Section II—External Anatomy
The body of the cat is covered almost entirely by hair (forming a thick coating of fur or pelage), a characteristic feature of mammals. Only the nose, lips, and thick pads of the feet are exceptions.
The head and trunk are separated by a distinct neck, which allows considerable mobility of the head (Figure 7.25). Dorsally the trunkshaft of fibula
(diaphysis) shaft of rib sternebrae sternum styloid process subscapular fossa supracondyloid foramen supraspinous fossa tarsals thoracic vertebrae tibia tibial crest tibial tuberosity transverse foramina transverse process trapezium trapezoid trochanteric fossa trochlea trochlea tali trochlear notch tuberculum ulna unciform vertebrae vertebral vertebral column vertebrochondral vertebrosternal wing xiphisternum xiphoid cartilage
FIGURE 7.25 External features of the cat.
is termed the dorsum. Ventrally, it is subdivided into the thorax anteriorly and the abdomen more posteriorly. The pelvis is the region of the trunk associated with the hindlimb, just anterior to the elongated tail.
On the head note the pinnae (sing., pinna), the mainly cartilaginous soft-tissue extension of the external ear. Upper and lower palpebrae (sing., palpebra) guard the large eyes. A third eyelid, the nictitating membrane, lies on the medial part of the eye. In life, it can be drawn laterally over the eye. The nares (sing., naris) are the external openings of the nose and are surrounded by a region of skin termed the rhinarium. The mouth is surrounded by lips. Vibrissae are stiff, tactile hairs or whiskers present mainly around the mouth and snout, but also over the eyes.
Each limb comprises three segments. In proximal to distal order, they are the brachium, antebrachium, and manus in the forelimb, and femur, crus, and pes in the hindlimb.
Each digit, except digit 1 of the pes, ends in a retractable claw. The walking surface of the forepaws and hindpaws each have epidermal thickenings of the skin termed tori (sing., torus) that act as pads during locomotion.The anus, the posterior opening of the intestine, lies ventral to the base of the tail. The urinary and reproductive structures lie just anterior to the anus. In the male the scrotum is a sac-like projection that contains the testes. Anterior to it is the penis, which is probably retracted and thus not readily apparent. Its tip contains the common opening of the urogenital ducts. In the female the urinary and reproductive tracts open into the urogenital aperture.
Key Terms: External Anatomy
abdomen
antebrachium (forearm)
anus
brachium (arm)
claw
crus (shank)
dorsum (back)
eyes
femur (thigh)
hair
head
lips
manus
mouth
nares (sing., naris)
(nostrils)
neck (cervix)
nictitating membrane palpebrae (sing.,
palpebra) (eyelid) pelvis penis pes pinnae (sing., pinna) rhinarium scrotum tail thorax tori (sing., torus) trunk urogenital aperture vibrissae (sing., vibrissa)
(whisker)