Iliopsoas
Encyclopedia
The term Iliopsoas refers to the combination of three muscles:
These muscles are distinct in the abdomen
, but usually indistinguishable in the thigh
. As such, they are usually given a common name and are referred to as the "dorsal hip muscles" or "inner hip muscles".
of T12 and L1-L5 and their associated intervertebral disc
s.
The Psoas minor, which presents in only some 40 percent of the population, originates at the transverse processes of L1-L5.
The Iliacus originates in the Iliac fossa
of the pelvis
.
and crosses the hip joint to insert on the lesser trochanter
. The Psoas minor inserts at the iliopectineal arch
, the thickened band at the iliac fascia
which separates the muscular lacuna
from the vascular lacuna
.
femoral nerve, L1, L2
(rectus femoris
, sartorius
, and tensor fasciae latae
), iliopsoas is important for standing, walking
, and running
.
It is, however, a typical posture muscle dominated by slow-twitch red type 1 fibers, and is therefore susceptible to pathological
shortening or contracture
(especially in older people with a sedentary lifestyle
) and requires regular stretching
to maintain normal tone
. Such shortening can lead to increased anterior pelvic tilt
and lumbar lordosis
(unilateral shortening), and limitation of hip extension (bilateral weakness).
The iliopsoas muscle is covered by the iliopsoas fascia, which begins as a strong tube-shaped psoas fascia, which surround the psoas major muscle as it passes under the medial arcuate ligament
. Together with the iliac fascia
, it continues down to the inguinal ligament
where it forms the iliopectineal arch
which separates the muscular
and vascular lacuna
e.
- psoas majorPsoas major muscle-External links: - "Posterior Abdominal Wall: Muscles of the Posterior Abdominal Wall"* *...
- psoas minorPsoas minor muscleThe psoas minor is a long, slender skeletal muscle which, when present, is located in front of the psoas major muscle. This muscle does not exist in about half the human population.-Course:...
- iliacusIliacus muscleThe iliacus is a flat, triangular muscle which fills the iliac fossa.- Course :The iliacus arises from the iliac fossa on the interior side of the hip bone, and also from the region of the anterior inferior iliac spine...
These muscles are distinct in the abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
, but usually indistinguishable in the thigh
Thigh
In humans the thigh is the area between the pelvis and the knee. Anatomically, it is part of the lower limb.The single bone in the thigh is called the femur...
. As such, they are usually given a common name and are referred to as the "dorsal hip muscles" or "inner hip muscles".
Origin
The Psoas major originates along the lateral surfaces of the vertebral bodiesBody of vertebra
The body is the largest part of a vertebra, and is more or less cylindrical in shape. For vertebrates other than humans, this structure is usually called a centrum....
of T12 and L1-L5 and their associated intervertebral disc
Intervertebral disc
Intervertebral discs lie between adjacent vertebrae in the spine. Each disc forms a cartilaginous joint to allow slight movement of the vertebrae, and acts as a ligament to hold the vertebrae together.-Structure:...
s.
The Psoas minor, which presents in only some 40 percent of the population, originates at the transverse processes of L1-L5.
The Iliacus originates in the Iliac fossa
Iliac fossa
The iliac fossa is a large, smooth, concave surface located on the internal surface of the ilium...
of the pelvis
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
.
Insertion
Psoas major unites with iliacus at the level of the inguinal ligamentInguinal ligament
The inguinal ligament is a band running from the pubic tubercle to the anterior superior iliac spine. Its anatomy is very important for operating on hernia patients.-Anatomy:...
and crosses the hip joint to insert on the lesser trochanter
Lesser trochanter
The lesser trochanter of the femur is a conical eminence, which varies in size in different subjects-Anatomy:It projects from the lower and back part of the base of the femur neck.From its apex three well-marked borders extend:...
. The Psoas minor inserts at the iliopectineal arch
Iliopectineal arch
The Iliopectineal arch is a thickened band of fused iliac fascia and psoas fascia passing from the posterior aspect of the inguinal ligament anteriorly across the front of the femoral nerve to attach to the iliopubic eminence of the hip bone posteriorly...
, the thickened band at the iliac fascia
Iliac fascia
The iliac fascia is a fascia in the pelvic area of the human body.It has the following connections:* laterally, to the whole length of the inner lip of the iliac crest....
which separates the muscular lacuna
Muscular lacuna
The Muscular lacuna is the lateral compartment beneath the inguinal ligament, for the passage of the iliopsoas muscle and femoral nerve; it is separated by the iliopectineal arch from the vascular lacuna....
from the vascular lacuna
Vascular lacuna
The vascular lacuna is the medial compartment beneath the inguinal ligament, for the passage to the femoral vessels, lymph node, and femoral branch of the genitofemoral nerve. Medial to lateral these are the: Rosenmuller lymph node, femoral vein, femoral artery, and gem oral branch of...
.
femoral nerve, L1, L2
Properties
Strongest of the hip flexorsHip flexors
In human anatomy, the hip flexors are a group of skeletal muscles that act to flex the femur onto the lumbo-pelvic complex, i.e., pull the knee upward....
(rectus femoris
Rectus femoris muscle
The rectus femoris muscle is one of the four quadriceps muscles of the human body. The others are the vastus medialis, the vastus intermedius , and the vastus lateralis...
, sartorius
Sartorius muscle
The Sartorius muscle – the longest muscle in the human body – is a long thin muscle that runs down the length of the thigh. Its upper portion forms the lateral border of the femoral triangle.-Origin and insertion:...
, and tensor fasciae latae
Tensor fasciae latae
The tensor fasciae latae or tensor fasciæ latæ is a muscle of the thigh. The English name for this muscle is the muscle that stretches the band on the side...
), iliopsoas is important for standing, walking
Walking
Walking is one of the main gaits of locomotion among legged animals, and is typically slower than running and other gaits. Walking is defined by an 'inverted pendulum' gait in which the body vaults over the stiff limb or limbs with each step...
, and running
Running
Running is a means of terrestrial locomotion allowing humans and other animals to move rapidly on foot. It is simply defined in athletics terms as a gait in which at regular points during the running cycle both feet are off the ground...
.
It is, however, a typical posture muscle dominated by slow-twitch red type 1 fibers, and is therefore susceptible to pathological
Pathology
Pathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....
shortening or contracture
Contracture
A muscle contracture is a permanent shortening of a muscle or joint.. It is usually in response to prolonged hypertonic spasticity in a concentrated muscle area, such as is seen in the tightest muscles of people with conditions like spastic cerebral palsy....
(especially in older people with a sedentary lifestyle
Sedentary lifestyle
Sedentary lifestyle is a medical term used to denote a type of lifestyle with no or irregular physical activity. A person who lives a sedentary lifestyle may colloquially be known as a couch potato. It is commonly found in both the developed and developing world...
) and requires regular stretching
Stretching
Stretching is a form of physical exercise in which a specific skeletal muscle is deliberately elongated, often by abduction from the torso, in order to improve the muscle's felt elasticity and reaffirm comfortable muscle tone. The result is a feeling of increased muscle control, flexibility and...
to maintain normal tone
Muscle tone
In physiology, medicine, and anatomy, muscle tone is the continuous and passive partial contraction of the muscles, or the muscle’s resistance to passive stretch during resting state. It helps maintain posture, and it declines during REM sleep.-Purpose:Unconscious nerve impulses maintain the...
. Such shortening can lead to increased anterior pelvic tilt
Pelvic tilt
The concept of pelvic tilt in anatomy refers to the orientation of the pelvis in respect to the femurs it rests upon and in space. It can tilt in four basic directions.-Forms:...
and lumbar lordosis
Lordosis
Lordosis is a medical term used to describe an inward curvature of a portion of the lumbar and cervical vertebral column. Two segments of the vertebral column, namely cervical and lumbar, are normally lordotic, that is, they are set in a curve that has its convexity anteriorly and concavity...
(unilateral shortening), and limitation of hip extension (bilateral weakness).
The iliopsoas muscle is covered by the iliopsoas fascia, which begins as a strong tube-shaped psoas fascia, which surround the psoas major muscle as it passes under the medial arcuate ligament
Medial arcuate ligament
The medial arcuate ligament is a tendinous fascia that arches over the psoas major muscle as it passes through the diaphragm.-Structure:...
. Together with the iliac fascia
Iliac fascia
The iliac fascia is a fascia in the pelvic area of the human body.It has the following connections:* laterally, to the whole length of the inner lip of the iliac crest....
, it continues down to the inguinal ligament
Inguinal ligament
The inguinal ligament is a band running from the pubic tubercle to the anterior superior iliac spine. Its anatomy is very important for operating on hernia patients.-Anatomy:...
where it forms the iliopectineal arch
Iliopectineal arch
The Iliopectineal arch is a thickened band of fused iliac fascia and psoas fascia passing from the posterior aspect of the inguinal ligament anteriorly across the front of the femoral nerve to attach to the iliopubic eminence of the hip bone posteriorly...
which separates the muscular
Muscular lacuna
The Muscular lacuna is the lateral compartment beneath the inguinal ligament, for the passage of the iliopsoas muscle and femoral nerve; it is separated by the iliopectineal arch from the vascular lacuna....
and vascular lacuna
Vascular lacuna
The vascular lacuna is the medial compartment beneath the inguinal ligament, for the passage to the femoral vessels, lymph node, and femoral branch of the genitofemoral nerve. Medial to lateral these are the: Rosenmuller lymph node, femoral vein, femoral artery, and gem oral branch of...
e.
See also
- psoas abscess
- Iliopsoas tendinitisSnapping hip syndromeSnapping hip syndrome is a medical condition characterized by a snapping sensation felt when the hip is flexed and extended. This may be accompanied by an audible snapping or popping noise and pain or discomfort. Pain often decreases with rest and diminished activity...
- Muscles of the hipMuscles of the hipIn human anatomy, the muscles of the hip joint are those muscles that cause movement in the hip. Most modern anatomists define 17 of these muscles, although some additional muscles may sometimes be considered...