Soft tissue connection between rectus capitus posterior minor and the posterior atlanto-occipital membrane: A cadaveric study

Abstract

This investigation determined the variation, prevalence, tissue-type, and sex bias in the soft-tissue bridge between rectus capitis posterior minor (RCPMi) and the posterior atlanto-occipital membrane (PAO). Seventy-five cadavers (27 females and 48 males) were surveyed. When RCPMi was revealed, its superior attachment was detached and the muscle was reflected inferiorly to determine if it was attached to the underlying PAO. If a soft-tissue bridge was identified, the fibers found within the bridge were classified by visual inspection into three categories: tendon-like, muscle-like, and fascia-like. A fourth category of no attachment was also noted. These results show that RCPMi was present bilaterally in 93% of all cadavers surveyed (89% of the female cadavers and 96% of the male cadavers). On the right side, a soft-tissue bridge was present in 67% of males and 78% of females. On the left side, the soft-tissue bridge was present in 69% of males and 82% of females. The number of male cadavers possessing tendon fibers in a soft-tissue bridge was 56% on the right side and 55% on the left side. In females, the number of cadavers possessing tendon fibers in a soft-tissue bridge was 44% on the right side and 64% on the left side. In males, muscle fibers were present in the soft-tissue bridge, 34% on the right side and 36% on the left. In females, muscle fibers were found in the soft-tissue bridge, 43% on the right side and 36% on the left. There were no significant associations of sex and the presence of the soft-tissue bridge and a fiber-type within a soft-tissue bridge.

Association of Cross-Sectional Area of the Rectus Capitis Posterior Minor Muscle with Active Trigger Points in Chronic Tension-Type Headache

“…Hack et al 36 found the existence of a connective tissue bridge between the RCPmin muscle and the dorsal spinal dura at the C0 -C1 junction, providing anatomic evidence to link the two disparate tissues. This muscle attachment to the cervical spine dura was later confirmed by Humphreys et al 37 and Zumpano et al 38 It is unknown whether this anatomic feature of the RCPmin muscle could make it more sensitive to atrophy than RCPmaj.…”

Anatomical Parameters of the Rectus Capitis Posterior Minor Muscle Based on a New Magnetic Resonance Scan Method

“…Many anatomical studies have focused on the connections of RCPmi in the past (Hack et al;Rutten et al;Yuan et al;Alix & Bates;Elliott et al, 2005;Zumpano et al, 2006;Hallgren, 2014;Hallgren et al, 2014;Scali et al, 2015), while few studies were related to the morphological parameters of the RCPmi. In this study, a quantitative MRI measurement of the RCPmi was developed and a reference value of imaging anatomical parameters of the RCPmi was set up.…”

Ligaments of the craniocervical junction

“…27,68,85 A study conducted by Hack et al 27 reported the presence of a connective tissue bridge joining the rectus capitis posterior minor muscle to the spinal dura in all cadaveric specimens. Zumpano and associates 90 found this connective tissue bridge to be present in 67% of cadavers, indicating that this represents normal anatomy rather than a rare anatomical anomaly. Nash et al, 49 expanding on these studies, reported that the PAO membrane is actually composed of the deep fascia of the rectus capitis posterior minor muscle and the vertebral vascular sheath.…”

“…77 This structure has been noted by several authors to extend laterally over the atlantooccipital joint capsules. 90 The PAO membrane runs adjacent to the rectus capitis posterior minor posteriorly and the dura mater anteriorly. Several authors have noted connection or interdigitation of the PAO membrane with both the rectus capitis posterior minor muscle and the spinal dura mater.…”

“…5,54,56,90 This may be due to its apparent interdigitation with the pain-sensitive spinal dural layer. Studies by Nash et al 49 and Zumpano et al 90 agreed that there is a connective tissue bridge between the rectus capitis posterior minor muscle, the PAO membrane, and the spinal dura mater. This connection may serve as a point of transfer of force from the spinal column to the dura.…”