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The coccygeus (ischiococcygeus) is a triangular muscle located on each side of the pelvis. It originates from the ischium and inserts in the coccyx and sacrum. It closes the back part of the outlet of the pelvis. The coccygeus muscle is innervated by the third and fourth sacral nerves. This muscle raises and supports the coccyx.
 Research Coccygeus
The coccyx (or 'tailbone') is composed of three to five rudimentary vertebrae. Often, the first of these coccygeal vertebrae is separate, while the remainder are fused together. The articulation between the coccygeal vertebrae and the sacrum allow some flexibility in the coccyx, which is particularly beneficial in taking the stresses of sitting and falling. The coccyx is extremely susceptible to shock fracture, as might be induced from a fall. Furthermore, since a number of nerve pathways pass near this area, damage to the coccyx threatens damage to the nerves of the lower body. The juncture of the first coccygeal vertebra with the sacrum occurs at the lower facet of the sacrum.
Research Coccyx
The gluteus maximus is the most powerful and largest muscle in the body. It is a thick, fleshy, quadrilateral muscle that forms the major volume of the buttock. It originates from the ilium and the posterior surface of the sacrum and coccyx, descends downward and outward from its origin and wraps around the outer back corner of the pelvis to insert in the iliotibial band and the gluteal ridge of the femur. It connects the ilium, sacrum, and coccyx to the femur by tissues of the thigh. The gluteus maximus is innervated by the inferior gluteal nerve and supplied by the inferior and superior gluteal arteries. This muscle consists of coarse muscle fibres that powerfully extend the thigh at the hip joint and moves it away from the body, as when walking or running. It is also used to raise the body from a sitting position.
Research Gluteus Maximus
The lower margin of each ilial wing features a sharp concavity where the ilium and the sacrum join. This is called the greater sciatic notch, and it allows the sciatic nerves to pass to the legs below.
Research Greater Sciatic Notch
The iliocostals lumborum consists of several muscle straps that link the lumbar vertebrae and sacrum with the lower six or seven ribs. The muscle straps have a number of tendons, varying in different individuals, which insert in all angles in the lower six ribs. The muscle is innervated by dorsal branches of the lumbar and thoracic nerves and supplied by branches from the aorta.
Research Iliocostalis Lumborum
The iliocostals thoracis (iliocostalis dorsi) consists of several muscle straps that link the thoracic vertebrae and sacrum with the lower six or seven ribs. The muscle straps have a number of tendons, varying in different individuals, which insert in all angles in the lower six ribs. The muscle is innervated by dorsal branches of the thoracic nerve and supplied by branches from the aorta. The illiocostalis consists of three subdivisions: iliocostalis lumborum,
iliocostalis thoracis, and iliocostalis cervicis. These muscles are a part of the external portion of the long erector spinae muscle group.
Research Iliocostalis Thoracis
The latissimus dorsi is a wide, flat triangular muscle located on the lower half of the back. It is the broadest of the back muscles. It originates along the lumbar and lower half of the thoracic vertebrae and the iliac crest and sacrum far below. The muscle fibres at its tip insert under the scapula and join to the humerus in the shoulder. The latissimus dorsi is innervated by the thorocodorsal nerve and supplied by the thorocodorsal artery. This muscle gives the arms motion. It is used when swimming or when swinging the arms back when jogging. It is also used to reach up to grab something above the head.
Research Latissimus Dorsi
The levator ani-coccygeus originates from the back of the pubis and inserts in the sides of the lower part of the sacrum and coccyx. This muscle draws the anus upward in defecation. It is innervated by the fourth sacral nerve.
Research Levator Ani-coccygeus
The levator ani-iliococcygeus is the posterior part of the levator ani muscle. It originates from the back of the pubis and inserts in the sides of the lower part of the sacrum and coccyx. This muscle supports pelvic organs. It is innervated by the fourth sacral nerve.
Research Levator Ani-iliococcygeus
The levator ani-puborectalis originates from the back of the pubis, passes around the anus and inserts in the sides of the lower part of the sacrum and coccyx. This muscle relaxes during defecation. It is innervated by the fourth sacral nerve.
Research Levator Ani-puborectalis
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The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
©1993 - 2009 The Probert Encyclopaedia
Southampton, United Kingdom
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