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Medial Border (medial + border)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Soft tissue landmark for ultrasound identification of the sciatic nerve in the infragluteal region: the tendon of the long head of the biceps femoris muscle

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2009
J. BRUHN
Background and objectives: The sciatic nerve block represents one of the more difficult ultrasound-guided nerve blocks. Easy and reliable internal ultrasound landmarks would be helpful for localization of the sciatic nerve. Earlier, during ultrasound-guided posterior approaches to the infragluteal sciatic nerve, the authors recognized a hyperechoic structure at the medial border of the long head of biceps femoris muscle (BFL). The present study was performed to determine whether this is a potential internal landmark to identify the infragluteal sciatic nerve. Methods: The depth and the thickness of this hyperechoic structure, its relationship with the sciatic nerve and the ultrasound visibility of both were recorded in the proximal upper leg of 21 adult volunteers using a linear ultrasound probe in the range of 7,13 MHz. The findings were verified by an anatomical study in two cadavers. Results: The hyperechoic structure at the medial border of the BFL extended in a dorsoventral direction between 1.4±0.6 cm (mean±SD) and 2.8±0.8 cm deep from the surface, with a width of 2.2±0.9 mm. Between 2.6±0.9 and 10.0±1.5 cm distal to the subgluteal fold, the sciatic nerve was consistently identified directly at the ventral end of the hyperechoic structure in all volunteers. The anatomical study revealed that this hyperechoic structure corresponds to tendinous fibres inside and at the medial border of the BFL. Conclusion: The hyperechoic BFL tendon might be a reliable soft tissue landmark for ultrasound localization of the infragluteal sciatic nerve. [source]

Avulsion of ascending lumbar and iliolumbar veins in anterior spinal surgery: An anatomical study

CLINICAL ANATOMY, Issue 5 2007
G. Sivakumar
Abstract To expose the disc between the 4th and 5th lumbar vertebrae in anterior spinal surgery, left to right retraction of inferior vena cava and aorta is required. This manoeuvre can be complicated by venous haemorrhage that, in most cases, is due to avulsion of the left ascending lumbar vein (ALV) or the left iliolumbar vein (ILV). We dissected 23 embalmed cadavers to assess the factors that contribute to the risk of tearing these two veins during retraction. We describe a triangular region that should help surgeons in identifying the ALV and ILV. This triangle is defined by the lateral border of the common iliac vein, the medial border of the psoas major muscle, and the superior end-plate of the L5 vertebral body. We observed that 3 cm between the termination of the left ALV, or a common stem with the ILV, and the termination of the common iliac vein is the critical distance, less than which the risk of venous avulsion is highest. Although the sample considered is small, our study seems to suggest that male patients tend to have a higher risk of venous avulsion than female patients. Clin. Anat. 20:553,555, 2007. © 2007 Wiley-Liss, Inc. [source]

Coexistence of a pectoralis quartus muscle and an unusual axillary arch: Case report and review

CLINICAL ANATOMY, Issue 5 2002
Victoria Bonastre
Abstract A pectoralis quartus muscle and an unusual axillary arch were found on the left side of a female cadaver. The axillary arch was a musculoaponeurotic complex continuous with the iliacal fibers of the latissimus dorsi. The muscular part, together with the tendon of pectoralis major, inserted into the lateral lip of the bicipital groove of the humerus, whereas the aponeurotic part was formed by a fibrous band that extended deep to the pectoralis major to insert into the coracoid process between the attachments of the coracobrachialis and pectoralis minor. The pectoralis quartus originated from the rectus sheath, and joined the inferior medial border of the fibrous band of the axillary arch, at the lateral edge of the pectoralis major. The axillary arch muscle crossed anteriorly the axillary vessels and the brachial plexus. The clinical importance of these muscles is reviewed. Clin. Anat. 15:366,370, 2002. © 2002 Wiley-Liss, Inc. [source]

Cellular and molecular tunnels surrounding the forebrain commissures of human fetuses

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 4 2005
Roberto Lent
Abstract Glial cells and extracellular matrix (ECM) molecules surround developing fiber tracts and are implicated in axonal pathfinding. These and other molecules are produced by these strategically located glial cells and have been shown to influence axonal growth across the midline in rodents. We searched for similar cellular and molecular structures surrounding the telencephalic commissures of fetal human brains. Paraffin-embedded brain sections were immunostained for glial fibrillary acidic protein (GFAP) and vimentin (VN) to identify glial cells; for microtubule-associated protein-2 (MAP-2) and neuronal nuclear protein (NeuN) to document neurons; for neurofilament (NF) to identify axons; and for chondroitin sulfate (CS), tenascin (TN), and fibronectin (FN) to show the ECM. As in rodents, three cellular clusters surrounding the corpus callosum were identified by their expression of GFAP and VN (but not MAP-2 or NeuN) from 13 to at least 18 weeks postovulation (wpo): the glial wedge, the glia of the indusium griseum, and the midline sling. CS and TN (but not FN) were expressed pericellularly in these cell groups. The anterior commissure was surrounded by a GFAP+/VN+ glial tunnel from 12 wpo, with TN expression seen between the GFAP+ cell bodies. The fimbria showed GFAP+/VN+ cells at its lateral and medial borders from 12 wpo, with pericellular expression of CS. The fornix showed GFAP+ cells somewhat later (16 wpo). Because these structures are similar to those described for rodents, we concluded that the axon guiding mechanisms postulated for commissural formation in nonhuman mammals may also be operant in the developing human brain. J. Comp. Neurol. 483:375,382, 2005. © 2005 Wiley-Liss, Inc. [source]