THE HEART. 99 



Flexor Brevis Pollicis,^ from the cuboid and external cuneiform bones, and the 

 prolonged tendon of the tibialis posticus, into both sides of the base of the 

 ist phalanx of the great toe, by 2 portions, of which one blends with the 

 abductor pollicis, the other with the adductor pollicis. Action, to flex the 

 great toe. Nerve, internal plantar. 



Adductor Pollicis, from the tarsal ends of the three middle metatarsal bones, 

 and the sheath of the tendon of the peroneus longus, into the base of the 

 ist phalanx of the great toe, externally. Action, to adduct the great toe. 

 Nerve, external plantar. 



Flexor Brevis Minimi Digiti/ from the base of the 5th metatarsal bone and 

 the sheath of the tendon of the peroneus longus, into the base of the f st 

 phalanx of the little toe externally. Action, to flex the little toe. Nerve, 

 external plantar. 



Transversus Pedis, from the under surface of the head of the 5th metatarsal 

 bone, and the transverse ligament of the metatarsus, into the outer side of 

 the ist phalanx of the great toe, blending with the tendon of the adductor 

 pollicis. Action, to adduct the great toe. Nerve, external plantar. 



Dorsal Interossei (4), each by two heads from the adjacent sides of two meta- 

 tarsal bones, into the base of the ist phalanx of the corresponding toe. 

 Action, to abduct the toes. Nerve, external plantar. 



Plantar Interossei./ (3), from the shafts of the 3d, 4th, and 5th metatarsal 

 bones, into the bases of the ist phalanges of the same toes. Action, to 

 adduct the toes towards the median line. Nerve, external plantar. 



THE HEART. 



What is the Pericardium ? It is a conical membranous closed sac, con- 

 taining the heart and the roots of the great vessels. It lies behind the sternum 

 and between the pleurae, its apex upwards, its base below and attached to the 

 central tendon of the diaphragm. It is composed of an outer fibrous coat, 

 and an inner serous one ; the latter consisting of two portions, a parietal layer, 

 lining the inner surface of the fibrous coat, and a visceral layer, which is re- 

 flected over the heart and vessels. The serous portion secretes a thin fluid, 

 about I drachm in quantity normally, for the lubrication of its surfaces. The 

 fibrous coat is prolonged on the outer surfaces of the great vessels, except the 

 inferior vena cava, and becomes continuous with the deep layer of the cervical 

 fascia. 



Describe the Endocardium. It is a serous membrane which lines the 

 inner surface of the heart, forming by its reduplications the cardiac, aortic, 

 and pulmonary valves, and continuous with the lining membrane of the grea f 

 vessels. 



