ABSTRACT
BACKGROUND: Knowledge of the anatomy of ligaments that bind the craniocervical junction is important for treating patients with lesions of this region. Although the anatomy and function of these ligaments have been well described, those of the transverse occipital ligament (TOL) have remained enigmatic. OBJECTIVE: To describe the anatomy and functions of the transverse occipital ligament. METHODS: Via a posterior approach, 9 cadaveric specimens underwent dissection of the craniocervical junction with special attention to the presence and anatomy of the TOL. RESULTS: The TOL was identified in 77.8% of the specimens. The ligament was found to be rectangular with fibers running horizontally between the lateral aspects of the foramen magnum. The attachment of each ligament near the occipital condyle was consistent, and each ligament was found superior to the transverse portion of the cruciform ligament and inserted just posterior to the lateral attachment sites of the alar ligaments. The average width, length, and thickness of the TOL was 0.34, 1.94, and 0.13 cm, respectively. The TOL in some specimens also had connections to the alar and transverse ligaments. CONCLUSION: The TOL was found in the majority of our specimens. The possible functions of this ligament when attached to the alar ligaments include providing additional support to these structures in stabilizing lateral bending, flexion, and axial rotation of the head. Knowledge of this ligament may aid in further understanding craniocervical stability and help in differentiating normal from pathology via imaging modalities.
Subject(s)
Atlanto-Axial Joint/anatomy & histology , Atlanto-Occipital Joint/anatomy & histology , Foramen Magnum/anatomy & histology , Ligaments/anatomy & histology , Occipital Bone/anatomy & histology , Aged , Atlanto-Axial Joint/physiology , Atlanto-Occipital Joint/physiology , Axis, Cervical Vertebra/anatomy & histology , Axis, Cervical Vertebra/physiology , Cadaver , Cervical Atlas/anatomy & histology , Cervical Atlas/physiology , Dissection/methods , Female , Foramen Magnum/physiology , Head Movements/physiology , Humans , Ligaments/physiology , Male , Middle Aged , Occipital Bone/physiology , Odontoid Process/anatomy & histology , Odontoid Process/physiology , Range of Motion, Articular/physiologyABSTRACT
BACKGROUND: There is a paucity in the literature regarding the reflected ligament. Therefore, the present study was performed in order to further elucidate this anatomy. MATERIAL AND METHODS: Eighteen formalin-fixed adult cadavers (35 sides) underwent dissection of the medial inguinal region. The reflected ligament was observed for and when identified, its dimensions were measured. RESULTS: 83% of sides were found to have a reflected ligament. These were identified in 16 male and 13 female bodies. The size and shape for the reflected ligaments were variable but overall, triangular in nature. In general, the reflected ligament was found to extend from the lacunar and medial inguinal ligaments and extended obliquely toward the midline at an approximate 45 degrees angle to insert near the linea alba. Two ligaments (6.9 %) were identified that interdigitated with the contralateral reflected ligament. The medial and lateral lengths of the ligament had a mean measurement of 2.28 and 2.58 cm. The base of the reflected ligament had a mean of 2.52 cm and the height of this ligament was found to have a mean of 2.56 cm. The mean area of the reflected ligament was calculated as 2.93 cm(2). There was no statistically significant difference between right or left sides or between genders. CONCLUSIONS: The reflected ligament was identified in the majority of our specimens and this structure usually contributed to the formation of the posteromedial wall of the external inguinal ring. Therefore, this fact should be included in future descriptions of this ligament.
