Search Results

Little is known about the aetiology or pathology of cluster headaches, and even less is known about its possible anatomical origins. In the complete form of a cluster headache, patients experience pain referred to by the first and second division of the trigeminal nerve, ocular sympathetic dysfunction (Homer's syndrome), forehead and facial sweating due to the stimulation of superior cervical ganglia projections, and parasympathetic activation which manifests as lachrymation, conjunctival injection, nasal congestion, and rhinorrhoea. Some severely affected patients are successfully treated with chemical- or heat-induced trigeminal lesions, whereas others benefit from the injection of local anaesthetics into the sphenopalatine fossa or from the removal of the sphenopalatine ganglion. It is believed that if a single ‘lesion’ does exist to explain all these symptoms and treatments, it must be small, and must reside within a remote region of the nervous system to escape detection by presently available diagnostic techniques. Recent anatomical data in primates suggest that such a disturbance may be localized to the superior aspect of the pericarotid cavernous sinus plexus.

Basic sciences: Applied anatomy

Which of the following nerves does not arise from the medial cord of the brachial plexus?

Medial cutaneous nerve of the forearm

Medial pectoral nerve

Musculocutaneous nerve

Ulnar nerve

Median cutaneous nerve of the arm...

It is essential that dental students and practitioners understand the structure and function of the temporomandibular joints and the muscles of mastication and other muscle groups that move them. The infratemporal fossa and pterygopalatine fossa are deep to the mandible and its related muscles; many of the nerves and blood vessels supplying the structures of the mouth run through or close to these areas, therefore, knowledge of the anatomy of these regions and their contents is essential for understanding the dental region. The temporomandibular joints (TMJ) are the only freely movable articulations in the skull together with the joints between the ossicles of the middle ear; they are all synovial joints. The muscles of mastication move the TMJ and the suprahyoid and infrahyoid muscles also play a significant role in jaw movements. The articular surfaces of the squamous temporal bone and of the condylar head (condyle) of the mandible form each temporomandibular joint. These surfaces have been briefly described in Chapter 22 on the skull and Figure 24.1A indicates their shape. The concave mandibular fossa is the posterior articulating surface of each squamous temporal bone and houses the mandibular condyle at rest. The condyle is translated forwards on to the convex articular eminence anterior to the mandibular fossa during jaw movements. The articular surfaces of temporomandibular joints are atypical; they covered by fibrocartilage (mostly collagen with some chondrocytes) instead of hyaline cartilage found in most other synovial joints. Figures 24.1B and 24.1C show the capsule and ligaments associated with the TMJ. The tough, fibrous capsule is attached above to the anterior lip of the squamotympanic fissure and to the squamous bone around the margin of the upper articular surface and below to the neck of the mandible a short distance below the limit of the lower articular surface. The capsule is slack between the articular disc and the squamous bone, but much tighter between the disc and the neck of the mandible. Part of the lateral pterygoid muscle is inserted into the anterior surface of the capsule. As in other synovial joints, the non-load-bearing internal surfaces of the joint are covered with synovial membrane.

Paula M. Niedenthal reflects on her most underappreciated work: her research on the relationship between facial expression and emotion based on the vascular theory of emotional efference (VTEE). Originally proposed by Robert B. Zajonc, VTEE suggested that facial muscular movement could constrict venous flow by its action on the cavernous sinus, causing the arterial blood flow to the brain to cool. This cooling alters the feeling of emotion. Niedenthal describes the reaction of the social psychology community to the findings of her study.