554 



SURGICAL ANATOMY. 



Relations. By its under surface, with the tendons of the long and short 

 Flexors and Lumbricales. By its upper surface, with the Interossei. 



Fig. 197. The Dorsal Interossei. 

 Left Foot. 



Fig. 198. The Plantar Interossei. 

 Left Foot. 



THE IXTEROSSEI. 



The Interossei muscles in the foot are simi- 

 lar to those in the hand. They are seven in 

 number, and consist of two groups, dorsal, and 

 plantar. 



The Dorsal Interossei, four in number, are 

 situated between the metatarsal bones. They 

 are bipenniform muscles, arising by two heads 

 from the adjacent sides of the metatarsal bones 

 between which they are placed, their tendons 

 being inserted into- the bases of the first pha- 

 langes, and into the aponeurosis of the common 

 Extensor tendon. In the angular interval left 

 between each muscle at its posterior extremity, 

 the perforating arteries pass to the dorsum of 

 the foot, except in the first Interosseous muscle, 

 where the interval allows the passage of the 

 communicating branch of the dorsalis pedis 

 artery. The first Dorsal interosseous muscle 

 is inserted into the inner side of the second toe ; 

 the other three are inserted into the outer sides 

 of the second, third, and fourth toes. They 

 are all abductors from an imaginary line or 

 axis drawn through the second toe. 



The Plantar Interossei, three in number, lie 

 beneath, rather than between, the metatarsal 

 bones. They are single muscles, and are each 

 connected with but one metatarsal bone. They 

 arise from the base and inner sides of the shaft 

 of the third, fourth, and fifth metatarsal bones, 

 and are inserted into the inner sides of the 

 bases of the first phalanges of the same toes, 

 and into the aponeurosis of the common 

 Extensor tendon. These muscles are all 

 adductors towards an imaginary line, extend- 

 ing through the second toe. 



Nerves. The internal plantar nerve supplies 

 the Abductor pollicis, Flexor brevis digitorum, 

 Flexor brevis pollicis, and the first and second 

 Lumbricales. The external plantar nerve sup- 

 plies the Abductor minimi digiti, Flexor 

 accessorius, third and fourth Lumbricales, Ad- 

 ductor pollicis, Flexor brevis minimi digiti, 

 Transversus pedis, and all the Interossei. 



SUEGICAL ANATOMY. 



The student should now consider the effects produced 

 by the action of the various muscles in fractures of 

 the bones of the lower extremity. The more common 

 forms of fracture may be especially selected for 

 illustration and description. 



