Extraarticular variants of the long head of the biceps brachii: a reminder of embryology.

Developmental anomalies of the long head of the biceps tendon are rare and have been described in the literature mainly dealing with anatomy and embryology. Because most basic embryologic research on this topic was conducted before 1966, a literature search was performed from archived anatomy textbooks and manuscript references. These data were compared with the scarce case descriptions of developmental anomalies of the long head of the biceps tendon. An additional case illustration from our own experience was provided. From the literature, it appears that during the embryologic phase of development, a staged migration of the long head of the biceps tendon occurs from a position between the fibrous capsule and synovial layer to an intraarticular position. Recent anatomic and arthroscopic case reports have shown that interruption of this migration can occur in any of these stages. Given the recent increase in arthroscopic shoulder surgery, anomalies of the long head of the biceps tendon will be encountered more frequently. Knowledge of their existence and origin can help in evaluating unexpected anatomic variations or the absence of the biceps tendon in preoperative medical imaging or during an arthroscopic procedure.

Anatomic research on the perioral muscles, functional matrix of the maxillary and mandibular bones.

The aim of this research was to study, on the basis of anatomic specimen, the insertion of and the existing correlation between the orbicularis oris, the perioral and the buccinator muscles. Dissections were performed on 40 embalmed caucasian specimens. The skin and the subcutaneous stratum were removed from the perioral zone starting from the base of the nose and the zygomatic arch down to the hyoid bone. The orbicularis oris and the facial muscles were isolated in the successive planes. In the more superficial layer, the following muscles were displayed: the orbicularis oris around the oral opening, the mentalis in the lower part, the transversus menti, the depressor anguli oris and the depressor labii inferioris, the risorius, and the zygomaticus major and minor positioned on the area of the labial commissure. The buccinator muscle was situated under this superficial stratum. In 85% of the specimens we found a fourth inferior band of the buccinator muscle that runs continuously from one side to the other of the mandible. This bundle always ran cranially to the foramen mentale. The findings have been compared with magnetic resonance images obtained from ten patients. One of the main findings was that the majority of these muscles were so densely interrelated that they could be considered parts of two functional units. A deep unit is composed of the buccinator muscle and the inner ring of the orbicularis oris and a superficial unit is built up by the depressor anguli oris, the zygomaticus, the risorius and the outer ring of the orbicularis oris. MR imaging confirmed these findings.

Atherosclerosis in the vertebral artery: an intrinsic risk factor in the use of spinal manipulation?

The presence of atherosclerotic plaques and their influence on the vertebral artery is of clinical importance within the scope of spinal manipulation. Manipulation may stimulate the development of atherosclerotic plaques, could detach an embolus with ensuing infarction, injure the endothelium or may directly cause a dissection in the presence of atherosclerotic plaques. In order to identify the sites and frequency of atherosclerotic plaques and to determine its relation to the tortuous course of the vertebral artery, a cadaveric study was performed. The vertebral arteries of 57 human cadavers were studied. The vertebral artery was virtually divided into four segments: the pre-vertebral (V1), the vertebral (V2), the atlanto-axial (V3), and the intracranial segment (V4). Abnormalities in the origin and course of the vertebral artery were noted, along with any associated osseous, or cartilaginous anomalies in the neck. After dissection, the artery was opened and macroscopically screened for the presence of atherosclerotic plaques. In 22.8% of the cases, no atherosclerotic plaques were present. In 35.1% of the cases, the atherosclerotic plaques were unilateral, of which 60.0% was on the left side, 40.0% on the right side, and in 42.1%, the occurrence was bilateral. Atherosclerotic plaques were significantly more present in the V3 segment than in the V1 (0.007) and V2 segment (0.049). In the V1 (P=0.008) and V2 segment (P=0.002), there was a correlation between a tortuous course of the vessel and the occurrence of atherosclerotic plaques. In individuals with marked atherosclerotic disease, stretching and compression effects of rotational manipulative techniques on atherosclerotic vessels impose a further risk factor for vertebrobasilar insufficiency. As direct evidence of atherosclerotic plaques are rarely available, therapists should avoid manipulative techniques at all levels of the cervical spine in the presence of any indirect sign of atherosclerotic disease or in the presence of calcified arterial walls or tortuosities of the vessels visible on routinely available X-ray images of the cervical or thoracic spine. It is strongly recommended, that if any doubt exists about the nature of a clinical presentation, vigorous manual procedures should be avoided until either the diagnosis is definitive or gentle manual therapy has proven effective.

Vertebral artery dominance and hand preference: is there a correlation?

The two vertebral arteries are usually unequal in size, the left one being generally larger than the right one. It is not clear why this asymmetry exists. One of the hypotheses is that this asymmetry is related to the vascular requirements of the brain. To support this statement, we investigated the correlation between a dominant left vertebral artery and right-handedness and vice versa. No correlation between differences in vertebral artery diameter and hand dominance was found. Hence, the hypothesis that a dominant left vertebral artery is associated with right-handedness and vice versa cannot be confirmed.

A vertebral artery without atlantic and intradural sections: a case report and a review of the literature.

This report covers a case in which the right vertebral artery (VA) did not participate in the formation of the basilar artery. The artery had an external diameter of about 1 mm. It ran trough the transverse foramina of C6 through C2, then turned backward and entered the spinal canal and the dural envelope between the posterior arch of C1 and the lamina of C2 as a medullary artery to end in the spinal arteries. The basilar artery was a continuation of the left VA only. Only very few cases of non-union of the VA with the basilar artery have been previously described. Cases with extreme reduction of one of the VAs are not exceptional. This variant is clinically important. On arteriography, this extremely rare condition could easily be misdiagnosed as an obstruction. In view of manipulative therapy and in the detection of vertebrobasilar insufficiency, one has to bear in mind that cases of non-union may influence the interpretation of these tests.

Extrinsic risk factors for compromised blood flow in the vertebral artery: anatomical observations of the transverse foramina from C3 to C7.

The vertebral artery (VA) is often involved in the occurrence of complications after spinal manipulative therapy. Due to osteophytes compressing the VA anteriorly from the uncinate process or posteriorly from the facet complex, the VAs are susceptible to trauma in the transverse foramina. Such altered anatomical configurations are of major clinical significance, as spinal manipulations may result in dissection of the VA with serious consequences for the blood supply to the vertebrobasilar region. The purpose of this study is to describe numerous structural features of the third to seventh cervical vertebrae in order to contribute to the understanding of pathological conditions related to the VA. The minimal and maximal diameter of 111 transverse foramina in dry cervical vertebrae were studied. The presence of osteophytes and their influence on the VA were evaluated at the vertebral body and at the superior and inferior articular facets. The diameter of the transverse foramina increased from C3 to C6, while the transverse foramina of C7 had the smallest diameter. At all levels the mean dimensions of the left foramina were greater than those of the right side. Osteophytes from the uncinate process of C5 and C6 vertebrae were found in over 60% of dry vertebrae. Osteophytes from the zygapophyseal joints were more frequent at C3 and C4 vertebrae. About half of the osteophytes of the uncinate and of the superior articular process partially covered the transverse foramina. This was less common with those of the inferior articular facets. Osteophytes covering the transverse foramen force the VAs to meander around these obstructions, causing narrowing through external compression and are potential sites of trauma to the VAs potentially even leading to dissection. We strongly advocate that screening protocols for vertebrobasilar insufficiency (VBI) be used prior to any manipulation of the cervical spine and should include not only extension and rotation but any starting position from which the planned manipulation will be performed.

A case of abnormal findings in the course of the vertebral artery associated with an ossified hyoid apparatus. A contraindication for manipulation of the cervical spine?

OBJECTIVE: To describe a case of a simultaneous occurrence of an ossified stylohyoid ligament in a 56-year-old male cadaver and anomalies of the vertebral artery, and to consider the clinical implications for manipulative therapists. INTERVENTION AND OUTCOME: Dissection showed a simultaneous occurrence of complete developmental ossification of the left hyoid apparatus, variants of the vertebral artery, and a left superior vena cava in a 56-year-old male cadaver. DISCUSSION: Developmental variants, posttraumatic and degenerative changes of the hyoid apparatus may result in variable degrees of ossification or calcification. CONCLUSION: This unusual disorder should be considered in the differential diagnosis of facial and neck pain especially within the scope of manipulation of the upper cervical spine. Cervical spine manipulation may exacerbate existing pathological conditions of the stylohyoid apparatus, thereby irritating neurovascular structures, and induce a fracture. Developmental ossification of this apparatus might be associated with anomalies in the atlantic section of the vertebral artery which make the patient more susceptible to vertebrobasilar insufficiency. We conclude that extreme care should be taken in the presence of such an ossification to avoid trauma to the stylohyoid apparatus and maybe even because of increased vertebrobasilar risk.

Changes in cerebellar blood flow after manipulation of the cervical spine using Technetium 99m-ethyl cysteinate dimer.

BACKGROUND: Cervical spine manipulation is one of the many interventions practiced by health professionals to treat musculoskeletal disorders of the cervical spine. Although serious consequences of manipulation have been documented, the incidence is thought to be rare. More frequently, there may be minor transient side effects after manipulation of the cervical spine, such as headache, dizziness, and nausea. One of the hypothesis is that these side effects are caused by ischemia in the areas perfused by the vertebral arteries. OBJECTIVE: The purpose of this study was to investigate whether manipulation of the cervical spine can influence blood flow in the brain. METHODS: Single photon emission computed tomography was used to examine changes in regional cerebral blood flow caused by cervical spine manipulation (CSM) performed by a physiotherapist to 15 volunteers, using a 1-day split-dose Technetium 99m-ethyl cysteinate dimer single photon emission computed tomography activation paradigm. RESULTS: One brain region was identified showing a decreased regional cerebral blood flow after manipulation. This region was situated in the anterior lobe of the left cerebellum (-42, -48, -24). CONCLUSIONS: These findings suggest that cerebellar hypoperfusion may occur after CSM. This could explain why certain people experience headache, dizziness, or nausea after CSM. Further investigation into patient symptoms in the presence of cerebellar hypoperfusion and the possible link of these findings with other adverse reactions are warranted.