Morphometric parameters and histological study of the filum terminale of adult human cadavers and magnetic resonance images.

BACKGROUND: Morphology and histology of filum terminale (FT) has a role in the pathophysiology of tethered cord syndrome (TCS). This research was implemented to investigate the morphometric parameters and histological structure of normal FT in adult human cadavers and magnetic resonance imaging (MRI) scans to correlate them with the pathophysiology of TCS. MATERIALS AND METHODS: Twenty five adult human cadavers (15 males, 10 females) and 100 MRI echo scans of lumbosacral region (50 males and 50 females), were used in this study. MRI patients were divided into 21-40 and 41-60 age groups. The cadavers were dissected at the prone position to explore their fila. The length of FT, filum terminale internum (FTI), filum terminale externum (FTE), vertebral level of beginning, dural piercing and termination of FT, and the initial, midpoint, and mid-FTE diameters were determined. Four segments were excised from lower conus, upper, middle, and lower thirds of FT. The specimens were processed for light microscopic examination. Statistical analysis was done for these parameters. RESULTS: MRI morphometrical parameters of FT, except FTI length, revealed no age effect or sex differences, where length of FTI, FTE, initial diameter, level of conus medullaris termination (CMT) and dural sac termination (DST) were 174.1 ± 16.8, 75.8 ± 9.5, 1.6 ± 0.21, L1-2 and S2U in males and 166.9 ± 18.9, 74.1 ± 9.3, 1.53 ± 0.25, L1-2 and S2M vertebrae in females, respectively. However, non-significant sex difference was observed in morphometric parameters of cadaveric FT, where length of FTI and FTE, initial diameter, CMT and DST levels were 164.2 ± 11.6, 76.7 ± 8.1, 1.7 ± 0.14, L1L and S2U vertebrae in males and 159.2 ± 10.1, 71.02 ± 7.3, 1.6 ± 0.29, L1L and S2U in females, respectively. Moreover, CMT below L2 vertebra was seen in 5% of MRI scans and 8% of cadavers. Also, the initial diameter of FT > 2 mm was recorded in 7% of MRI and 8% of cadaveric cases. Histologically, the structure of FT showed gradual reduction in nervous, glial, and vascular tissues with converse increase in collagen content in FTE compared with those of FTI. CONCLUSIONS: Knowledge of the morphometric parameters and the histological structure of FT are necessary for clinicians who dealing with diagnosis or treatment of tethered cord syndrome.

Vertebral level and measurements of conus medullaris and dural sac termination with special reference to the apex of the sacral hiatus: anatomical and magnetic resonance imaging radiologic study.

BACKGROUND: Anatomical orientation of the caudal space and termination level of conus medullaris (CMT) and dural sac (DST) has great significance for anaesthetists and neurosurgeons. This study aimed to explore the anatomical landmarks important to perform save spinal anaesthesia, lumber puncture and caudal analgesia through the correlation between the vertebral level of CMT, DST and sacral hiatus apex (SHA) in human cadavers and by using magnetic resonance imaging (MRI). MATERIALS AND METHODS: Sixty adult cadavers (40 males, 20 females) and 200 (100 males, 100 females) MR lumbosacral images of 16-69-year-old persons were used in this study. Vertebral level of CMT, DST and SHA and their linear distances were determined in cadavers and MRI. Also, anteroposterior diameter at SHA, length and thickness of sacrococcygeal membrane were measured as well, and correlate these levels and their distances with age and sex. RESULTS: Mean and highest frequent number of MRI vertebral level of CMT was observed at lower third of L1 in men and L1-2 disc in women, that of DST at upper third of S2 in men and middle third of S2 in women, while SHA was seen at middle third of S4 in both men and women with no significant (p > 0.05) age or gender differences. In 5% of cases, CMT, DST and SHA were seen at vertebral level below L2, below S2-3 and above S3, respectively. However, mean vertebral level of CMT, DST, SHA was observed at L1L, S2M and S4U without sex differen-ce in cadaveric specimens, respectively. All linear distances of men MRI revealed significant difference (p < 0.05) compared with those of women except thickness of sacrococcygeal membrane and anterposterior diameter at SHA. CONCLUSIONS: Accurate knowledge of vertebral level of CMT, DST and SHA and the distances in-between might decrease the iatrogenic injury of dural sac, spinal cord and cauda equina.

Myocardial bridge and coronary arteries: morphological study and clinical significance.

Myocardial bridge (MB) is the myocardial bundles covering a segment of a coronary artery or one of its branches. This work aimed to study the morphological properties of MB and their effects on the structure of the dominant coronary artery. Sixty adult human hearts (40 male and 20 female) were obtained from the Anatomy Department, Faculty of Medicine, King Abdulaziz University. Dissection o fthe coronary arteries and their main branches was done. Number, site, length and thickness of MB were determined in correlation with coronary dominancy. External diameter of proximal and distal segments of bridged branches and histology of the different segments of the anterior interventricular artery were examined as well. Thirty-six MB were observed in 27 (45%) hearts (18 male and 9 female). MB were mostly observed on the middle segment of the anterior interventricular artery (52.8%) and to a lesser extent on its diagonal branch (13.8%), posterior interventricular artery (13.8%), median and left marginal branches (5.6%), and right coronary artery stem (2.8%). In 30% out of 56.7% of right, in 8.3% out of 26.7% of balanced and in 6.7% out of 16.7% of left dominant hearts revealed MB. The mean length of MB was 24.9 ± 1.98 mm and that of their thickness was 2.28 ± 0.13 mm. Morphological differences in external diameter and histological structure of the different parts of bridged branch were observed. Knowledge of morphological aspects and effects of MB provide better therapeutic and surgical interventions for clinicians dealing with patients having MB.

The radial artery and its variations: anatomical study and clinical implications.

BACKGROUND: To describe the radial artery and its variants in origin, branching pattern, mode of termination, and measurements of its length and external diameter. MATERIAL AND METHODS: One hundred upper limbs of 30 men and 20 women adult cadavers were used in this study. The cadavers were obtained from the Anatomy Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia. The axillary region, arm, forearm, and hand of each limb were dissected to clarify the course and branches of the radial artery. This anatomical descriptive study was conducted between September 2010 and August 2012 after approval of the Ethical Committee. RESULTS: The mean distance of the normal origin of the radial artery as one of two terminal branches of the brachial artery was 38.7 ± 9.5 mm in men and 36.5 ± 8.5 mm in the upper limbs of women below the intercondylar line, and variant origin of the radial artery was found in eight limbs. The mean of radial artery length was 226.2 ± 21.7 mm in men and 209.9 ± 13.9 mm in women and that of its external diameter was 3.3 ± 0.7 mm in men and 3.2 ± 0.66 mm in women at 1 cm distal to its origin; 3.1 ± 0.73 mm in men and 3.0 ± 0.66 in women at 2 cm proximal to the styloid process of the radius. The radial artery showed different branching patterns and three modes of termination. CONCLUSIONS: Knowledge of radial artery description and its variants has great importance in different clinical fields and basic medical studies.