within the PCT., Methods: The PCT was dissected in 30 cadaveric sides. Measurements were made between the SAN and surrounding landmarks. The mean distances between the entry site of the SAN into the trapezius and a midpoint of the clavicle, mastoid process, acromion process, and lateral aspect of the sternocleidomastoid (SCM) muscle were 6, 7, 5.5, and 3.5 cm, respectively. The mean distances between the angle of the mandible and the mastoid process and the exit point of the SAN from the posterior border of the SCM muscle were 6 and 5 cm, respectively. The mean width and length of the SAN were 3 and 3.5 cm, respectively., Conclusions: It is the authors' hope that these data will aid those who may need to locate or avoid the SAN while undertaking surgery in the PCT and thus decrease morbidity that may follow manipulation of this region.

Variations of the adductor pollicis muscle of the hand are seemingly rare. We describe an unusual finding of this muscle made during the routine dissection of a cadaveric hand as part of our medical school's gross anatomy course. We believe this case report represents persistence of a portion of the contrahentes digitorum in a human hand. As muscle variations may compress the median nerve while in the carpal tunnel, the clinician should be aware of such a variation., (Copyright 2005 Wiley-Liss, Inc)

The anatomy of the posterior cricoid cartilage region was examined to obtain a better quantitative understanding of this region. The mean height and width of the posterior cricoid cartilage in the midline measured 24.5 mm and 25 mm respectively. The mean distance between the fibres for the left and right posterior cricoarytenoid muscles was 5 mm at the midpoint of the posterior cricoid cartilage. The height of these muscles averaged 19 mm for left sides and 20 mm for right sides. The mean distances from the midpoint and superior midline of the posterior cricoid cartilage to the inferior laryngeal nerve were 14 mm and 15 mm respectively for left sides and 17 mm and 18 mm respectively for right sides. It is hoped that these data will be of use to clinicians performing invasive procedures in this area.

An unusual drainage of the testicular veins was found during routine cadaveric dissection. Specifically, the lateral division of each testicular vein on both left and right sides was found to drain into the subcostal veins. No other anomalies of the veins of the abdomen were found. Knowledge of the many anomalies that can potentially occur in the abdominal region is necessary in interpretation of images of this anatomical area. Additionally, knowledge of these variations is important surgically; for example, anomalous veins that ought to be ligated during surgery for varicocele go unnoticed and result in recurrence of the varicocele., (Copyright (c) 2005 Wiley-Liss, Inc.)

We report a 94-year-old male who died of pneumonia. During the routine dissection of the head and neck for a gross anatomy course at our institution a mass was noted in the region of the right cheek. Macroscopic and microscopic observation of this mass revealed an aneurysm of the facial artery. A traumatic defect was noted at the apex of the aneurysmal wall related to an intraoral prosthetic clasp that had penetrated the buccinator muscle. Traumatic aneurysms of the face have been caused by blunt trauma to the jaw with or without fracture, surgical manipulation around the teeth and jaw, and following missile injury. Some have described compression of neighboring structures such as cranial nerves and other blood vessels with resultant compromise. We believe our case to be the first report of a facial artery aneurysm in a cadaver and we are unaware of other reports from the literature describing the production of a facial artery aneurysm from a puncture of an intraoral prosthesis through the medially placed buccinator muscle. Although seemingly rare, health care professionals should make efforts to ensure that oral prostheses do not develop sharp or irregular edges that could potentially perforate the lateral oral cavity with potential perforation of the overlying vasculature., (Copyright (c) 2005 Wiley-Liss, Inc.)

The authors report a rare anomaly of the upper cervical spine. After an automobile accident, an 8-year-old child underwent CT of the head. Imaging showed a bony anomaly of the neck that was further imaged with thin cuts through the atlas and axis. This demonstrated an unfused anterior arch of the atlas and fusion of the odontoid process to the anterior arch of the atlas. Neurologically, the child is normal with no decreased range of motion about the cervical spine. After a review of the literature, this seems to be only the sixth reported case., (Copyright 2005 Wiley-Liss, Inc.)

Object: The filum terminale externum (FTE) is the extradural component of the filum terminale internum and little attention has been dedicated to this structure in the literature. The authors theorized that the rare intrasacral ependymomas may originate from ependymal cell collections within the FTE., Methods: To address this hypothesis, the FTE was dissected and analyzed histologically in 15 adult cadavers. None of the specimens was found to harbor ependymal or other glial cell collections., Conclusions: The authors found previously undescribed smooth-muscle cells within the FTE. Furthermore, histological analysis identified adipose, nerve, bone, and cartilage cells.

During the routine dissection of a 62-year-old male cadaver, bilateral atrophy of the supra and infraspinatus muscles was observed. The suprascapular nerves, cervical spinal cord and surrounding muscles were found to be normal. We propose that, in the face of normal histology and other normal shoulder girdle muscles and normal nerves, this case represents an instance of Parsonage-Turner syndrome. To our knowledge, this is the first report of bilateral spinati atrophy in a cadaver.

During routine dissections carried out in the course of our medical gross anatomy work, an unusual structure was found unilaterally on the left side of an adult male cadaver. Upon investigation, this was determined to be a hugely dilated transverse facial artery. Also noted was the complete absence of the ipsilateral facial artery. To our knowledge, this is the first report of complete agenesis and not simply diminution of the facial artery with compensatory enlargement of the transverse facial artery.

Carpal tunnel syndrome is the most common entrapment neuropathy dealt with by the clinician. Multiple techniques have been used to surgically treat this pathological condition and all of these approach the carpal tunnel from the palmar surface of the hand or wrist. We have developed a novel endoscopic approach to the carpal tunnel utilizing a dorsal approach that necessitates a good appreciation of the anatomy of this region. This approach was carried out in 10 hands. Through a single dorsal incision we were able to transect the flexor retinaculum in all specimens without obvious damage to neural or vascular tissues. The microscissors used in our study were found to be too delicate for transection of the flexor retinaculum thus another cutting tool should be considered. Our dorsal approach with visualization of the internal aspect of the flexor retinaculum may obviate many of the complications that are seen with the current techniques used to surgically treat carpal tunnel syndrome such as injury to the median nerve and its branches. Clinical trials are now necessary with prospective randomized studies that will determine which techniques are most efficacious and minimize complications most effectively.

Object: There is a paucity of literature regarding the surgical anatomy of the quadrangular space (QS), which is a potential site of entrapment for the axillary nerve. Muscle hypertrophy of this geometrical area and fascial bands within it have been implicated in compression of the axillary nerve., Methods: Fifteen human cadavers (30 sides) were dissected for this study. Measurements of the QS and its contents were made. The mean height of this space was 2.5 cm and the mean width 2.5 cm; its mean depth was 1.5 cm. The axillary nerve was always the most superior structure in the space, and in all cases the nerve and artery hugged the surgical neck of the humerus just superior to the origin of the lateral head of the triceps brachii muscle. This arrangement placed the axillary nerve in the upper lateral portion of the QS in all cadaveric specimens. The nerve branched into its muscular components within this space in 10 sides (33%) and posterior to it in 20 sides (66%). The cutaneous component of the axillary nerve branched from the main trunk of the nerve posterior to the QS in all specimens. Fascial bands were found in this space in 27 (90%) of 30 sides., Conclusions: Knowledge of the anatomy of the QS may aid the surgeon who wishes to explore and decompress the axillary nerve within this geometrical confine.

The authors report a presumably unusual bony attachment of the pectoralis minor muscle in an adult cadaver. The specimen's left pectoralis minor had no attachment to the coracoid process of the scapula but attached directly to the fibrous capsule of the glenohumeral joint. Some have theorized that the coracohumeral ligament represents fibers of the pectoralis minor that attach to this bone in some animals but that has degenerated in man. This case report seems to support this possibility., (Copyright 2005 Wiley-Liss, Inc.)

Object: There is a paucity of literature regarding the surgical anatomy of the dorsal scapular nerve (DSN). The aim of this study was to elucidate the relationship of this nerve to surrounding anatomical structures., Methods: Ten formalin-fixed human cadavers (20 sides) were dissected, and measurements made between the DSN and related structures. The nerve pierced the middle scalene muscle at a mean distance of 3 cm from its origin from the cervical spine and was more or less centrally located at this exit site. It lay a mean distance of 1.5 cm medial to the vertebral border of the scapula between the serratus posterior superior, posterior scalene, and levator scapulae muscles. It was found to have a mean distance of 2.5 cm medial to the spinal accessory nerve as it traveled on the anterior border of the trapezius muscle. The nerve intertwined the dorsal scapular artery in all specimens and was found along the anterior border of the rhomboid muscles. On 19 sides the DSN originated solely from the C-5 spinal nerve, and on one side it arose from the C-5 and C-6 spinal nerves., Conclusions: Knowledge of the anatomy of the DSN will aid the surgeon who wishes to explore and decompress this structure.

Objective: Neurosurgical procedures such as proximal brachial plexus repair, scalenotomy, and direct isolation of the proximal vertebral artery require a good working knowledge of the triangle of the vertebral artery. This deep triangle of the neck is bound by the subclavian artery and the anterior scalene and longus cervicis muscles. In addition to the vertebral artery, many important structures are found in this area, such as the ganglionated sympathetic chain and certain cervical spinal nerves., Methods: Twenty formalin-fixed cadavers were used for this study. Dissection of this triangle was performed, and measurements were made not only of parts of its borders, but also distances from these borders to neurologically important structures within its confines, such as the C8 spinal nerve., Results: In all specimens, the middle scalene muscle was noted to form part of the posterior wall of the triangle. The mean height of the triangle was found to be 3.2 cm, and the mean width of its base was 1.3 cm. We observed that the C8 spinal nerve had a mean distance of 1.2 cm inferior to the apex of the triangle and that the C7 spinal nerve was found inside the triangle in 5% of sides. If the phrenic nerve entered the triangle, it was never found more than 6 mm medial to the anterior scalene muscle. The vertebral artery always traveled intimately along the lateral border of the longus cervicis muscle, and its lateral edge ranged 5 to 8 mm medial to the medial edge of the anterior scalene muscle., Conclusion: The C7 spinal nerve was observed in the triangle of the vertebral artery. In addition, the posterior border of the triangle of the vertebral artery was clearly defined in this study, and the middle scalene muscle could be used as a landmark. These data, coupled with our quantitation of parts and structures within the triangle, may assist neurosurgeons who operate on this area of the neck.

Anatomic landmarks are often quite useful in localizing structures within the human body, especially in the surgical realm. We have reviewed the medical literature and multiple texts of surgery and anatomy and culled together many anatomic landmarks regarding important nerves of the neck. This region is complicated by formidable anatomy, and a single collection of the relationships of the nerves in this region is lacking in the literature. It is our hope that this collection will serve to assist the surgeon who operates in this region of the body.

The anatomy of the greater petrosal nerve while within the middle cranial fossa is lacking in the English literature and must be well understood by the surgeon who operates in this area. Twenty-two sides from six female and five male cadavers were examined. Measurements were made between the greater petrosal nerve as it coursed through the middle cranial fossa and surrounding structures such as the arcuate eminence and lateral wall of the middle cranial fossa. Mean distances from the arcuate eminence to the hiatus of the greater petrosal nerve into the middle cranial fossa measured 17.5 mm (SD = 2.2). The length of this nerve within the middle fossa was approximately 10 mm (SD = 2). From the lateral wall of the middle fossa to a midpoint of the greater petrosal nerve mean distances measured 39 mm (SD = 2.4). The mean distance from the foramen spinosum to the exit of this nerve inferior to the trigeminal ganglion measured 7 mm (SD = 1.8). These measurements will hopefully aid the surgeon who wishes to expose or avoid the greater petrosal nerve within the middle cranial fossa., ((c) 2005 Wiley-Liss, Inc.)

This article describes an extremely rare case, encountered in the anatomy laboratory, of a skull base found to have duplication of both occipital condyles. In addition, this specimen was noted to have a large bony excrescence near the basion, a small third occipital condyle, a left paracondylar process, elongation of the right styloid process, and a bony septation of both hypoglossal canals. The embryology and clinical implications are discussed., (Copyright 2005 Wiley-Liss, Inc.)

Object: Reports describing surgical landmarks with which to identify the branches of the lumbar plexus found on the posterior abdominal wall are lacking in the English-language literature., Methods: The authors examined 22 sides from six female and five male cadavers. Measurements were made between the branches of the lumbar plexus and various bone landmarks such as the midline vertebral bodies, supracristal plane--a horizontal line connecting the superior-most aspect of the left and right iliac crests approximating the LA-5 vertebrae--and anterior superior iliac spine (ASIS). The mean distances from the midline and as they emerged through or lateral to the psoas major muscle to the subcostal, iliohypogastric, ilioinguinal, lateral femoral cutaneous, genitofemoral, and femoral nerves, were 5.5, 6, 6.5, 6, 4.5, and 4.5 cm, respectively. At a vertical line through the midpoint between the ASIS and the midline, the subcostal, iliohypogastric, and ilioinguinal nerves were superior to the supracristal plane at mean distances of 8, 4, and 5 cm, respectively. Inferior to the supracristal plane and in a vertical line through a midpoint between the ASIS and the midline, the lateral femoral and femoral nerves were found to have mean distances of 5 and 5.5 cm, respectively. The obturator nerve had a mean distance of 3 cm lateral to the midline. Additionally, the lateral femoral cutaneous nerve had a mean distance of 1.5 cm inferomedial to the ASIS., Conclusions: A good working knowledge of the locations and anatomy of the nerves of the lumbar plexus on the posterior abdominal wall is necessary for the surgeon who operates in this region. The measurements provided herein will aid the surgeon who wishes to expose or avoid these nerves, thus precluding injury.

An unusual origin of the right omohyoid muscle was found during cadaveric dissection. The muscle originated from the transverse process of C6 and inserted into the scapula. No other muscular anomalies of the neck were found. Although many anomalies of the omohyoid muscle have been described, a proximal attachment to the cervical spine is apparently quite rare. Knowledge of the many anomalies that can potentially occur in the cervical region is necessary in routine surgical intervention of this area. We believe this to be the first reported instance of the superior belly of the "omo" hyoid originating from the cervical region as we have described., (Copyright 2004 Wiley-Liss, Inc.)

Objective: The stability of the joints connecting the cranium to the upper cervical spine is of vital importance. The ligaments of this region, for the most part, have been thoroughly investigated, with the exception of the accessory atlantoaxial ligament., Methods: Ten cadaveric specimens were examined to observe the anatomy of this ligament., Results: This ligament was found in all specimens, and in each, it not only connected the atlas to the axis but also continued cephalically to the occipital bone. The approximate dimensions of this structure were 3 cm x 5 mm. Functionally, this ligament became maximally taut with a rotation of the head of 5 to 8 degrees. Laxity was observed with cervical extension, and maximal tautness was seen at 5 to 10 degrees of cervical flexion., Conclusion: The accessory atlantoaxial ligament seems to participate in craniocervical stability and perhaps should be renamed the accessory alar ligament or accessory atlantoaxialoccipital ligament; both of these terms better denote its anatomic characteristics. Perhaps in the future, better magnetic resonance imaging techniques and machines will be able to identify this structure so as to appreciate its integrity after upper cervical spine trauma.

We report an adult male cadaver with persistence of the ductus arteriosus and a right retroesophageal artery. The retroesophageal artery was first appreciated as a retropharyngeal mass during the dissection of this area. Both the left and right vertebral arteries originated in normal fashion. The thoracic duct of our specimen drained into the junction of the left internal jugular and left subclavian veins. We believe this to be the first report of simultaneous right retroesophageal subclavian artery and patent ductus arteriosus. The anatomy and embryology of these two anomalies in the same specimen are discussed.

This article describes the condition known as hyoid bone syndrome, its diagnosis by exclusion, and the histopathologic evidence of focal, degenerative muscle injury. The injury involves the origin fibers of the middle pharyngeal constrictor muscle on the greater cornu of the hyoid bone. The importance of the dentist and physician in recognizing the condition is emphasized, because dental and nondental pain reference sites make up the syndrome.

A patient with the classic signs and symptoms of temporal tendonitis was treated with excisional surgery of the temporal tendon and its respective mandibular coronoid process. The excised tissue was submitted to pathology for microscopic analysis, and the results were confirmed by two pathologists. Degenerative signs of focal atrophy and tissue necrosis were evident and served to describe the focal nature of the painful condition of temporal tendonitis. The description for the pain pattern is given, along with the recommended method for diagnostic testing. The current method of surgical management using radiofrequency thermal ablation is described, which replaces the more tissue-destructive, excisional approach.

An anatomical study of the acromioclavicular (AC) joint and its supporting ligaments was performed using both macroscopic and microscopic methods. The project used 63 cadaver shoulders of unknown ages. Fifty-three joints were used for macroscopic and 10 for microscopic study. The data consisted of micrometer measurements of the dimensions of the extrinsic and intrinsic ligaments of the AC joint; measurement and description of the intraarticular meniscus and the superior and inferior capsular ligaments of the AC joint; and the anatomical course and relationship of the coracoacromial (CA) ligament to the supporting ligaments of the AC joint and a description of its insertion on the acromion process. The following observations were made: The coracoclavicular ligament, especially the trapezoid ligament, provides significant soft tissue restraints to upward displacement of the clavicle. A complete AC joint disc was found in only one, meniscoid discs in 25, remnants of discs in 16, and no discs in 11 of the 53 joints studied macroscopically. (No age correlation was made since the ages of the cadavers were unknown). The CA ligament interconnects with the inferior capsular ligament of the AC joint as well as with the coracoclavicular and coracohumeral ligaments. It also has a broad area of insertion on the inferior acromial surface. The CA ligament appears to function as a buffer between the acromion and the rotator cuff, and to provide support for the AC joint. Transection of the CA ligament may result in loss of this buffering function.