Posterior Recess

Fig. 16.33. Normal posterior recess of the ankle joint. Longitudinal 12-5 MHz US image over the Achilles tendon (A) reveals the concave appearance of the posterior recess (arrows) of the ankle joint that lies between the posterior malleolus of the tibia (T) and the posterior talus (Ta). Note the deep location of this recess relative to the soleus (so) and the flexor hallucis longus (fhl) muscles. It contains a physiologic small amount of fluid (asterisk). Star, posterior fat pad. The photograph at the upper left of the figure indicates probe positioning...

Other causes of posterior impingement include osteochondral damage of the posterior talar dome and posterior talocalcaneal joint, and thickening and inflammation of the synovial folds of the posterior recesses of the ankle and subtalar joints. US has a limited value in the evaluation of these latter... 

Synovitis in the anterior subtalar joint can also be assessed with US by placing the transducer just below and anterior to the anterior talofibular ligament to examine the groove between calcaneus and talus synovitis of the posterior subtalar joint is best evaluated by scanning its posterior recess that is located just caudal to the posterior recess of the ankle joint (Fig. 16.88). 

Fig. 16.87 a,b. Synovitis of the ankle joint posterior recess, a Sagittal 12-5 MHz US image over the posterior ankle demonstrates hypoechoic fluid (arrows) within the posterior recess of the ankle joint between the posterior malleolus (PM) and the talus, in close relation to the flexor hallucis longus tendon (fhl). b Lateral radiograph shows increased density (arrows) at the level of the posterior recess, reflecting synovitis... 

Fig. 16.88a,b. Synovitis of the posterior subtalar joint, a Sagittal 12-5 MHz US image over the Achilles tendon (A) with b T2-weighted MR imaging correlation reveals abundant fluid within a distended posterior recess of the posterior subtalar joint (arrows), deep to the Kager fat space (asterisk). Note the close relation of this recess with the superior margin of the calcaneus... 

Fig. 18.9. Schematic drawing of a transverse view through the shouider iiiustrates the technique for US-guided arthrocente-sis using a posterior approach. The needle is advanced from lateral to medial to reach the posterior recess of the glenohumeral joint. This path facilitates gliding of the needle over the humeral head and below the posterior labrum...

FIGURE 14-2 The histaminergic system of the rat brain. (A) Frontal sections through the posterior hypothalamus showing the location of histaminergic neurons. Arc, arcuate nucleus DM, dorsomedial nucleus LM, lateral mammillary nucleus MM, medial mammillary nucleus MR, mammillary recess PM, premammillary nucleus 3V, third ventricle VMH, ventromedial hypothalamic nucleus. (Modified with permission from reference [5].)... 

The upper respiratory tract, particularly the nose, has a unique anatomy that performs normal physiologic functions as well as innate defense against inhaled toxicants. The nose extends from the nostrils to the pharynx. Inspired air enters the nose through the nostrils. The nasal cavity is divided longitudinally by a septum into two nasal compartments. In most mammalian species, each nasal cavity is divided into a dorsal, ventral, and middle (lateral) meatus by two turbinate bones, the nasoturbinate and maxilloturbinate. These turbinates project from the dorsolateral and ventrolateral wall of the cavity, respectively. In the posterior portion of the nose, the ethmoid recess contains the ethmoturbinate. The nasal cavity is lined by a vascular mucosa that consists of four distinct types of epithelia. In rodents, these epithelia are (1) the stratified squamous epithelium that lines the nasal vestibule and the floor of the ventral meatus in the anterior portion of the nose (2) the non-ciliated, pseudostratified, transitional epithelium that lies between the squamous epithelium and the respiratory epithelium and lines the lateral meatus (3) the ciliated respiratory epithelium that lines the remainder of the nasal cavity anterior and ventral to the olfactory epithelium and (4) the olfactory epithelium (neuroepithelium) that lines the dorsal meatus and ethmoturbinates in the caudal portion of the nose. The relative abundance and exact locations of these upper respiratory epithelium differ among mammalian species. 

In contrast the ventral valve of forma turbinata is heavily calcified, with only slightly recessed posterior adductor scars, and with prominent anterior adductor scars separated by a short ridge and supported on a raised platform, their acme of development being seen in specimens from Tarifa (Fig. 8.3(9) and West Africa (Fig. 8.3(H)). If this is the internal rostellum of Reeve (1862) then our findings differ from his. 

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