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The purpose of this study was to correlate the four types of acromial shape with the existence of enthesophytes, which together comprise two important parameters for subacromial impingement syndrome and rotator cuff tears. In addition, a review of the literature was carried out. Four hundred twenty-three dried scapulas were studied at the Department of Anatomy in the University of Cologne, Germany. Four types of acromion were found: the three classical ones as described by Bigliani et al. ([1986] Orthop Trans 10:216) and a fourth one, where the middle third of the undersurface of acromion was convex (Gagey et al. [1993] Surg Radiol Anat 15:63–70). The correlation between the four types of acromion and the presence of enthesophytes at its anterior undersurface was also recorded. The distribution of acromial types was as follows: type I, flat, 51 (12.1%); type II, curved, 239 (56.5%); type III, hooked, 122 (28.8%); and type IV, convex, 11 (2.6%). Enthesophytes were found in 1 of type I (2%), in 19 of type II (7.9%), in 46 of type III (37.7%), and in 0 (0%) of type IV acromions. Overall, 66 (15.6%) out of 423 scapulas had enthesophytes. In all cases, they were localized at the site of the coracoacromial ligament insertion on the acromion. Enthesophytes were significantly (P < 0.05) more common in type III acromions and this combination is particularly associated with subacromial impingement syndrome and rotator cuff tears. In type I and in type IV acromions, the incidence of enthesophytes is very small and, according to other studies, with these two acromial types rotator cuff tears are also rare. Clin Anat. 20:267–272, 2007. © 2006 Wiley-Liss, Inc.

The anatomical relationships of the greater occipital nerve (GON) to the semispinalis capitis muscle (SCM) and the trapezius muscle aponeurosis (TMA) were examined to identify topographic landmarks for use in anesthetic blockade of the GON in occipital neuralgia. The course and the diameter of the GON were studied in 40 cadavers (29 females, 11 males), and the points where it pierced the SCM and the TMA were identified. The course of the GON did not differ between males and females. A left–right difference was detected in the site of the GON in the TMA region but not in the SCM region. The nerve became wider towards the periphery. This may be relevant to entrapment of the nerve in the development of occipital neuralgia. In three cases, the GON split into two branches before piercing the TMA and reunited after having passed the TMA, and it pierced the obliquus capitis inferior muscle in another three cases. The GON and the lesser occipital nerve reunited at the level of the occiput in 80% of the specimens. The occiput and the nuchal midline are useful topographic landmarks to guide anesthetic blockade of the GON for diagnosis and therapy of occipital neuralgia. The infiltration is probably best aimed at the site where the SCM is pierced by the GON. Clin. Anat. 19:332–336, 2006. © 2005 Wiley-Liss, Inc.

Purpose Collagen crosslinking of the cornea (CXL) has been developed recently as a promising treatment of keratoconus. In vitro measurements have demonstrated a significant increase in biomechanical stiffness of the crosslinked cornea. The aim of the present study was to evaluate the effect of this procedure on the collagen fiber diameter of the rabbit cornea over time. Methods The corneas of 10 New Zealand White albino rabbits were crosslinked by application of the photosensitizer riboflavin and exposure to UVA light (365 nm, 3 mW/cm2) for 30 minutes. The fellow control eyes were left untreated. On ultrathin sections of samples from the central and peripheral cornea, the collagen fiber diameter were measured with the help of morphometric computer software. Results In the anterior stroma, 48 hours after the CXL the collagen fiber diameter in the treated corneas was significantly increased by 10% compared with the control fellow eyes. Four months after the CXL, the mean collagen fiber diameters were decreased as compared to the 48 h specimens. In the 6 month specimens the diameter of the collagen fibers was further decreased as compared to the control fellow eyes up to -8%. Conclusion CXL leads to a significant increase in corneal collagen diameter 48 hours after the procedure. Interestingly, 4 months after the CXL, there is a decrease in the mean diameter of the collagen fiber and at 6 months, there is a further decrease up to 8% compared to the fellow eye. We can assume that the rigidity and the biomechanical stability of the cornea after CXL is increased because of the new intercollagen connections and collagen fiber diameter has little or no role in this procedure.