Precise Localization of the Posterior Clinoid Process in the Fetal Skull Base.

OBJECTIVE: To determine the precise position of the posterior clinoid process (PCP) in fetuses. MATERIALS AND METHODS: Skull bases of 32 fetuses (11 males/21 females) aged 17 to 32 weeks in utero were included in the study. The distances of PCP to certain reference points were measured. RESULTS: The distances of PCP to the foramen ovale, foramen rotundum, superior orbital fissure, anterior clinoid process, foramen magnum, and crista galli were measured as 7.70±1.86 mm, 6.99±1.65 mm, 6.07±1.85 mm, 3.85±1.10 mm, 15.34±3.38 mm, and 14.49±2.65 mm, respectively. All parameters were similar for both sides (P>0.05). Apart from the distance of PCP to the foramen magnum, the remaining parameters were similar for both genders. This parameter was greater in males than females (P=0.001). All parameters were greater in the third-trimester fetuses than the second-trimester fetuses. All parameters increased with advancing gestational weeks (P<0.001). Linear functions were calculated for the distances of PCP to the crista galli (y = 1.311 + 0.551 × age), to the foramen magnum (y = 0.086 + 0.638 × age), to the anterior clinoid process (y = -0.303 + 0.174 × age), to the superior orbital fissure (y = - 2.013 + 0.338 × age), to the foramen rotundum (y = 1.803 + 0.217 × age), and to the foramen ovale (y = 0.760 + 0.290 × age). CONCLUSION: The measured distances increased with growth. The linear functions displaying the growth dynamics of PCP-related parameters may be used to estimate the distances.

Crista Galli Morphology in Fetuses.

OBJECTIVE: To determine alterations in the crista galli (CG) size in fetuses with advancing weeks. METHODS: Skull bases of 32 fetuses (11 males/21 females) aged 17 to 32 weeks in utero were included in the study. The width (width of CG), height (height of CG), and length (length of CG) of CG were measured, and also olfactory fossa depth (OFD) was measured to determine the relation of CG with OFD. RESULTS: Width of CG, height of CG, length of CG, and OFD were measured as 1.77 ± 0.59 mm, 5.10 ± 1.70 mm, 12.32 ± 2.25 mm, and 1.56 ± 0.56 mm, respectively. No significant difference was observed between the measurements in terms of sex and side (P> 0.05). Apart from OFD, the parameters were greater in the third-trimester fetuses than in the second-trimester fetuses (P< 0.001). Olfactory fossa depth was similar in both trimester fetuses (P= 0.798). Olfactory fossa depth did not alter with advancing gestational weeks (P= 0.077), but the others increased (P< 0.01). Only one configuration regarding Keros types was observed. Type 1 was detected in all fetuses (100%). A linear function was calculated as y=1.442+0.455×age for the length of CG, y=-2.566+0.321×age for the height of CG, y=0.641+0.039×age for OFD, and y=-1.088+0.119×age for the width of CG. CONCLUSIONS: Crista galli size increased with advancing fetal weeks. The authors detected Keros type 1 in all fetuses. The authors' linear functions representing the growth pattern of CG and OFD in fetuses may be useful in estimating their dimensions.

Posterior clinoid process in children: morphometric analysis, pneumatization ratio, and surgical implications.

PURPOSE: To describe pneumatization and topographic position of the posterior clinoid process (PCP) in healthy children when approaching the anterior and middle fossae. METHODS: The study consisted of computed tomography images of 180 pediatric patients (90 males / 90 females), aged 1-18 years. The presence or absence of PCP pneumatization was noted, and the distances of certain landmarks to PCP were measured. RESULTS: The distances of the foramen ovale, foramen rotundum, superior orbital fissure, anterior clinoid process (ACP), foramen magnum and crista galli to PCP were measured as 18.59 ± 3.36 mm, 15.37 ± 3.45 mm, 14.60 ± 3.05 mm, 5.27 ± 3.24 mm, 32.03 ± 3.27 mm, and 30.45 ± 3.93 mm, respectively. These parameters increased with growth (between 1-18 years), but the distance between PCP and ACP decreased with an irregular pattern. In 11 sides (3.10%), a fusion between PCP and ACP was determined. PCP pneumatization was identified in 32 sides (8.9%). Its pneumatization correlated with pediatric ages (p < 0.001), but not gender (p = 0.459) or side (p = 0.711). Most of PCP pneumatization appeared after late childhood period (i.e., between 10-18 years). CONCLUSION: Our study provides beneficial data for neurosurgeons to use PCP as a reference point for creating a skull base map in children, because of the incomparable position of PCP in the skull base center.

Radiologic evaluation of the Vidian canal in the pediatric population.

PURPOSE: This examination aimed to display the size and topographic position of the Vidian canal (VC) in normal children. METHODS: 180 pediatric subjects aged 1-18 years were included this computed tomography examination. The distances of VC to certain landmarks, and VC length were measured. The locations of VC according to the sphenoid sinus, and the medial plate of pterygoid process were classified as three types, separately. RESULTS: The distances of VC to the vomerine crest, midsagittal plane, round foramen, and the superior wall of sphenoid sinus were measured as 12.68 ± 3.17 mm, 10.76 ± 2.52 mm, 8.62 ± 2.35 mm, and 14.16 ± 5.00 mm, respectively. The length and angle of VC were measured as 12.00 ± 2.52 mm, and 16.60 ± 9.76°, respectively. According to the sphenoid bone, VC location was identified as Type 1 in 113 sides (47.5%), as Type 2 in 70 sides (29.4%), and as Type 3 in 55 sides (23.1%). According to the medial plate of pterygoid process, VC location was identified as Type A in 274 sides (76.1%), as Type B in 55 sides (15.3%), and as Type C in 31 sides (8.6%). VC location types correlated with pediatric ages, but not sex or side. CONCLUSION: With advancing pediatric age, the protrusion of VC into the sphenoid sinus increases, and VC shifts from medial to lateral side of the medial plate of pterygoid process.

Arnold Kirkpatrick Henry (1886-1962) and his eponym (Master Knot of Henry): a narrative review.

PURPOSE: The aims of this review were to form a more precise description for Master Knot of Henry (MKH), and to modify classifications related to interconnections between flexor hallucis longus (FHL) and flexor digitorum longus (FDL) for showing all configurations in the literature. METHODS: A literature search was performed in main databases to obtain information related to anatomical definitions and variations of MKH. The search was carried out using the following keywords: "Master Knot of Henry", "Chiasma plantare", "Flexor hallucis longus" and "Flexor digitorum longus". Information extracted from the studies was: sample size, numerical values, classifications, variation types, incidence of types, anatomical definitions of MKH, year of publication, and type of study. RESULTS: This study proposes that MKH should be defined as the intersection territory where FDL crosses over FHL in the plantar foot. The postchiasmatic plantar area located at distal to MKH (the narrow space between MKH and the division of FDL) should be termed as the triangle of Henry. Moreover, the classification systems showing different configurations related to interconnections situated at Henry's triangle were updated as eight types to present all forms in the literature. CONCLUSION: Our definitions may assist in determining the precise anatomical boundaries of MKH, and thus facilitate the use of MKH as a surgical landmark. In addition, our modified classification systems covering all variations in the current literature may be helpful for surgeons and anatomists to understand formations of the triangle of Henry, and the long flexor tendons of the lesser toes.