CAbdomen and Pelvis DUustration 104

THE OBTURATOR EXTERNUS MUSCLE

There are two obturator muscles, one internus and one externus—internal and external. The obturator externus muscle arises from the pubic and ischial rami. It covers the obturator foramen as a broad flat muscle which converges and travels under the neck of the femur to insert in the fossa of the trochanter on the femur. A fossa is an indentation of bone.

Obturator comes from the Latin obdurare, to harden or be inflexible. Ischium is Latin for hip joint and ramus is Latin for branch. The ischial ramus is the bony part that hurts when you've sat too long on a hard seat. Fossa comes from the Latin word for trench.

Obturator Internus And Externus
Obdurator Externus M.

THE OBTURATOR INTERNUS MUSCLE

Lying partly within the basin of the pelvis, this muscle arises in attachments all around the obdurator foramen, its fibers converging toward the groove formed between the ischial spine and the ischial tuberosity on the pelvis. It then curves around the lesser sciatic notch and ends in a tendon which inserts on the surface of the greater trochantor on the femur.

Trochanter is Greek, meaning "the runner." It also refers to the ball of the femur which fits into the hip socket. Foramen is Latin for opening or hole.

THE GEMELLUS MUSCLE, SUPERIOR AND INFERIOR

These two muscles are above and below the obturator inter-nus muscle, with their tendinous fibers combining with the obturator's tendinous insertion on the greater trochanter. The superior muscle arises from the undersurface of the ischial spine and the inferior one from the ischial tuberosity. Both muscles embrace the obdurator internus muscle from above and below.

GEMELLUS M

Superior Gemellus Muscle

Superior

Inferior

Obdurator Quadratus

Internus M. Femoris M.

GEMELLUS M

Superior

Inferior

Obdurator Quadratus

Internus M. Femoris M.

Gemellus is the Latin dimuative of geminus meaning a twin.

THE QUADRATUS FEMORIS MUSCLE

The quadratus femoris muscle arises from the outer, upper aspect of the ischial tuberosity and passes behind the neck of the femur to insert on the crest of the trochanter and onto the bone below.

THE PIRIFORMIS MUSCLE

This muscle arises along the front surface of the sacrum in three projections that surround the middle two foremina. It passes obliquely out of the pelvic girdle and through the greater sciatic foramen to insert as a rounded tendon on the crest of the greater trochanter.

Piriformis is derived from the Latin words pirum and jorma to mean pear shaped.

THE GLUTEUS MINIMUS MUSCLE

Along with the gluteus medius muscle, the gluteus minimus assists in abducting, or lifting, the thigh outwards and they play an important part in keeping the torso upright when the foot of the opposite side is off the ground during walking and running. Both muscles work to keep the body erect when you stand with one foot raised. The gluteus minimus muscle, the deepest of the three gluteus muscles, arises from a broad area on the outer surface of the illium and then descends, narrowing to a tendon that inserts on a ridge on the greater trochanter.

Gluteus comes from the Greek glutos which means buttocks. Gluteus minimus thus means the smallest buttocks muscle.

Gluteus Minimus Muscle

THE GLUTEUS MEDIUS MUSCLE

Lying just over the gluteus minimus, this muscle arises from the outer surface of the ilium, over an area just behind (or posterior to) the gluteus minimus. It too is fan shaped but thicker and broader than the minimus. In descending it narrows to form a tendon which attaches on the greater trochanter just behind and above where the gluteus minimus muscle inserts.

What Muscle Right Above The Gluteal

THE GLUTEUS MAXIMUS MUSCLE

The gluteus maximus muscle, which forms the shape of the buttocks, is the largest, thickest, and most superficial of the three gluteus muscles. It brings the leg back to a straight position after you lift it forward and also helps to right the body after you bend over. In addition, it helps you to walk, climb stairs and lift your leg sideways. Its large size is characteristic of homo sapiens in comparison with other primates. The reason this muscle is so developed in humans is that it is crucial to maintaining our upright stance. It arises from the posterior portion of the ilium, from the posterior part of the iliac crest, from the aponeurosis of the erector spinae which is attached to the sacrum, from the bony surface of the sacrum, from the side of the coccyx, and from the fascia which covers the gluteus medius. It travels obliquely out and down to cover most but not all of the gluteus medius muscle and ends in a broad tendinous sheath. This sheath passes over the greater trochanter to join with the ill— otibial tract of the fascia lata, a structure which I shall discuss below in the section on the upper leg.

Gluteus Maximus Facts
Gluteus Maximus M.

THE BONES OF THE RIGHT LEG AND PELVIS, ANTERIOR AND POSTERIOR VIEWS

Here you see the right side of the pelvis or innonimate bone, the femur, the tibia and fibula, the patella, and the bones of the ankle and foot. The features you should note on the pelvis are the inferior and superior rami of the pubis and the ischial ramus. The features to note of the upper leg, or the femur are: the head of the femur which fits neatly into the acetabulum, the socket provided by the pelvis; the neck, which provides the leg bone sufficient distance out from the pelvis so that the leg can move about, the trochanter found at the base of the neck, the shaft, which descends down to the knee area where it broadens into the medial and lateral condyles. The patella is in front sitting just between the two condyles.

Trochanter is Greek for runner. Femur is Latin for thigh. Patella comes from the Latin patina, meaning pan, and the verb patere, meaning "to be open."

Shaft Femur

Lateral Condyle Lateral Condyle

Lateral Malleolus

Cancer The Ischium Ramus

Ischial Ramus

Medial Malleolus

Talus Metatarsals Phalanges

Tarsals

Patella

Medial Condyle Medial Condyle

Squelette Jambe

Calcaneous

Shaft Femur

Ischial Ramus

Calcaneous

Lateral Condyle Lateral Condyle

Lateral Malleolus

Tarsals

Patella

Medial Condyle Medial Condyle

Medial Malleolus

Talus Metatarsals Phalanges

THE BONES OF THE RIGHT THIGH, ANTERIOR AND POSTERIOR VIEW

A cross section of the shaft of the femur shows it to be three sided. One side is in front and the other two meet in the back at the linea aspera. The two rear sides meet as two rough edges which split as they descend, one becoming the lateral condylar line and the other the medial condylar line.

Linea aspera in Latin means "rough line."

Adductor Minimus Muscle

THE ADDUCTOR MAGNUS AND ADDUCTOR MINIMUS MUSCLES

The adductor magnus muscle and the adductor minimis work together. "Adduction"means to bring toward the center. When you are standing and your leg is out, gravity more than by muscular action will bring it down. However, if you are lying down or sitting with you legs open, bringing them together requires work of these muscles. The adductors also assist in maintaining posture and in rotating the thigh-turn-ing the thigh inward.

This three part muscle arises in a continuous line on the inferior ramus of the pubis and the ischial ramus. The fibers arising from the inferior ramus run almost horizontally to the shaft of the femur to insert onto the gluteal tuberosity, just above where the linea aspera begins. This part is sometimes referred to as the adductor minimus. The fibers that arise from the ischial ramus insert along the medial side of the linea aspera, on the posterior side of the shaft of the femur. The fibers that arise from the ischial tuberosity descend as a thick round muscle that feeds into a round tendon which inserts on the medial condyle of the femur.

Minimus M.

Adductor MagnusAdductor Magnus

Adductor Magnus M.

Minimus M.

Adductor Magnus M.

THE ADDUCTOR BREVIS MUSCLE

The adductor brevis muscle arises as a small attachment to the inferior ramus of the pubis. It travels obliquely out and down, gradually broadening to insert along a line just below the lesser trochanter, not far from where linea aspera begins. Its place of insertion is just lateral to where the upper part of the magnus muscle inserts.

Abdomen Adductor Muscles

THE ADDUCTOR LONGUS MUSCLE

The adductor longus muscle arises as a tendon on the front of the pubis and descends obliquely, and more downward than the brevis muscle, to insert almost parallel to and very close to the insertion of the magnus muscle, discussed above.

Magnus Muscle

Adductor Longus M.

THE PECTINEUS MUSCLE

As with the adductors, I have illustrated the pectineus muscle from the posterior and anterior views so that you can see both the origin and the insertion. This muscle is also an adductor working with the three muscles mentioned above. It also helps to flex the thigh. It arises from the pubis and courses laterally and a bit downwards to insert on the back of the femur in a line that begins just below the lesser trochanter and descends to where the linea aspera begins.

Pecten is Latin for pubic bone.

Pectineus Muscle

THE GRACILIS MUSCLE

This narrow flat muscle helps to bend the leg (flexion) and turn it inward (medial rotation). It arises from the pubis, along the lower border of the pubic ramus and the ischial ramis. Its fibers course downward to end in a round tendon which first descends over the medial condyle of the femur and then passes behind and around the medial condyle of the tibia. The insertion appears as fibers spread out over the surface of the tibia just below the medial condyle.

Gracilis is Latin for slender.

Cancer The Ischium Ramus

THE VASTUS INTERMEDIUS, THE VASTUS LATERALIS AND THE VASTUS MEDIALIS MUSCLES

The vastus intermedius, the vastus lateralis and the vastus medialis muscles appear to be one muscle surrounding a large tendoninous sheath. They are three quarters of the group of muscles called the quadraceps There is a fourth muscle of this group, the rectus femoris muscle which I will discuss with the following illustration. However I will describe the actions of this muscle group as a whole. They act together to straighten the leg by extending the knee. The rectus portion of this group assists in bending the thigh. The group also allows you to bend your thigh and straighten your leg at the same time.

The vastus intermedius muscle arises from the front and the lateral side of the upper two thirds of the femur's shaft. Its fibers insert into an aponeurosis-like tendon which covers about half of the lower shaft of the femur. The fibers insert into the lateral border of the patella and others on the lateral condyle of the tibia.

The vastus medialis and lateralis muscles are a pair, one on each side of the tendon. The medialis muscle fibers arise as a narrow band from just beneath the greater trochanter and

Vastus Lateralis

Vastus Lateralis

Vastus Intermedius

Vastus Intermedius M.

Tendon

Vastus Medialis M

Vastus Intermedius M.

Tendon

Vastus Medialis M

along the medial side of the linea aspera. They then curl around while descending with the most of the upper fibers inserting into the tendinous aponeurosis I wrote of above— the tendon associated with the vastus intermedius. The lower fibers insert along the medial border of the patella. The lateralis muscle fibers arise just beneath the greater trochanter and half way along the lateral side of the linea aspera and curl around in almost a mirror image of the medialis. The upper fibers insert into the aponeurosis of the vastus intermedius and the lower ones become tendinous fibers that insert along the lateral border of the patella. These fibers become the tendon which covers the patella and contribute to the fascia which forms the capsule of the knee joint. Some fibers continue descending to attach to the lateral condyle of the tibia.

Quadri is Latin for four and -ceps is from the Latin caput meaning head—i.e., four heads. Vastus is Latin, meaning "of large extent," and intermedius means "in the middle."

THE RECTUS FEMORIS MUSCLE

The Rectus Femoris muscle is the fourth of the Quadraceps muscles and originates as two tendons. It originates at the anterior inferior iliac spine. Behind it is a smaller and flatter tendon which begins at a point just above the acetabulum and the capsule of the hip joint. The two tendons form an aponeurosis which merges into the muscle's fibers. The muscle ends as a flat tendon which inserts at the superior edge of the patella. When you look at the previous illustration of the lateralis and medialis, you can see where the rectus femoris neatly fits on top of those muscles and their tendon, the lateralis and the medialis on on either side of the rectus femoris.

Rectus Femoris Tumors
Rectus Femoris

THE SARTORIUS MUSCLE

The sartorius muscle helps to flex the knee and the thigh and plays a role in moving the leg outward (abduction) and in outward rotation. It also assists in the motion needed to cross one leg over the other and helps us climb stairs. It plays a very small part in walking. After arising on the tip of the anterior superior iliac spine (that's the bone you can feel on each side of your lower abdomen) and the notch just below it, it crosses over the quadriceps muscle at an oblique downward angle and then descends to cover the medial side of the knee joint as a flat tendon. This tendon has fibers that join the capsule of the knee joint. Further down it becomes a broad aponeurosis which attaches to the upper, medial side of the tibia, just in front of the attachments of the semitendi-nosus and gracilis muscles. The sartorius muscle is the longest single in the body. It looks like a strap in its shape and functions to hold all the muscles beneath it in place.

Its name is from the Latin sartor meaning "tailor."

Sartorius M

THE TENSOR FASCIAE LATAE MUSCLE

The tensor fasciae latae helps to extend the knee and to keep our posture upright. As well as having fibers that arise along the iliac crest, it arises from just beneath the origin of the sartorius muscle. It inserts into a large band of tendon called the iliotibial tract or the facsiae latae. The iliotibial tract, or fasciae latae, travels from its origin on the iliac crest to its insertion on the lateral condyle of the tibia. The muscle works in conjunction with the fasciae latae.

Tensor fasciae latae, from Latin means "stretcher of the side fascia." Tensor comes from the Latin verb tendere, meaning to stretch. The word tendon has the same origin.

Iliotibial Tract
Iliotibial Tract

There are three muscles of the posterior leg which comprise what are called the hamstrings—the biceps femoris muscle, the semitendinosus muscle, and the semimembranosus muscle. Acting as knee flexors, they assist in moving the upper leg backward (extension of the thigh). With their insertions on either side of the knee these muscles work together to rotate the knee, to maintain a stance with the knees slightly bent, to limit just how far one can bend over when trying to touch the toes without bending the knees, and by straightening out the lower curvature of the spine to curve the pelvis forward when sitting.

31 Days To Bigger Arms

31 Days To Bigger Arms

You can have significantly bigger arms in only 31 days. How much bigger? That depends on a lot of factors. You werent able to select your parents so youre stuck with your genetic potential to build muscles. You may have a good potential or you may be like may of the rest of us who have averages Potential. Download this great free ebook and start learns how to build your muscles up.

Get My Free Ebook


Post a comment