The caudofemoralis (from the Latin ''cauda'', tail and ''femur'', thighbone) is a
muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
found in the pelvic limb of mostly all animals possessing a tail. It is thus found in nearly all
tetrapods.
Location
The caudofemoralis spans
plesiomorphic
In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades.
Plesiomorphy, symplesiomorphy, apomorphy, and ...
ally between femur (thigh) and tail; in mammals it is reduced and found directly
posterior/
caudal
Caudal may refer to:
Anatomy
* Caudal (anatomical term) (from Latin ''cauda''; tail), used to describe how close something is to the trailing end of an organism
* Caudal artery, the portion of the dorsal aorta of a vertebrate that passes into the ...
to the
gluteus maximus
The gluteus maximus is the main extensor muscle of the hip. It is the largest and outermost of the three gluteal muscles and makes up a large part of the shape and appearance of each side of the hips. It is the single largest muscle in the human ...
and directly
anterior
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
/
cranial to the
biceps femoris.
Origin and insertion
The caudofemoralis originates from the transverse processes of the second, third and fourth caudal vertebrae.
The caudodistal portion of the muscle in mammals lies deep to the proximocranial portion of the Biceps femoris; near the middle of the thigh, the caudofemoralis gives rise to a long, thin, and narrow tendon that passes distally to the knee joint and inserts into the fascia lata
The fascia lata is the deep fascia of the thigh. It encloses the thigh muscles and forms the outer limit of the fascial compartments of thigh, which are internally separated by the medial intermuscular septum and the lateral intermuscular septu ...
that is anchored to the lateral border of the patella.[
]
Among
archosaurians the caudofemoralis is divided in a ''pars pelvica/brevis'' (characterized by a pelvic origin) and a ''pars caudalis/longa'' (caudal origin), and the insertion on the femur is marked by the
fourth trochanter (but this becomes reduced in
maniraptorans and absent in
birds
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
).
Action
In mammals the caudofemoralis acts to flex the tail laterally to its corresponding side when the pelvic limb is bearing weight. When the pelvic limb is lifted off the ground, contraction of the caudofemoralis causes the limb to abduct and the shank to extend by extending the
hip
In vertebrate anatomy, hip (or "coxa"Latin ''coxa'' was used by Celsus in the sense "hip", but by Pliny the Elder in the sense "hip bone" (Diab, p 77) in medical terminology) refers to either an anatomical region or a joint.
The hip region is ...
joint (acetabulofemoral or coxofemoral joint). In other tetrapods contraction of the caudofemoralis retracts the hindlimb.
Cited References
Vertebrate anatomy
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