What is the precaecocolic fascia?

The precaecocolic fascia, previously known as Jackson's membrane, is a variable vascular peritoneal fold between the ascending colon and the right posterolateral abdominal wall. First described in 1913, it was originally thought to be of developmental or inflammatory origin and associated with abdominal pain. This investigation aimed to review its frequency, form and structure and look for evidence of association with malformation of the bowel, or previous inflammation. 26 dissecting room cadavers were studied to identify the precaecocolic fascia, any malrotation of the colon or signs of previous inflammation: adhesions, surgical scars, or absence of the appendix. Its structure was examined histologically and latex injections were used to trace the arteries. Membranes comparable with previous descriptions of the precaecocolic fascia occurred in 12 of 26 abdomens. They varied in form and size from long and translucent to short, thick, and opaque. In structure, the fascia resembled a fold of peritoneum containing a thickened fibrous lamina. Large thin-walled arteries in the fascia crossed the arteries in the wall of the colon at the point of attachment. No significant association with colonic malrotation or markers of previous inflammation were found. Attention should be paid to the definition of the precaecocolic fascia and "membrane" seems a more appropriate term than "fascia". It is one of a recognized group of peritoneal folds/bands, doubtful in origin but unlikely to be post-inflammatory. It may modify colonic mobility or complicate colonic operations.

Arterial Anastomosis in the Tongue.

PURPOSE: Radical surgery for neoplasms of the tongue can endanger at least 1 lingual artery, threatening the survival of the remaining tissue and the recovery of speech and swallowing. Although there is little anastomosis in the substance of the tongue, this study investigated whether arterial anastomoses outside the tongue could provide collateral circulation to protect the surviving tissue. MATERIALS AND METHODS: Parts of 9 embalmed cadaver heads were examined. In 2 specimens, the arteries had been previously injected with latex and India ink. In the remaining, a mixture of latex and India ink was injected into the lingual artery at its origin on 1 side. Five injections were successful. RESULTS: There was considerable variation in the course and distribution of the lingual arteries. Arteries did not cross the midline of the tongue, but actual or potential anastomoses could be seen round the base of the tongue, in the floor of the mouth, and with facial artery branches. After the experimental injections, the mass filled the lingual artery and its branches on the injected side, but also reached the trunk and main branches of the opposite side. CONCLUSION: A mass injected into the lingual artery of 1 side can reach the trunk and territory of the lingual artery of the opposite side. In life, it is likely that a similar collateral circulation would exist. Some clinical literature supports this conclusion, but preoperative arteriography might be a reasonable precaution.

The precision of four commonly used surgical landmarks for locating the facial nerve in anterograde parotidectomy in humans.

In addition to using intra-operative facial nerve monitoring in helping to locate the position of the facial nerve in anterograde parotidectomy, numerous soft tissue and bony landmarks have been proposed to assist the surgeon in the early identification of this nerve. There is still dispute within the literature as to the most effective method, if any, of locating the nerve. The purpose of this study was to measure the distance (in twenty-six embalmed cadavers) from four of the most commonly used surgical landmarks to the main trunk of the facial nerve-the posterior belly of digastric muscle (PBDM), the tragal pointer (TP), the junction between the bony and cartilaginous ear canal (EAM) and the tympanomastoid suture (TMS). The main trunk of the facial nerve was found 5.5+/-2.1mm from the PBDM, 6.9+/-1.8 mm from the TP, 10.9+/-1.7 mm from the EAM and 2.5+/-0.4 mm from the TMS. From this, the TMS can be used as a reliable indicator for locating the main trunk of the facial nerve. In addition, this study also demonstrated a statistically significant difference between the sexes in relation to the two bony landmarks used here, the EAM and the TMS, with the facial nerve found further away from those landmarks in females compared to males. With the advent of 3D construction and reformatting of images, these values may come to the forefront in pre-operative planning for locating the facial nerve in anterograde parotidectomy.

Improving respiration in patients with tetraplegia by functional electrical stimulation: an anatomical perspective.

Patients with tetraplegia often have respiratory complications because of paralysis of the abdominal and intercostal muscles. Functional electrical stimulation (FES) has been used to improve breathing in these patients by applying surface stimulation to the abdominal muscles. We aimed to find the best nerves to stimulate directly to increase tidal volume and make cough more effective. Surface electrodes were placed on a patient's abdominal wall to find the optimum points for surface stimulation. These positions were plotted on a transparent sheet. The abdomino-intercostal nerves were dissected in five male dissecting room cadavers matched for size with the patient. The plastic sheet was then superimposed over each of the dissections to clarify the relationship between optimum surface stimulation points and the underlying nerves. Results show that the optimum surface stimulation points overlie the course of abdomino-intercostal nerves T9, 10, and 11. The success with selecting stimulation points associated with T9, 10, and 11 is probably because of the large mass of abdominal muscle supplied by these nerves. The constant position of the nerves below the ribs makes the intercostal space a possible site for direct stimulation of the abdomino-intercostal nerves.

The effect of surgical resection in the region of the retromolar trigone.

Tumours in the mucosa of the retromolar trigone (RMT) are rare, but develop insidiously and spread rapidly into surrounding structures. Resection may require radical dissection beginning usually on the medial side of the mandible. Such surgery can put important structures at risk. The normal anatomy of the RMT and its relations has been studied together with simulated surgical incisions and resections. Tissue removed was processed by histological techniques in order to demonstrate structures excised or damaged by the operation. The simulated incision showed that the lingual nerve, submandibular duct and palatoglossus were at particular risk. This could affect sensation, speech, swallowing and movements of the tongue. The findings pose immediate concerns for surgeons operating in this area. Although cancer surgery often involves sacrificing tissue, care should be taken to preserve structures vital to the patient's oral function without compromising oncological principles.

The functional intraoral Glasgow scale (FIGS) in retromolar trigone cancer patients.

BACKGROUND: Surgical incisions in the retromolar trigone (RMT) cause injury to underlying structures. The functional intraoral Glasgow scale (FIGS) is used to determine the ability of patients to speak, chew and swallow. FIGS could be used to investigate whether there is a correlation between clinical tumour stage and the function of the oral cavity following surgery in the RMT. MATERIALS AND METHODS: FIGS scores for 58 patients speech, chewing and swallowing collected pre-operatively, then at 3 and 20 weeks post-operatively, were used to calculate a total 'Global Oral Disability' value and compared with the clinical tumour size using the TMN staging method. RESULTS: Patients with RMT cancer who undergo surgical resection can expect a degree of functional impairment which is proportional to the clinical tumour size. DISCUSSION: FIGS is a simple and reproducible way of assessing a patient's functional impairment following surgery in the RMT, especially when using the new global oral disability value.