174 LABORATORY MANUAL OF HUMAN ANATOMY 



medialis and the ligamentum deltoideurn ; the other, descending, 

 is attached to the processus medialis tuberis calcanei. 



The tendon of the long flexor of the great toe is contained 

 within a special sheath, altogether independent of the ligamen- 

 tum laciniatum. The fibres of this sheath arise from the medial 

 tip of the sulcus M. flexoris hallucis longi and from the summit 

 of the sustentaculum tali. They terminate upon the medial tip 

 of the same sulcus and the medial face of the os calcaneum about 

 one centimetre below the sustentaculum tali. The vessels run 

 above this sheath covered by the ligament, but generally the 

 medial and plantar arteries are separated from each other by a 

 septum. 



Detach the ligament from the malleolus medialis and dissect 

 it towards the os calcaneum, determining its exact attachment 

 and the position of the septa above mentioned. Make a drawing 

 of these structures at this stage of the dissection. 



PLANTAR EEGION OF THE FOOT (EEGIO PLAN- 

 TAEIS PEDIS). 



Before beginning this dissection, review the anatomy of the 

 bones entering into the formation of the foot. Note the number 

 and the exact position of each. (Vide Spalteholz, Figs. 198-99.) 

 Study in the bony foot and upon your subject the following : 



Arches. 



(a) Longitudinal arch. This arch extends from the heel to the meta- 

 tarsophalangeal joints. It is capped by the talus and 

 may be divided into 



(aa) A posterior limb, formed by the os calcaneum and the pos- 



terior part of the talus. Note the thickness and the 

 strength of this posterior limb, which serves as a point 

 of attachment for the tendo calcaneus [Achillis]. Study 

 the skeletons of the white, the negro, and the monkey 

 and compare the relative lengths of this posterior limb. 



(ab) An anterior limb. This limb is formed by the remaining 



bones of the tarsus and metatarsus. Examine a model 

 of a foot in which the joint-cavities are represented, and 

 note the amount of synovial membrane found in the 

 joints of the anterior limb. These membranes produce 

 an elastic resistance to any force applied to the anterior 

 limb of the longitudinal arch. Shocks transmitted 

 through it to the leg, pelvis, and trunk are much lessened 

 by this arrangement. The anterior limb is subdivided 

 into a medial pillar, formed by the talus, the navicular, 

 the three cuneiform, and the three medial metatarsal 



